Detection of Early Cardiac Affection in Post- COVID Syndrome Using Heart Rate Variability and 2D Global Longitudinal Strain Echocardiographic Assessment of the Left Ventricle

Abstract

T he aim of our study is to estimate two-dimensional left ventricular global longitudinal strain (LVGLS) by speckle tracking echocardiography (2D STE) and the Heart Rate Variability (HRV) in post-COVID-19 patients after mild to moderate acute SARS COV-2 infection. This study included fifty consecutive subjects between 18 & 80 years of age who were symptomatic after four weeks up to 4 months of experiencing mild to moderate COVID19 illness according to the NIH criteria of severity. Patients enrolled were coming for follow-up clinic visits at Ain Shams University Hospitals between June 2021- Jan2022. All patients had normal LVEF upon enrollment as assessed by M-mode and Modified Simpson's method. 2D Left Ventricular Global Longitudinal Strain (LVGLS) and 24-hours Holter monitoring were performed for all patients. The LVGLS and HRV were significantly impaired in the symptomatic post-COVID-19. LVGLS was below -16 in 20% of the patients while 22% were in the grey zone; between -18 and -16. Standard Deviation Of N-N Intervals (SDNN) was decreased (< 100 msec) in 24% of the patients. Root Mean Square of Successive Differences Between Different Heartbeats (rMSSD) values favored a mean below 40 msec with a prevalence of 58% among the study population. Low-frequency band/High-frequency band (LF/HF ratio) was above 2 in 42% of the patients. Our research suggested a highly significant association between LVGLS and HRV; as 66.7% of patients with decreased SDNN had impaired LVGLS, as opposed to 33% who had normal LVGLS (p-value < 0.001). LVGLS measured by Speckle Tracking Echocardiography (STE) is an important bedside tool, an alternative to CMR, which is the gold standard, in assessing LV systolic functions post COVID-19. HRV can explain a lot of post- COVID symptoms attributed to dysautonomia. Our study targeted the patients having prolonged symptoms after COVID-19 illness. GLS and HRV were assessed, trying to explain the cardiac involvement and if it is the cause of the so-called" long COVID." We found a high incidence of GLS impairment using STE as well as a significant prevalence of diminished HRV. HRV (especially SDNN) and GLS were significantly correlated as 80% of the patients with impaired GLS had decreased SDNN (p-value < 0.001).