Clinical Characteristics of Induced Nonclinical Ventricular Tachycardia in Nonischemic Cardiomyopathy.

The clinical significance of induced nonclinical ventricular tachycardia (NCVT) in nonischemic dilated cardiomyopathy (DCM) remains controversial. Twenty-eight patients with sustained VT or ventricular fibrillation related to DCM underwent programmed ventricular stimulation (PVS) to induce VT. However, VT was not induced in four patients. Based on the morphology of induced ventricular arrhythmia, we classified the remaining 24 patients into NCVT (n = l1 ) and clinical VT (CVT) groups (n = 13), then evaluated the prognosis for a mean follow-up period of 22 months. The cycle length of induced NCVT was significantly shorter than that of induced CVT (277 +/- 38 ms vs 325 +/- 63 ms, P < 0.05). Appropriate antiarrhythmic agents were selected by serial PVS in 36% of the NCVT group and in 38% of the CVT group (4/11 vs 5/13). Among patients who had been treated by PVS guided drug therapy, arrhythmic events were observed in 75% of the NCVT group and 80% of the CVT group (3/4 vs 4/5). The total incidence of sudden death in the NCVT group was higher than that in the CVT group (5/11: 45% vs 4/13: 31%). In conclusion, induced NCVT and CVT are refractory to pharmacological therapy and both have an important characteristic value in DCM.