Effects of Physical Training on the Recovery of the Autonomic Nervous Activity During Exercise After Coronary Artery Bypass Grafting

Abstract

Analysis of heart rate variability (HRV) can identify patients at risk of sudden cardiac death after myocardial infarction. The present study examined the effect of 2 weeks of supervised aerobic exercise training on the recovery of the autonomic nervous activity, exercise capacity, and cardiac output (CO) after coronary artery bypass grafting (CABG). Twenty-eight patients were randomly divided into the training group or the control group and performed exercise tests at 1 week, 3 weeks, 3 months, 6 months and 1 year after CABG. The HRV was measured, and the high-frequency component of HRV was used as an index of parasympathetic nerve activity (PNA); the plasma norepinephrine concentration (NE) was used as an index of sympathetic nervous activity. Cardiac output was also measured. In the training group, peak VO2, peak CO and PNA during exercise had improved at 3 weeks, but there was no improvement in these indices in the control group. NE decreased 1 week after CABG in both groups. These results indicate that physical training soon after CABG improves not only the exercise capacity, but also PNA.

Effects of Endoscopic Transthoracic Sympathicotomy on Hemodynamic and Neurohumoral Responses to Exercise in Humans.

“…7,8 In the laboratory, the reproducibility of this technique, as determined by 25 duplicate measurements in 25 patients, was -1.1±16% (mean ± SD). Mean arterial pressure was calculated by adding one-third of the pulse pressure to the diastolic pressure.…”

Improvements in heart rate variability with exercise therapy

“…angioplasty, caBg and unstable angina Among patients with coronary artery disease who have undergone PTCA or CABG, exercise therapy has been found to significantly increase various indexes of HRV (68)(69)(70)(71) (Table 3). These findings suggest that analysis of HRV can be used to assess the effect of exercise training on cardiac autonomic dysfunction in this population.…”

Prognostic Significance of Exercise Plasma Noradrenaline Levels for Cardiac Death in Patients With Mild Heart Failure.

“…Fourth, we did not assess the effects of various medications and exercise and these factors may have influenced the prognosis. 28,29 Finally, there is a limitation in using plasma NA level as an index of sympathetic nervous system activity, because plasma NA concentration is regulated by multiple factors. 30 However, a good correlation between muscle sympathetic nerve activity and plasma NA level has been reported in patients with heart failure, 31 suggesting the clinical usefulness of the plasma NA level as an overall sympathetic outflow.…”