Long-term effect of endoscopic transthoracic sympathicotomy on heart rate variability and QT dispersion in severe angina pectoris

We evaluated short and long-term effects on QT dispersion and autonomic bal ance after endoscopic transthoracic sympathicotomy (ETS). Heart rate variab ility (HRV) reflects autonomic balance of the heart. QT dispersion is a mar ker of cardiac electrical instability in patients with ischemic heart disea se. Holter recordings for 24 h and a twelve-lead ECG were made prior to, 1 month, 1 year and 2 years after ETS. HRV was analysed in time domain and sp ectral analysis was performed during controlled respiration in supine posit ion and during head up tilt. Dispersion of QT time and QTc were calculated. Of 88 patients, 62 (60) were eligible for HRV (QT-dispersion) analysis aft er 1 month, 39 (38) patients after 1 year and 23 (24) patients after 2 year s. The HRV analysis showed a significant change of indices reflecting sympa tho-vagal balance indicating significantly reduced sympathetic (LF) and inc reased vagal (HF, rMSSD) tone. These changes still persisted after 2 years. Global HRV increased over time with significant elevation of SDANN after 2 years. QT dispersion was significantly reduced 1 month after surgery and t he dispersion was further diminished 2 years later. Conclusion: ETS changed HRV and QT dispersion which could imply reduced risk for malignant arrhyth mias and death after ETS, (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.