Novel ECG predictor of difficult cases of outflow tract ventricular tachycardia: peak deflection index on an inferior lead

Circ J. 2010 Feb;74(2):256-61. doi: 10.1253/circj.cj-09-0540. Epub 2009 Dec 14.

Abstract

Background: An ECG predictor of ablation success has not been determined for difficult cases of outflow tract ventricular tachycardia/ventricular premature contractions (OT-VT/VPC).

Methods and results: 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.

Conclusions: A PDI >0.6 is more likely to be associated with a higher rate of RFCA failure.

MeSH terms

  • Adult
  • Catheter Ablation
  • Electrocardiography*
  • Female
  • Heart Conduction System / physiopathology*
  • Heart Conduction System / surgery
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Tachycardia, Ventricular / diagnosis*
  • Tachycardia, Ventricular / physiopathology
  • Tachycardia, Ventricular / surgery
  • Time Factors
  • Treatment Failure
  • Ventricular Premature Complexes / diagnosis*
  • Ventricular Premature Complexes / physiopathology
  • Ventricular Premature Complexes / surgery