Related Experiment Videos
[Risks of treatment with beta-blocking agents in acute myocardial infarction (author's transl)]
Insights
Intravenous propranolol in acute myocardial infarction reduced cardiac output and increased pulmonary pressures. Its use is beneficial only when cardiac index exceeds 3.0 L/min/m², otherwise it can worsen heart failure.
Area of Science:
- Cardiology
- Pharmacology
- Physiology
Context:
- Acute myocardial infarction (AMI) management involves balancing hemodynamic stability with therapeutic interventions.
- Beta-blockers are commonly used, but their effects in AMI require careful consideration.
Purpose:
- To investigate the hemodynamic effects of intravenous propranolol in patients with acute myocardial infarction.
- To determine the influence of baseline cardiac index on propranolol's efficacy and safety.
Summary:
- Hemodynamic investigations in 40 AMI patients showed intravenous propranolol (6 mg) decreased cardiac index, heart rate, and stroke volume, while increasing pulmonary capillary pressure.
- Left ventricular stroke work decreased beneficially when baseline cardiac index was >3.0 L/min/m², but worsened when <3.0 L/min/m², leading to heart failure ranges.
- Arterial blood pressure remained largely unchanged, but pulmonary and peripheral vascular resistance increased.
Impact:
- Findings highlight cardiac index as a critical determinant for using beta-blockers in AMI.
- Suggests that indiscriminate use of beta-blocking agents in AMI can be detrimental, particularly in patients with lower cardiac output.
Abstract:
Haemodynamic investigations were performed in 40 patients with acute myocardial infarction before and after intravenous application of 6 mg propranolol. Cardiac index was significantly decreased caused by reduction of cardiac frequency and stroke volume. Pulmonary capillary pressure increased significantly. As a consequence pulmonary and peripheral vascular resistance increased. Arterial blood pressure remained largely unaffected. Propranolol showed a haemodynamically beneficial decrease of left ventricular stroke work without signs of negative cardiodepression at a cardiac index of more than 3.0 l/min . m2. At a cardiac index of less than 3.0 l/min . m2 a haemodynamically detrimental lowering of cardiac index to ranges of insufficiency of 2.0 l/min . m2 on average occurred. Thus cardiac index is an important factor for the decision of use of beta-blocking agents in acute myocardial infarction. Indiscriminate use of beta-blocking substances should not be accepted.