Heart rate variability of patients with acute myocardial infarction submitted to a physiotherapy intervention 24 hours after the cardiac event: phase I of cardiac rehabilitation

Purpose

To evaluate the heart rate (HR) variability at rest, during the deep breathing test (DBT) and during an exercise protocol, in patients with acute myocardial infarction (AMI) submitted to a hospital physiotherapy intervention 24 hours after the cardiac event. Additionally, to evaluate the safety of the protocol applied.

Methods and results

Eight male patients (mean age 50 ± 12 years), admitted to the Coronary Care Unit of the Irmandade Santa Casa de Misericórdia de São Carlos with noncomplicated AMI, were studied. All patients were hemodynamically stable and used conventional medications. The patients were submitted to the hospital physiotherapy intervention 24 hours after their admission. The instantaneous HR was acquired and monitored by an HR monitor (Polar^® S810i) during 10 min at rest pre-exercise, 4 min of DBT, 5 min of exercise protocol (active hand and foot exercises, and active-assisted lower extremities exercises) and 10 min at rest post-exercise in the supine position. The blood pressure (BP) was measured before, during and after the exercise protocol. The R–R intervals (ms) were analyzed by time domain (RMSSD and RMSM) and frequency domain methods, and the power spectral components were expressed as normalized units (nu) at low (LF) and high (HF) frequencies, and as the LF/HF ratio. Data are presented as the mean ± standard deviation (Table 1). The statistical analysis was performed by ANOVA and the Tukey post-hoc test with the level of significance set at 5%.

Table 1

Conclusion

The physiotherapy intervention protocol appeared to be effective as it induced hemodynamic repercussion and modification of the autonomic control of HR, without any clinical intercurrence.