A comparison of sprint versus progressive treadmill exercise in the evaluation of cardiac arrhythmias

Although exercise testing is commonly used in the evaluation of patients with known or suspected ventricular arrhythmias, the optimal exercise protocol for arrhythmia provocation has not been established. Therefore, progressive treadmill and sprint exercise tests were performed in 122 consecutive patients referred for arrhythmia evaluation to compare the arrhythmogenicity of these protocols in patients with known or suspected cardiac arrhythmias. Exercise testing was performed in all patients both in the absence of antiarrhythmic medications as well as during therapy felt to be effective on the basis of 24-hour ambulatory ECG recording. The mean age of the group was 57 ± 15 years, 84 patients were male. Group mean ejection fraction was 47 ± 19%. Ventricular arrhythmias were analyzed for frequency as well as complexity, including duration of ventricular tachycardia. The frequency and complexity of observed arrhythmias were similar during progressive and sprint exercise. Although there was no significant difference in VPD density during progressive and sprint exercise when compared with baseline, progressive exercise resulted in a statistically significant increase in the number of ventricular couplets. There was a trend toward an increased number of runs of ventricular tachycardia with progressive treadmill exercise; however, this difference did not reach statistical significance (1.8 ± 8.5 runs with progressive exercise, 0.48 ± 1.8 runs at baseline). Two patients developed sustained ventricular tachycardia during progressive treadmill exercise. One additional patient developed ventricular tachycardia during recovery from both sprint and progressive exercise. Seven patients developed sustained ventricular tachycardia with exercise during antiarrhythmic therapy felt to be effective on the basis of 24-hour ambulatory ECG recording. The overall frequency and complexity of ventricular arrhythmias is similar with progressive treadmill and sprint exercise, and not statistically different from baseline with the exception that repetitive ventricular ectopy was seen more frequently during progressive exercise. Although sustained ventricular tachycardia is infrequent during exercise even in patients at high risk for ventricular arrhythmias, it appears to be more frequent during progressive treadmill exercise as compared with vigorous sprinting. Although baseline exercise testing has limited utility in the evaluation of patients undergoing arrhythmia evaluation, exercise testing during antiarrhythmic therapy may detect drug inefficacy or proarrhythmia.