[Heart rate variability in patients treated with percutaneous transluminal coronary angioplasty]

Abstract

Decreased heart rate variability (HRV) is an independent risk factor for sudden cardiac death in patients with coronary artery disease (CAD) and previous myocardial infarction. The influence of myocardial revascularization on HRV parameters has been investigated for the past few years. However, little is known about HRV behaviour in patients with CAD treated with percutaneous transluminal coronary angioplasty (PTCA). The purpose of this study was to estimate HRV parameters before PTCA and during a one year follow-up. We examined 65 patients (47 men, 18 women; mean age 51.2 +/- 7.6), who underwent successful and uncomplicated PTCA. Thirty eight patients had a prior myocardial infarction. The mean left ventricular ejection fraction was 59.8 +/- 8.1%. Thirty-nine patients had a single-vessel disease, 25 patients had a double-vessel disease and one patient had a triple-vessel disease. Serial 24-hour Holter monitoring (before PTCA, 14 days, 3, 6, 12 months after PTCA) was performed in all patients. The following time domain measures of HRV were calculated from each recording, for 24-hours: pNN50, SDNN, SDANN and rMSSD. During the one year follow-up, a significant increase of pNN50, SDNN and SDANN was observed. We noted, that the statistically significant increase of the above-mentioned parameters occurred during the first 3 month follow-up. The results of the next serial recordings (6 and 12 months after PTCA) demonstrated no additional changes in HRV values, however they were still significantly higher than before procedure. Mean values of HRV parameters before PTCA and 3 months after were as follows: pNN50: 8.8 +/- 6.8%, vs 11.7 +/- 9.4% (p < 0.05), SDNN: 121.2 +/- 33.5 ms vs 148.2 +/- 29.3 ms (p < 0.05), SDANN: 113.6 +/- 16.2 ms vs 125.1 +/- 22.3 ms (p < 0.05). Parameter rMSSD did not change significantly during the whole observation.

Conclusions: 1. Myocardial revascularisation with successful PTCA leads to an improvement in the autonomic modulation of heart rate. 2. The increase in parasympathetic control of the heart rate is already being observed 2 weeks after successful PTCA. 3. Beneficial increased influence of both parts of the autonomic nervous system on heart rate persists for 12 months after coronary angioplasty.