Objectives: Heart rate variability (HRV) is the beat-to-beat variation of heart rate and an important non-invasive tool to study the cardiac autonomic nervous system activity. Ischaemic heart disease (IHD) patients are often considered to have a state of sympathetic predominance. Elimination of myocardial ischaemia with percutaneous coronary intervention (PCI) could restore autonomic balance. Hence, this study aimed to evaluate HRV measures, after successful revascularisation among IHD patients. Materials and Methods: A total of 145 male IHD patients planned for coronary angiography were recruited. Fifteen minutes of electrocardiogram recording was done. Short-term HRV analyses of all the patients were acquired and time-domain indices (standard deviation of normal-to-normal intervals [SDNN], root-mean-squared differences of successive R-R intervals [rMSSD]) and frequency-domain indices (low-frequency [LF] power, high-frequency [HF] power and total power [TP]) were analysed. Before and after PCI, all measurements were made. Results: This study included 145 male IHD patients with the mean age of 54.57 ± 10.81 years. There was a significant decrease in SDNN, rMSSD, LF, HF and TP whereas increase in LF/HF ratio following revascularisation. These changes in measures of neurocardiac regulation correlated with risk factors and medication on regression analysis. Conclusion: Increase in LF/HF ratio with the decrease in SDNN, rMSSD, LF, HF and TP in patients with IHD who underwent coronary intervention infers changed cardiac autonomic balance with this surgical procedure. These measures could be potentially used as prognostic measures in the future studies.

Objectives To assess the predictive value of pre-discharge heart rate variability (HRV) parameters in patients with acute coronary syndrome (ACS) treated by percutaneous coronary intervention (PCI). Methods 145 consecutive male patients with ACS (aged 57.12 ± 10.81 years) were included in this study. Fifteen minutes electrocardiogram recording was done to measure time-domain [standard deviation of N–N intervals (SDNN), root-mean square differences of successive R–R intervals (rMSSD)] and frequency-domain [low-frequency (LF) power, high-frequency (HF) power and total power (TP)] HRV parameters before and after PCI. The primary end point was the occurrence of major clinical events (MCE) defined as death, sudden death or re-acute myocardial infarction at the end of 3 months follow-up. Results At a follow-up of 3 months, MCE occurred in 06 patients (4.14%) (Cardiac death was 3.01%, while that of sudden death was 1.13%). Out of six-MCE, four deaths and two re-AMIs occurred. Pre-discharge HRV values (SDNN, rMSSD, TP, LF and HF) were significantly lower in patients with ACS without MCE. Only total power HRV index (AUC=0.748; p=0.040) showed greater prognostic accuracy. Conclusions In conclusion, study showed an increase in SDNN, rMSSD, LF, HF and TP after successful revascularization with PCI in patients who had MCE. The resultant sensitivity, specificity of HRV is still limited in the present study. Particularly, its sensitivity is higher (33–83%) with a modest specificity (61–72%).