Impacto do exercício combinado na modulação autonômica cardíaca em pacientes pós-cirurgia cardíaca

Abstract

Objective: To evaluate the impact of combined physical exercise on the autonomic modulation of post-cardiac surgery patients. Materials and Methods: This is a randomized clinical trial (RBR-9tfcwh4), conducted in the Cardiologic Intensive Care Unit of Dr. Carlos Macieira Hospital, in São Luís, Maranhão, Brazil. Patients of both sexes aged between 18 and 70 years in the postoperative period of cardiac surgery were included. Patients were randomized into two groups: the Control Group (CG), which underwent conventional physiotherapy, and the Intervention Group (IG), which followed a combined exercise protocol. The protocol consisted of 3 sessions lasting 30 minutes over one week (20 minutes of resistance training + 10 minutes of cycle ergometer, OMNI-RES scale 4-5, modified Borg scale 5-6, respectively). Medical history, functional physical evaluation (sit-to-stand test – STS, and Time Up and Go – TUG), handgrip dynamometry to measure muscle strength, and blood tests were performed. Heart rate variability (HRV) was analyzed using an electrocardiogram (ECG), considering time and frequency domains, with Kubios software version 3.5. After normality testing, Student's t-test and two-way ANOVA were used. Data were expressed as mean ± standard deviation or median (interquartile range). Results: A total of 21 patients were evaluated, distributed into two groups: CG (n=11) and IG (n=10), aged between 53 and 58 ± 8 years. The sample was predominantly male (76.2%). Improvement in TUG test performance time was observed in both groups, as well as an increase in phosphorus levels after the protocol in the IG. In the frequency domain, no significant differences were found between the groups. However, in the time domain, the CG showed an increase in mean RR interval (Mean RR), whereas no changes were observed in the IG. Furthermore, the triangular index (RR Tri Index) indicated impairment in the CG, which was not seen in the IG. Conclusion: The combined exercise protocol (3 sessions) did not show significant improvement in cardiac autonomic modulation. However, it also did not result in harm to the variables analyzed in the IG. Additionally, exercise contributed to maintaining functional capacity. It is essential to highlight the significant clinical improvement observed, which warrants further investigation in the studied sample. Moreover, optimizing the control of physiological components involved in exercise sessions for postoperative patients is necessary to enhance their effects on autonomic modulation.