Prevalence of ventricular tachycardia in patients with different underlying heart diseases: A study by Holter ECG monitoring

Twenty-four-hour Holter ECGs were recorded in 1089 patients. Ventricular tachycardia (VT) was observed in 184 tapes obtained from 81 patients (73 men and 8 women). Underlying heart diseases were present in 72 patients and no organic heart diseases were found in nine patients. The analysis of continuous 1-hour rhythm strips immediately before VT revealed that, in ischemic heart disease and hypertrophic cardiomyopathy, there was no correlation between the incidence of VT and the number or complexity of premature ventricular complexes (PVCs) within 1 hour before VT. In contrast, frequent or multiform PVCs were often observed during the pre-VT period in the patients with rheumatic heart disease or dilated cardiomyopathy. These findings suggest that the mechanism of VT may be different among the various underlying heart diseases. In addition, the mode of initiation of VT was evaluated. Only few episodes of VT occurred with the prematurity index value smaller than 1.0 or the vulnerability index value greater than 1.1. The correlation between the rate of VT and the preceding sinus rate was not significant, and the correlation between the rate of VT and the coupling interval of VT was weak. These facts suggest that the malignancy of VT, represented by the rate of VT, cannot be predicted by the preceding sinus rate or by the coupling interval of VT.