Patient selection for cardiac resynchronization therapy: from the Council on Clinical Cardiology Subcommittee on Electrocardiography and Arrhythmias and the Quality of Care and Outcomes Research Interdisciplinary Working Group, in collaboration with the Heart Rhythm Society

Cardiac resynchronization therapy (CRT) is a relatively new therapy for patients with symptomatic heart failure resulting from systolic dysfunction. CRT is achieved by simultaneously pacing both the left and right ventricles. Biventricular pacing resynchronizes the timing of global left ventricular depolarization and improves mechanical contractility and mitral regurgitation. Published clinical trials have demonstrated that CRT results in improved clinical status and lower mortality rate when selected patients with systolic ventricular dysfunction and heart failure are treated with CRT. This advisory identifies appropriate candidates for CRT on the basis of the inclusion criteria and results from the published clinical trials.     

Incidence of complete atrioventricular block following attempted radiofrequency catheter modification of the atrioventricular node in 880 patients: Results of the Multicenter European Radiofrequency Survey (MERFS)

The Multicenter European Radiofrequency Survey (MERFS) retrospectivelyanalysed the incidence of procedurerelated complications in4463 patients who had undergone radiofrequency catheter ablationin 69 European institutions between 1987 and 1992. Of these4463 patients, 880 underwent modification of the atrioventricularnode to cure atrioventricular nodal reentrant tachycardia. Thisreport presents a detailed analysis of the incidence of completeatrioventricular block with respect to the target site and thenumber of patients reported per institution. The most common complication of modification of the atrioventricularnode was the unintended induction of complete atrioventricularblock (41 of 880 patients, 4.7%). In 684 of 880 patients (78%),detailed information about the approached target site for modificationof the atrioventricular node was available. Complete atrioventricularblock occurred significantly more often in patients who underwent ablation of the fast pathway (19/361, 5 3%)or in whom ablationof the slow and fast pathway was attempted after failure atthe initial site (4/25, 16%) than in patients who underwentslow pathway ablation (6/298, 20%, P<0.05). The overall incidenceof complete atrioventricular block was significantly higher(6.3%) in centres with limited experience in radiofrequencymodification of the atrioventricular node (30 patients treated;group I: n=526) compared to centres that had treated >30patients (group TI: n=354; 2.3% P<0.05). In addition, inthose patients in whom the target site was available, the incidenceof complete atrioventricular block after fast pathway ablationwas significantly higher in group I (n= 168 patients) when comparedto group II (n=193 patients) (7.7% vs 3.1%, P<0.05) and alsotended to be higher after slow pathway ablation in group I(2.4%in group I vs 1.5% in group II; P=ns) CONCLUSIONS: In this analysis of collaborative data, radiofrequency cathetermodification of the atrioventricular node carried a risk ofapproximately 5% of complete atrioventricular block. The incidenceof complete atrioventricular block was significantly higherin patients who underwent fast pathway ablation or fast andslow pathway ablation after failure at the initial site comparedwith slow pathway ablation. In addition, the results indicatethat there is a learning curve, regarding the incidence of completeatrioventricular block, which is a significant complicationof the procedure, when modifying the atrioventricular node.Thus, caution is recommended when performing radiofrequencymodification of the atrioventricular node using the so-calledanterior approach to abolish fast pathway conduction, especiallywhen the experience of the institution or investigator/s islimited. (Eur Heart J 1996; 17: 82–88)     

Spanish Registry on Catheter Ablation. Second official report of the Working Group on Electrophysiology and Arrhythmias of the Spanish Society of Cardiology (2002)

INTRODUCTION AND OBJECTIVES: We present the results (success rates and complication rates) for the second consecutive year of the 2002-Spanish Catheter Ablation Registry, developed by the Spanish Society of Cardiology. MATERIAL AND METHOD: Data were collected retrospectively by questionnaires sent to all interventional cardiology laboratories in Spain. The outcomes and complications of ablation procedures performed during 2002 were classified according to the substrate or mechanism of arrhythmia treated. RESULTS: Forty-three centers voluntarily submitted completed questionnaires. The number of procedures analyzed was 4970, performed at 42 centers, for a mean of 118 78 procedures per center. Global outcome rates were success in 93%, major complications in 1.2%, and death in 0.04% of the patients. The three main substrates treated were AV nodal reentry (29%), accessory pathways (28%) and common atrial flutter (24%). CONCLUSIONS: The 2002 Spanish National Catheter Ablation Registry reports the activity of the majority (90%) of interventional cardiology laboratories in Spain. The efficacy of catheter ablation procedures in Spain is high, and the complication and mortality rates are low.     

The Influence of Gender on Heart Rhythm Disease

This paper deals with cardiac arrhythmias, focusing on differences between genders. We sought to examine the potential effect of gonadal hormones on heart rhythm disorders, and sex‐related differences in incidence and clinical course of arrhythmias—differences that may require specific approaches to detection and management of heart rhythm disease.     

Spanish Registry of Catheter Ablation. Third Official Report of the Working Group on Electrophysiology and Arrhythmias of the Spanish Society of Cardiology (2003)

INTRODUCTION: The results of the Third Spanish Catheter Ablation Registry, developed by the Working Group on Electrophysiology and Arrhythmias, are presented for the third consecutive year (2003). MATERIAL AND METHOD: In contrast to previous years, data were collected in two different ways at the discretion of the participating center. Retrospective were obtained with a standard questionnaire, as in previous years. Prospective data were obtained from a database of records completed after each ablation was performed. Results and complications are presented according to different arrhythmic substrates. RESULTS: Thirty-nine centers participated in the registry (25 supplied prospective data and 14 retrospective data), representing more than 80% of all electrophysiological laboratories in Spain. A total number of 4354 ablations were recorded (111 procedures per center, 2723 from the prospective registry and 1631 from the retrospective one). The substrate most frequently treated was AV nodal reentry tachycardia (31.6%, 98% success), followed by accessory pathways (26%, 89% success) and atrial macro-reentry tachycardia (23%, 90% success). The incidence of complications was 1.7% and mortality was 0.11%. With the prospective registry we obtained more comprehensive information individualized for each procedure (age, sex, underlying cardiomyopathy, anticoagulation, sedation, type of catheter, etc.). CONCLUSIONS: The high rate of participation in the registry and the consistency of the results with previous years help to consolidate the registry as a reference for the rest of the scientific community. The results from the prospective registry showed better-quality information and more detailed reporting of results and complications.