Effects of digoxin on left ventricular function in coronary artery disease patients

To assess whether digitalis modifies or prevents the deterioration of the left ventricular ejection fraction and wall motion during acute ischemia, we performed gated blood pool radionuclide ventriculograms in 15 patients with angiographically documented coronary artery disease. All patients were studied in the resting state and during maximal supine bicycle exercise, both before and 1 hour after 1 mg intravenous digoxin.There was no significant difference, pre-digoxin vs post-digoxin, in exercise tolerance (415 ± 84 vs 418 ± 107 seconds), number of segments with abnormal resting wall motion (12 vs 11) or exercise wall motion (21 vs 19). Ten patients developed angina during the same exercise load, irrespective of digoxin administration. Twelve patients had subnormal left ventricular ejection fraction during exercise pre-digoxin, vs 13 patients post-digoxin (P = ns). In the resting state, the left ventricular ejection fraction was higher after digoxin (53 ± 14% pre vs 58 ± 14% post, P < 0.05). During exercise, however, the left ventricular ejection fraction was not significantly improved after digoxin (50 ± 16% pre vs 53 ± 17% post, P = ns).These data indicate that although acute administration of digoxin improves the resting left ventricular function, it does not improve exercise tolerance to angina. Furthermore, intravenous digoxin does not appear to prevent the deterioration of left ventricular wall motion and ejection fraction during exercise induced ischemia.