[The influence of age on left ventricular function in patients with recent myocardial infarct]

To assess the effects of age on the left ventricular function at rest and during exercise in patients with first recent myocardial infarction, a symptom-limited exercise test was performed in 470 patients within 2 months from the acute episode, in supine position during hemodynamic and electrocardiographic monitoring after drug interruption and wash-out period. According to the age, the patients were divided into 3 groups: group 1 (less than or equal to 40 years) 68 patients; group 2 (41-59 years) 319 patients and group 3 (greater than or equal to 60 years) 83 patients. Coronary angiography was performed within 6 months in 159 patients. The possible differences in the hemodynamic pattern of these groups were analyzed with ANOVA and chi 2 test. Pulmonary artery end-diastolic pressure and cardiac output of each patient were compared to the normal values obtained in different age groups. The normal limits adopted are reported. At rest cardiac output and stroke volume were significantly lower and the rate pressure product higher in patients of group 3. Maximal work load was significantly lower (62 +/- 26 watts p less than .05) and pulmonary artery end-diastolic pressure higher (27 +/- 7 mmHg, p less than .05) in group 3 as compared to groups 2 (78 +/- 29 watts, 23 +/- 8 mmHg) and 1 (94 +/- 28 watts, 19 +/- 9 mmHg). However using different normal limits according to age (less than or equal to 20 mmHg in patients less than or equal to 60 years and less than or equal to 25 mmHg in patients greater than 60 years) the number of patients with an abnormal increase of pulmonary artery end-diastolic pressure was similar in all groups: 39.7%, 60.6% and 50.6% (NS) in group 1, 2 and 3 respectively. On the contrary cardiac output was abnormally low during exercise in 16.8% of group 3 vs 5.6% and 5.8% of groups 2 and 1 (p less than .05). The greater hemodynamic impairment of group 3 was independent from the electrocardiographic size of necrosis, from ST-segment depression during exercise and from the number of involved coronary vessels. In conclusion, age seems to play a significant role in determining the hemodynamic pattern in patients with recent myocardial infarction.