Comparison between heart rate variability and recovery in ischemic patients.

Both heart variability (HRV) and heart rate recovery (HRR) after exercise are considered to reflect the sympathetic-vagal balance and low values of them have negative prognostic significance, especially in ischemic patients. The main goal of the research was to establish if there is a correlation between HRR and HRV in ischemic patients and if interchangeability between them is possible. There were studied 63 patients with ischemic heart disease: old myocardial infarction, stable angina. unstable angina and silent ischemia. All patients performed exercise stress testing, the heart rate recovery being calculated as the difference between peak heart rate and the rate determined at one minute after the exercise was stopped. The "time-domain" HRV parameters SDANN, SDNN, RMSSD were automatically calculated during a 24 hours Holter ECG monitoring. The mean values were HRR: 39.24 +/- 17.47 beats/min (abnormal in 6% of the patients); HRV: SDNN-112.75 +/- 37.87 msec, SDANN-103.02 +/- 33.25 msec, RMSSD-50.21 +/- 48.15 msec (low HRV in 68.3% of the patients). There was no significant correlation between HRR and HRV's parameters (p > 0.05). There was no significant difference between HRR's mean in subjects with normal or abnormal values of HRV parameters (p > 0.05). Thus, in our study, the HRV values cannot be predicted by the determination of HRR, HRV parameters being more sensible than HRR to reveal increased sympathetic drive.