Circadian modulation of ventricular tachycardia cycle length variability in ICD patients with dilated cardiomyopathy.

VT is usually characterized by stability of the RR intervals after a few cycles from the onset. The aim of this study was to evaluate the VT cycle length (VTCL) variability in patients with dilated cardiomyopathy (DCM), in whom a third-generation ICD was previously implanted. Eighty-three episodes of VT were analyzed in 10 patients (8 male, 2 female, 65 +/- 6 years) with DCM, and NYHA Class II (7 patients) or III (3 patients).