Key result
Precordial transitional zone index < 0 predicts LVOT ventricular arrhythmia origin with ~96% sensitivity.
Observational (n=49)
No
Effect estimate: Sensitivity 95.65%, Specificity 96.15%
Combining the TZ index and QRS morphology in lead I is a reliable method to predict the origin site of VOT ventricular arrhythmias with specific V1 patterns, facilitating RFCA procedures.
TZ index <0 may aid LVOT prediction in VOT arrhythmias; leaves open prospective validation before guiding RFCA.
BACKGROUND: Ventricular outflow tract(VOT) ventricular arrhythmias(VAs) presenting qrS pattern or QS pattern with a notch on the descending limb in lead V1 were consistently thought of arising from the commissure between left and right coronary cusp (L-RCC) by previous studies. However, we found they could originate from other anatomic structures in VOT. This study aimed to investigate the exact origin of this kind VAs. METHODS: Forty-nine patients of VOT premature ventricular contrations/ventricular tachycardia(PVCs/VT) with lead V1 presenting qrS pattern or QS pattern with a notch on the descending limb undergoing successful radiofrequency catheter ablation(RFCA) in our center were analyzed. RESULTS: 12-lead electrocardiogram(ECG) of these PVCs/VT were summarized. Among these PVCs/VT, 37 cases exhibited qrS morphology in lead V1, 12 cases presented QS pattern with a notch on the descending limb in the same lead. Based on the successful ablation sites, these PVCs/VT were divided into 2 groups: (1)Right ventricular outflow tract(RVOT) group (26 cases), and (2) Left ventricular outflow tract (LVOT) group(23 cases, 4 cases originating from the left coronary cusp(LCC), 2 from the right coronary cusp(RCC), 16 from the L-RCC, 1 from the area inferior to LCC(ILCC)). The ECG characteristics of each PVCs/VT were analyzed. Among these PVCs/VT, applying the precordial transitional zone index(TZ index) < 0 to predict LVOT origin was demonstrated with sensitivity of 95.65%, specificity of 96.15%, positive predicting value(PPV) of 95.65% and negative predicting value(NPV) of 96.15%. In LVOT group, further applying the r, R, m,or Rs morphology in lead I to predict L-RCC and RCC origin was demonstrated with sensitivity of 94.44%, specificity of 60.00%, PPV of 89.47% and NPV of 75.00%. CONCLUSIONS: Ventricular outflow tract PVCs/VT with lead V1 presenting qrS pattern or QS pattern with a notch on descending limb not only arising from L-RCC, but also RVOT, LCC, RCC and ILCC. Combining TZ index and QRS morphology in lead I to predict origin site of these kind VAs is a convenient, simple and reliable method and facilitates the RFCA procedure.
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Cong et al. (2017) conducted an observational in Ventricular outflow tract premature ventricular contractions/ventricular tachycardia (n=49). Electrocardiogram analysis (TZ index and QRS morphology) was evaluated on Prediction of LVOT origin using precordial transitional zone index (TZ index) < 0 (Sensitivity 95.65%, Specificity 96.15%). Applying a precordial transitional zone index < 0 predicted LVOT origin of ventricular arrhythmias with a sensitivity of 95.65% and specificity of 96.15%.
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