Acute volume expansion increased left ventricular ejection fraction and parasympathetic heart rate variability in normal subjects, but decreased them in dilated cardiomyopathy patients (P<0.001).
Does acute isotonic volume expansion affect heart rate variability and left ventricular volumes differently in patients with dilated cardiomyopathy compared to normal subjects?
Acute volume overload induces parasympathetic activation in normal subjects but exacerbates parasympathetic withdrawal and depresses left ventricular ejection fraction in patients with dilated cardiomyopathy.
p-value: p=<0.001
This study evaluated the effects of acute isotonic volume expansion on heart rate variability (HRV) in 10 patients with dilated cardiomyopathy (DCM) and in 10 age- and sex-matched normal volunteers. Echocardiographic left ventricular volumes and HRV measurements by continuous Holter recording were assessed at baseline, at 60 and 120 min during intravenous saline load (0.9% NaCl, 0.25 ml. kg(-1). min(-1)), and 60 min after infusion was terminated. Data analysis was performed by repeated-measures ANOVA. After volume expansion, left ventricular ejection fraction increased (F = 9.8; P 50 ms (F = 97.6; P < 0.001), high-frequency power (F = 50.1; P < 0.001), and low-frequency power (F = 41.6; P < 0.001), all of which reflect parasympathetic modulation of heart rate; in fact, these measurements increased in normal subjects and decreased in DCM patients. In normal subjects, the increase in HRV measurements during volume expansion suggests a parasympathetic activation, mediated by stimulation of cardiopulmonary and arterial mechanoreceptors. On the contrary, in DCM patients the parasympathetic withdrawal, already detectable at baseline, increases during volume expansion.
Spinelli et al. (Fri,) conducted a other in Dilated cardiomyopathy (n=20). Intravenous saline load vs. Normal volunteers was evaluated on Heart rate variability and left ventricular ejection fraction (p=<0.001). Acute volume expansion increased left ventricular ejection fraction and parasympathetic heart rate variability in normal subjects, but decreased them in dilated cardiomyopathy patients (P<0.001).