Novel ECG predictor of difficult cases of outflow tract ventricular tachycardia: peak deflection index on an inferior lead.
ABSTRACT An ECG predictor of ablation success has not been determined for difficult cases of outflow tract ventricular tachycardia/ventricular premature contractions (OT-VT/VPC).
ECG analysis and radiofrequency catheter ablation (RFCA) were performed in 70 patients with OT-VT/VPC. The peak deflection index (PDI) was determined in the inferior lead presenting the tallest R wave by dividing the time from QRS onset to peak QRS deflection by total QRS duration. In 10 (14%) of the 70 patients, RFCA performed at a septal or epicardial site was unsuccessful (group 1), but was successful in the remaining 60 patients (group 2). Neither activation time (35+/-15 ms vs 40+/-12 ms, P=0.3) nor QRS duration (141+/-19 ms vs 137+/-19 ms, P=0.6) were significantly different between groups 1 and 2. However, PDI was significantly higher in group 1 than in group 2 (0.62+/-0.06 vs 0.55+/-0.06, P=0.002). A PDI >0.6 identified unsuccessful OT-VT/VPC with 80% sensitivity and 90% specificity, and may indicate that the origin of the OT-VT/VPC is deep within the ventricular septum or at an epicardial site.
A PDI >0.6 is more likely to be associated with a higher rate of RFCA failure.
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ABSTRACT: Although several reports address characteristic 12-lead ECG findings of outflow tract ventricular arrhythmias (OT-VAs), accuracy of the ECG algorithms to predict OT-VA origin is sometimes limited.Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; · 4.56 Impact Factor