Chronic administration of beta blocking agents: left ventricular hemodynamics in myocardial infarctions during exercise
Blümchen, G.; Esche, H.H.
Zeitschrift für Kardiologie 70(9): 678-686
1981
ISSN/ISBN: 0300-5860 PMID: 7303806 Document Number: 174203
Patients (23) with coronary heart disease (22 postmyocardial infarction and 1 with 3- vessel disease), mild angina pectoris and good exercise tolerance were treated for 20 days orally with .beta.-receptor-blocking agents: 9 patients with 120-160 mg propranolol/day and 14 patients with 160-320 mg sotalol/day. Before and after the medication period, Swan-Ganz catheter examinations were performed at rest and during maximal exercise. At rest no significant mean changes were seen in pulmonary mean pressure, in pulmonary capillary pressure and in cardiac output. The exercise tolerance and the heart volume did not change significantly after the medication period. For the remaining parameters the following significant changes were seen: the heart rate at rest fell from 76-60/min (21%), the maximal heart rate (during exercise all values were compared at comparable work-loads) decreased from 127-106/min (16.5%). The systolic blood pressure at rest decreased from 136-123 mm Hg (9.5%) and the maximal systolic blood pressure decreased from 178-157 mm Hg (13%). The diastolic blood pressure at rest decreased from 88-80 mm Hg (9%). The mean pulmonary pressure during maximal exercise increased from 28-37 mm Hg (32%). The pulmonary-capillary pressure increased during exercise from 18-26 mm Hg (44.5%). The cardiac output at rest decreased from 6.9-5.8 l/min (19%). The cardiac output decreased at maximal exercise from 13.9-11.7 l/min (19%). The maximal work-tolerance decreased from 107-100 W (7%) not significantly. In the 3 normal persons the mean pulmonary pressure during maximal exercise was 26 mm Hg before and 24 mm Hg after the medication period. The pulmonary-capillary pressure during maximal exercise was 13 mm Hg before and 14 mm Hg after .beta.-blockade. In this group of normals the maximally reached cardiac output was 15.9 l/min before and 14.4 l/min after the medication period. Because of the small group of patients these results were not evaluated statistically, but the values show that left ventricular function tends to stay normal at rest and during exercise after long-term with .beta.-blocking agents. In patients with postmyocardial infarction there was a decrease of left ventricular function during exercise after a 20-day period of treatment with .beta.-blocking agents. Filling pressures during exercise increased after 20 days of .beta.-blocking agents in all patients, in most cases from normal to pathological values. This indicates a depression on left ventricular function in long-term treatment with .beta.-blocking agents in this group of patients. .beta.-Blocking medication evidently should be prescribed in postmyocardial infarction patients in increasing dosage and only up to the angina pectoris-pain threshold.