Abstract 14896

Introduction: Frequent ventricular ectopy (PVCs) is known to be associated and cause non-ischemic cardiomyopathy (PVC-cardiomyopathy). Similar to PVCs, few studies and a single animal model have suggested that frequent premature atrial contractions (PACs) have similar consequences due to HR irregularity and / or associated post-extrasystolic potentiation.

Hypothesis: Like PVCs, PACs are also associated with left ventricular (LV) dysfunction.

Methods: A total of 404 patients with a 2-week ambulatory ECG holter monitors (Ziopatch^TM) were analyzed for mean heart rate (HR), PVC and PAC burden, supraventricular tachycardia (SVT) and ventricular tachycardia (VT) episodes. Echocardiogram was available in 285 patients within 6 months of Ziopatch. Data was analyzed based on different groups of PVC burden, PAC burden and LV function (Table) to assess relationship between PVCs, PACs and LV ejection fraction (LVEF).

Results: Table summarizes the prevalence of arrhythmia burden and LVEF in these patients. PVCs have a clear association with LV dysfunction, the larger the PVC burden the lower the LVEF and episodes of non-sustained VT. PAC burden is associated with episodes of SVT burden, however, PACs do not to have a clear association with LV dysfunction. When we analyze patients based on available echo data, subjects with lower LVEF have a clear association with PVC burden, but this association does not exist with PACs. Yet, LV dysfunction is associated with both non-sustained SVT and VT episodes.

Conclusions: In contrast to high burden PVCs, high PAC burden is not associated with LV dysfunction (LVEF <50%). This finding is significant since it suggests that HR variability and /or post-extrasystolic potentiation are unlikely to play a major role on the pathophysiology of PVC-induced cardiomyopathy.