Favorable effects of orally administered digoxin on left heart size and ventricular wall motion in patients with previous myocardial infarction

Abstract

The effects of maintenance oral digoxin therapy on segmental left ventricular wall motion (wall motion videotracking) and left heart size (radiographic left heart dimension) were evaluated in 14 patients with a prior myocardial infarction but without clinical signs or symptoms of congestive heart failure. The left heart dimension decreased in all six patients with cardiomegaly from an average of 55.0 ± 1.6 (standard deviation) to 52.2 ± 2.7 mm/m 2 body surface area ( P < 0.01) during digoxin therapy. However, there was no significant change in the eight patients with normal heart size. In the resting state, the average extent of shortening in normal segments increased significantly from 3.1 ± 0.8 to 4.2 ± 1.2 mm during digoxin therapy. During submaximal handgrip exercise, the extent of shortening averaged 4.0 ± 1.3 mm and increased further with digoxin therapy to 5.1 ± 2.1 mm. The effects of digoxin therapy on the maximal velocity of shortening in normal segments at rest and during handgrip exercise were similar. In all 14 patients, there was a decrease in the number of segments with abnormal wall motion at rest or with handgrip exercise during digoxin therapy. With therapy, the number of abnormal sites decreased from 52 to 35 in the resting state and from 84 to 49 during handgrip exercise. Thus, in patients 6 or more months after transmural myocardial infarction, orally administered digoxin decreases cardiomegaly, increases the extent and maximal velocity of shortening in normal left ventricular segments and often reduces the extent of abnormal wall motion at rest or during isometric exercise.