Objective-To assess whether a normal electrocardiogram can identify good left ventricular functio... more Objective-To assess whether a normal electrocardiogram can identify good left ventricular function and obviate the need for routine left ventriculography in patients undergoing cardiac catheterisation for suspected coronary artery disease. Design-A prospective study of patients undergoing cardiac catheterisation. Setting-A regional cardiac centre. Patients-The electrocardiograms, coronary angiograms, and left ventriculograms of 391 consecutive patients undergoing investigations for suspected coronary artery disease were entered into the study. Patients with arrhythmias and cardiac pathologies other than coronary artery disease were excluded. Main outcome measures-The electrocardiogram was assessed using a 29 point QRS scoring system, and classified by two cardiologists and a trainee cardiologist as normal or abnormal. Left ventricular function was assessed by digital ventriculography. Results-The sensitivity, specificity, and negative predictive value of a QRS score of 0 (normal QRS complexes) for discriminating good left ventricular function (ejection fraction > 50%) were 92.6%, 41.5%, and 97.2%, respectively. The figures for a normal electrocardiogram as assessed by a doctor were 96.3%, 40.4%, and 98.6% for cardiologist A; 96.3%, 37.4%, and 98.4% for cardiologist B; and 94.4%, 49.6%, and 98.2% for the cardiology trainee. Conclusions-If a cardiologist judges the ECG to be normal, left ventriculography is unnecessary and a formal QRS score does not improve reliability of this clinical judgment. Adopting this strategy would save £30-40 000 in consumables and 65-87 hours of catheter laboratory and staV time for a department catheterising 3000 patients with suspected coronary artery disease annually.
Pacing and Clinical Electrophysiology, Mar 1, 2004
ABSTRACT The traditional pulse generator implantation site lies subcutaneous on the fascia of the... more ABSTRACT The traditional pulse generator implantation site lies subcutaneous on the fascia of the pectoralis major muscle. This article describes a subpectoral pocket approach, which on anatomic investigation is actually "intrapectoral" and offers a much improved cosmetic result with the potential advantage of less erosion. In the authors' experience with over 1000 initial pacemaker implants and pulse generator replacements, the potential concerns of neurovascular and muscular damage have not been realized. There has been no pulse generator damage from the ribs, serious loculated hematomas, or unusual postoperative or chronic pain. From experience with pulse generator recalls, the replacement procedure has not been significantly more difficult than with the subcutaneous approach. The intrapectoral approach has now become the authors' routine in patients without significant adipose tissue overlying the pectoralis major muscle.
Journal of Cardiovascular Electrophysiology, Apr 30, 2004
A 16-year-old boy presented with exertional palpitations, which occurred particularly when he was... more A 16-year-old boy presented with exertional palpitations, which occurred particularly when he was playing tennis. There was no history of syncope or family history of sudden cardiac death. The boy was otherwise well and had not been taking any medications. ECG showed sinus rhythm with no evidence of preexcitation and a normal corrected QT interval. A 24-hour Holter monitor demonstrated an irregular broadcomplex tachycardia with varying QRS morphology. At electrophysiologic study, the HV interval was normal at 35 ms. During atrial pacing with a single extrastimulus, tachycardia with a variable cycle length was induced (Fig. 1). During tachycardia, the QRS complexes demonstrated varying degrees of left bundle branch block (LBBB) morphology. Following reinduction, tachycardia with a right bundle branch block (RBBB) morphology was present, with the variation in tachycardia cycle length less apparent (Fig. 2). What is the mechanism of the tachycardia, and what accounts for the variation in tachycardia cycle lengths?
Journal of Cardiovascular Electrophysiology, Aug 5, 2004
Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) ... more Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) activity from a pulmonary vein (PV) focus, but how AF is maintained it is not known. The crista terminalis (CT) is an important line of block in atrial flutter (AFL), but its role in AF has not been determined. The aim of this study was to examine the conduction properties of the CT during onset of AF. In 10 patients (mean age 38 +/- 8 years), we analyzed conduction across the CT during onset of focal AF from an arrhythmogenic PV and during pacing from the same PV at cycle lengths of 700 and 300 ms. A 20-pole catheter was positioned on the CT using intracardiac echocardiography. In 10 control patients with no history of AF, we analyzed conduction across the CT during pacing from the distal coronary sinus at 700 and 300 ms. In all 10 AF patients, AF was initiated with 1 to 9 AE beats (median 5) from a PV. During sinus rhythm, there were no split components (SC) recorded on the CT. During PV AE activity, discrete SC were recorded on the CT in all patients over 6.3 +/- 0.9 bipoles (3.7 +/- 0.3 cm). Maximal splitting of SC was 66 +/- 31 ms (37-139). There was an inverse relationship between AE coupling intervals and the degree of splitting between SC in all patients. Degeneration to AF was preceded by progressive decrement across the CT. SC were recorded during PV pacing at 700 and 300 ms (maximal distance between SC of 24 +/- 3 ms and 43 +/- 5 ms, respectively, P < 0.001). Maximum SC at CT in controls was 13 +/- 8 ms at 700 ms (P = 0.06 vs AF patients) and 16 +/- 9 ms at 300 ms (P < 0.01 vs AF patients). (1) These observations provide evidence of anisotropic, decremental conduction across the CT during onset of focal AF and during pacing from the same PV. A line of functional conduction block develops along this anatomic structure (CT). Whether this line of block acts as an initiator of AF or simply contributes passively to nonuniform fibrillatory conduction is unknown. (2) In some patients with focal AF, development of conduction block along the CT may provide a substrate for typical AFL.
Journal of the American College of Cardiology, 2005
In recent years, the pioneering work of Wijffels et al. (1) has demonstrated the importance of at... more In recent years, the pioneering work of Wijffels et al. (1) has demonstrated the importance of atrial remodeling in development of an atrial substrate conducive to sustained atrial fibrillation (AF). A range of factors has been implicated in this process. Among these factors, indirect evidence suggests a role for the renin-angiotensin system. In differing animal models, angiotensin-converting enzyme inhibition or angiotensin II (AII) antagonists has been shown to prevent both acute (hours) (2) electrical remodeling and chronic (weeks) structural remodeling (3). Although the mechanism for these effects remains uncertain, the inhibition of acute AF-induced remodeling by these agents suggests that AII may have direct effects on atrial electrophysiology. In the current study, we examined the acute effects of AII on atrial electrophysiology in humans. Our study population included 12 patients with supraventricular tachycardia who were undergoing curative ablation. Autonomic blockade was administered at commencement. Continuous heart rate and blood pressure monitoring was performed. Multipolar catheters included: 1) a coronary sinus (CS) catheter; 2) a crista terminalis (CT) catheter; 3) a lateral right atrium (RA) catheter; and 4) a His bundle catheter. Atrial effective refractory period (ERP) was measured at the distal CS and high lateral RA at cycle lengths of 600, 500, and 400 ms. Dispersion of atrial ERP was defined as the difference between the averaged atrial ERP at both sites. Atrial conduction was measured in both atria at pacing cycle lengths of 600, 500, and 400 ms. Local conduction time was measured along the lateral RA and CS catheters. Conduction delay was analyzed by the presence of discrete double potentials and fractionated electrograms and assessed during pacing at 600, 500, and 400 ms and during extra stimulus testing from distal CS and high lateral RA. The inducibility of AF (Ͼ5 s) was recorded during ERP testing. Angiotensin II was obtained from Clinalfa AG (Laufelfingen,
Aims Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillatio... more Aims Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal). Methods and results Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 + 14.6 vs. 41.5 + 13.1 min; P , 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 + 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P ¼ 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P , 0.01). Conclusion There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033).
Journal of the American College of Cardiology, Jul 1, 2004
The purpose of this study was to characterize the pattern of atrial remodeling seen with human ag... more The purpose of this study was to characterize the pattern of atrial remodeling seen with human aging. BACKGROUND Atrial fibrillation (AF) occurs in 3% to 4% of the population over 65 years of age. It is associated with thromboembolic complications, worsening heart failure, and increased mortality, yet the electrical and structural remodeling that occurs with human aging remains unknown. METHODS Thirteen patients (66.4 Ϯ 1.7 years) Ն60 years (group A), 13 patients (50 Ϯ 2.1 years) age 31 to 59 years (group B), and 15 patients (24.7 Ϯ 1.0 years) Յ30 years (group C) underwent conventional electrophysiologic studies and electroanatomic mapping. We measured atrial refractoriness (ERP) at the distal coronary sinus (CS); low and high lateral right atrium (LRA) and the high septal right atrium at 600, 500, and 400 ms; maximum corrected sinus node recovery time (CSNRT); P-wave duration (PWD); conduction time (CT) along the CS and LRA; and discrete double potentials (DP) along the crista. RESULTS Aging was associated with an increase in atrial ERP, prolonged CT along the CS, increased PWD and CSNRT. There was no significant change in dispersion of refractoriness or rate adaptation. Electroanatomic mapping revealed diffuse areas of low voltage with regional conduction slowing. Both techniques demonstrated a greater number of DPs and fractionated signals along the crista terminalis with aging. CONCLUSIONS Aging is associated with regional conduction slowing, anatomically determined conduction delay at the crista, and structural changes that include areas of low voltage. In addition, impairment of sinus node function and an increase in atrial ERP occurred with aging. This electrical and structural remodeling may explain the increased propensity to AF with aging.
Background: We describe our procedural outcomes and technical success rates of Watchman ® LAA clo... more Background: We describe our procedural outcomes and technical success rates of Watchman ® LAA closure devices from our centre with a focus on peri-device leaks. Results: Fifty-three patients aged 65.5 ± 7.3 years (range 43-82 years, 72% male, CHADS2 score 1.94 ± 0.9, CHADSVASC score 2.8 ± 1.0) underwent successful implantation of a Watchman ® LAA occluder device in our centre since Nov 2009. Forty-four patients had concomitant pulmonary vein isolation (44/53). The average device size was 24 ± 3 mm (range 21-30 mm). No acute procedural complications occurred. Post implant transoesophageal echocardiogram (TOE) was performed at six weeks, and again at six months if any persistent peri-device leaks seen at initial follow up. At implant, 4/53 patients had a small peri-device leak detected on colour flow Doppler by TOE ≤ 3 mm. At six week TOE, 12 patients had a peri-device leak (nine new, three persistent), with four of these showing persistent small leaks at six month TOE (two present since implant). There was no significant age or sex distribution of patients who developed new peri-device leaks, however all patients who demonstrated leaks at implant were male. At six week follow up, the interatrial septal puncture sites had healed in all but 12 patients, with no age or sex distribution observed. Conclusion: Despite high procedural success rates and low incidence of peri-device leaks at implant, we have observed development of small leaks at first TOE followup in approximately 17% of patients which then tend to close again. This may reflect a period of "seating" with the device.
Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrh... more Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrhythmias are increasingly recognized and associated with significant morbidity and mortality. We aim to describe the clinical and electrophysiological characteristics of patients with atrial arrhythmias occurring late after CTX. Methods and results Sixteen patients with prior CTX who presented with late atrial arrhythmias for electrophysiological studies (EPS) were identified at two cardiac transplant centres. Among 859 patients, 16 (mean age 52 + 14 years, 11 of 16 were men) patients underwent EPS for atrial arrhythmias presenting 8.6 + 5.7 years following CTX. Among 16 patients, 14 underwent cardiac alone and 2 included lung transplantation. There were no cases of cardiac rejection. Arrhythmias were due to counterclockwise cavotricuspiddependent atrial flutter (AFL) in 10 of 16, atrial tachycardia (AT) in 6 (1 patient had AFL and AT), and 1 due to atrioventricular nodal re-entrant tachycardia. Recipient-donor atrial electrical connection was seen in two of six AT and in no cases of AFL. In two cases, a focal AT was mapped to the remnant atrium conducting 2 : 1 or at variable block to the donor atrium. In four cases a focal/micro re-entrant AT originated within the vicinity of the interatrial suture scar. All cases were successfully ablated with radiofrequency energy; however, one case of AFL required a repeat ablation. Patients remained free of arrhythmia at 34 + 15 months post-ablation. Conclusion Typical AFL and AT are the most frequent supraventricular arrhythmias occurring late following CTX. Focal ATs may originate in low-voltage or border zones immediately adjacent to the atrio-atrial anastomosis. Radiofrequency ablation is an effective treatment strategy with high long-term success.
Introduction The outcome of persistent atrial fibrillation (PeAF) ablation remains suboptimal and... more Introduction The outcome of persistent atrial fibrillation (PeAF) ablation remains suboptimal and procedures may be long and painful. Little evidence is available on outcome for procedures under general anaesthetic (GA) compared to conscious sedation (CS). We performed a single-centre observational study to assess whether use of GA in PeAF ablation improved outcome and was cost-effective. Methods 292 patients undergoing first ablation procedures for PeAF by radio-frequency point-by-point technique under CS (n=220) or GA (n=72) were followed. End points were
Case Report: We report a fifty-year-old male with paroxysmal atrial fibrillation presenting with ... more Case Report: We report a fifty-year-old male with paroxysmal atrial fibrillation presenting with EHRA III symptoms who underwent pulmonary vein isolation (PVI). The PVI was planned with a 28mm cryoballon under deep sedation. After uncomplicated transseptal puncture, angiography of the left atrium (LA) was done showing four independent pulmonary veins (PV). Heparin was given to maintain an activated clotting time of .300s. Following successful left PV isolation, the circular diagnostic catheter (CDC) was advanced in the right inferior PV (RIPV) and one successful freeze was delivered. After thawing of the cryoballon, it turned out not to be possible to remove the CDC from the RIPV. The fluoroscopy showed that the CDC was stuck in a small branch of the RIPV. While pulling the CDC the patient started to cough. The surrounding lung tissues seemed to be tightened and dragged together with the CDC. While turning the CDC, the shaft of the CDC broke close to the holder of the steerable sheath. With use of the remaining shaft, we further tried to remove the CDC from the PV, however, the CDC was again completely torn from the base of the circular part in the branch of RIPV. We then removed the proximal shaft and isolated the superior right PV with one freeze using a newly unpacked CDC. Final LA angiography demonstrated neither obstructions of major PVs nor exit of contrast agent out of LA, although the circular part of the CDC remained in the small branch of RIPV. After the procedure the patient showed no complaints such as cough, dyspnea or other symptoms. A pericardial effusion was also excluded. Discussion: Due to the tying in a small branch of the RIPV the CDC was stuck and we could not recover the catheter anymore. No practical way to resolve this situation has been described yet. Further catheter pulling was not an option due to the risk of a fatal bleeding because the surrounding lung tissue was tied. Another option could be an open-heart surgery. As the remaining part of the catheter did not move at all, we decided to leave the remaining circular part after a consultation with heart surgery unit. After a follow-up of one month the patient showed neither AF event nor clinical symptoms such as cough, dyspnea. We here reported a break of the CDC shaft during PVI with cryoballoon, which has been not yet reported.
Introduction In selecting patients that may benefit from cardiac resynchronisation therapy (CRT),... more Introduction In selecting patients that may benefit from cardiac resynchronisation therapy (CRT), dyssynchrony assessment by echocardiography based only upon the timing of regional contraction is limited by being inherently independent of underlying myocardial contractility. We hypothesised that patient selection may be enhanced using a strain-based parameter based not only the timing of myocardial segmental motion, but also on the amplitude of contraction, a potential measure of contractile reserve. We assessed a combined early and late strain index (ELSI) to predict CRT response. Methods Speckle tracking radial strain was performed in 67 heart failure patients scheduled for CRT (age 69±9 years, ischaemic 56%, QRS 154±12 ms, NYHA III/IV—63/4, ejection fraction 23±7%). The ELSI was calculated as the sum for each of the 12 non apical segments of the difference in peak radial strain and strain at aortic valve closure. CRT response was defined as a >15% reduction from baseline in LV end systolic volume (LVESV) at 6 months. The predictive value of the ELSI was compared to previously reported dyssynchrony measures including the SD of time to peak myocardial longitudinal velocity of the 12 non apical segments (Ts SD12), the anteroseptal–posterior wall radial strain delay (AS-P delay) and the SD of time to peak radial strain of 12 segments (Rs-SD12). Results Response to CRT occurred in 38/67 (57%) patients. Significant differences were seen between responders and non responders in the ELSI (91±45 vs 27±14%, p<0.01), AS-P delay (256±158 vs 94±87 ms) and the Rs-SD12 (143±62 vs 75±50 ms). There was no difference in the Ts SD12 between responders and non responders. The ELSI had the best correlation with LVESV reduction (r=0.61, p<0.001) and using an optimal cut-off of 40% (AUC=0.94), the ELSI was able to predict response to CRT with a sensitivity of 93% and specificity of 95%. This was much higher than for the AS-P (cut-off 130 ms, AUC=0.79, sensitivity 71%, specificity 74%) and Rs –SD12 (95 ms, AUC=0.82, sensitivity 73% specificity 75%). Conclusion A combined early and late strain parameter based on both the timing and amplitude of segmental strain has a stronger predictive value in determining CRT response compared to widely reported dyssynchrony parameters based on segmental timing alone.
procedures defined as when the patient first emerged from their 3 month blanking period free of A... more procedures defined as when the patient first emerged from their 3 month blanking period free of AF/AT (or failure accepted), that is, when AF was first successfully eliminated whether after one CA or several. Results Two hundred eighty-five patients underwent 530 procedures. Mean age was 57611 years, 75% male, 20% had structural heart disease and 53% paroxysmal AF. Left atrial diameter was 4.360.8 cm and 17% had left ventricular systolic dysfunction. Mean number of procedures was 1.9 per patient (1.7 for PAF and 2.0 for PeAF). Procedural complications included stroke or TIA in 0.6% (all of which resolved) and pericardial effusions which were drained without sequelae in 1.7%. There were no peri-procedural deaths. Of 285 patients, 270 were contacted for follow-up. During 3.3 (2.4 to 7.5) years from the first procedure, there were seven deaths (unrelated to their ablation or AF) and three strokes or TIA (0.3% per year). Freedom from AF/AT at 2.7 (0.2 to 7.4) years after the last procedure was 86% for PAF and 68% for PeAF. Most recurrence occurred in the first year, with late recurrence >3 years occurring in 3/100 years of follow-up. KaplaneMeier analysis showed that CFE ablation improved outcome for PeAF after the first cluster of procedures (p¼0.04), with a trend towards improved final outcome (p¼0.13). Conclusion Long term freedom from AF is achievable in the majority of patients with PAF and PeAF with low rates of late recurrence. Rates of periprocedural complications are low, and late adverse events including stroke are few. Targeting CFE in addition to PVI and linear lesions improves outcome for PeAF.
67AE6). AF was persistent in 2 and intermittent in 5. Mean duration of AF mean 84.4 AE 75.2 month... more 67AE6). AF was persistent in 2 and intermittent in 5. Mean duration of AF mean 84.4 AE 75.2 months. Common characteristics of these tachycardias were the endocardial breakout over a broad area adjacent to the LOM region, presence of pre-systolic or mid-diastolic potentials and abolition by ablation of the pre-systolic or mid-diastolic potentials remote from the endocardial breakout site. In six cases, tachycardias were present after isolation of the veins and posterior left atria. All demonstrated characteristic areas of very slow conduction in the LOM region highlighted by the presence of either low voltage, long duration fractionated potentials or mid diastolic potentials with a fixed temporal relationship to the subsequent endocardial activation. The pattern of activation and termination of tachycardia during ablation were consistent with an arrhythmia utilizing an electrically insulated tract within LOM and the PV-LAA ridge region. Conclusion: We identified a novel mechanism of Organised Atrial Tachycardias characterized by the following: 1) Tachycardias in the presence of documented isolation of all PVs and LA posterior wall; 2) Re-entrant mechanism suggested involving the PV-LAA Ridge in LOM region; 3) Slow conduction in the LOM region with low voltage, long duration, fractionated potentials or discrete mid-diastolic potentials; 4) Concealed pre-systolic and mid-diastolic components; 5) Broad endocardial breakout site related to the LOM region; 6) Successful termination by ablating pre-systolic or mid-diastolic potentials remote from the earliest endocardial breakout site.
Journal of Interventional Cardiac Electrophysiology, Jun 1, 2004
We report an unusual case of bundle branch reentrant tachycardia, in a patient with normal left v... more We report an unusual case of bundle branch reentrant tachycardia, in a patient with normal left ventricular function, cured by radiofrequency catheter ablation. However, the long-term prognosis of these patients is uncertain. We discuss the indications for an implantable defibrillator in this group.
Journal of the American College of Cardiology, Apr 1, 2011
Background: Left ventricular (LV) lead placement to the latest area of contraction is associated ... more Background: Left ventricular (LV) lead placement to the latest area of contraction is associated with enhanced response to cardiac resynchronization therapy (CRT). We conducted a randomised controlled trial to compare the effect on acute change in cardiac output (CO) between patients undergoing either echocardiographically guided LV lead placement or standard usual CRT implantation. Methods: A total of 180 patients with left bundle branch block (age 71 ± 8 yrs, NYHA III 92%, EF 23 ± 7%, QRS 156 ± 9 ms) were recruited and underwent speckle tracking 2D radial strain at baseline to determine the latest site of activation. Patients were subsequently randomized into one of 2 groups. In group 1 (targeted group-TAR) the CRT implanters were aware of the echocardiographic findings and attempted to position the LV lead to the latest site of activation. In group 2 (control-CON) patients underwent standard CRT implantation without echocardiographic guidance. In all patients the LV lead position was defined by biplane fluoroscopy. Patients were classified according to the relation of the LV lead to the latest site as: Concordant (C-lead position at latest site), Adjacent (A-within 1 segment) or Remote (R-2 or more segments away from latest site). All patients underwent AV and VV delay optimization. Within 24 hours of implantation all patients underwent non invasive CO determination using a commercially available system (NICOM) during optimised CRT and with CRT switched off (baseline). The peak improvement in CO was compared between the two groups. Results: There were no differences in baseline characteristics between the two groups. There were more C and less R leads in the targeted group (TAR vs. CON: C 68.9% vs 46.7% p<0.01, A: 24.4% vs. 30.0% p=0.46, R: 6.7% vs. 23.3% p<0.01). There were no differences in CO at baseline between the two groups (TAR vs. CON: 4.77 ± 1.1 vs. 4.67 ± 1.1 L/min, p=0.76). CO was significantly higher during CRT in patients with a targeted LV lead compared to the control group (6.06 ± 1.3 vs 5.57 ± 1.2 L/min, p=0.021). Conclusions: Targeting LV lead placement to the latest areas of activation using speckle tracking 2D radial strain is associated with a better CO response to CRT compared to standard treatment.
Cardiac device implantations are increasingly carried out using local anaesthesia (LA) with intra... more Cardiac device implantations are increasingly carried out using local anaesthesia (LA) with intravenous conscious sedation. The advantages include reduction of patients' anxiety and discomfort, and avoidance of risks of general anaesthesia (GA). However, concerns about the safety of sedation used without an anaesthetist have been expressed. The National Patient Safety Agency (NPSA) has identified serious problems in the use of intravenous midazolam for conscious sedation and reliance on flumazenil for reversal of over-sedation [1]. The aim of the study is to determine the safety of intravenous conscious sedation in patients undergoing cardiac device implantation and to determine patients' experience and comfort using conscious sedation. All patients undergoing device implantations (pacemaker and Cardiac Resynchronisation Therapy (CRT) implantation, elective unit replacements (EUR) andpacing leads revision) under conscious sedation were eligible. Patients with devices that were implanted under GAwere excluded. Intravenous midazolam and fentanyl could be administered alone or in combination based on operators' discretion. LA with 1% lignocaine without adrenaline was used in all patients. All data were prospectively collected. A patient questionnaire (Appendix A) was given to patients late after the procedure to allow as much time for effects of sedation towear off. A pain score of 10 reflects the worst pain possible, whereas score 1 reflects no pain. Written informed consent for the procedures was obtained. Patient participation for the questionnaire was voluntary. Verbal informed consent was obtained as per the ethics committee of the hospital. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. The primary outcome was to determine the safety of conscious sedation administered without the presence of anaesthetist. The secondary outcome was to assess patients' satisfaction intraand postprocedure. Statistical comparisons for continuous data were performed using ANOVAs single factor, unpaired t-tests and chi-squared tests for categorical data. Logistic regression analysis was performed for multivariable predictors. All testswere two-sided and p values of a level≤0.05 were considered statistically significant.
Journal of Cardiovascular Electrophysiology, Feb 1, 2002
Early Repeated Cardioversion for AF Recurrence. Introduction: The clinical value of cardioversion... more Early Repeated Cardioversion for AF Recurrence. Introduction: The clinical value of cardioversion (CV) of persistent atrial brillation (AF) is limited by the high rate of early AF recurrence, which may be related to the persistence of atrial electrical remodeling. We examined the hypothesis that the likelihood of maintaining sinus rhythm after CV of persistent AF is signi cantly enhanced by a policy of early repeated CV. Methods and Results: Fifty-nine patients with persistent AF underwent internal CV (CV 1). Those patients cardioverted were monitored with daily transtelephonic ECG. In the event of AF recurrence, these patients were admitted rapidly for repeat CV (CV 2) and, if further recurrence occurred, a third CV (CV 3) was performed. Daily ECG monitoring was continued until 1 month of sinus rhythm was maintained or a total of three CVs were performed. Of the 59 patients undergoing CV 1, 43 were discharged in sinus rhythm and 29 subsequently had AF recurrence during monitoring. Twenty-three of these underwent CV 2 and 11 of these underwent CV 3. Of those having repeated CVs, only 4 patients maintained sinus rhythm for 1 month (3 after CV 2 and 1 after CV 3). The remaining patients had repeated AF recurrence during the monitoring period. Mean time from AF recurrence to CV 2 was 20 6 13 hours and from AF recurrence to CV 3 was 13 6 7.2 hours. Atrial effective refractory periods increased from 189 6 16 msec at CV 1 to 215 6 18 msec at CV 3 (P < 0.05), indicating reversal of atrial electrical remodeling during this period. Conclusion: A policy of early repeated CVs for AF recurrence has very limited clinical value despite evidence of reversal of atrial electrical remodeling. The time between AF recurrence and repeat CV may need to be reduced further if such a policy is to succeed.
Background-Episodes of atrial fibrillation (AF) are known to cause both a rapid reduction in atri... more Background-Episodes of atrial fibrillation (AF) are known to cause both a rapid reduction in atrial refractoriness (atrial electrical remodeling) and a more delayed increase in AF stability thought to be due to a so-called "second factor." The aim of this study was to quantify the effects and time course of such a factor on AF stability in the chronic goat model. Methods and Results-AF was maintained in 6 goats by burst atrial pacing for 3 consecutive 4-week periods separated a mean of 6Ϯ2.1 days of sinus rhythm. Six days of sinus rhythm was just sufficient for refractoriness changes to reverse fully in all goats. Atrial effective refractory period, AF inducibility, and duration of individual episodes of AF were assessed at regular intervals. There was a progressive reduction from month 1 to 2 to 3 in the mean duration of burst pacing required to induce individual episodes of AF of 60 seconds (178Ϯ251, 110Ϯ102, and 21Ϯ30 hours), 1 hour (229Ϯ224, 136Ϯ104, and 68Ϯ51 hours), and 24 hours (277Ϯ218, 192Ϯ190, and 102Ϯ75 hours; PϽ0.03). The frequency with which AF was induced during extrastimulus pacing increased progressively from 16.7% in month 1 to 31.7% in month 2 and 46.9% in month 3 (PϽ0.001). Conclusions-Sequential 4-week periods of atrial fibrillation result in a progressive increase in AF stability independent of baseline atrial refractory period. This finding suggests the presence of a second factor in the self-perpetuation of AF with a time course comparable to that of AF-induced ultrastructural changes in the atria. (Circulation. 2004;109:1434-1439.
Objective-To assess whether a normal electrocardiogram can identify good left ventricular functio... more Objective-To assess whether a normal electrocardiogram can identify good left ventricular function and obviate the need for routine left ventriculography in patients undergoing cardiac catheterisation for suspected coronary artery disease. Design-A prospective study of patients undergoing cardiac catheterisation. Setting-A regional cardiac centre. Patients-The electrocardiograms, coronary angiograms, and left ventriculograms of 391 consecutive patients undergoing investigations for suspected coronary artery disease were entered into the study. Patients with arrhythmias and cardiac pathologies other than coronary artery disease were excluded. Main outcome measures-The electrocardiogram was assessed using a 29 point QRS scoring system, and classified by two cardiologists and a trainee cardiologist as normal or abnormal. Left ventricular function was assessed by digital ventriculography. Results-The sensitivity, specificity, and negative predictive value of a QRS score of 0 (normal QRS complexes) for discriminating good left ventricular function (ejection fraction > 50%) were 92.6%, 41.5%, and 97.2%, respectively. The figures for a normal electrocardiogram as assessed by a doctor were 96.3%, 40.4%, and 98.6% for cardiologist A; 96.3%, 37.4%, and 98.4% for cardiologist B; and 94.4%, 49.6%, and 98.2% for the cardiology trainee. Conclusions-If a cardiologist judges the ECG to be normal, left ventriculography is unnecessary and a formal QRS score does not improve reliability of this clinical judgment. Adopting this strategy would save £30-40 000 in consumables and 65-87 hours of catheter laboratory and staV time for a department catheterising 3000 patients with suspected coronary artery disease annually.
Pacing and Clinical Electrophysiology, Mar 1, 2004
ABSTRACT The traditional pulse generator implantation site lies subcutaneous on the fascia of the... more ABSTRACT The traditional pulse generator implantation site lies subcutaneous on the fascia of the pectoralis major muscle. This article describes a subpectoral pocket approach, which on anatomic investigation is actually &quot;intrapectoral&quot; and offers a much improved cosmetic result with the potential advantage of less erosion. In the authors&#39; experience with over 1000 initial pacemaker implants and pulse generator replacements, the potential concerns of neurovascular and muscular damage have not been realized. There has been no pulse generator damage from the ribs, serious loculated hematomas, or unusual postoperative or chronic pain. From experience with pulse generator recalls, the replacement procedure has not been significantly more difficult than with the subcutaneous approach. The intrapectoral approach has now become the authors&#39; routine in patients without significant adipose tissue overlying the pectoralis major muscle.
Journal of Cardiovascular Electrophysiology, Apr 30, 2004
A 16-year-old boy presented with exertional palpitations, which occurred particularly when he was... more A 16-year-old boy presented with exertional palpitations, which occurred particularly when he was playing tennis. There was no history of syncope or family history of sudden cardiac death. The boy was otherwise well and had not been taking any medications. ECG showed sinus rhythm with no evidence of preexcitation and a normal corrected QT interval. A 24-hour Holter monitor demonstrated an irregular broadcomplex tachycardia with varying QRS morphology. At electrophysiologic study, the HV interval was normal at 35 ms. During atrial pacing with a single extrastimulus, tachycardia with a variable cycle length was induced (Fig. 1). During tachycardia, the QRS complexes demonstrated varying degrees of left bundle branch block (LBBB) morphology. Following reinduction, tachycardia with a right bundle branch block (RBBB) morphology was present, with the variation in tachycardia cycle length less apparent (Fig. 2). What is the mechanism of the tachycardia, and what accounts for the variation in tachycardia cycle lengths?
Journal of Cardiovascular Electrophysiology, Aug 5, 2004
Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) ... more Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) activity from a pulmonary vein (PV) focus, but how AF is maintained it is not known. The crista terminalis (CT) is an important line of block in atrial flutter (AFL), but its role in AF has not been determined. The aim of this study was to examine the conduction properties of the CT during onset of AF. In 10 patients (mean age 38 +/- 8 years), we analyzed conduction across the CT during onset of focal AF from an arrhythmogenic PV and during pacing from the same PV at cycle lengths of 700 and 300 ms. A 20-pole catheter was positioned on the CT using intracardiac echocardiography. In 10 control patients with no history of AF, we analyzed conduction across the CT during pacing from the distal coronary sinus at 700 and 300 ms. In all 10 AF patients, AF was initiated with 1 to 9 AE beats (median 5) from a PV. During sinus rhythm, there were no split components (SC) recorded on the CT. During PV AE activity, discrete SC were recorded on the CT in all patients over 6.3 +/- 0.9 bipoles (3.7 +/- 0.3 cm). Maximal splitting of SC was 66 +/- 31 ms (37-139). There was an inverse relationship between AE coupling intervals and the degree of splitting between SC in all patients. Degeneration to AF was preceded by progressive decrement across the CT. SC were recorded during PV pacing at 700 and 300 ms (maximal distance between SC of 24 +/- 3 ms and 43 +/- 5 ms, respectively, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Maximum SC at CT in controls was 13 +/- 8 ms at 700 ms (P = 0.06 vs AF patients) and 16 +/- 9 ms at 300 ms (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01 vs AF patients). (1) These observations provide evidence of anisotropic, decremental conduction across the CT during onset of focal AF and during pacing from the same PV. A line of functional conduction block develops along this anatomic structure (CT). Whether this line of block acts as an initiator of AF or simply contributes passively to nonuniform fibrillatory conduction is unknown. (2) In some patients with focal AF, development of conduction block along the CT may provide a substrate for typical AFL.
Journal of the American College of Cardiology, 2005
In recent years, the pioneering work of Wijffels et al. (1) has demonstrated the importance of at... more In recent years, the pioneering work of Wijffels et al. (1) has demonstrated the importance of atrial remodeling in development of an atrial substrate conducive to sustained atrial fibrillation (AF). A range of factors has been implicated in this process. Among these factors, indirect evidence suggests a role for the renin-angiotensin system. In differing animal models, angiotensin-converting enzyme inhibition or angiotensin II (AII) antagonists has been shown to prevent both acute (hours) (2) electrical remodeling and chronic (weeks) structural remodeling (3). Although the mechanism for these effects remains uncertain, the inhibition of acute AF-induced remodeling by these agents suggests that AII may have direct effects on atrial electrophysiology. In the current study, we examined the acute effects of AII on atrial electrophysiology in humans. Our study population included 12 patients with supraventricular tachycardia who were undergoing curative ablation. Autonomic blockade was administered at commencement. Continuous heart rate and blood pressure monitoring was performed. Multipolar catheters included: 1) a coronary sinus (CS) catheter; 2) a crista terminalis (CT) catheter; 3) a lateral right atrium (RA) catheter; and 4) a His bundle catheter. Atrial effective refractory period (ERP) was measured at the distal CS and high lateral RA at cycle lengths of 600, 500, and 400 ms. Dispersion of atrial ERP was defined as the difference between the averaged atrial ERP at both sites. Atrial conduction was measured in both atria at pacing cycle lengths of 600, 500, and 400 ms. Local conduction time was measured along the lateral RA and CS catheters. Conduction delay was analyzed by the presence of discrete double potentials and fractionated electrograms and assessed during pacing at 600, 500, and 400 ms and during extra stimulus testing from distal CS and high lateral RA. The inducibility of AF (Ͼ5 s) was recorded during ERP testing. Angiotensin II was obtained from Clinalfa AG (Laufelfingen,
Aims Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillatio... more Aims Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal). Methods and results Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 + 14.6 vs. 41.5 + 13.1 min; P , 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 + 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P ¼ 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P , 0.01). Conclusion There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033).
Journal of the American College of Cardiology, Jul 1, 2004
The purpose of this study was to characterize the pattern of atrial remodeling seen with human ag... more The purpose of this study was to characterize the pattern of atrial remodeling seen with human aging. BACKGROUND Atrial fibrillation (AF) occurs in 3% to 4% of the population over 65 years of age. It is associated with thromboembolic complications, worsening heart failure, and increased mortality, yet the electrical and structural remodeling that occurs with human aging remains unknown. METHODS Thirteen patients (66.4 Ϯ 1.7 years) Ն60 years (group A), 13 patients (50 Ϯ 2.1 years) age 31 to 59 years (group B), and 15 patients (24.7 Ϯ 1.0 years) Յ30 years (group C) underwent conventional electrophysiologic studies and electroanatomic mapping. We measured atrial refractoriness (ERP) at the distal coronary sinus (CS); low and high lateral right atrium (LRA) and the high septal right atrium at 600, 500, and 400 ms; maximum corrected sinus node recovery time (CSNRT); P-wave duration (PWD); conduction time (CT) along the CS and LRA; and discrete double potentials (DP) along the crista. RESULTS Aging was associated with an increase in atrial ERP, prolonged CT along the CS, increased PWD and CSNRT. There was no significant change in dispersion of refractoriness or rate adaptation. Electroanatomic mapping revealed diffuse areas of low voltage with regional conduction slowing. Both techniques demonstrated a greater number of DPs and fractionated signals along the crista terminalis with aging. CONCLUSIONS Aging is associated with regional conduction slowing, anatomically determined conduction delay at the crista, and structural changes that include areas of low voltage. In addition, impairment of sinus node function and an increase in atrial ERP occurred with aging. This electrical and structural remodeling may explain the increased propensity to AF with aging.
Background: We describe our procedural outcomes and technical success rates of Watchman ® LAA clo... more Background: We describe our procedural outcomes and technical success rates of Watchman ® LAA closure devices from our centre with a focus on peri-device leaks. Results: Fifty-three patients aged 65.5 ± 7.3 years (range 43-82 years, 72% male, CHADS2 score 1.94 ± 0.9, CHADSVASC score 2.8 ± 1.0) underwent successful implantation of a Watchman ® LAA occluder device in our centre since Nov 2009. Forty-four patients had concomitant pulmonary vein isolation (44/53). The average device size was 24 ± 3 mm (range 21-30 mm). No acute procedural complications occurred. Post implant transoesophageal echocardiogram (TOE) was performed at six weeks, and again at six months if any persistent peri-device leaks seen at initial follow up. At implant, 4/53 patients had a small peri-device leak detected on colour flow Doppler by TOE ≤ 3 mm. At six week TOE, 12 patients had a peri-device leak (nine new, three persistent), with four of these showing persistent small leaks at six month TOE (two present since implant). There was no significant age or sex distribution of patients who developed new peri-device leaks, however all patients who demonstrated leaks at implant were male. At six week follow up, the interatrial septal puncture sites had healed in all but 12 patients, with no age or sex distribution observed. Conclusion: Despite high procedural success rates and low incidence of peri-device leaks at implant, we have observed development of small leaks at first TOE followup in approximately 17% of patients which then tend to close again. This may reflect a period of "seating" with the device.
Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrh... more Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrhythmias are increasingly recognized and associated with significant morbidity and mortality. We aim to describe the clinical and electrophysiological characteristics of patients with atrial arrhythmias occurring late after CTX. Methods and results Sixteen patients with prior CTX who presented with late atrial arrhythmias for electrophysiological studies (EPS) were identified at two cardiac transplant centres. Among 859 patients, 16 (mean age 52 + 14 years, 11 of 16 were men) patients underwent EPS for atrial arrhythmias presenting 8.6 + 5.7 years following CTX. Among 16 patients, 14 underwent cardiac alone and 2 included lung transplantation. There were no cases of cardiac rejection. Arrhythmias were due to counterclockwise cavotricuspiddependent atrial flutter (AFL) in 10 of 16, atrial tachycardia (AT) in 6 (1 patient had AFL and AT), and 1 due to atrioventricular nodal re-entrant tachycardia. Recipient-donor atrial electrical connection was seen in two of six AT and in no cases of AFL. In two cases, a focal AT was mapped to the remnant atrium conducting 2 : 1 or at variable block to the donor atrium. In four cases a focal/micro re-entrant AT originated within the vicinity of the interatrial suture scar. All cases were successfully ablated with radiofrequency energy; however, one case of AFL required a repeat ablation. Patients remained free of arrhythmia at 34 + 15 months post-ablation. Conclusion Typical AFL and AT are the most frequent supraventricular arrhythmias occurring late following CTX. Focal ATs may originate in low-voltage or border zones immediately adjacent to the atrio-atrial anastomosis. Radiofrequency ablation is an effective treatment strategy with high long-term success.
Introduction The outcome of persistent atrial fibrillation (PeAF) ablation remains suboptimal and... more Introduction The outcome of persistent atrial fibrillation (PeAF) ablation remains suboptimal and procedures may be long and painful. Little evidence is available on outcome for procedures under general anaesthetic (GA) compared to conscious sedation (CS). We performed a single-centre observational study to assess whether use of GA in PeAF ablation improved outcome and was cost-effective. Methods 292 patients undergoing first ablation procedures for PeAF by radio-frequency point-by-point technique under CS (n=220) or GA (n=72) were followed. End points were
Case Report: We report a fifty-year-old male with paroxysmal atrial fibrillation presenting with ... more Case Report: We report a fifty-year-old male with paroxysmal atrial fibrillation presenting with EHRA III symptoms who underwent pulmonary vein isolation (PVI). The PVI was planned with a 28mm cryoballon under deep sedation. After uncomplicated transseptal puncture, angiography of the left atrium (LA) was done showing four independent pulmonary veins (PV). Heparin was given to maintain an activated clotting time of .300s. Following successful left PV isolation, the circular diagnostic catheter (CDC) was advanced in the right inferior PV (RIPV) and one successful freeze was delivered. After thawing of the cryoballon, it turned out not to be possible to remove the CDC from the RIPV. The fluoroscopy showed that the CDC was stuck in a small branch of the RIPV. While pulling the CDC the patient started to cough. The surrounding lung tissues seemed to be tightened and dragged together with the CDC. While turning the CDC, the shaft of the CDC broke close to the holder of the steerable sheath. With use of the remaining shaft, we further tried to remove the CDC from the PV, however, the CDC was again completely torn from the base of the circular part in the branch of RIPV. We then removed the proximal shaft and isolated the superior right PV with one freeze using a newly unpacked CDC. Final LA angiography demonstrated neither obstructions of major PVs nor exit of contrast agent out of LA, although the circular part of the CDC remained in the small branch of RIPV. After the procedure the patient showed no complaints such as cough, dyspnea or other symptoms. A pericardial effusion was also excluded. Discussion: Due to the tying in a small branch of the RIPV the CDC was stuck and we could not recover the catheter anymore. No practical way to resolve this situation has been described yet. Further catheter pulling was not an option due to the risk of a fatal bleeding because the surrounding lung tissue was tied. Another option could be an open-heart surgery. As the remaining part of the catheter did not move at all, we decided to leave the remaining circular part after a consultation with heart surgery unit. After a follow-up of one month the patient showed neither AF event nor clinical symptoms such as cough, dyspnea. We here reported a break of the CDC shaft during PVI with cryoballoon, which has been not yet reported.
Introduction In selecting patients that may benefit from cardiac resynchronisation therapy (CRT),... more Introduction In selecting patients that may benefit from cardiac resynchronisation therapy (CRT), dyssynchrony assessment by echocardiography based only upon the timing of regional contraction is limited by being inherently independent of underlying myocardial contractility. We hypothesised that patient selection may be enhanced using a strain-based parameter based not only the timing of myocardial segmental motion, but also on the amplitude of contraction, a potential measure of contractile reserve. We assessed a combined early and late strain index (ELSI) to predict CRT response. Methods Speckle tracking radial strain was performed in 67 heart failure patients scheduled for CRT (age 69±9 years, ischaemic 56%, QRS 154±12 ms, NYHA III/IV—63/4, ejection fraction 23±7%). The ELSI was calculated as the sum for each of the 12 non apical segments of the difference in peak radial strain and strain at aortic valve closure. CRT response was defined as a >15% reduction from baseline in LV end systolic volume (LVESV) at 6 months. The predictive value of the ELSI was compared to previously reported dyssynchrony measures including the SD of time to peak myocardial longitudinal velocity of the 12 non apical segments (Ts SD12), the anteroseptal–posterior wall radial strain delay (AS-P delay) and the SD of time to peak radial strain of 12 segments (Rs-SD12). Results Response to CRT occurred in 38/67 (57%) patients. Significant differences were seen between responders and non responders in the ELSI (91±45 vs 27±14%, p<0.01), AS-P delay (256±158 vs 94±87 ms) and the Rs-SD12 (143±62 vs 75±50 ms). There was no difference in the Ts SD12 between responders and non responders. The ELSI had the best correlation with LVESV reduction (r=0.61, p<0.001) and using an optimal cut-off of 40% (AUC=0.94), the ELSI was able to predict response to CRT with a sensitivity of 93% and specificity of 95%. This was much higher than for the AS-P (cut-off 130 ms, AUC=0.79, sensitivity 71%, specificity 74%) and Rs –SD12 (95 ms, AUC=0.82, sensitivity 73% specificity 75%). Conclusion A combined early and late strain parameter based on both the timing and amplitude of segmental strain has a stronger predictive value in determining CRT response compared to widely reported dyssynchrony parameters based on segmental timing alone.
procedures defined as when the patient first emerged from their 3 month blanking period free of A... more procedures defined as when the patient first emerged from their 3 month blanking period free of AF/AT (or failure accepted), that is, when AF was first successfully eliminated whether after one CA or several. Results Two hundred eighty-five patients underwent 530 procedures. Mean age was 57611 years, 75% male, 20% had structural heart disease and 53% paroxysmal AF. Left atrial diameter was 4.360.8 cm and 17% had left ventricular systolic dysfunction. Mean number of procedures was 1.9 per patient (1.7 for PAF and 2.0 for PeAF). Procedural complications included stroke or TIA in 0.6% (all of which resolved) and pericardial effusions which were drained without sequelae in 1.7%. There were no peri-procedural deaths. Of 285 patients, 270 were contacted for follow-up. During 3.3 (2.4 to 7.5) years from the first procedure, there were seven deaths (unrelated to their ablation or AF) and three strokes or TIA (0.3% per year). Freedom from AF/AT at 2.7 (0.2 to 7.4) years after the last procedure was 86% for PAF and 68% for PeAF. Most recurrence occurred in the first year, with late recurrence >3 years occurring in 3/100 years of follow-up. KaplaneMeier analysis showed that CFE ablation improved outcome for PeAF after the first cluster of procedures (p¼0.04), with a trend towards improved final outcome (p¼0.13). Conclusion Long term freedom from AF is achievable in the majority of patients with PAF and PeAF with low rates of late recurrence. Rates of periprocedural complications are low, and late adverse events including stroke are few. Targeting CFE in addition to PVI and linear lesions improves outcome for PeAF.
67AE6). AF was persistent in 2 and intermittent in 5. Mean duration of AF mean 84.4 AE 75.2 month... more 67AE6). AF was persistent in 2 and intermittent in 5. Mean duration of AF mean 84.4 AE 75.2 months. Common characteristics of these tachycardias were the endocardial breakout over a broad area adjacent to the LOM region, presence of pre-systolic or mid-diastolic potentials and abolition by ablation of the pre-systolic or mid-diastolic potentials remote from the endocardial breakout site. In six cases, tachycardias were present after isolation of the veins and posterior left atria. All demonstrated characteristic areas of very slow conduction in the LOM region highlighted by the presence of either low voltage, long duration fractionated potentials or mid diastolic potentials with a fixed temporal relationship to the subsequent endocardial activation. The pattern of activation and termination of tachycardia during ablation were consistent with an arrhythmia utilizing an electrically insulated tract within LOM and the PV-LAA ridge region. Conclusion: We identified a novel mechanism of Organised Atrial Tachycardias characterized by the following: 1) Tachycardias in the presence of documented isolation of all PVs and LA posterior wall; 2) Re-entrant mechanism suggested involving the PV-LAA Ridge in LOM region; 3) Slow conduction in the LOM region with low voltage, long duration, fractionated potentials or discrete mid-diastolic potentials; 4) Concealed pre-systolic and mid-diastolic components; 5) Broad endocardial breakout site related to the LOM region; 6) Successful termination by ablating pre-systolic or mid-diastolic potentials remote from the earliest endocardial breakout site.
Journal of Interventional Cardiac Electrophysiology, Jun 1, 2004
We report an unusual case of bundle branch reentrant tachycardia, in a patient with normal left v... more We report an unusual case of bundle branch reentrant tachycardia, in a patient with normal left ventricular function, cured by radiofrequency catheter ablation. However, the long-term prognosis of these patients is uncertain. We discuss the indications for an implantable defibrillator in this group.
Journal of the American College of Cardiology, Apr 1, 2011
Background: Left ventricular (LV) lead placement to the latest area of contraction is associated ... more Background: Left ventricular (LV) lead placement to the latest area of contraction is associated with enhanced response to cardiac resynchronization therapy (CRT). We conducted a randomised controlled trial to compare the effect on acute change in cardiac output (CO) between patients undergoing either echocardiographically guided LV lead placement or standard usual CRT implantation. Methods: A total of 180 patients with left bundle branch block (age 71 ± 8 yrs, NYHA III 92%, EF 23 ± 7%, QRS 156 ± 9 ms) were recruited and underwent speckle tracking 2D radial strain at baseline to determine the latest site of activation. Patients were subsequently randomized into one of 2 groups. In group 1 (targeted group-TAR) the CRT implanters were aware of the echocardiographic findings and attempted to position the LV lead to the latest site of activation. In group 2 (control-CON) patients underwent standard CRT implantation without echocardiographic guidance. In all patients the LV lead position was defined by biplane fluoroscopy. Patients were classified according to the relation of the LV lead to the latest site as: Concordant (C-lead position at latest site), Adjacent (A-within 1 segment) or Remote (R-2 or more segments away from latest site). All patients underwent AV and VV delay optimization. Within 24 hours of implantation all patients underwent non invasive CO determination using a commercially available system (NICOM) during optimised CRT and with CRT switched off (baseline). The peak improvement in CO was compared between the two groups. Results: There were no differences in baseline characteristics between the two groups. There were more C and less R leads in the targeted group (TAR vs. CON: C 68.9% vs 46.7% p<0.01, A: 24.4% vs. 30.0% p=0.46, R: 6.7% vs. 23.3% p<0.01). There were no differences in CO at baseline between the two groups (TAR vs. CON: 4.77 ± 1.1 vs. 4.67 ± 1.1 L/min, p=0.76). CO was significantly higher during CRT in patients with a targeted LV lead compared to the control group (6.06 ± 1.3 vs 5.57 ± 1.2 L/min, p=0.021). Conclusions: Targeting LV lead placement to the latest areas of activation using speckle tracking 2D radial strain is associated with a better CO response to CRT compared to standard treatment.
Cardiac device implantations are increasingly carried out using local anaesthesia (LA) with intra... more Cardiac device implantations are increasingly carried out using local anaesthesia (LA) with intravenous conscious sedation. The advantages include reduction of patients' anxiety and discomfort, and avoidance of risks of general anaesthesia (GA). However, concerns about the safety of sedation used without an anaesthetist have been expressed. The National Patient Safety Agency (NPSA) has identified serious problems in the use of intravenous midazolam for conscious sedation and reliance on flumazenil for reversal of over-sedation [1]. The aim of the study is to determine the safety of intravenous conscious sedation in patients undergoing cardiac device implantation and to determine patients' experience and comfort using conscious sedation. All patients undergoing device implantations (pacemaker and Cardiac Resynchronisation Therapy (CRT) implantation, elective unit replacements (EUR) andpacing leads revision) under conscious sedation were eligible. Patients with devices that were implanted under GAwere excluded. Intravenous midazolam and fentanyl could be administered alone or in combination based on operators' discretion. LA with 1% lignocaine without adrenaline was used in all patients. All data were prospectively collected. A patient questionnaire (Appendix A) was given to patients late after the procedure to allow as much time for effects of sedation towear off. A pain score of 10 reflects the worst pain possible, whereas score 1 reflects no pain. Written informed consent for the procedures was obtained. Patient participation for the questionnaire was voluntary. Verbal informed consent was obtained as per the ethics committee of the hospital. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. The primary outcome was to determine the safety of conscious sedation administered without the presence of anaesthetist. The secondary outcome was to assess patients' satisfaction intraand postprocedure. Statistical comparisons for continuous data were performed using ANOVAs single factor, unpaired t-tests and chi-squared tests for categorical data. Logistic regression analysis was performed for multivariable predictors. All testswere two-sided and p values of a level≤0.05 were considered statistically significant.
Journal of Cardiovascular Electrophysiology, Feb 1, 2002
Early Repeated Cardioversion for AF Recurrence. Introduction: The clinical value of cardioversion... more Early Repeated Cardioversion for AF Recurrence. Introduction: The clinical value of cardioversion (CV) of persistent atrial brillation (AF) is limited by the high rate of early AF recurrence, which may be related to the persistence of atrial electrical remodeling. We examined the hypothesis that the likelihood of maintaining sinus rhythm after CV of persistent AF is signi cantly enhanced by a policy of early repeated CV. Methods and Results: Fifty-nine patients with persistent AF underwent internal CV (CV 1). Those patients cardioverted were monitored with daily transtelephonic ECG. In the event of AF recurrence, these patients were admitted rapidly for repeat CV (CV 2) and, if further recurrence occurred, a third CV (CV 3) was performed. Daily ECG monitoring was continued until 1 month of sinus rhythm was maintained or a total of three CVs were performed. Of the 59 patients undergoing CV 1, 43 were discharged in sinus rhythm and 29 subsequently had AF recurrence during monitoring. Twenty-three of these underwent CV 2 and 11 of these underwent CV 3. Of those having repeated CVs, only 4 patients maintained sinus rhythm for 1 month (3 after CV 2 and 1 after CV 3). The remaining patients had repeated AF recurrence during the monitoring period. Mean time from AF recurrence to CV 2 was 20 6 13 hours and from AF recurrence to CV 3 was 13 6 7.2 hours. Atrial effective refractory periods increased from 189 6 16 msec at CV 1 to 215 6 18 msec at CV 3 (P < 0.05), indicating reversal of atrial electrical remodeling during this period. Conclusion: A policy of early repeated CVs for AF recurrence has very limited clinical value despite evidence of reversal of atrial electrical remodeling. The time between AF recurrence and repeat CV may need to be reduced further if such a policy is to succeed.
Background-Episodes of atrial fibrillation (AF) are known to cause both a rapid reduction in atri... more Background-Episodes of atrial fibrillation (AF) are known to cause both a rapid reduction in atrial refractoriness (atrial electrical remodeling) and a more delayed increase in AF stability thought to be due to a so-called "second factor." The aim of this study was to quantify the effects and time course of such a factor on AF stability in the chronic goat model. Methods and Results-AF was maintained in 6 goats by burst atrial pacing for 3 consecutive 4-week periods separated a mean of 6Ϯ2.1 days of sinus rhythm. Six days of sinus rhythm was just sufficient for refractoriness changes to reverse fully in all goats. Atrial effective refractory period, AF inducibility, and duration of individual episodes of AF were assessed at regular intervals. There was a progressive reduction from month 1 to 2 to 3 in the mean duration of burst pacing required to induce individual episodes of AF of 60 seconds (178Ϯ251, 110Ϯ102, and 21Ϯ30 hours), 1 hour (229Ϯ224, 136Ϯ104, and 68Ϯ51 hours), and 24 hours (277Ϯ218, 192Ϯ190, and 102Ϯ75 hours; PϽ0.03). The frequency with which AF was induced during extrastimulus pacing increased progressively from 16.7% in month 1 to 31.7% in month 2 and 46.9% in month 3 (PϽ0.001). Conclusions-Sequential 4-week periods of atrial fibrillation result in a progressive increase in AF stability independent of baseline atrial refractory period. This finding suggests the presence of a second factor in the self-perpetuation of AF with a time course comparable to that of AF-induced ultrastructural changes in the atria. (Circulation. 2004;109:1434-1439.
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