Long-term beta-blocker therapy improves autonomic nervous regulation in advanced congestive heart failure: A longitudinal heart rate variability study

Background p-Blocker therapy is believed to modulate the detrimental effect of overcompensating neurohormonal activation in chronic heart failure. How ever, clinical doubts remain, particularly the physiologic sympathovagal ba lance. Methods To respond to clinical concern about worsening autonomic nervous pe rturbation in P blocker therapy of advanced congestive heart failure, 15 co nsecutive patients were longitudinally studied to elucidate the evolution o f cardiac function versus 24-hour heart rate variability (HRV) before and a fter 1, 3, and 6 to 9 months of atenolol-combined therapy. Results Two patients died prematurely within 1 month. All 13 surviving pati ents showed improvement in New York Heart Association functional class, wit h decrease in left ventricular end-systolic and end-diastolic dimensions an d increase in fraction shortening and election fraction by echocardiography after at least 3 months of atenolol use. The retarded therapeutic effect w as accompanied by a general rise of total, very low, low-, and high-frequen cy components (9.0 +/- 0.5, 8.8 +/- 0.5, 6.2 +/- 0.6, and 6.1 +/- 0.5 vs 10 .9 +/- 0.3, 10.7 +/- 0.4, 8.6 +/- 0.3, and 7.8 +/- 0.3; all P < .02) of dai ly HRV. This implied recovery of parasympathetic and baroreceptor function. Return of sympathovagal interaction was further supported by the suppressi on of Cheyne-Stokes type HRV as detected by Wigner-Ville distribution. Conclusions Long-term P-blocker therapy for advanced congestive heart failu re upwardly regulates the autonomic nervous interaction in synchrony with t he evolution of cardiac function performance.