PVC-induced cardiomyopathy: the cut-off value for the premature ventricular complex burden

Previously published studies have demonstrated that premature ventricular complex (PVC) burden of >20% (cut-off value) per day was found to induce cardiomyopathy.1,2 In our study,3 we found that a cut-off PVC burden of >26% per day was significantly associated with left ventricular (LV) dysfunction. However, our study group was subjected to selection bias, as pointed out by Hasdemir. We included the study patients as idiopathic symptomatic frequent PVCs (PVC burden ≥10%/24 h). Moreover, patients with potential PVC-induced cardiomyopathy but with a lower (<10%) PVC burden were excluded. In fact, the PVC burden was wide in range. Therefore, our study population may not represent the entire patient population with idiopathic PVCs. In a preliminary study, we evaluated 148 patients who underwent catheter ablation for idiopathic symptomatic PVC including all patients within the wide PVC burden range (3–61%). Thirty-one (20.9%) patients had an LV dysfunction. The cut-off PVC burden was 24% per day, although the sensitivity and specificity were 69 and 75%, respectively. Moreover, 21 patients (14.2%) had a PVC burden of <10%. To assess the effect of frequent PVCs on and to identify other prognostic factors, besides the PVC burden, affecting LV dysfunction, we selected patients with a PVC burden of ≥10% and observed similar cut-off PVC burden along with better sensitivity and specificity. Therefore, obtaining a cut-off value similar to those in previous studies indicates that our study population is acceptable when idiopathic PVCs are considered. If a cut-off value ≥16% as in the study of Hasdemir et al. is applied in our series, we found only 56.4% of the patients had LV dysfunction. A recent study showed that the duration and absence of symptoms were significantly associated with LV dysfunction.4 Other factors and symptom duration may also affect the cut-off PVC burden that could result in LV dysfunction; however, no statistical significance was noted. In our study, the presence of retrograde P-wave was related to PVC-induced LV dysfunction among patients with PVC burden ≥10%/24 h.3 Therefore, other factors influencing the cut-off PVC burden also should be considered when PVC-induced cardiomyopathy is studied. Conflict of interest: none declared.