Catheter Ablation Of Idiopathic Ventricular Tachycardia

摘要

Objectives: To describe the techniques and results of catheter ablation of idiopathic ventricular tachycardia (IVT). Methods: Radiofrequency catheter ablation was attempted in 11 patients with IVT of 2-15 years. Both activation and pace mapping techniques were used to locate the VT foci for ablation. Results: IVT was originated from the left interventricular septum in 5, right ventricular outflow tract in 5 and right ventricular free wall in 1. All VT was successfully ablated with the procedure time ranged from 60-120 min and total energy delivery time of 90-150 s. There were no complications during and after the treatment. There was no recurrence after a followed-up of 6-24 months without antiarrhythmic drugs. Conclusions: Radiofrequency catheter ablation is a safe and effective curative therapy for IVT. Idiopathic ventricular tachycardia (IVT) accounts for about 10% of the VT. IVT is usually associated with a benign prognosis and causes minimal hemodynamic compromise.1 Radiofrequency catheter ablation has been used to manage VT with a higher curative rate for IVT.2 In this report we described the methodology and long-term results of IVT ablation in 11 patients. Patients and Methods Six male and 5 female patients aged between 35-56 years underwent catheter ablation of IVT in our hospital. All patients had recurrent VT for more than 2 years (ranged from 2 to 15 years). In 3 patients, a single episode of VT lasted as long as 5 days without pharmacological intervention before the ablation. The major symptoms of IVT include palpitations (11 cases), dizziness (11 cases), chest pain (1 case) or syncope (1 case). Physical examination, resting ECG, chest X-ray and echocardiography revealed no pathological changes of the heart.The blood pressure during VT attacks in these patients ranged from 80-110/40-60 mmHg. During the VT episodes, 6 showed right bundle branch block (RBBB) morphology and 5 were in the form of left bundle branch block (LBBB). Esophageal ECG was performed in all patients showing atrioventricular dissociation during VT. Intracardiac Mapping And Catheter Ablation After acquisition of surface ECG, the right jugular vein and the femoral veins of both sides were canulated. Six French quadripolar electrode catheters were sent to the coronary sinus, right ventricular apex and bundle of His via the intravenous sheath. Programmed intracardiac stimulation was routinely performed to exclude supraventricular tachycardia and also to terminate or induce VT.For IVT of the left ventricular origin, a 7 French Webster ablation catheter was sent to the left ventricle via the right femoral artery. Attempts were made to map the arrhythmic foci under sinus rhythm trying to locate a P potential, which is usually 10 ms behind His potential recorded by the quadripolar electrode catheter in the right atrioventricular junctional region (Fig 1). If the mapping was undertaken during VT, the ablation was targeted on the site where a P potential that was 20ms earlier than the QRS complex on the body surface ECG was recorded. For the right ventricular VT, the Webster ablation catheter was inserted to the right ventricle via the right femoral vein. Pace mapping was used, commencing from the right ventricular outflow tract.