Reversal of outflow tract ventricular premature depolarizationinduced cardiomyopathy with ablation: Effect of residual arrhythmia burden and preexisting cardiomyopathy on outcome

Background: Outflow tract ventricular premature depolarizations (VPDs) can be associated with reversible left ventricular cardiomyopathy (LVCM). Limited data exist regarding the outcome after ablation of outflow tract VPDs from the LV and the impact of residual VPDs or preexisting LVCM prior to the diagnosis of VPDs on recovery of LV function. Objective: To examine the safety, efficacy, and long-term effect of radiofrequency ablation on LV function in patients with LVCM and frequent outflow tract VPDs and examine the effect of ablation in patients with LVCM known to precede the onset of VPDs and the impact of residual VPD frequency on recovery of LV function. Methods: Sixty-nine patients (43 men; age 51 ± 16 years) with nonischemic LVCM (left ventricular ejection fraction [LVEF] 35% ± 9%, left ventricular diastolic diameter [LVDD] 5.8 ± 0.7 cm) were referred for ablation of frequent outflow tract VPDs (29% ± 13%). Results: VPDs originated in the right ventricular outflow tract in 27 (39%) patients and the left ventricular outflow tract in 42 (61%) patients. After follow-up of 11 ± 6 months, 44 (66%) patients had rare (<2%) VPDs, 15 (22%) had decreased VPD burden (>80% reduction and always <5000 VPDs), and 8 (12%) had no clinical improvement with persistent (5 patients) or recurrent (3 patients) VPDs. Only patients with either rare or decreased VPD burden had a significant improvement in LVEF (ΔLVEF 14% ± 9% vs 13% ± 7% vs 3% ± 6%, respectively, P <.001) and LVDD (ΔLVDD 4 ± 5 vs 2 ± 4 vs 0 ± 4, respectively, P =.038), regardless of chamber of origin. The magnitude of LVEF improvement correlated with the decline in residual VPD burden (r = 0.475, P =.007). Patients with preexisting LVCM had a more modest but still significant improvement in LV function compared to patients without preexisting LVCM (ΔLVEF 8% vs 13%, P =.046). Multivariate analysis revealed ablation outcome, higher LVEF, and absence of preexisting LVCM were independently associated with LVEF improvement. Conclusion: Frequent outflow tract VPDs are associated with LVCM regardless of ventricle of origin. Significant (>80%) reduction in VPD burden has comparable improvement in LV function to complete VPD elimination. Successful VPD ablation may be beneficial even in patients with preexisting LVCM.