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Depression of heart function after angiotensin II infusion in patients on chronic hemodialysis
Insights
Patients on regular hemodialysis may have subclinical heart dysfunction. Angiotensin II (AT II) infusion revealed a significant depression in ejection fraction (EF), indicating a limited heart reserve in these patients.
Area of Science:
- Nephrology
- Cardiology
- Pharmacology
Background:
- Patients undergoing regular hemodialysis often exhibit underlying cardiovascular complications.
- Assessing cardiac reserve in hemodialysis patients is crucial for early detection of heart dysfunction.
Purpose of the Study:
- To investigate the cardiac response to angiotensin II (AT II) infusion in patients on maintenance hemodialysis.
- To identify subclinical abnormalities in heart function using AT II as a provocative agent.
Main Methods:
- Eighteen patients on regular hemodialysis received an infusion of angiotensin II (AT II).
- Systolic blood pressure was elevated by 40 mmHg.
- M-mode echocardiograms were performed before and after AT II infusion to assess left ventricular function, including ejection fraction (EF).
Main Results:
- While resting cardiac indices were mostly normal, AT II infusion caused a significant depression in ejection fraction (EF) in hemodialysis patients compared to healthy controls.
- The observed fall in EF in patients (0.64 +/- 0.10) was significantly greater than in healthy subjects (0.76 +/- 0.04).
- No significant changes were noted in left ventricular end-diastolic dimension, stroke index, or cardiac index post-AT II infusion.
Conclusions:
- Angiotensin II (AT II) infusion can unmask subclinical cardiac dysfunction in hemodialysis patients.
- This method is valuable for detecting a limited heart function reserve in patients who may appear to have normal cardiac function at rest.
- Early identification of cardiac abnormalities is essential for managing cardiovascular risk in this population.
Abstract:
The response of heart function to angiotensin II (AT II) was studied in 18 patients on regular hemodialysis. The mean age was 33 years and they had been dialyzed for 55 months in the average. AT II was infused from a large vein and systolic blood pressure was raised by 40 mmHg. Before and after the change in blood pressure, M-mode echocardiogram of left ventricle was recorded. Left ventricular enddiastolic dimension, stroke index and cardiac index were found to be normal except for 9 patients who showed cardiac index above 4.0L/min/m2. No significant change was found in these parameters after the rise of blood pressure by AT II. Control ejection fraction (EF) was slightly but nonsignificantly lower in the patients than the healthy subjects; 0.73 +/- 0.13 vs. 0.80 +/- 0.05. Though significant falls in EF were found in the patient and in the healthy group, the former showed a profound depression of EF to 0.64 +/- 0.10. This value was significantly lower than the value of the latter group; 0.76 +/- 0.04 (p less than 0.01). Since none had overt heart failure, a depression of EF after AT II can be regarded as subclinical abnormality of heart function. AT II will be useful to detect this limited reserve of heart function in patients on regular hemodialysis who may show normal function at rest.