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C Anwar A Chahal, Omer Ali, Ross J Hunter, Richard J SchillingDepartment of Cardiology Research, St Bartholomew's Hospital, London, United KingdomAbstract: Atrial fibrillation (AF) is a substantial cause of mortality and morbidity in the Western world. It is a massive burden on health care systems, and its prevalence is expected to double over the next 20 years. Trials evaluating antiarrhythmic drugs or catheter ablation have focused on recurrence of arrhythmia, perhaps neglecting outcomes relevant to patients, such as symptoms, need for antiarrhythmic drugs, need for hospitalization, and rates of stroke and death. An association has been demonstrated between sinus rhythm and survival in several studies, and there is evidence emerging that successful catheter ablation may reduce rates of stroke and death. Similarly, dronedarone has been shown to reduce hospitalizations and death in patients with paroxysmal AF or persistent AF of recent onset, although it may cause adverse events in permanent AF. New antiarrhythmic drugs are a welcome addition to the armamentarium, since there are limitations to current antiarrhythmic drugs. In particular, sotalol, flecainide, and propafenone cannot be used safely in those with structural heart disease, and amiodarone has important adverse reactions that limit long-term use. Indeed, the use of conventional antiarrhythmic drugs may negate any survival benefit derived from maintaining sinus rhythm. Although dronedarone appears promising with respect to hard endpoints such as stroke and death in certain patients, it may not be safe for those with heart failure or those with permanent AF. Furthermore, the trials suggesting that dronedarone may impact on these endpoints were compared with placebo rather than with an active comparator group. Further "head-to-head" comparisons between dronedarone and other antiarrhythmic drugs are needed to determine whether this property is unique to dronedarone alone.Keywords: atrial fibrillation, rhythm, antiarrhythmics, ablation, stroke, dronedarone

Objective To investigate whether catheter ablation of atrial fibrillation (AF) reduces stroke rate or mortality. Methods An international multicentre registry was compiled from seven centres in the UK and Australia for consecutive patients undergoing catheter ablation of AF. Long-term outcomes were compared with (1) a cohort with AF treated medically in the Euro Heart Survey, and (2) a hypothetical cohort without AF, age and gender matched to the general population. Analysis of stroke and death was carried out after the first procedure (including peri-procedural events) regardless of success, on an intention-to-treat basis. Results 1273 patients, aged 58±11 years, 56% paroxysmal AF, CHADS(2) score 0.7±0.9, underwent 1.8±0.9 procedures. Major complications occurred in 5.4% of procedures, including stroke/TIA in 0.7%. Freedom from AF following the last procedure was 85% (76% off antiarrhythmic drugs) for paroxysmal AF, and 72% (60% off antiarrhythmic drugs) for persistent AF. During 3.1 (1.0-9.6) years from the first procedure, freedom from AF predicted stroke-free survival on multivariate analysis (HR=0.30, CI 0.16 to 0.55, p<0.001). Rates of stroke and death were significantly lower in this cohort (both 0.5% per patient-year) compared with those treated medically in the Euro Heart Survey (2.8% and 5.3%, respectively; p<0.0001). Rates of stroke and death were no different from those of the general population (0.4% and 1.0%, respectively). Conclusion Restoration of sinus rhythm by catheter ablation of AF is associated with lower rates of stroke and death compared with patients treated medically. [ABSTRACT FROM AUTHOR]

We reviewed outcomes in our primary prevention implantable cardioverter defibrillator ( ICD) population according to whether the device was programmed with a single ventricular fibrillation (VF) zone or with two zones including a ventricular tachycardia (VT) zone in addition to a VF zone. This retrospective study examined 137 patients with primary prevention ICDs implanted at our institution between 2004 and 2006. Device programming and events during follow-up were reviewed. Outcomes included all-cause mortality, time to first shock, and incidence of shocks. Eighty-seven ICDs were programmed with a single VF zone (mean >193 ± 1 beats per minute [bpm]) comprising shocks only. Fifty ICDs had two zones (mean VT zone >171 ± 2 bpm; VF zone >205 ± 2 bpm), comprising antitachycardia pacing (100%), shocks (96%), and supraventricular (SVT) discriminators (98%) . Discriminator 'time out' functions were disabled. Mean follow-up was 30 ± 0.5 months and similar in both groups. All-cause mortality (12.6% and 12.0%) and time to first shock were similar. However, the two-zone group received more shocks (32.0% vs 13.8% P = 0.01). Five of 16 shocks in these patients were inappropriate for SVT rhythms. The single-zone group had no inappropriate shocks for SVTs. Eighteen of 21 appropriate shocks were for ventricular arrhythmias at rates >200 bpm (three VF, 15 VT). This suggests that primary prevention ICD patients infrequently suffer ventricular arrhythmias at rates <200 bpm and that ATP may play a role in terminating rapid VTs. Patients with two-zone devices received more shocks without any mortality benefit. (PACE 2010; 1353-1358) [ABSTRACT FROM AUTHOR]

OBJECTIVE: To see if strategy of ablating the tricuspid annulus-inferior vena cava isthmus (TV-IVC) is superior to electrical cardioversion to prevent recurrences in patients with coarse atrial fibrillation. DESIGN: Prospective randomised controlled multicentre study. SETTING: Four tertiary referral hospitals in the UK. PATIENTS: 57 patients with persistent coarse atrial fibrillation (irregular P waves > or =0.15 mV in > or =1 ECG lead). INTERVENTIONS: Patients were randomised to receive external cardioversion (group A, n = 30) or TV-IVC ablation +/- DC cardioversion (group B, n = 27). MAIN OUTCOME MEASURES: Cardiac rhythm, scores on quality of life and symptom questionnaires were assessed at 4, 16 and 52 weeks after the procedure. RESULTS: 20 (67%) patients in group A and 19 (70%) patients in group B were in sinus rhythm immediately after their index procedure. At 4, 16 and 52 weeks, the number of patients in sinus rhythm were 5, 3 and 2 in group A and 3, 3 and 1 in group B (p = NS). The quality of life and symptom questionnaire scores were similar in the two groups at each period of follow-up, although they were significantly better for sinus rhythm than for atrial fibrillation at each follow-up visit. CONCLUSIONS: As a first-line strategy, TV-IVC ablation offers no advantages over direct current cardioversion for the management of coarse atrial fibrillation. [ABSTRACT FROM AUTHOR]

Cure of typical atrial flutter (AFL) by catheter ablation to produce bidirectional block across the tricuspid annulus-inferior vena cava isthmus (IS) is highly effective, but failures may occur. We describe a technique that may allow creation of bidirectional block where a conventional strategy has failed. AFL ablation was performed using the conventional approach with a mapping/ablation (ablation) catheter introduced via the right femoral vein (RFV) to create a line of bidirectional block across the IS. If this was not achieved after five passes of the ablation catheter from the tricuspid annulus to the inferior vena cava (IVC) a catheter inversion technique was used. This allowed stable positioning of the ablation catheter at the IVC end of the isthmus. In 11 patients, a mean of 17 (range 3 to 45) radiofrequency (RF) applications was given before the catheter inversion technique was applied. Following catheter inversion a mean of 4 (1 to 14) further RF applications achieved bidirectional isthmus block in every patient. No complications occurred. Catheter inversion provides a simple, safe, and effective means of achieving bidirectional isthmus conduction block in cases where a conventional ablation strategy might have failed. [ABSTRACT FROM AUTHOR]