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 wi th known or suspected ventricular arrhythmias, the optimal exercise protoco l for arrhythmia provocation has not been established. Therefore, progressi ve treadmill and sprint exercise tests were performed in 122 consecutive pa tients referred for arrhythmia evaluation to compare the arrhythmogenicity of these protocols in patients,vith known or suspected cardiac arrhythmias. Exercise testing was performed in all patients both in the absence of anti arrhythmic medications as well as during therapy felt to be effective on th e 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 co mplexity, including duration of ventricular tachycardia. The frequency and complexity of observed arrhythmias were similar during progressive and spri nt exercise. Although there was no significant difference in VPD density du ring progressive and sprint exercise when compared with baseline, progressi ve exercise resulted in a statistically significant increase in the number of ventricular couplets. There was a trend toward an increased number of ru ns of ventricular tachycardia with progressive treadmill exercise; however, this difference did not reach statistical significance (1.8 +/- 8.5 runs w ith progressive exercise, 0.48 +/- 1.8 runs at baseline). Two patients deve loped sustained ventricular tachycardia during progressive treadmill exerci se. One additional patient developed ventricular tachycardia during recover y from both sprint and progressive exercise. Seven patients developed susta ined ventricular tachycardia with exercise during antiarrhythmic therapy fe lt to be effective on the basis of 24-hour ambulatory ECG recording. The ov erall frequency and complexity of ventricular arrhythmias is similar with p rogressive treadmill and sprint exercise, and not statistically different f rom baseline with the exception that repetitive ventricular ectopy was seen more frequently during progressive exercise. Although sustained ventricula r tachycardia is infrequent during exercise even in patients at high risk f or ventricular arrhythmias, it appears to be more frequent during progressi ve treadmill exercise as compared with vigorous sprinting. Although baselin e exercise testing has limited utility in the evaluation of patients underg oing arrhythmia evaluation, exercise testing during antiarrhythmic therapy may detect drug inefficacy or proarrhythmia.