Diastolic ventricular interaction in chronic heart failure: relation to heart rate variability and neurohumoral status.

It is likely that abnormal baroreflex control mechanisms are at least partially responsible for autonomic dysfunction in chronic heart failure. We recently demonstrated that diastolic ventricular interaction is associated with impaired baroreflex control of vascular resistance in heart failure. We reasoned that by constraining left ventricular filling, such interaction would decrease baroreflex activity and, thereby, increase sympathetic and decrease parasympathetic outflow. We hypothesized, therefore, that diastolic ventricular interaction in chronic heart failure patients would be associated with autonomic dysfunction. We used radionuclide ventriculography to measure changes in left and right ventricular end-diastolic volumes during acute volume unloading achieved by -30 mm Hg lower-body negative pressure in 30 patients with chronic heart failure. An increase in left ventricular volume in association with a reduction in right ventricular volume indicates diastolic ventricular interaction (a larger increase indicating a greater degree of interaction). We also measured heart rate variability (n = 23) and resting venous plasma norepinephrine (n = 24), epinephrine (n = 24), and atrial natriuretic peptide (ANP) (n = 14). During lower-body negative pressure, while right ventricular volume decreased in all patients (P < 0.001), left ventricular end-diastolic volume increased (from 152 +/- 25 to 157 +/- 36 ml/m2, P = 0.01). The change in left ventricular volume was positively correlated with resting plasma norepinephrine (P < 0.01) and ANP (P < 0.005), and negatively correlated with the standard deviation of normal to normal R-R intervals (P < 0.005), the root-mean-square of differences between successive normal to normal R-R intervals (P < 0.05), total power (P < 0.01), low-frequency power (P < 0.01), and high-frequency power (P < 0.05). Diastolic ventricular interaction in patients with chronic heart failure is associated with sympathetic nervous system activation evidenced by increased plasma norepinephrine and reduced heart rate variability.