PVC-INDUCED CARDIOMYOPATHY Recommendations for PVC-Induced Cardiomyopathy References that support the recommendations are summarized in Online Data Supplement 50. COR LOE Recommendations I B-NR For patients who require arrhythmia suppression for symptoms or declining ventricular function suspected to be due to frequent PVCs (generally >15% of beats and predominately of 1 morphology) and for whom antiarrhythmic medications are ineffective, not tolerated, or not the patient s preference, catheter ablation is useful.S9-1,S9-2 IIa B-NR In patients with PVC-induced cardiomyopathy, pharmacological treatment (eg, beta blocker, amiodarone) is reasonable to reduce recurrent arrhythmias and improve symptoms and LV function.S9-3,S9-4 Recommendation-Specific Supportive Text 1. Frequent PVCs (usually >15% of the total num- ber of beats) may produce a reversible form of However, it is sometimes difficult to ascertain whether the PVCs caused LV dysfunction or whether progressive LV dysfunc- tion caused frequent PVCs. LV dysfunction has been associated with greater PVC burden (>10% and usually >20%), NSVT, a retrograde P-wave after the PVCs, and interpolated PVCs.S9-6,S9-15 In a prospective study of catheter ablation for PVC-induced cardiomyopathy, ablation was com- pletely successful in 80% of patients.S9-19 LV func- tion normalized within 6 months in 82% of the 22 patients who had depressed ventricular dys- function at baseline. Thus, frequent PVCs may be a reversible cause of LV dysfunction that can be effectively treated with catheter ablation. It is often difficult to determine if apparent LV dys- function reflects impaired LV function or inability to accurately assess LV function due to the fre- quent ectopic activity. In patients who have a high density of PVCs with normal ventricular function, optimal treatment and surveillance for prevention and detection of decline in ventricular function have not been established. 2. 