628 Radiofrequency Catheter Ablation for Disabling Frequent Premature Ventricular Contractions: A Single-Center Experience

ICD, in the absence of antiarrhythmic medication; and cardiac MRI. The left ventricular mass, ejection fraction (EF) and volume were calculated. The mass of core scar, scar border zone and the total scar were measured by delayed Gadolinium enhancement. For primary prevention patients, VTCL was measured with the first VT recorded by ICD. For secondary prevention, the indexed clinical VT was used for cycle length measurement. The correlation of scar, border zone characters, and VTCL were studied. The follow up period was from 2008 to 2010. RESULTS: Total of 15 patients (all male, 72 11 y) were included, in which 7 had ICD for primary prevention and 8 for secondary prevention. All patients had a prior myocardial infarction. All but two were taking beta blockers. No patients were on antiarrhythmic medications. The average EF was measured 28 14%. The spontaneous VTCL was in the range of 300ms-444ms, median of 366ms. The core scar, scar border zone and the total scar measurements were a median of 24.2g (range 2.4-44.4g); 10.7g (range 2.9-33.8g); and 34.7g (range 5.5-72.0g), respectively. With univariate regression analysis, there was no statistic significant correlation between the absolute MRI scar characteristics and the VTCL. There was a trend of inverse correlation between the ratio of scar border zone/core scar and VTCL(r 0.49, p 0.06). The bigger the ratio, the shorter the VTCL would be. CONCLUSION: This pilot study demonstrated that the VTCL in ischemic heart disease without antiarrhythmic medication might have an inverse correlation with the ratio of scar boarder zone/core scar. This finding might be helpful to locate the origin of clinical VT. Further study with larger sample size is warranted.