Abstract & Commentary
Is Catheter Ablation Superior to Antiarrhythmic Drugs in Treating Premature Ventricular Contractions?
By Edward P. Gerstenfeld, MD
Professor of Medicine, Chief, Cardiac Electrophysiology, University of California, San Francisco
Source: Zhong L, et al. Relative efficacy of catheter ablation vs antiarrhythmic drugs in treating premature ventricular contractions: A single-center retrospective study. Heart Rhythm 2014;11:187-193.
Frequent premature ventricular contractions (PVCs) may lead to a cardiomyopathy or worsen a pre-existing cardiomyopathy. Beta-blockers and antiarrhythmic drugs (AADs) have been considered first-line treatment for PVCs; however, catheter ablation has emerged as a reasonable alternative. This study sought to compare radiofrequency catheter ablation (RFCA) and AADs as first-line therapy for treating patients with frequent PVCs. This was a retrospective study from the Mayo Clinic. Patients with frequent PVCs (> 1000/24 hours) on Holter monitor between January 2005 and December 2010 who had baseline and follow-up echocardiograms and Holter monitors were included. Patients who underwent treatment with AADs were compared to those undergoing RFCA. Five hundred ten patients were identified, 215 undergoing RFCA and 295 treated with AADs. The RFCA group was younger than the AAD group (47 ± 16 vs 62 ± 18; P < 0.001) and had less coronary artery disease (6% vs 13%; P < 0.01). The PVC origin was the outflow tract in 37% and non-outflow tract in 42%, multiple in 5%, and undefined in 16%. The average PVC reduction with AADs was 49%; true AADs including amiodarone, flecainide, mexilitene, sotalol, and propafenone were more effective (82%) than beta-blockers (36%; P < 0.001) and calcium channel blockers ([CCBs], 43%; P < 0.001). RFCA reduced PVCs by 93%, significantly more than AADs (P = 0.04). The acute success rate of PVC ablation was 94%. The left ventricular ejection fraction (LVEF) increased significantly in the RFCA group, but not in the AAD group. Complications occurred in 12 patients (5.6%), and include arterial access complications (n = 7, including descending aortic dissection in one) and cardiac tamponade requiring pericardiocentesis (n = 5). The authors concluded that RFCA was more effective than AAD for reducing PVC burden and improving LVEF.
Commentary
PVCs in the setting of a structurally normal heart were previously largely considered benign. However, the recognition of frequent PVCs as a cause of cardiomyopathy has increased the recognition and treatment of patients with frequent PVCs. The number of patients referred to our practice with frequent PVCs has dramatically increased in the past 5 years. Treatment options include beta-blockers, CCBs, AADs, or RFCA. In this study, RFCA was significantly more effective than drug therapy for suppressing PVCs (93%) and improving LVEF. It is useful to note that true AADs (Class IC or III) were much better at suppressing PVCs (82%) than beta-blockers (36%) or CCBs (43%). Should all patients with frequent PVCs be referred for catheter ablation? Of concern is the high rate of procedural complications in patients undergoing RFCA (5.6%) in this study, including such complications as aortic dissection (related to retrograde aortic instrumentation), cardiac perforation, and tamponade. In our experience, these complications are quite rare during PVC ablation, particularly for PVCs originating from the right ventricular outflow tract. However, it is a reminder that any procedure has risks. The study found that improvement in ejection fraction occurred mainly in patients with more than 10,000 PVCs over 24 hours (or 10% burden). This supports findings from prior studies.1
To summarize, patients who are asymptomatic with < 10% PVCs can be reassured. For patients with symptomatic PVCs, or > 10% PVCs and LV dysfunction, we often start treatment with benign drugs such as beta-blockers. Those patients with continued PVCs on beta-blockers, side effects, or a desire to not be on chronic medical therapy should be offered the option of catheter ablation vs Class I or III antiarrhythmic therapy, after a discussion of the risks and benefits. In patients with frequent PVCs and left ventricular dysfunction, I often move more quickly to catheter ablation because of the greater efficacy in completely eliminating PVCs. In experienced centers, the success rate of catheter ablation for eliminating PVCs is quite high (> 90%).
REFERENCE
1. Baman TS, et al. Relationship between burden of premature ventricular complexes and left ventricular function. Heart Rhythm 2010;7:865-869.
