Background: This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmia (VA) arising from epicardial and endocardial areas adjacent to mitral annual (MA). Methods: This study involved 283 patients with MA-VA who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively. Results: The origin of MA-VA was judged based on the ECG variables. Among all MA-VAs, IDT > 77 ms or MDI > 0.505 predicted the VAs arising from 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 MA. It had 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 MA. It had 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 mid-septal portion adjacent to MA. It had sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively. Conclusion: ECG characteristics of VAs from the different sites adjacent to MA can judge the arrhythmia’s origin and design the ablation plan accordingly.

BACKGROUND For ventricular arrhythmias (VAs) originating from the left ventricular epicardium adjacent to the transitional area from the great cardiac vein to the anterior interventricular vein (DGCV-AIV), the most efficient catheter manipulation approach has not been fully elucidated. OBJECTIVE This study aimed to investigate a more appropriate catheter manipulation approach for DGCV-AIV VAs. METHODS One hundred twenty-three consecutive patients with DGCV-AIV VAs were retrospectively analyzed. All these patients were firstly mapped and ablated by conventional approach （Non-Swartz sheath support (NS) approach）. When target sites not been reached, Swartz sheath support (SS) approach was attempted. If target sites still unreached, the hydrophilic coated guide wire and left coronary angiographic catheter-guided deep engagement of Swartz sheath in GCV to support ablation catheter was performed. RESULTS A total of one hundred three VAs (103/123, 83.74%) were successfully eliminated in DGCV-AIV. By NS approach, the tip of catheter reached DGCV in 39.84% VAs (49/123), reached target sites in 35.87% VAs (44/123), and achieved successful ablation in 30.89% VAs (38/123), which was significantly lower than by SS approach (88.61% (70/79), 87.34 % (69/79), and 84.81% (67/79), P<0.05). In left anterior oblique (LAO) view, angle between DGCV and AIV<83° indicated an inaccessible AIV by catheter tip with a predictive value of 94.5%. Width/height of coronary venous system>0.69 more favored a SS approach with a predictive value of 87%. CONCLUSION For RFCA of VAs arising from DGCV-AIV, the SS approach facilitates the catheter tip achieve target sites and contributes to a successful ablation.