A novel ECG criterion to differentiate left from right ventricular outflow tract premature complex

Objectives. Catheter ablation is an effective method in the treatment of idiopathic ventricular arrhythmias. The mapping methods used for predicting the original site of arrhythmias are difficult to use and time-consuming. Consequently, developing methods using surface ECG for guiding the location is important. Here, we have tested a new ECG criterion to differentiate the left from the right ventricular originated complexes (PVCs) or tachycardias (VTs). Designs. Sixty patients with idiopathic PVC or VT who had undergone a successful radiofrequency catheter ablation (RFA) of arrhythmia were enrolled. The surface ECG during sinus rhythm and arrhythmia was analyzed. Initial r wave Surface Area (ISA) index was measured by multiplying the R wave duration in milliseconds by the R wave amplitude in terms of millivolt in V1 or V2 leads. Results. Thirty-seven patients with right ventricular (RVOT) and 23 with left ventricular outflow tract (LVOT) originated VT or PVC were enrolled. The ISA index was significantly greater in LVOT-VT/PVC compared to RVOTs (63.6 ± 78.9 vs. 8.3 ± 7.3, p < .001). With a cut off value of ≥15, the index could differentiate a left from right arrhythmia with 94.6% specificity and 78.2% sensitivity (Area on the curve, 0.81; p < .001). Compared to other previously reported indices, ISA is the most specific one. Conclusion. ISA index can serve as a very useful ECG criterion for differentiating a LVOT- from RVOT-originated VTs or PVCs.