Key references: biventricular pacing

Heart Rhythm, 2004

OBJECTIVES/BACKGROUND The aim of this article is to critically review the data accumulated to date on the application of cardiac resynchronization therapy (CRT) via biventricular pacing techniques to manage patients with advanced heart failure. The data from studies evaluating the effects of long-term right ventricular (RV) pacing are also briefly reviewed. METHODS MEDLINE and selective journal searches of English-language reports and a search of references of relevant papers were conducted. RESULTS Cardiac dyssynchrony as reflected by a prolonged QRS complex, often in the form of left bundle branch block, is encountered in about 30% of patients with moderate-to-advanced heart failure. Among these patients, 10% to 15% are candidates for CRT via biventricular pacing. Accumulated evidence from randomized controlled studies over the last few years has indicated a significant hemodynamic and clinical improvement conferred by CRT to class III or IV heart failure patients with idiopathic or ischemic dilated cardiomyopathy having a low left ventricular ejection fraction (Յ35%) and a wide QRS complex (Ն120 -150 ms). Newer data suggest a significant reduction in overall mortality and heart failure hospitalization, particularly when CRT is combined with automatic defibrillator backup. Technical advances with percutaneous methods accessing the tributaries of the cardiac veins have raised the success rate of implantation of left ventricular leads to Ͼ90%. Further confirmation from ongoing trials is awaited, and more data from cost-effectiveness studies are needed before CRT is considered for prime time therapy in the heart failure population. If the data confirm a survival benefit from CRT, use of this electrical therapy at earlier stages of heart failure might be contemplated. New evidence from recent studies suggests a deleterious effect of the long-standing practice of producing an iatrogenic left bundle branch block by conventional RV apical pacing in patients receiving permanent pacemakers. Thus, having already become poignantly aware of the harmful effects of spontaneous left bundle branch block, this emerging new evidence about RV apical pacing would dictate a change of attitude and direct our attention to alternate sites of pacing, such as the left ventricle and/or the RV outflow tract, if not for all patients then at least for those with left ventricular dysfunction. CONCLUSIONS CRT offers hemodynamic and clinical improvement to patients with moderate-toadvanced heart failure, and it might significantly prolong survival in selected patients, particularly if devices with defibrillation backup are used. Further confirmatory data from randomized mortality trials are needed, and issues of cost efficacy must be resolved before this vital therapeutic alternative is ready for prime time therapy of heart failure patients.

Journal of the American College of Cardiology, 2001

We sought to investigate the impact of six months of cardiac resynchronization therapy (CRT) on echocardiographic variables of left ventricular (LV) function. BACKGROUND Cardiac resynchronization therapy has recently been introduced as a new therapeutic modality in patients with advanced heart failure (HF) and conduction abnormalities. However, most studies have only investigated the early hemodynamic effects of CRT. METHODS Twenty-five patients (12 women and 13 men; 59.8 Ϯ 5.1 years old) with advanced HF caused by ischemic (n ϭ 7) or idiopathic dilated cardiomyopathy (n ϭ 18) and a prolonged QRS complex were analyzed. All patients underwent early hemodynamic testing with a randomized testing protocol; echocardiographic measurements were compared before implantation and after six months of CRT. RESULTS Left ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD, respectively) were significantly reduced after six months (LVEDD from 71 Ϯ 10 to 68 Ϯ 11 mm, p ϭ 0.027; LVESD from 63 Ϯ 11 to 58 Ϯ 11 mm, p ϭ 0.007), as were LV end-diastolic and end-systolic volumes (LVEDV from 253 Ϯ 83 to 227 Ϯ 112 ml, p ϭ 0.017; LVESV from 202 Ϯ 79 to 174 Ϯ 101 ml, p ϭ 0.009). Ejection fraction was significantly increased (from 22 Ϯ 7% to 26 Ϯ 9%, p ϭ 0.03). "Nonresponders," with regard to LV volume reduction, had significantly higher baseline LVEDV, compared with "responders" (351 Ϯ 52 vs. 234 Ϯ 74 ml, p ϭ 0.018). Overall, there was only mild mitral regurgitation at baseline, with a minor reduction by semiquantitative analysis. The results of early hemodynamic testing did not predict the volume response. CONCLUSIONS Cardiac resynchronization therapy may lead to a reduction in LV volumes in patients with advanced HF and conduction disturbances. Volume nonresponders have significantly higher baseline LVEDV.

Srpski arhiv za celokupno lekarstvo, 2005

INTRODUCTION. Resynchronisation therapy with biventricular permanent pacing stimulation is one method of treating patients with systolic heart failure, with echocardiograph signs of ventricular asynchrony and a prolonged QRS of longer than 120 milliseconds. This method has been accepted in most medical centers around the world and was instigated in our Pacemaker Centre in December 2001, 3 months after FDA approval for human use. OBJECTIVE. The aim of the study was to present this new procedure and the results obtained from our own group of patients. METHOD. A multi-site, biventricular pacemaker, with a special electrode for left-half heart stimulation was implanted in the coronary sinus of 17 patients who had suffered systolic heart failure (12 male and 5 female, average age 59.9 years). For all of them, the duration of the QRS interval was longer than 120 ms, with left bundle branch morphology, and an ejection fraction below 30%. All the patients were NYHA class II or III. Prior to...

Heart Failure is the result of heterogeneous structural heart diseases, especially ischemic disease, and is becoming increasingly common in all Western countries.

2021

Achieving Cardiac resynchronization therapy (CRT) with Biventricular pacing(BiVP) pacing for patients with moderate-tosevere heart failure (HF), left ventricular (LV) systolic dysfunction and ventricular dyssynchrony is well established and is currently the standard of care. Multiple studies have demonstrated significant improvement in quality of life, functional status, and exercise capacity in patients with New York Heart Association (NYHA) class III and IV heart failure who underwent resynchronization therapy1,2. In addition, resynchronization therapy is associated with survival benefit3. However, one third of patients do not respond to BIVP. New modalities for resynchronization have emerged namely His bundle pacing (HBP) and left ventricular septal pacing (LVSP). In this paper, we will review the benefits and limitations of BiVP and also the role of new pacing modalities such as HBP and LVSP in patients with HF with reduced left ventricular ejection fraction (LVEF) and electrical dysynchrony.

Journal of the American College of Cardiology, 2011

This thesis assesses the mechanisms by which biventricular and left ventricular pacing improves cardiac performance in patients with heart failure. We demonstrated for the first time that CRT results in an improvement in acute haemodynamic variables in heart failure patients with a narrow QRS duration that is comparable to the effects seen in heart failure patients with a broad QRS duration. In addition, we have shown that both biventricular (BIVP) and left ventricular pacing (LVP) significantly reduce external constraint to left ventricular filling, resulting in an increase in effective filling pressure. In heart failure patients with evidence of external constraint at rest, the acute haemodynamic benefits of both BIVP and LVP were principally due to the relief of external constraint and preload recruitment. However, in those patients with evidence of electrical dyssynchrony and a broad QRS duration, a significant haemodynamic benefit was derived from an enhancement in left ventricular contractility, presumably as a result of a reduction in left ventricular dyssynchrony. Patients with external constraint appear to derive a greater haemodynamic benefit from pacing due to the significant increase in stroke work that is associated with relief of external constraint and preload recruitment, in addition to the increase in stroke work derived from enhanced contractility due to a reduction in dyssynchrony. These findings will inform better patient selection for this therapy and also optimisation of pacing strategy in individual patients. STATEMENT OF CONTRIBUTION I undertook screening (with echocardiography, ECG and metabolic exercise testing) and recruitment of potential participants with a narrow QRS duration, as well as recruiting patients undergoing implantation of a biventricular pacemaker with a broad QRS duration. I undertook the acquisition of the invasive haemodynamic data in 85% of all patients, and completed analysis of the data in all cases recruited. I was also involved in the collection and analysis of all echocardiographic data included in this thesis.

Pace-pacing and Clinical Electrophysiology, 2007

There are few studies on cardiac resynchronization therapy (CRT) in heart failure (HF) patients with preexisting right ventricular (RV) pacing. The purpose of this study was to determine the efficacy of CRT upgrading in RV-paced patients and the predictivity of electromechanical dyssynchrony parameters (EDP) evaluated by standard echocardiography (ECHO) and tissue Doppler imaging (TDI). Methods: Thirty-eight consecutive patients with HF [New York Heart Association (NYHA) class III or IV, LVEF < 35%], prior continuous RV pacing, and absence of atrial fibrillation were enrolled in the presence of a paced QRS ≥ 150 ms and evaluated by ECHO and TDI. A responder was defined as a patient with a favorable change in NYHA class and neither HF hospitalization nor death, plus an absolute increase of LVEF ≥ 10 units. Results: At six-months follow-up, the whole study population had significant improvement in symptoms, systolic function, and QRS duration (P < 0.001); 32 (84%) patients had a favorable clinical outcome, 25 (66%) were considered responders according to the previous definition. Postimplant QRS was similarly reduced in both responders and nonresponders, whereas EDP had a significant improvement only in responders (P < 0.05). Using EDP, 23 (79%) patients were responders compared with 2 (22%) patients without mechanical dyssynchrony (P = 0.002). Conclusions: In HF patients with previous RV pacing, CRT is effective to improve clinical, functional outcome, and LV performance and to reduce electromechanical dyssynchrony in a large proportion of patients. Dyssynchrony evaluated by standard and TDI ECHO can be useful for CRT selection of paced patients. (PACE 2007; 30:1096-1104 heart failure, ventricular dyssynchrony, cardiac resynchronization therapy, biventricular upgrading

Expert Review of Cardiovascular Therapy, 2005

Congestive heart failure (CH F) is a leading cause of morbidit y and mor tality worldwide . Many CHF patien ts have in traventricular conduction delays such as right or left bundle branch block or non-specific QRS widening on the body surface ECG .In traven tricular conduction delays cause dyssynchrony of the ven tricles , leading to regional movement abnormalities and worsening of cardiac function .R ecent clinical t rials have indicated t hat cardiac resynchronization therapy improves cardiac function class, exercise tolerance , maximum oxygen consumption and qualit y of life in patien ts wit h moderate to severe heart failure .I t is also associated with a significant reduction in mortalit y and hospital admissions for hear t failure .

Revista Española de Cardiología (English Edition), 2004

Heart failure is one of the most prevalent diseases in industrialized countries. Although the prognosis of patients with heart failure is still poor, in recent decades new therapies have been investigated in order to improve quality of life and survival. However, up to 30% of the patients with advanced heart failure present disturbances in intraventricular conduction, and this produces asynchrony of ventricular contractility, leading to further deterioration in heart function. Cardiac resynchronization therapy can improve the synchrony of ventricular contractility. Numerous studies have demonstrated the benefits of biventricular stimulation therapy for improving hemodynamic parameters, quality of life, 6-minute walking test performance and functional class in patients with heart failure, ventricular systolic dysfunction and disturbances in intraventricular conduction. Some studies have demonstrated longer survival times in patients treated with cardiac resynchronization plus a defibrillator. Nonetheless, many questions about the benefits of heart resynchronization therapy, site of stimulation and best type of device (pacemaker or defibrillator) remain unresolved.

Journal of the American College of Cardiology, 2001

We sought to investigate the impact of six months of cardiac resynchronization therapy (CRT) on echocardiographic variables of left ventricular (LV) function. BACKGROUND Cardiac resynchronization therapy has recently been introduced as a new therapeutic modality in patients with advanced heart failure (HF) and conduction abnormalities. However, most studies have only investigated the early hemodynamic effects of CRT. METHODS Twenty-five patients (12 women and 13 men; 59.8 Ϯ 5.1 years old) with advanced HF caused by ischemic (n ϭ 7) or idiopathic dilated cardiomyopathy (n ϭ 18) and a prolonged QRS complex were analyzed. All patients underwent early hemodynamic testing with a randomized testing protocol; echocardiographic measurements were compared before implantation and after six months of CRT. RESULTS Left ventricular end-diastolic and end-systolic diameters (LVEDD and LVESD, respectively) were significantly reduced after six months (LVEDD from 71 Ϯ 10 to 68 Ϯ 11 mm, p ϭ 0.027; LVESD from 63 Ϯ 11 to 58 Ϯ 11 mm, p ϭ 0.007), as were LV end-diastolic and end-systolic volumes (LVEDV from 253 Ϯ 83 to 227 Ϯ 112 ml, p ϭ 0.017; LVESV from 202 Ϯ 79 to 174 Ϯ 101 ml, p ϭ 0.009). Ejection fraction was significantly increased (from 22 Ϯ 7% to 26 Ϯ 9%, p ϭ 0.03). "Nonresponders," with regard to LV volume reduction, had significantly higher baseline LVEDV, compared with "responders" (351 Ϯ 52 vs. 234 Ϯ 74 ml, p ϭ 0.018). Overall, there was only mild mitral regurgitation at baseline, with a minor reduction by semiquantitative analysis. The results of early hemodynamic testing did not predict the volume response. CONCLUSIONS Cardiac resynchronization therapy may lead to a reduction in LV volumes in patients with advanced HF and conduction disturbances. Volume nonresponders have significantly higher baseline LVEDV.