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 parti ally responsible for autonomic dysfunction in chronic heart failure. We rec ently demonstrated that diastolic ventricular interaction is associated wit h impaired baroreflex control of vascular resistance in heart failure. We r easoned that by constraining left ventricular filling, such interaction wou ld decrease baroreflex activity and, thereby, increase sympathetic and decr ease parasympathetic outflow. We hypothesized, therefore, that diastolic ve ntricular 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 b y -30 mm Hg lower-body negative pressure in 30 patients with chronic heart failure. An increase in left ventricular volume in association with a reduc tion in right ventricular volume indicates diastolic ventricular interactio n (a larger increase indicating a greater degree of interaction). We also m easured heart rate variability (n = 23) and resting Venous plasma norepinep hrine (n = 24), epinephrine (n = 24), and atrial natriuretic peptide (ANP) (n = 14). During lower-body negative pressure, while right ventricular volume decreas ed in all patients (P < 0.001), left ventricular end-diastolic volume incre ased (from 152 +/- 25 to 157 +/- 36 ml/m(2), P = 0.01). The change in left ventricular volume was positively correlated with resting plasma norepineph rine (P < 0.01) and ANP (P < 0.005), and negatively correlated with the sta ndard deviation of normal to normal. R-R intervals (P < 0.005), the root-me an-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 hig h-frequency power (P < 0.05). Diastolic ventricular interaction in patients with chronic heart failure is associated with sympathetic nervous system a ctivation evidenced by increased plasma norepinephrine and reduced heart ra te variability.