Role of Heart Rate Variability Testing in Predicting Coronary Stenosis in Non-Acute Clinical Setting

BACKGROUND Reduced heart rate variability (HRV) is associated with an increased risk of cardiovascular morbidity and mortality. The aim of the study was to determine whether reduced HRV is predictive of angiographic coronary artery disease (CAD) METHODS This study was done among 71 clinically stable subjects who underwent elective coronary angiography for diagnosis or pre-operative evaluation. High frequency (HF; 0.15 – 0.40 Hz), low frequency (LF; 0.04 – 0.15 Hz), LF / HF ratio, total power ≤ 0.4 Hz were used as the conventional indices of HRV. Analysis of variance (ANOVA) and chi square test was used to assess the statistical analysis. Statistical significance analysis was carried out with International Business Machines Statistical Package for the Social Sciences (IBM SPSS) version 22. RESULTS Out of 71 subjects, only 58 were available for final analysis. 20 subjects had normal coronary arteries, 19 had single vessel disease and remaining 19 had multi vessel disease. The HF power of HRV showed decreasing trend as the severity of angiographic stenosis increased. The median values of LF power for single vessel disease and multi vessel disease were 148 ms2 and 160 ms2 respectively. The group without coronary artery disease has a median of 215 ms2 for LF power. The median HF power was lower in single vessel disease group (133 ms2 ) compared to group with normal coronaries (139 ms2 ) and it was very low in multi vessel disease (81 ms2 ) group compared to group with normal coronaries. CONCLUSIONS A weak association of HF and LF power of HRV with degree of angiographic stenosis was observed.