Ablation within the aortic sinus of Valsalva for the treatment of ventricular arrhythmias: the preliminary result. Background: Ablation within the aortic sinus of Valsalva for ventricular tachycardia (VT), premature ventricular complexes (PVCs) has been reported in only small patient cohorts. Limited data exists concerning the outcome and safety of aortic ablation. Aims: The aim was to study the preliminary result and safety of catheter ablation for VT/PVCs originating from the aortic cusps at the Vietnam Heart Institute. Methods: The study consisted of 49 consecutive patients with symptomatic VTIPVCs who underwent radiofrequency catheter ablation within aortic sinus cusps from January 2010 to April 2012. Aortic root angiography were used to define coronary cusp and catheter position. The ablation target sites were defined by pace mapping and early activation mapping techniques. Ablation parameters including tissue temperature and tissue impedance were also measured. Ablation success and recurrence was defined by ECG and clinical follow up and 24-hour Holter monitoring after 3 months. All the procedurerelated complications were documented. Results: Of the 49 patients (24 men and 25 women, mean age 51.1 + or - 13.7 years), the site of origin was the left coronary cusp (LCC) in 36 (73.4 percent), the right coronary cusp (RCC) in 5 (10.2 percent), the noncoronary cusp (NCC) in 2 (4.1 percent), and at the junction between the LCC and RCC (L-RCC) in 6 (12.3 percent) cases. Pace mapping with pulse amplitude/width up to 10 VlO.4 ms failed to capture in all cases. The mean early activation time (EA T) measured at the successful ablation target sites was 30.3 + or - 10.5 milliseconds. The mean procedure time was 80.9 + or - 25.1 mins and the mean fluoroscopic time was 15.2 + or - 7.7 mins. The initial success rate was 93.9 percent (46/49). After 3 months of follow up, 41/49 (83.7 percent) were free of VT/PVCs without anti-arrhythmic drugs proven by 24-hour Holter monitoring. No severe complications (MI, strokes, aortic valve perforation...) have been documented. Conclusion: Ablation within the aortic sinus of Valsalva is safe and effective for the treatment of ventricular arrhythmias.