24-hour ambulatory ECG monitorings and treadmill exercise tests were carried out in thirty three healthy men who had frequent premature ventricular contractions. In some of them, both examinations were held three times in a short period.
　Judging from 24-hour ambulatory ECG monitorings, they were divided into four groups (day-type, night-type, all day-type and indefinite-type).
　Judging from exercise tests, they were divided into two groups (exercise-increased-type and exercise-decreased-type). But in most cases, PVC tended to disappear during marked tachycardia.
　Most of exercise-increased-type corresponded to day-type and most of exercise-decreased-type corresponded to night-type.
　The reproducibility of each pattern in 24-hour ambulatory ECG monitorings and exercise tests was good.

DESCENTE SPORTS SCIENCE Vol.5/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE