Papers by Dimitrios Karayiannis
Current Medical Research and Opinion, 2009
Respiratory Research
Background Before the pandemic of coronavirus disease (COVID-19), rapidly improving acute respira... more Background Before the pandemic of coronavirus disease (COVID-19), rapidly improving acute respiratory distress syndrome (ARDS), mostly defined by early extubation, had been recognized as an increasingly prevalent subphenotype (making up 15–24% of all ARDS cases), associated with good prognosis (10% mortality in ARDSNet trials). We attempted to determine the prevalence and prognosis of rapidly improving ARDS and of persistent severe ARDS related to COVID-19. Methods We included consecutive patients with COVID-19 receiving invasive mechanical ventilation in three intensive care units (ICU) during the second pandemic wave in Greece. We defined rapidly improving ARDS as extubation or a partial pressure of arterial oxygen to fraction of inspired oxygen ratio (PaO2:FiO2) greater than 300 on the first day following intubation. We defined persistent severe ARDS as PaO2:FiO2 of equal to or less than 100 on the second day following intubation. Results A total of 280 intubated patients met cri...
Nutrients, 2022
The recent COVID-19 pandemic, which resulted from SARS CoV-2 coronavirus infection, contributed t... more The recent COVID-19 pandemic, which resulted from SARS CoV-2 coronavirus infection, contributed toa rapid increasein hospital and intensive care unit (ICU) admissions [...]
Nutrients, 2020
Although several studies have reported an association between malnutrition and the risk of severe... more Although several studies have reported an association between malnutrition and the risk of severe complications after abdominal surgery, there have been no studies evaluating the use of Global Leadership Initiative on Malnutrition (GLIM) criteria for predicting postoperative pulmonary complications (PPCs) following major abdominal surgery in cancer patients. This study aimed to investigate the association among the diagnosis of malnutrition by GLIM criteria, PPCs risk and 90-day all-cause mortality rate following major abdominal surgery in cancer patients. We prospectively analyzed 218 patients (45% male, mean age 70.6 ± 11.2 years) with gastrointestinal cancer who underwent major abdominal surgery at our hospital between October 2018 and December 2019. Patients were assessed preoperatively using GLIM criteria of malnutrition, and 90-day all-cause mortality and PPCs were recorded. In total, 70 patients (32.1%) were identified as malnourished according to GLIM criteria, of whom 41.1%...
Nutrients, 2021
There is an ongoing need for new therapeutic modalities against SARS-CoV-2 infection. Mast cell h... more There is an ongoing need for new therapeutic modalities against SARS-CoV-2 infection. Mast cell histamine has been implicated in the pathophysiology of COVID-19 as a regulator of proinflammatory, fibrotic, and thrombogenic processes. Consequently, mast cell histamine and its receptors represent promising pharmacological targets. At the same time, nutritional modulation of immune system function has been proposed and is being investigated for the prevention of COVID-19 or as an adjunctive strategy combined with conventional therapy. Several studies indicate that several immunonutrients can regulate mast cell activity to reduce the de novo synthesis and/or release of histamine and other mediators that are considered to mediate, at least in part, the complex pathophysiology present in COVID-19. This review summarizes the effects on mast cell histamine of common immunonutrients that have been investigated for use in COVID-19.
Clinical Nutrition ESPEN, 2018
Clinical Nutrition ESPEN, 2018
Background & aims: Poor nutritional intake is a common problem in patients with hematologic disea... more Background & aims: Poor nutritional intake is a common problem in patients with hematologic diseases. Recurrent infections and chemotherapy complications are some of the possible causes. Malnutrition is correlated to slow recovery, prolonged hospitalization, and higher mortality. Audits about the nutritional support of hospitalized patients may detect significant failures in patient care and help towards the correct application of the international guidelines. This study was a prospective observational audit on hospitalized patients with hematologic diseases to investigate their nutritional status and whether they received the appropriate nutritional support was performed Methods: 122 consecutive patients with hematologic diseases admitted from March 31, 2016 to June 8, 2016 in two Hematologic Units of a Tertiary University Hospital in Athens, Greece were included. A questionnaire based on the Malnutrition Universal Screening Tool (MUST) with additional questions on demographic, somatometric and medical data was completed. The questionnaire was applied by 6th-year medical students to all patients within 48 hours of admission. Patients were classified as high, intermediate, and low-risk per the MUST score and were reassessed at predefined intervals. During reassessment, food intake and the nutritional interventions (nutritional supplements, enteral or parenteral nutrition) applied were also recorded. Results: Ninety-three patients were included in the final analysis (5 refused to participate, 22 were excluded due to short-term hospitalization, 2 were absent during reassessment). Forty-one (38%) patients had a MUST score !2 (high risk) but none of them received nutritional supplements. One patient was supported with parenteral nutrition. Conclusions: Our audit revealed a lack of nutritional support of the hospitalized patients. A presentation of the results to the involved health professionals was organized the possible causes (lack of sensitization of the staff, high regimen cost, shortness of staff) were illustrated. Proposals to change the current situation were made. A re-audit was programmed and is in progress. Disclosure of interest: None declared.
Clinical nutrition ESPEN, 2018
Observational studies examining the association between body mass index (BMI) and the outcome of ... more Observational studies examining the association between body mass index (BMI) and the outcome of cardiac arrest (CA) shows controversial results. We reviewed literature for studies assessing the impact of BMI on survival and neurological outcome following CA. Eligible studies were subsequently meta-analyzed and pooled odds ratios and their corresponding 95% confidence intervals for post CA survival and neurological status were derived. A total of 7 studies with 24,651 patients were evaluable for this meta-analysis. The studies were also categorized by location of the CA and the use of therapeutic hypothermia. Our results suggested that BMI between 25 and 29.9 kgr/m had a favorable impact on survival after CA (OR = 1.172, 95% CI, 1.109-1.236) in comparison to normal weight subjects. Likewise, overweight patients presented increased odds for a favorable neurological outcome after CA (OR = 1.112, 95% CI, 1.020-1.213). On the contrary, underweight subjects presented decreased odds of su...
Clinical nutrition ESPEN, 2018
were observed. The main deviation from DIATROFI's additional requirements was the use of fats/oil... more were observed. The main deviation from DIATROFI's additional requirements was the use of fats/oils other than extra virgin/virgin olive oil (10.5% deviations). Spoilage microbes (Listeria spp. and Enterobacteriaceae strains) and mycotoxins were detected in 17 out of 108 samples. Most deviations were observed in food suppliers located in the provincial region (p ¼ 0.006), with inadequate hygiene preparation/storage practices being more prevalent (p < 0.001). A significant association was revealed between deviations from DIATROFI requirements and hygiene practice violations (r ¼ 0.955, p ¼ 0.001). The association was most evident in spoilage microbes (r ¼ 0.891, p ¼ 0.007) and mycotoxins detections (r ¼ 0.898, p ¼ 0.006). Suppliers were encouraged to increase the frequency of preventive laboratory tests and to effectively check the flow-chart diagrams. Conclusions: The procedures followed ensured both the hygiene and quality of the DIATROFI meals, potentially leading to the amelioration of hygiene practices in food suppliers' facilities and consequently to the continuous distribution of high quality products.
Clinical Nutrition, 2017
Background: The new definition of malnutrition in adults proposed recently by The European Societ... more Background: The new definition of malnutrition in adults proposed recently by The European Society for Clinical Nutrition and Metabolism (ESPEN) changed the view on the issue and raised the question of the reliability of available diagnostic tools. Therefore, the aim of this study was to verify the accuracy of the two most commonly used screening tools by comparing their findings with the new ESPEN criteria. Methods: Nutritional screening was performed in 1146 (median age 60 years, interquartile range: 44-73 years, 617 males, 529 females) patients on admission to hospitals with two nutritional screening tools: Nutritional Risk Screening 2002 (NRS2002) and Malnutrition Universal Screening Tool (MUST). The screening results were then compared to the ESPEN new diagnostic criteria for malnutrition. Results: According to the NRS2002 13.5% and 27.9% of the outpatients and hospitalized patients respectively were found to be at moderate/high risk of malnutrition. With the use of MUST 9.1% and 14.9% of the outpatients and hospitalized patients respectively were found to be at moderate/high risk of malnutrition. According to the ESPEN diagnostic criteria 6.4% and 11.3% of outpatients and hospitalized patients respectively were classified as malnourished. MUST was found to be better correlated to the latter for both outpatients (K=0.777, p<0.001) and hospitalized patients (K=0.843, p<0.001) as compared to NRS2002 (k=0.256, p<0.001 and k=0.228, p<0.001). ROC plots Area Under the Curve (AUC) was found to be higher for MUST compared to NRS2002 (0.964 vs. 0.695 for outpatients and 0.980 vs 0.686 for hospitalized patients respectively). Conclusion: To our knowledge, this study is the first to analyze the clinical value of a malnutrition screening tool in the light of the new ESPEN definition for malnutrition. According
Proceedings of the 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (Cat. No.00CH37143), 2000
This study investigates the applicability of a smart card network expected to interconnect health... more This study investigates the applicability of a smart card network expected to interconnect health care service providers. In this paper, the current development of the proposed network and its infrastructure are highlighted. The goal of this project is to benefit healthcare service providers as well as patients. A private network is being implemented to which insurance companies and healthcare service providers are connected. A central database stores electronic administrative profiles for contracted providers, as well as electronic medical records for individual insurance company customers. The smart card is used by insurance company customers as a key to the network and also as their personal portable emergency medical record.
International Journal of Healthcare Technology and Management, 2010
... Sneha, S. and Varshney, U. (2007) &amp;amp;amp;amp;amp;#x27;A wireless ECG monitoring sys... more ... Sneha, S. and Varshney, U. (2007) &amp;amp;amp;amp;amp;#x27;A wireless ECG monitoring system for pervasive healthcare&amp;amp;amp;amp;amp;#x27;, International Journal of Electronic Healthcare, Vol. ... Verma, P., Ghosh, K., Huck, C., Cheng, S., Chen, S., Martens, M. and Kaul, A. (2009) &amp;amp;amp;amp;amp;#x27;Designing a wireless sensor system for ...
Alimentary Pharmacology & Therapeutics, 2010
The lead authors (PWYC, SCN and FKLC) were appointed by APSDE to review the literature and to inv... more The lead authors (PWYC, SCN and FKLC) were appointed by APSDE to review the literature and to invite experts. and developed the position statement. The members of the writing committee were selected based on the following criteria: (1) international experts of digestive endoscopy in Asia; (2)
2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2001
In this study we present a multipurpose health care telemedicine system, which can be used for em... more In this study we present a multipurpose health care telemedicine system, which can be used for emergency or patient monitoring cases. Ambulances, Rural Health Centers (RHC) or other remote health location, Ships navigating in wide seas and Airplanes in flight are common examples of possible emergency sites, while critical care telemetry and telemedicine home followups are important issues of patient monitoring. The telemedicine system is a combined real-time and store and forward facility that consists of a base unit and a telemedicine (mobile) unit. The telemedicine unit (patient site) allows the transmission of vital biosignals (3-12 lead ECG, SPO2, NIBP, IBP, Temp) and still images of the patient from the incident place to the base unit (consultation site). The transmission is performed through GSM, Satellite links or POTS. Using this device a specialist doctor can telematically "move" to the patient site and instruct medical personnel when handling a patient. The consultation site is equipped with a multimedia database able to store and manage the data collected by the system. The system was validated in four different countries using a standardized medical protocol.
Η απώλεια βάρους μετά απο λαπαροσκοπική τοποθέτηση δακτυλίου (LAGB-laparoscopic adjustable gastri... more Η απώλεια βάρους μετά απο λαπαροσκοπική τοποθέτηση δακτυλίου (LAGB-laparoscopic adjustable gastric banding) εξαρτάται απο πολλές παραμέτρους. Το σύνηθες πρωτόκολλο που υιοθετείται απο τους περισσότερους χειρουργούς είναι η σταδιακή αύξηση του βαθμού περιορισμού που επιτρέπει στον ασθενή να καταναλώνει περίπου το 1/3 της προ-εγχειρητικής ποσότητας. Ο σκοπός της εργασίας είναι να αναγνωρίσει παράγοντες που σχετίζονται με την αποτελεσματικότητα της μεθόδου. Demographics Υλικό Συνολικά 79 ασθενείς υπεβλήθησαν σε Γαστρικό Δακτύλιο κατα τη διάρκεια του 2006. Ο μέσος όρος ηλικίας ήταν 36,3 έτη (διακύμανση 16-63 έτη). Η πλειοψηφία ήταν γυναίκες (49), ενώ οι άντρες ήταν 30. Η πολυδύναμη ομάδα παρακολούθησης των ασθενώς αποτελείται απο το χειρουργό, γαστρεντερολόγο, σύμβουλο υγείας και κλινικό διατροφολόγο. Emotional & Cognitive Factors Culture Eating Behaviour Sosioeconomic Factors Family Nutritional Habbits Coping Strategies Biological Factors Genetics Αποτελέσματα Σχεδιάγραμμα 2: Σχεδιάγραμμα 2: Το σχεδιάγραμμα 2 Το σχεδιάγραμμα 2 δείχνει τις ομάδες. Η ομάδα Α είχε δείχνει τις ομάδες. Η ομάδα Α είχε περισσότερες απο 3 συναντήσεις με την περισσότερες απο 3 συναντήσεις με την πολυδύναμη ομάδα κατα το 2006, η ομάδα πολυδύναμη ομάδα κατα το 2006, η ομάδα Β είχε 3 συναντήσεις και η ομάδα Γ: 0-2 Β είχε 3 συναντήσεις και η ομάδα Γ: 0-2 συναντήσεις. συναντήσεις.
Objective:
To describe the management of gastro-oesophageal reflux disease (GERD) in primary care... more Objective:
To describe the management of gastro-oesophageal reflux disease (GERD) in primary care, as part of the
RANGE (Retrospective ANalysis of GERD) study.
Methods:
Over 4 months, at 134 primary care practices in six European countries, 12 815 patients consulted for
GERD-related reasons. A random selection of these patients was invited to enter the study. Data were then
collected retrospectively (from the initial consultation) and prospectively (from a follow-up visit). This
included information on GERD diagnosis, symptoms and complications, medication use and healthcare
resource utilisation.
Results:
Of 12 815 patients who underwent consultation for GERD-related reasons, 2678 were randomly selected
and accepted the invitation to participate in the study. Across countries, 28–47% of patients reported a
significant GERD symptom load at initial consultation. Thereafter, 30–100% of patients were prescribed a
proton pump inhibitor (PPI), but a significant GERD symptom load was still experienced by 15–30%
(all patients combined) at follow-up (median 5.0–7.5 months after initial consultation). In the majority of
patients (65–88%), no diagnostic procedures were performed between initial consultation and follow-up.
During the follow-up period, the most common form of healthcare utilisation comprised additional GERDrelated
consultations with a physician.
Conclusions:
The findings of this pan-European study indicate that current management of primary care patients with
GERD is far from optimal, and accounts for a marked burden on patients and healthcare systems alike. A
more structured approach to GERD management, by tailoring treatment according to the impact of the
disease, may reduce this burden.
STUDY OBJECTIVE:
to investigate whether an encircling procedure without ventriculotomy, not invo... more STUDY OBJECTIVE:
to investigate whether an encircling procedure without ventriculotomy, not involving the endocardium, may have a protective effect against ventricular fibrillation (VF), by achieving a physiological rather than anatomic entrenchment.
DESIGN:
the occurrence of VF was tested by DC application within an area entrenched by a circular "dotted" line formed by LASER (Nd-Yag) point by point applications. The result was compared with that from similar DC applications before the successful LASER entrenchment or beyond the restricted area.
SUBJECTS:
16 anaesthetized mongrel dogs, weights 14-20 kg were used.
MEASUREMENTS AND RESULTS:
VF occurred 13/118 times by applying DC within the entrenched area and 86/114 times by applying the current outside this area or before the intervention (P less than 0.0005). The pacing threshold was significantly (P less than 0.001) increased within the circumscribed area (4.625 +/- 5.335 vs 0.859 +/- 0.947 mA). The maximal rate at which the ventricles could be driven by pacing at double threshold intensity was not significantly altered by the encircling procedure. Histological examination showed crater-like epicardial destruction with necrosis, loss of myocardial striation, haemorrhage, and polymorphonuclear infiltration, extending about 0.5 cm from the necrotic tissue. The subendocardial area was spared showing only hyperaemia, while the endocardium was intact.
CONCLUSIONS:
Encircling a small area by LASER point by point applications prevents the occurrence of VF when DC is applied within the restricted area, while permitting the conduction of paced beats. The size of the encircled area necessary to this effect is of importance, possibly reflecting the critical mass needed for the occurrence and maintenance of VF.
European Journal of Clinical Nutrition, 2003
The aim of the present study, which was part of the Health Behavior in School Aged Children (HBSC... more The aim of the present study, which was part of the Health Behavior in School Aged Children (HBSC) study, was to provide national estimates for overweight and obesity in Greek school-aged children and adolescents. A nationwide multistage procedure was followed to obtain a representative sample of children and adolescents aged 11.5, 13.5 and 15.5 y. The resultant sample consisted of 4299 students, 51.3% girls and 48.7% boys. Self-reported weight and height data were used. According to the body mass index cutoff points adopted by the International Obesity Task Force (IOTF), 9.1% of girls and 21.7% of boys were classified as overweight, and 1.2% of girls and 2.5% of boys as obese. Corresponding values using CDC growth charts were 8.1% of girls and 18.8% of boys for overweight, and 1.7% of girls and 5.8% of boys for obese. Compared to most other western countries, the prevalence of obesity is lower in Greek children aged 11-16 y.
European Journal of Clinical Nutrition, 2004
Objective: To investigate nutrition-related habits of Greek school-aged adolescents. Design: Epid... more Objective: To investigate nutrition-related habits of Greek school-aged adolescents. Design: Epidemiological survey. Setting and subjects: The study was part of the Health Behavior in School Aged Children (HBSC) survey. A representative sample of school-aged adolescents aged 11.5, 13.5, and 15.5 y was obtained. The final sample consisted of 4211 students (51.6% girls and 48.4% boys). They were asked to complete a translated form of the international HBSC questionnaire, including several thematic entities. The Unhealthy Food Choices Score (UFCS) was devised in order to evaluate the overall quality of reported eating habits of respondents; the higher the score, the lower the diet quality. Results: Among all students surveyed, 14.7% were reported to be on a diet to lose weight (girls: 19.5%; boys: 9.7%; Po0.001), and 22.9% were dissatisfied with their body weight but not on a diet. Girls were found to have lower UFCS values compared to boys (24.774.6 vs 24.174.5, Po0.001). Girls dissatisfied with their weight, but not on a diet, showed the highest UFCS values compared to both those on a diet and those not on a diet. TV viewing was positively associated with the consumption of sodas, crisps, cakes and pastries, and sweets and chocolates. Conclusions: Dieting is becoming a major problem, especially among older girls. The findings of this study suggest that eating habits of Greek school-aged adolescents are in the process of changing from more traditional to more Westernized ones.
In this study we present a multipurpose health care telemedicine system, which can be used for em... more In this study we present a multipurpose health care telemedicine system, which can be used for emergency or patient monitoring cases. Ambulances, Rural Health Centers (RHC) or other remote health location, Ships navigating in wide seas and Airplanes in flight are common examples of possible emergency sites, while critical care telemetry and telemedicine home followups are important issues of patient monitoring. The telemedicine system is a combined real-time and store and forward facility that consists of a base unit and a telemedicine (mobile) unit. The telemedicine unit (patient site) allows the transmission of vital biosignals (3-12 lead ECG, SPO2, NIBP, IBP, Temp) and still images of the patient from the incident place to the base unit (consultation site). The transmission is performed through GSM, Satellite links or POTS. Using this device a specialist doctor can telematically "move" to the patient site and instruct medical personnel when handling a patient. The consultation site is equipped with a multimedia database able to store and manage the data collected by the system. The system was validated in four different countries using a standardized medical protocol.
Uploads
Papers by Dimitrios Karayiannis
To describe the management of gastro-oesophageal reflux disease (GERD) in primary care, as part of the
RANGE (Retrospective ANalysis of GERD) study.
Methods:
Over 4 months, at 134 primary care practices in six European countries, 12 815 patients consulted for
GERD-related reasons. A random selection of these patients was invited to enter the study. Data were then
collected retrospectively (from the initial consultation) and prospectively (from a follow-up visit). This
included information on GERD diagnosis, symptoms and complications, medication use and healthcare
resource utilisation.
Results:
Of 12 815 patients who underwent consultation for GERD-related reasons, 2678 were randomly selected
and accepted the invitation to participate in the study. Across countries, 28–47% of patients reported a
significant GERD symptom load at initial consultation. Thereafter, 30–100% of patients were prescribed a
proton pump inhibitor (PPI), but a significant GERD symptom load was still experienced by 15–30%
(all patients combined) at follow-up (median 5.0–7.5 months after initial consultation). In the majority of
patients (65–88%), no diagnostic procedures were performed between initial consultation and follow-up.
During the follow-up period, the most common form of healthcare utilisation comprised additional GERDrelated
consultations with a physician.
Conclusions:
The findings of this pan-European study indicate that current management of primary care patients with
GERD is far from optimal, and accounts for a marked burden on patients and healthcare systems alike. A
more structured approach to GERD management, by tailoring treatment according to the impact of the
disease, may reduce this burden.
to investigate whether an encircling procedure without ventriculotomy, not involving the endocardium, may have a protective effect against ventricular fibrillation (VF), by achieving a physiological rather than anatomic entrenchment.
DESIGN:
the occurrence of VF was tested by DC application within an area entrenched by a circular "dotted" line formed by LASER (Nd-Yag) point by point applications. The result was compared with that from similar DC applications before the successful LASER entrenchment or beyond the restricted area.
SUBJECTS:
16 anaesthetized mongrel dogs, weights 14-20 kg were used.
MEASUREMENTS AND RESULTS:
VF occurred 13/118 times by applying DC within the entrenched area and 86/114 times by applying the current outside this area or before the intervention (P less than 0.0005). The pacing threshold was significantly (P less than 0.001) increased within the circumscribed area (4.625 +/- 5.335 vs 0.859 +/- 0.947 mA). The maximal rate at which the ventricles could be driven by pacing at double threshold intensity was not significantly altered by the encircling procedure. Histological examination showed crater-like epicardial destruction with necrosis, loss of myocardial striation, haemorrhage, and polymorphonuclear infiltration, extending about 0.5 cm from the necrotic tissue. The subendocardial area was spared showing only hyperaemia, while the endocardium was intact.
CONCLUSIONS:
Encircling a small area by LASER point by point applications prevents the occurrence of VF when DC is applied within the restricted area, while permitting the conduction of paced beats. The size of the encircled area necessary to this effect is of importance, possibly reflecting the critical mass needed for the occurrence and maintenance of VF.
To describe the management of gastro-oesophageal reflux disease (GERD) in primary care, as part of the
RANGE (Retrospective ANalysis of GERD) study.
Methods:
Over 4 months, at 134 primary care practices in six European countries, 12 815 patients consulted for
GERD-related reasons. A random selection of these patients was invited to enter the study. Data were then
collected retrospectively (from the initial consultation) and prospectively (from a follow-up visit). This
included information on GERD diagnosis, symptoms and complications, medication use and healthcare
resource utilisation.
Results:
Of 12 815 patients who underwent consultation for GERD-related reasons, 2678 were randomly selected
and accepted the invitation to participate in the study. Across countries, 28–47% of patients reported a
significant GERD symptom load at initial consultation. Thereafter, 30–100% of patients were prescribed a
proton pump inhibitor (PPI), but a significant GERD symptom load was still experienced by 15–30%
(all patients combined) at follow-up (median 5.0–7.5 months after initial consultation). In the majority of
patients (65–88%), no diagnostic procedures were performed between initial consultation and follow-up.
During the follow-up period, the most common form of healthcare utilisation comprised additional GERDrelated
consultations with a physician.
Conclusions:
The findings of this pan-European study indicate that current management of primary care patients with
GERD is far from optimal, and accounts for a marked burden on patients and healthcare systems alike. A
more structured approach to GERD management, by tailoring treatment according to the impact of the
disease, may reduce this burden.
to investigate whether an encircling procedure without ventriculotomy, not involving the endocardium, may have a protective effect against ventricular fibrillation (VF), by achieving a physiological rather than anatomic entrenchment.
DESIGN:
the occurrence of VF was tested by DC application within an area entrenched by a circular "dotted" line formed by LASER (Nd-Yag) point by point applications. The result was compared with that from similar DC applications before the successful LASER entrenchment or beyond the restricted area.
SUBJECTS:
16 anaesthetized mongrel dogs, weights 14-20 kg were used.
MEASUREMENTS AND RESULTS:
VF occurred 13/118 times by applying DC within the entrenched area and 86/114 times by applying the current outside this area or before the intervention (P less than 0.0005). The pacing threshold was significantly (P less than 0.001) increased within the circumscribed area (4.625 +/- 5.335 vs 0.859 +/- 0.947 mA). The maximal rate at which the ventricles could be driven by pacing at double threshold intensity was not significantly altered by the encircling procedure. Histological examination showed crater-like epicardial destruction with necrosis, loss of myocardial striation, haemorrhage, and polymorphonuclear infiltration, extending about 0.5 cm from the necrotic tissue. The subendocardial area was spared showing only hyperaemia, while the endocardium was intact.
CONCLUSIONS:
Encircling a small area by LASER point by point applications prevents the occurrence of VF when DC is applied within the restricted area, while permitting the conduction of paced beats. The size of the encircled area necessary to this effect is of importance, possibly reflecting the critical mass needed for the occurrence and maintenance of VF.