Key result
V6R/V4R index >0.55 predicts aortic cusp ventricular arrhythmias with ~87% diagnostic accuracy.
Why the study?
Although ablation within the aortic cusp can eliminate LVOT-VAs, many cases require targeting outside the cusp, prompting the need for ECG indices to differentiate these origins.
Does the V6R/V4R amplitude index accurately identify idiopathic ventricular arrhythmias originating from the aortic cusp in patients with LVOT-VAs?
Observational (n=159)
Blinded observers for ECG assessment
Yes
Does the V6R/V4R amplitude index accurately identify idiopathic ventricular arrhythmias originating from the aortic cusp in patients with LVOT-VAs?
Answers are grounded in this paper and cite their sources.
The V6R/V4R amplitude index > 0.55 is a simple and highly accurate ECG criterion for distinguishing idiopathic ventricular arrhythmias originating from the aortic cusp from those arising outside the cusp among LVOT-VAs.
Background Radiofrequency catheter ablation within the aortic cusp can eliminate left ventricular outflow tract (LVOT) ventricular arrhythmias (VAs). However, in a significant proportion of cases, successful ablation requires targeting the aorto‐mitral continuity, the endocardium just below the left ventricular summit, and/or the mitral annulus. This study aimed to identify electrocardiographic (ECG) indices useful for differentiating VAs originating from the aortic cusp from those arising outside the cusp among LVOT‐VAs. Methods This retrospective study included 159 idiopathic VAs (79 in the derivation cohort and 80 in the validation cohort) successfully ablated from the LVOT. Based on the site of VA origin, VAs were classified into cusp ( n = 125) and non‐cusp ( n = 34) groups. Detailed PVC morphologies were compared between the two groups. Results In the derivation cohort (mean age 60 ± 16 years, 43 men), the ratio of R‐wave amplitude in lead V6 to that in lead V4 was significantly higher in the cusp group than in the non‐cusp group (0.64 [0.56–1.00] vs. 0.32 [0.24–0.40], p < 0.001). Receiver operating characteristic curve analysis showed that a V6R/V4R amplitude index > 0.55 predicted cusp‐origin VAs with 0.80 sensitivity and 0.88 specificity (area under the curve, 0.865; 95% confidence interval [CI], 0.762–0.967). In the validation cohort, the sensitivity and specificity of a V6R/V4R amplitude index > 0.55 for predicting cusp origin were 84% and 82%, respectively. Conclusion The V6R/V4R index is a simple and practical ECG criterion for distinguishing VAs originating from the aortic cusp from those arising outside the cusp among LVOT‐VAs, with high accuracy.
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Naruse et al. (2026) conducted an observational in Idiopathic ventricular arrhythmias originating from the left ventricular outflow tract (n=159). Aortic cusp origin vs. Non-cusp LVOT origin was evaluated on V6R/V4R amplitude index (AUC 0.865, 95% CI 0.762-0.967, p=<0.001). A V6R/V4R amplitude index > 0.55 predicted aortic cusp-origin ventricular arrhythmias with 80% sensitivity, 88% specificity, and an AUC of 0.865.
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