Abstract:

Objective   To investigate the electrocardiogram (ECG) characteristics and radiofrequency catheter ablation(RFCA) of ventricular tachycardias (VTs) or premature ventricular contractions (PVCs) originating from the aortic sinus and tricuspid annulus. Methods   6 patients with VT or PVCs diagnosed by ECG and clinical symptoms underwent electrophysiological study and RFCA in our hospital. After the successful ablations, the 12 leads ECG characteristics were analyzed in accordance with the location of target sites. Results   All 6 patients were successfully ablated. The VT/PVCs originated from the aortic sinus in 3 patients, in which 2 arose from the right sinus and 1 from the left sinus. The VT/PVCs originated from the tricuspid annulus in the remaining 3 patients, including 2 arose from the free wall and 1 from the septal portion. The ECG pattern of the VT/PVCs originated from the aortic sinus showed a monomorphic left bundle branch block (LBBB) QRS and an inferior axis in the frontal plane, towering R-waves in leads Ⅱ, Ⅲ, aVF and the precordial R-wave transition before lead V3. A small S wave was not found in lead V5 or V6. The ECG pattern of the VT/PVCs originated from tricuspid annulus showed a LBBB QRS morphology, upright R-waves in leads Ⅰ, aVL, V5 and V6, positive or negative QRS complex in leads Ⅱ, Ⅲ and aVF and the precordial R-wave transition in lead V3~V5. Compared with the VT/PVCs originated from the septal portion of tricuspid annulus, the cases from the free wall showed some characteristics, including a greater QRS duration, “Notching” of the QRS complex in the limb lead and a later precordial R-wave transition. Conclusions   VT/PVCs originating from the two non-classical sites have specific electrocardiographic characteristics, and can be safely and effectively cured by RFCA.

Key words: Ventricular tachycardia; Premature ventricular contraction; Aortic sinus; Tricuspid annulus; Electrocardiogram; Radiofrequency catheter ablation