Decreased heart rate variability and multivessel coronary artery disease.

Purpose: According to reports from the WHO, coronary artery disease (CAD) is an increasing cause of death in the developing countries. Public education and inexpensive testing for early diagnosis and risk stratification of CAD can be important tools in reducing cardiovascular morbidity and mortality. Decreased heart rate variability (HRV) is common among subjects suffering of CAD. We explored the hypothesis that very low HRV as assessed by 24-hour ECG-monitoring might be of help to identify patients with advanced CAD. Methods: We studied 150 patients referred for coronary angiography according to clinical needs. The severity of coronary atherosclerosis was evaluated by the presence of single-vessel versus multi-vessel disease. We assessed time domain measures of HRV by 24-hour ECG-monitoring. Previously validated cut off points of HRV were used for this analysis. PNN50<3%, RMSSD<25 ms, SDANN< 50ms and SDNN <100ms were indexes of very low HRV. Results: PNN50 <3%, RMSSD <25ms, SDNN <100 ms, and SDANN <50 ms resulted remarkably higher in multi-vessel than single-vessel disease (p<0.005). The discriminatory capacity of the cut-off values is shown in table. PNN50