Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus

Background: This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmias (VAs) arising from epicardial and endocardial areas adjacent to the mitral annulus (MA). Methods: This study involved 283 patients with MA-VAs who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively. Results: The origin of MA-VAs was judged based on the ECG variables. Among all MA-VAs, intrinsicoid deflection time (IDT) > 77 ms or maximum deflection index (MDI) > 0.505 predicted the VAs arising from the epicardium (sensitivity of 70.20% and 73.51%, specificity of 94.70% and 82.58%, positive predictive value (PPV) of 93.81% and 82.84%, and negative predictive value (NPV) of 73.53% and 73.15%). Among all epicardial MA-VAs, the RV1/RV2 ratio > 0.87 predicted the VAs originating from the epicardial anteroseptal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 62.86%, 98.06%, 91.67%, and 88.60%, respectively. Among all endocardial MA-VAs, Q(q)R(r) morphology in lead V1 predicted the VAs arising from the endocardial septal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 92.98%, 100%, 100%, and 94.94%, respectively. Among all endocardial septal MA-VAs, a predominant positive wave in lead II and a predominant negative wave in lead III predicted the VAs arising from the endocardial midseptal portion adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively. Conclusion: the ECG characteristics of VAs from the different sites adjacent to the MA can enable judging the arrhythmia's origin and designing the ablation plan accordingly.