The HRV analysis showed a significant change of indices reflecting sympatho-vagal balance indicating significantly reduced sympathetic (LF) and increased 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 the dispersion was further diminished 2 years later.
http://www.sciencedirect.com/science/article/pii/S0167527399001011
http://www.sciencedirect.com/science/article/pii/S0167527399001011