Rate and extent of recovery of left ventricular function in patients following acute myocardial infarction

To determine the rate and extent of recovery of left ventricular (LV) performance following acute myocardial infarction (MI), peak aortic blood acceleration was measured serially in 26 patients and in 11 normal volunteers with a continuous wave Doppler placed suprasternally. In patients, Doppler measurements were made 20 ± 2 hours after the acute onset of chest discomfort and were repeated daily for 6 consecutive days. Infarction patients were divided into two groups. Group I consisted of 15 patients who did not have a previous MI and whose present course was not complicated by congestive heart failure (CHF). Group II consisted of 11 patients who had either a previous MI or developed CHF during the present admission. Peak acceleration in the normal volunteers showed minimal daily variations over a period of 6 days. Peak acceleration in the entire group of 26 MI patients increased from 13 ± 3 m/sec/sec on the day of admission (day 1) to 18 ± 6 m/sec/sec on day 6 (p < 0.001). In group I, peak acceleration increased from 13 ± 4 to 20 ± 6 m/sec/sec between day 1 and day 6 (p < 0.001). In group II, however, peak acceleration was 12 ± 2 m/sec/sec on day 1 and increased to only 15 ± 4 m/sec/sec on day 6 (NS). These results indicate that LV performance, based upon peak acceleration of blood in the ascending aorta, improves markedly within 6 days in patients suffering their first MI uncomplicated by CHF. In patients with a previous MI or in patients with a first MI complicated by CHF, LV performance shows a statistically insignificant recovery by the sixth day.