Beneficial effects of nitroglycerin on abnormal ventricular wall motion at rest and during exercise in patient with previous myocardial infarction.

The effects of sublingually administered nitroglycerin on segmental left ventricular wall motion determined by videotracking and radiographic left heart size were evaluated at rest and during submaximal hand grip exercise in 10 patients with previous transmural myocardial infarction. After nitroglycerin, diastolic left heart size decreased in the resting state from an average of 49.5 +/- 5.7 (standard deviation) to 47.9 +/- 5.6 mm/m2 body surface area (P less than 0.01) and during handgrip exercise from a mean of 50.7 +/- 590 to 49.1 +/- 4.7 mm/m2 (P less than 0.05). In the resting state, the average maximal velocity of shortening in segments with normal wall motion increased after nitroglycerin from 18.1 +/- 3.0 to 23.5 +/- 5.5 mm/sec (P less than 0.01), whereas during handgrip exercise alone, the velocity of shortening averaged 25.6 +/- 6.9 mm/sec and increased further after nitroglycerin to 30.1 +/- 10.6 mm/sec (P less than 0.05). The effects of nitroglycerin on the average extent of shortening in normal segments were similar. In all 10 patients, there was a decrease in the number of segments with abnormal wall motion. The number of sites with dyssynergy decreased after nitroglycerin from 24 to 15 in the resting state and from 40 to 22 when nitroglycerin was administered before handgrip exercise. Sublingually administered nitroglycerin appears to decrease left heart size, increase the velocity and extent of shortening in normal left ventricular segments and often reduce the extent of left ventricular wall motion abnormalities at rest and during isometric exercise in patients with previous transmural myocardial infarction.