2014 focused update of the Canadian Cardiovascular Society Guidelines for the management of atrial fibrillation.

Background— There is a lack of data on the comparative efficacy and procedural safety of open irrigated radiofrequency (RF) and cryoballoon catheter (CB) ablation for pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

Methods and Results— In a prospective, noninferiority study, 315 patients were randomly assigned to RF (n=159) or CB (n=156) ablation. The primary end point was freedom from atrial arrhythmia with absence of persistent complications. Patients were largely comparable between groups with more vascular disease in the RF group (8.2% versus 2.6% for CB; P =0.028). The primary end point at 12 months was achieved by 70.7% with RF and 73.6% with CB (multiple procedure success), including 31 redo procedures in each group (19.5% of RF versus 19.9% of CB; P =0.933). For the intention-to-treat population, noninferiority of CB was revealed for the predefined inferiority margin (risk difference, 0.029; 95% confidence interval, −0.074 to 0.132; P <0.001). Rates at 6 months were 63.1% and 64.1% for the RF and CB groups (single procedure success), and noninferiority was confirmed (risk difference, 0.010; 95% confidence interval, −0.097 to 0.116; P =0.002). Periprocedural complications for the index procedure were more frequent in the CB group (5.0% RF, 12.2% CB; P =0.022) with a significant difference in phrenic nerve palsies (0% RF, 5.8% CB; P =0.002).

Conclusion— This large, prospective, randomized, controlled study demonstrates noninferiority of CB ablation versus RF ablation for treating patients with paroxysmal atrial fibrillation.

Clinical Trial Registration— URL: . Unique identifier: [NCT00774566][1].

# CLINICAL PERSPECTIVE {#article-title-36}

 [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00774566&atom=%2Fcirculationaha%2F132%2F14%2F1311.atom

Cryoballoon Versus Open Irrigated Radiofrequency Ablation in Patients With Paroxysmal Atrial Fibrillation: The Prospective, Randomized, Controlled, Noninferiority FreezeAF Study

Background— The use of second-generation cryoballoon for pulmonary vein isolation in patients with paroxysmal atrial fibrillation has demonstrated encouraging acute and mid-term results. Long-term outcome data are not yet available.

Methods and Results— Fifty patients (18 women; mean age, 61±11 years; mean left atrial diameter, 43±5 mm) with paroxysmal (36 of 50 patients; 72%) or short-standing ( 30 seconds excluding a 3-month blanking period. A total of 192 pulmonary veins were identified, and 191 of 192 (99%) pulmonary veins were successfully isolated. Phrenic nerve palsy occurred in 1 of 50 (2%) patients. Follow-up was available for 49 of 50 (98%) patients with a mean follow-up duration of 440±39 days. Thirty-nine of 49 (80%) patients remained in stable sinus rhythm. Of 8 of 10 patients with arrhythmia recurrence, a second procedure using radiofrequency ablation demonstrated left atrial to pulmonary vein reconduction.

Conclusions— The use of second-generation 28-mm cryoballoon for pulmonary vein isolation results in an 80% 1-year success rate.

One-year clinical outcome after pulmonary vein isolation using the second-generation 28-mm cryoballoon.

https://www.heartrhythmjournal.com/article/S1547-5271(14)01544-6/pdf

Single 3-minute freeze for second-generation cryoballoon ablation: One-year follow-up after pulmonary vein isolation

Background— Catheter ablation of atrial fibrillation (AFCA) is an established therapeutic option for rhythm control in symptomatic patients. Its efficacy and safety among patients with left ventricular systolic dysfunction is based on small populations, and data concerning long-term outcome are limited. We performed this meta-analysis to assess safety and long-term outcome of AFCA in patients with left ventricular systolic dysfunction, to evaluate predictors of recurrence and impact on left ventricular function.

Methods and Results— A systematic review was conducted in MEDLINE/PubMed and Cochrane Library. Randomized controlled trials, clinical trials, and observational studies including patients with left ventricular systolic dysfunction undergoing AFCA were included. Twenty-six studies were selected, including 1838 patients. Mean follow-up was 23 (95% confidence interval, 18–40) months. Overall complication rate was 4.2% (3.6%–4.8%). Efficacy in maintaining sinus rhythm at follow-up end was 60% (54%–67%). Meta-regression analysis revealed that time since first atrial fibrillation ( P =0.030) and heart failure ( P =0.045) diagnosis related to higher, whereas absence of known structural heart disease ( P =0.003) to lower incidence of atrial fibrillation recurrences. Left ventricular ejection fraction improved significantly during follow-up by 13% ( P <0.001), with a significant reduction of patients presenting an ejection fraction <35% ( P <0.001). N-terminal pro-brain natriuretic peptide blood levels decreased by 620 pg/mL ( P <0.001).

Conclusions— AFCA efficacy in patients with impaired left ventricular systolic function improves when performed early in the natural history of atrial fibrillation and heart failure. AFCA provides long-term benefits on left ventricular function, significantly reducing the number of patients with severely impaired systolic function.

/pdf/catheter-ablation-of-atrial-fibrillation-in-patients-with-goo5ms11yd.pdf

Catheter ablation of atrial fibrillation in patients with left ventricular systolic dysfunction: a systematic review and meta-analysis.

Long-term outcomes after cryoballoon pulmonary vein isolation: results from a prospective study in 605 patients.

Aims Dual coil (DC) electrodes are preferred to single coil (SC) electrodes because of an assumed higher shock efficacy. However, DC-electrodes may be associated with an increased difficulty and risk of lead extraction. We aimed to compare SC- and DC-electrodes with respect to the first shock efficacy (FSE) after implantable cardioverter defibrillator (ICD) implantation. Methods and results One thousand and seventy-seven patients of the NORDIC ICD trial were randomly assigned to first time ICD implantation with or without defibrillation (DF) testing. The electrode configuration was determined before randomization. One thousand and sixty-seven patients eventually received an ICD, 516 (48.4%) with a SC- and 551 (51.6%) with a DC-electrode. DC-electrodes were preferentially selected in older patients, renal failure, atrial fibrillation, dual chamber, Cardiac Resynchronization Therapy (CRT) devices, angiotensin-converting-enzyme (ACE) inhibitors/angiotensin (AT) receptor blockers and without Sotalol. However, the preference of the investigational site was dominant over clinical parameters. The DF energy at the final electrode position was higher in SC-electrodes (adjusted difference +1.15 J; P = 0.005; only patients tested). Less patients with DC-electrodes required intra-operative system reconfiguration (adjusted difference -3.9; P = 0.046; only patients tested). Using mixed logistic regression, the FSE was 92.6% in SC- and 97.8% in DC-electrodes (adjusted odds ratio 4.3 (95% confidence interval [1.9, 9.8]; P < 0.001)). Conclusion Dual coil-electrode selection mainly depends on the preference of the investigational site and seems to be preferred in older patients, renal failure, atrial fibrillation, dual chamber, and CRT devices. Patients with DC-electrodes required less intraoperative system reconfigurations. Dual coil-electrodes provided a substantially higher FSE during follow-up. Mortality rates were not significantly different in patients with DC- and SC-electrodes. (Less)

Shock efficacy of single and dual coil electrodes-new insights from the NORDIC ICD Trial.

Robots have gained their place in almost all areas of our daily life. Robotic systems have been introduced for ablation therapies associated with the hope of automation of procedures, increase in precision of lesion placement, improved energy transmission to the tissue and reduction in radiation exposure of the patients and the interventionalist. Finally, they may be associated with higher comfort for the operator by transferring his work into the control room and thereby supersede wearing sterile and radiation protective clothing. Systems providing a remote mechanical replacement of the operators´ hands have been introduced as well as systems guiding the catheter tip by external magnets. Guiding of the catheter tip has major impact on contact to the tissue and thereby modifies energy transmission. This may be advantageous in terms of higher catheter stability and modification of contact towards a more constant than intermittent type of contact. However, increasing contact bears the risk of mechanical perforation and excessive energy delivery. Many clinical studies have been conducted evaluating novel remotely guiding techniques in atrial fibrillation ablation procedures. Although only a few of them are prospectively randomized, reduction in fluoroscopy exposure has been found in most of the trials. Data on outcome is less uniform. It seems that remote navigation does not improve outcomes and on the other hand does not increase complication rates. However, large prospectively randomized trials conducted by operators well skilled not only in manual but also in remote techniques would be needed to compare outcomes particularly in terms of decrease in complication rates. Finally, the type of navigation chosen actually is and probably will remain a question of personal preference.

Klaus Jürgen Gutleben

Papers

Long-term outcomes after cryoballoon pulmonary vein isolation: results from a prospective study in 605 patients.

Shock efficacy of single and dual coil electrodes-new insights from the NORDIC ICD Trial.

Differences In Tissue Injury and Ablation Outcomes In Atrial Fibrillation Patients - Manual versus Robotic Catheters.