Introduction: Patients submitted to cardiac transplant surgery present an increase in resting heart rate. This fact is related to the reduction of direct autonomic control over the organ that, when implanted, is denervated, with reduced heart rate variability (HRV). Electrical stimulation in PC5 and PC6 acupuncture points has been described as possible complementary therapy capable of increasing heart rate variability in healthy individuals with cardiovascular diseases.
Objective: The aim of this study was to analyze the acute effect of transcutaneous electrostimulation in acupuncture points (TEAS) at points PC5 and PC6 on the autonomic balance in cardiac transplant recipients and to analyze the risks that the procedure offers.
Methods: This pilot study is an uncontrolled clinical trial. Cardiac transplant patients older than 18 years were recruited on outpatient follow-up at a cardiology hospital. The experiment started with the monitoring through the heart rate monitor that recorded the RR intervals. The patient remained lying down for 20 min for accommodation, 40 min for TEAS application with Jianshi (PC5) and Neiguan (PC6) electrodes in forearm region and 20 min for recovery. The indices in the time and frequency domains were considered for study. It was observed if there was an adverse effect during the protocol and in the subsequent 48 hours through telephone contact, such as dizziness, nausea, vomiting, hemodynamic instability.
Results and discussion: SDNN increased (P < 0.05) during TEAS and recovery. The very low frequency (VLF), low frequency (LF) and high frequency (HF) indices were not altered by TEAS. However, the simpatovagal index increased during TEAS in relation to the accommodation period (P < 0.001). Both the diastolic pressure variation and the mean arterial pressure were higher (P < 0.01) in the recovery period when compared to the accommodation. There was also a moderate correlation (r = 0.52, P < 0.05) between the sympathovagal index and the effect of TEAS on heart rate. There was also a correlation between the time after surgery and the effect of TEAS on the variation of sistolic bloop pressue (r = 0.51, P = 0.016) and double product (r = 0.47, P < 0.05). No adverse effects were identified during the experimental protocol or in the 48 hours following the protocol.
Conclusion: The results suggest that TEAS modulates the autonomic balance of cardiac transplant patients submitted to TEAS and has been shown to be a safe practice for these patients.
Keywords: Transcutaneous electrical nerve stimulation; Acupuncture points; Autonomic nervous system; Heart transplantation.