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V3R/V7 Index: A Novel Electrocardiographic Criterion for Differentiating Left From Right Ventricular Outflow Tract
Dian Cheng1, Weizhu Ju1, Lili Zhu1
1Division of Cardiology, First Affiliated Hospital of Nanjing Medical University, China (D.C., W.J., L.Z., K.C., F.Z., H.C., G.Y., X.L., M.L., K.G., K.C., B.Y., M.C.).
Insights
A new ECG index using right precordial and posterior leads accurately predicts the origin of outflow tract ventricular arrhythmias (VAs). This V3R/V7 index improves upon existing methods for diagnosing VA sources.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Standard 12-lead ECG algorithms for outflow tract (OT) ventricular arrhythmias (VAs) lack accuracy.
- The diagnostic contribution of additional right precordial and posterior ECG leads remains unclear.
Purpose of the Study:
- To develop and validate a novel algorithm using right precordial and posterior ECG leads to differentiate left ventricular OT (LVOT) and right ventricular OT (RVOT) VA origins.
- To assess the additive value of these leads in predicting VA origin.
Main Methods:
- A development cohort of OT-VA patients underwent standard 12-lead ECG, right precordial (V3R-V5R), and posterior (V7-V9) lead recordings.
- A novel algorithm incorporating the V3R/V7 index was developed.
- The algorithm was prospectively validated in a separate cohort and compared to existing criteria.
Main Results:
- The V3R/V7 index showed high accuracy in differentiating LVOT and RVOT origins (87% sensitivity, 96% specificity for LVOT).
- The V3R/V7 index demonstrated superior performance (AUC 0.954) compared to previously reported ECG criteria.
- The index was effective across various patient subgroups, including those with atypical presentations.
Conclusions:
- The V3R/V7 index is a novel, accurate, and reliable ECG criterion for predicting the origin of outflow tract ventricular arrhythmias.
- Incorporating right precordial and posterior leads significantly enhances the diagnostic capability for OT-VAs.
Background:
Several algorithms have been proposed to predict the origin of outflow tract (OT) ventricular arrhythmias (VAs) using standard 12-lead ECG. However, the additive value of right precordial and posterior leads is unknown.
Methods:
Standard 12-lead ECG, right precordial leads ECG (V3R, V4R, V5R) and posterior leads ECG (V7, V8, V9) were recorded and analyzed in a development cohort of consecutive patients undergoing OT-VAs ablation at a single center. These findings informed the development of a novel algorithm incorporating right precordial and posterior leads to discriminate between left ventricular OT (LVOT) and right ventricular OT (RVOT) foci. The performance of this novel algorithm which includes the V3R/V7 index was prospectively tested in a validation cohort of consecutive patients undergoing OT-VA ablation at 4 centers and compared with published algorithms. The location of the foci was determined by the successful ablation site.
Results:
One hundred ninety-one patients were recruited, of which 94 formed the validation cohort (mean age of 45.7±15.6, 39% male, 79% RVOT foci). During OT-VAs, a QS pattern in lead V3R and an S wave in lead V7 were exclusively recorded in RVOT and LVOT foci, respectively. The V3R/V7 index of LVOT origin was significantly greater than that of RVOT (1.05±0.83 versus 0.28±0.23, P<0.001). The V3R/V7 index ≥0.85 predicted an LVOT origin with 87% sensitivity and 96% specificity. In the prospective evaluation, when the V3R/V7 index ≥0.85, an RVOT origin could be excluded with 98.6% accuracy. The area under the curve of V3R/V7 index (0.954) was larger than that of previously reported ECG criteria, including V2S/V3R (0.896), V2 transition ratio (0.792), and transition zone index (0.666). This novel index was also accurate in both patients without obvious LVOT or RVOT origins and subgroups with cardiac rotation or lead V3 R/S transition.
Conclusions:
The V3R/V7 index is a novel and accurate ECG criterion that predicts OT-VAs origin.
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