Utilizing Lead aVR QRS Morphology to Localize Abnormal Substrates in Arrhythmogenic Right Ventricular Cardiomyopathy

The electrocardiography (ECG) morphology of lead aVR has been associated with arrhythmic risk in Brugada syndrome, but its role in arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. To evaluate the clinical significance of aVR morphology in ARVC patients.

A total of 45 subjects diagnosed with ARVC who underwent epicardial-endocardial mapping were enrolled in the study. The patients were divided into two groups based on the presence of an epicardial right ventricular outflow tract (RVOT) scar: the n-RVOT group (scar area <50%, n=10) and the p-RVOT group (scar area ≥50%, n=35). The aVR morphology was classified into QR pattern, R pattern (including R wave, rS or Rs), and QS pattern. The baseline characteristics and procedural parameters were analyzed.

A higher incidence of inferior axis ventricular arrhythmia (VA) was observed in the p-RVOT group (64.2% vs. 33.3%, p=0.050). An R wave and QS pattern in aVR were associated with epicardial RVOT scar involvement. Among patients with QR pattern, an R/Q ratio<0.582 discriminated epicardial RVOT scar involvement (area under the receiver operating characteristic curve=0.88), with a sensitivity of 93.3% and specificity 80.0%. An R pattern was associated with reduced right ventricular ejection fraction (p=0.033) and a higher incidence of clinical or inducible ventricular fibrillation (p=0.021). There was no significant difference in post-ablation VA recurrence based on the presence of RVOT scar and aVR morphology.

In patients with ARVC, the ECG morphology of lead aVR was associated with scar distribution and right ventricular dysfunction.