Response to upright exercise after myocardial infarction

The left ventricular response to upright bicycle exercise was studied in 39 unselected, non-beta blocked patients (mean(SEM) age 54.2(1.7)yr) (mean(SEM) resting ejection fraction 41.9(2.3)%) 8-10 weeks after myocardial infarction. Nine healthy, age matched, sedentary adult men were studied for compa...

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Veröffentlicht in:Cardiovascular research 1987-06, Vol.21 (6), p.399-406
Hauptverfasser: HETHERINGTON, MAXINE, TEO, KOON K, HAENNEL, ROBERT G, ROSSALL, RICHARD E, KAPPAGODA, TISSA
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Sprache:eng
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Zusammenfassung:The left ventricular response to upright bicycle exercise was studied in 39 unselected, non-beta blocked patients (mean(SEM) age 54.2(1.7)yr) (mean(SEM) resting ejection fraction 41.9(2.3)%) 8-10 weeks after myocardial infarction. Nine healthy, age matched, sedentary adult men were studied for comparison (mean(SEM) age 49.8(0.9) yr). The stroke volume and cardiac output were measured by impedance cardiography at rest and after each 3 min workload until symptom limited maximum. The patients were separated into three groups based on stroke volume response to graded exercise. Group 1 (n=14) had a normal stroke volume response to increasing heart rate. In group 2 (n=13) stroke volume increased initially then decreased by >15% at a heart rate >100-105 beats·min−1. In group 3 (n= 12) stroke volume failed to increase during exercise. In group 1 cardiac output and mean arterial pressure increased whereas vascular resistance decreased during exercise in a normal fashion. Group 2 had an increased mean arterial pressure and systemic vascular resistance throughout exercise while heart rate increased in a similar fashion to group 1 until work of >70 W was undertaken, at which time heart rate increased in a curvilinear fashion and cardiac output was attenuated. Group 3 had an attenuated cardiac output and a higher heart rate during exercise. In this group of patients systemic vascular resistance failed to decrease normally during exercise. These results suggest that non-invasive identification of patient groups by determining the stroke volume to heart rate response to exercise (a) defined patients with increased vascular resistance and reduced ventricular function, which was not apparent by other available clinical data, and (b) may be important in planning long term management, such as exercise prescription and vasodilator treatment or inotropic treatment, or both.
ISSN:0008-6363
1755-3245
DOI:10.1093/cvr/21.6.399