Effects of COVID-19 on the Autonomic Cardiovascular System: Heart Rate Variability and Turbulence in Recovered Patients

Background: COVID-19 may be a risk factor for developing cardiovascular autonomic dysfunction. Data are limited, however, on the association between heart rate variability, heart rate turbulence, and COVID-19. The aims of this study were to evaluate the effect of COVID-19 on the cardiovascular autonomic system in patients with persistent symptoms after recovering from COVID-19 and to determine whether these patients showed changes in ambulatory electrocardiography monitoring. Methods: Fifty-one adults who had confirmed SARS-CoV-2 infection and presented with persistent symptoms to the cardiology outpatient clinic after clinical recovery between April and June 2021 were included. Patients were prospectively followed for 6 months. The patients were evaluated at the time of first application to the cardiology outpatient clinic and at 6 months after presentation. Ambulatory electrocardiography monitoring and echocardiographic findings were compared with a control group of 95 patients. Results: Patients in the post-COVID-19 group had significantly higher mean (SD) turbulence onset (0.39% [1.82%] vs -1.37% [2.93%]; P <.001) and lower heart rate variability than those in the control group at both initial and 6-month evaluations. The post-COVID-19 group had no significant differences in echocardiographic findings compared with the control group at 6 months, except for right ventricle late diastolic mitral annular velocity (P =.034). Furthermore, turbulence onset was significantly correlated with turbulence slope (r = -0.232; P =.004), heart rate variability, and the parameters of left (r = -0.194; P=.049) and right (r = 0.225; P =.02) ventricular diastolic function. Conclusions: COVID-19 may cause cardiovascular autonomic dysfunction. Heart rate variability and turbulence parameters can be used to recognize cardiovascular autonomic dysfunction in patients who have recovered from COVID-19 but have persistent symptoms.