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[Functional state of the myocardium during stenocardia induced by isoproterenol]
Insights
Patients with chronic coronary heart disease exhibit a diminished inotropic response to isoproterenol, especially when experiencing angina. Myocardial ischemia significantly impairs contractility, correlating with disease severity.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Context:
- Investigating hemodynamic responses in chronic coronary heart disease (CHD).
- Comparing physiological reactions between healthy individuals and CHD patients.
Purpose:
- To compare hemodynamic changes in healthy subjects versus patients with chronic coronary heart disease.
- To assess the inotropic effect of isoproterenol and its relation to myocardial ischemia in CHD patients.
Summary:
- Isoproterenol-induced tachycardia revealed a less pronounced beneficial inotropic effect in CHD patients who developed angina compared to healthy subjects and angina-free patients.
- Myocardial contractility, measured by the rheographic index, initially increased with drug infusion but reversed course during ST segment depression, indicating worsening ischemia.
- Impairments in the inotropic response correlated with the severity of myocardial ischemia and the clinical course of the disease.
Impact:
- Highlights the compromised cardiac function in CHD patients, particularly during ischemic episodes.
- Provides insights into the physiological mechanisms underlying reduced contractility in coronary heart disease.
- Suggests potential for monitoring disease severity and therapeutic response through hemodynamic assessments.
Abstract:
Hemodynamic changes in healthy subjects versus patients with chronic coronary heart disease are compared. In cases of isoproterenol caused tachycardia, the patients developing angina showed a less prominent beneficial inotropic effect as compared with healthy subjects and angina-free patients. The initiation of drug infusion led to a marked increase in the rheographic index of myocardial contractility; however, already in the initial stages of ST segment depression, this parameter was characterized by a reversed time-course which progressed with the increasing electrocardiographic signs of myocardial ischemia. The degree of the observed impairments of the patients' inotropic response correlated with the severity of myocardial ischemia and the nature of the disease course.