Prevalence and reproducibility of exercise-induced ventricular arrhythmias during maximal exercise testing in normal men

The occurrence of ventricular arrhythmias at rest or during ordinary daily activities has been implicated as a risk factor for future coronary-related events and sudden death. However, the clinical significance of exercise-induced ventricular arrhythmias remains uncertain. To assess the prevalence and reproducibility of such arrhythmias, two serial maximal treadmill exercise tests were performed in a study population of 543 male Indiana State policemen at an average interval of 2.9 years. Four hundred sixty-two subjects were clinically free of evidence of cardiovascular disease, and 81 had evidence of definite or suspected cardiovascular disease. The prevalence of exercise-induced ventricular arrhythmias during the first test was 30 percent in men aged 25 to 34 years, 32 percent in those aged 35 to 44 years and 36 percent in those aged 45 to 54 years. The prevalence rate in these age groups with repeat testing was 36, 38 and 42 percent, respectively. These differences were not statistically significant. The group with definite or suspected cardiovascular disease had a greater prevalence of exercise-induced ventricular arrhythmias than normal subjects during both tests but the prevalence rate with repeat testing remained constant. The occurrence of exercise-induced ventricular arrhythmias was reproducible in individual subjects during the second test in 55 percent of 25 to 34 year olds, 58 percent of 35 to 44 year olds and 62 percent of 45 to 54 year olds. Thus, individual reproducibility in two consecutive tests was only slightly greater than reproducibility by chance alone. The group with known or suspected cardiovascular disease demonstrated a trend toward greater reproducibility with repeat testing. Exercise-induced ventricular arrhythmias were not reproducible by type or complexity. The marked variability of exercise-induced ventricular arrhythmias during repeat maximal exercise testing in a clinically normal population appears to negate the usefulness of this finding during a single test as a marker of future cardiovascular disease. Nevertheless, subjects whose arrhythmias were reproducible may form a group destined to manifest clinical cardiovascular disease in long-term follow-up studies.