OBJECTIVES To determine whether catheter ablation is safe and effective in patients over the age of 80. BACKGROUND There is a tendency to withhold invasive therapy in the elderly until it has been proven safe and effective. METHODS Over a two-year period from February 1, 1996 to February 1, 1998, 695 consecutive patients underwent 744 catheter ablation procedures of supraventricular and ventricular arrhythmias. These patients were divided into three groups based on age: greater than or equal to 80 years, 60 to 79 years and <60 years. Acute ablation success, using standard criteria and complication rates for these three groups were determined. RESULTS There were 37 patients greater than or equal to 80 years, 275 patients 60 to 79 years and 383 patients <60 years old. The overall acute ablation success rate for the entire group was 95% with no difference in rates among the three groups (97%, greater than or equal to 80 years; 94%, 60-79 years; 95%, <60 years). The percentage of patients undergoing His bundle ablation was greatest in the greater than or equal to 80-year-old group (43% vs. 19% vs. 2%, p < 0.01), and the percentage of patients undergoing accessory pathway ablation was greatest in the <60-year-old patients (0% vs. 4% vs. 25%, p < 0.01). The overall complication rate for the entire group was 2.6%, and there was only one major/life-threatening complication. There was no difference in complication rates among the groups (0%, greater than or equal to 80 years; 2.2%, 60 to 79 years; 3.1%, <60 years). Based on the sample size, the 95% confidence interval is 0% to 7.8% for an adverse event in the octogenarian. CONCLUSIONS Catheter ablative therapy for the: arrhythmias attempted in the very elderly appears to be effective with low risk. Ablation results appear to be comparable with those noted in younger patients. (J Am Coil Cardiol 2000;35:458-62) (C) 2000 by the American College of Cardiology.