Tachycardia-induced cardiomyopathy in patients with idiopathic ventricular arrhythmias: the incidence, clinical and electrophysiologic characteristics, and the predictors.

INTRODUCTION: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia-induced cardiomyopathy (TICMP). The aim of this study was to determine the incidence, clinical and electrophysiologic characteristics, and the predictors of TICMP in patients with idiopathic ventricular arrhythmias.
METHODS: Study population consisted of 249 consecutive patients (148 F/101 M, 45 ± 20 y/o) with frequent PVCs and/or VT. All patients underwent transthoracic echocardiography and 24-hour Holter monitoring. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF ≥15% following effective treatment of index ventricular arrhythmia.
RESULTS: Seventeen (6.8%) patients had TICMP. Patients with TICMP compared to patients with preserved LVEF were more likely to be male (65% vs 39%, P = 0.043) and asymptomatic (29% vs 9%, P = 0.018), and were more likely to have higher PVC burden (29.4 ± 9.2 vs 8.1 ± 7.4, P < 0.001), persistence of PVCs throughout the day (65% vs 22%, P = 0.001), and repetitive monomorphic VT (24% vs 0.9%, P < 0.001). PVC burden of 16% by ROC curve analysis best separated the patients with TICMP compared to patients with preserved LVEF (sensitivity 100%, specificity 87%, area under curve 0.96).
CONCLUSIONS: TICMP was relatively common (∼1 in every 15 patients) in our study population. The predictors of TICMP were male gender, absence of symptoms, PVC burden of ≥16%, persistence of PVCs throughout the day, and the presence of repetitive monomorphic VT.