Influence of Deep Breathing on Heart Rate Variability in Patients with Ischemic Heart Disease

Abstract

HRV was assessed in 121 consecutive patients on 3-7 days after admission. Patients were instructed to take 6 deep respirations in 1 minute while changes in heart rate were measured and calculated by an electrocardiographic recorder automatically. The test result was defined as a difference between the shortest and longest heart rate interval: HRV = [60.000/Short R-R interval (msec)] - [60.000/Long R-R interval (msec)], measured in beats per minute. HRV was less than 10 beats/min in 27% of the patients, between 10 to 20 beats/min in 46% of patients, and more than 20 beats/min in 27% of patients. HRV less than 10 beats/min was in 35% of patients with myocardial infarction, 27.6% in patients with coronary artery stenosis and 18.4% in patients without coronary artery stenosis. The value of HRV during deep breathing test was found to be lower in patients with coronary artery stenosis ≥ 50 % comparing to the patients with coronary artery stenosis ≤30% (respectively 14.2±1.0 and 19.6±2.1; p=0.02). That has shown diminished vagal-cardiac activity in patients with coronary artery disease. Ill. 2, bibl. 9 (in English; summaries in Lithuanian, English and Russian).