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Effects of losartan treatment on cardiac autonomic control during volume loading in patients with DCM
M Petretta1, L Spinelli, F Marciano
1Department of Internal Medicine, Cardiology and Heart Surgery, University of Naples Federico II, 80131 Naples, Italy.
Insights
Losartan treatment improves cardiac autonomic control and increases urine output in patients with dilated cardiomyopathy (DCM) during volume overload. This enhances heart failure management by improving autonomic adaptation and fluid balance.
Area of Science:
- Cardiology
- Pharmacology
- Autonomic Nervous System
Background:
- Idiopathic dilated cardiomyopathy (DCM) affects cardiac autonomic control.
- Heart failure patients often have impaired responses to volume loads.
- Angiotensin II receptor blockers are used in heart failure management.
Purpose of the Study:
- To evaluate the effect of losartan on cardiac autonomic control and urine output in DCM patients with volume overload.
- To assess changes in heart rate variability and left ventricular function before and after losartan treatment during saline infusion.
Main Methods:
- 14 patients with DCM underwent saline load before and after 2 months of losartan treatment.
- Measurements included left ventricular volumes, ejection fraction, and heart rate variability (time-domain and frequency-domain).
- Urine output was monitored during the saline load.
Main Results:
- Losartan treatment lowered blood pressure and increased left ventricular ejection fraction.
- Ejection fraction decreased during saline load before losartan but remained stable afterward.
- Urinary volume increased post-losartan treatment during saline load.
- Vagal modulation of heart rate and heart rate variability power spectra improved after losartan treatment.
Conclusions:
- Losartan treatment improves cardiac autonomic adaptation in DCM patients during volume overload.
- Angiotensin II receptor blockade enhances urine output in response to volume challenges.
- Losartan offers a therapeutic benefit for autonomic dysfunction and fluid management in DCM.
Abstract:
This study evaluated the effect of angiotensin II receptor blockade on cardiac autonomic control adaptation and urine output in response to acute isotonic volume load in patients with idiopathic dilated cardiomyopathy (DCM) and asymptomatic to mildly symptomatic heart failure. Left ventricular volumes and heart rate variability measurements were assessed at baseline and during intravenous saline load in 14 patients before and after 2 mo of losartan treatment. After losartan treatment, blood pressure values were lower, whereas left ventricular ejection fraction was higher (F = 79, P < 0.001), than before treatment. During saline load, ejection fraction decreased before losartan treatment (F = 5.6, P < 0.05) but did not change after treatment. Urinary volume, unchanged during saline load in untreated patients, increased after losartan (F = 9.38, P < 0. 001). Time-domain measurements that represent vagal modulation of heart rate (root-mean-square successive differences and percentage of differences between successive R-R intervals >50 ms) decreased during saline load in untreated patients (F = 3.1, P < 0.05 and F = 6.5, P < 0.01, respectively), but not after losartan. Similarly, a decrease in very low frequency (F = 3.2, P < 0.05), low-frequency (F = 2.9, P < 0.05), and high-frequency power (F = 6.1, P < 0.01) after saline load was observed only in untreated patients. In patients with DCM, losartan treatment improves the cardiac autonomic adaptation and increases urine output in response to volume overload.