Abstract 2680: Electrocardiographic Recognition of Ventricular Tachycardia With Successful Endocardial Catheter Ablation in Patients With Non-Ischemic Cardiomyopathy
Catheter Ablation (CA) of ventricular tachycardia (VT) from endocardium in patients with non-ischemic cardiomyopathy (NICM) showed low success rate, because critical common pathway of the reentry circuit may be located subepicardially in difficult cases. It has been reported that prolongation of the time to maximum deflection (TMD) in precordial leads and maximum deflection index (MDI=TMD/QRS duration [%]) suggested epicardial origin in idiopathic VT. The aim of this study was to define the parameter of successful endocardial CA for VT and the origin of VT in NICM patients. <Methods and Results> Consecutive 35 NICM patients with 71 induced sustained reentrant monomorphic VTs in electrophysiologic study were examined in this study. Both ventricular endocardial mapping and CA were attempted in all patients. Age, LVEF, ECG and signal-averaged ECG (total QRS, LAS40 and RMS40) were analyzed, and examined the correlation with the result of CA. As special ECG parameters, we analyzed TMD and MDI in each VT. There were no differences in age, LVEF and RR interval of VT (TCL) between 14 successfully (group 1) and 57 unsuccessfully (group 2) ablated VTs (Table⇓). However, the values of TMD, MDI and total QRS in SAECG showed significantly shorter in group 1 than those in group 2 (p<0.0001, p<0.0001, p<0.00001). When a MDI of more than 55% is considered to predict the epicardial origin and unsuccessful endocardial CA, sensitivity of 42.1%, specificity of 92.9% and positive predictive value of 96.0% were attained. When a MDI of less than 45% is considered to predict the endocardial origin and successful endocardial CA, sensitivity of 85.7%, specificity of 84.2% and positive predictive value of 57.1% were attained. Coronary vein mapping via coronary sinus suggested the epicardial origin in 17 of 26 VTs (65.4%) with unsuccessful endocardial CA. ECG could suggest the subendocardil origin of VT with successful CA from endocardium in NICM patients.