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Angiotensin infusion effects on left ventricular function. Assessment in normal subjects and in patients with
Insights
Angiotensin infusion impairs left ventricular function in both healthy individuals and those with coronary artery disease (CAD). This effect differs significantly from exercise, making it unsuitable for radionuclide ventriculography.
Area of Science:
- Cardiology
- Nuclear Medicine
- Pharmacology
Background:
- Assessing left ventricular (LV) function is crucial for diagnosing and managing cardiovascular diseases.
- Radionuclide ventriculography is a common technique for evaluating cardiac performance.
- Understanding the hemodynamic effects of vasoactive substances like angiotensin is important for clinical applications.
Purpose of the Study:
- To evaluate the impact of angiotensin infusion on left ventricular function in normal subjects and patients with coronary artery disease (CAD).
- To compare the effects of angiotensin infusion with supine exercise on cardiac performance.
- To determine the suitability of angiotensin infusion as a stress agent in intervention radionuclide ventriculography.
Main Methods:
- Radionuclide multigated acquisition (MUGA) scans were used to assess cardiac cycle.
- Hemodynamic parameters including heart rate (HR) and systolic blood pressure (BP) were monitored.
- Left ventricular ejection fraction (EF) was calculated before and during angiotensin infusion and exercise.
Main Results:
- In normal subjects, angiotensin infusion decreased HR and EF while increasing systolic BP.
- Supine exercise in normal subjects increased HR, systolic BP, and EF.
- In patients with CAD, angiotensin infusion did not change HR, increased systolic BP, and decreased EF.
Conclusions:
- Angiotensin infusion induces left ventricular depression in both normal individuals and patients with CAD.
- The hemodynamic response to angiotensin infusion is not comparable to exercise.
- Angiotensin infusion is not a suitable substitute for exercise in intervention radionuclide ventriculography.
Abstract:
Radionuclide multigating of the cardiac cycle was employed to assess effects of angiotensin infusion on left ventricular function. In six normal subjects, angiotensin infusion decreased heart rate (HR) from 72 +/- SEM 2 to 57 +/- 2 beats/min (P less than 0.001); while systolic blood pressure (BP) increased from 119 +/- 2 to 178 +/- 1 mm Hg (P less than 0.001), and ejection fraction (EF) declined from 58 +/- 1 to 47 +/- 2 percent (P less than 0.05). In contrast, in 11 normal subjects, supine exercise increased HR and systolic BP by 55 and 49 percent, whereas EF increased from 64 +/- 1 to 71 +/- 1 (P less than 0.001). In ten patients with CAD, angiotensin infusion produced no change in HR, increased systolic BP by 34 percent, and decreased EF by 11 percent. Angiotensin infusion induced left ventricular depression in normal subjects and in patients with CAD. It cannot substitute for exercise in intervention radionuclide ventriculography.