Reduced heart rate variability in ischemic heart disease is only partiallycaused by ischemia - An HRV study before and after PTCA

Background: Reduced heart rate variability (HRV) after acute myocardial inf arction (AMI) indicates poor prognosis. HRV in patients with uncomplicated coronary artery disease is reduced, and an association with poor prognosis has been suggested. The mechanism of the HRV reduction is not known, but is chemia is a possibility. Aim: To evaluate, in angina patients with no prior AMI, no other disease and drug-free, if complete revascularization and thu s important reduction of ischemia by means of PTCA influences HRV. Patients and Methods: Twenty-four-hour Holter recordings were performed at baseline prior to PTCA in 48 patients with angina and in 41 age-matched healthy con trol subjects. The recording was repeated 1 and 6 months after complete rev ascularization. in addition, HRV was registered during controlled respirati on in the supine and standing positions and during cold pressure test at ba seline in all angina patients and controls and in 17 consecutive angina pat ients 6 months after PTCA. Results: Compared to controls, angina patients h ad a significantly reduced mean RR interval (p = 0.02), SD (g = 0.003), rMS SD (p = 0.03), pNN50 (p = 0.03), total power (p = 0.003), low- (p = 0.004) and high-frequency peak (p = 0.04), but normal SDNN, SDANN and LF/HF. One a nd 6 months after PICA, 42/46 and 32/ 40 follow-up patients, respectively, were free of angina. Six months after PICA, there was a significant recover y of vagal modulation seen in the frequency domain during controlled respir ation, but only nonsignificant trends in HRV parameters analyzed over 24 h. Conclusion: Patients with uncomplicated angina had reduced HRV, mainly aff ecting vagal activity, but normal low frequency variability associated with mortality. Complete revascularization caused a partial normalization of va gal modulation indicating that ischemia may be one of but not the only mech anism of the HRV reduction in uncomplicated chronic coronary artery disease . Copyright (C) 2001 S. Karger AG, Basel.