Heart rate variability reflects autonomic balance of the heart. QT dispersion is a marker of cardiac electrical instability in patients with ischemic heart disease.
The HRV analysis showed a significant change of indices reflecting sympatho-vagal balance indicating significantly reduced sympathetic and increased vagal 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.
Int J Cardiol. 1999 Aug 31;70(3):283-92.