Inappropriate sinus tachycardia in post-covid-19 Syndrome

Abstract Funding Acknowledgements Type of funding sources: None. Background Persistent symptoms after the acute phase of SARS-CoV-2 infection are referred to as "post-COVID-19 syndrome" (PCS), with a reported incidence ranging between 35% and 87%. Fatigue, palpitations and exercise intolerance are common complains among PCS patients in whom unexplained sinus tachycardia, occasionally exacerbated by postural changes, is a frequent observation that remains poorly characterized. Purpose We sought to characterize the prevalence of inappropriate sinus tachycardia (IST) and postural orthostatic tachycardia (POTS) in a consecutive and prospective population of patients with PCS. Methods Consecutive patients with persistent symptoms 3 months after an acute SARS-CoV-2 infection were prospectively evaluated at a multi-disciplinary PCS unit. All patients were screened for IST or POTS and those with confirmed criteria underwent comprehensive cardiovascular examination including echocardiography, 24-hour Holter, Minnesota Living with Heart Failure Questionnaire (MLHFQ), six-minute walking test (6MWT) and inflammation and myocardial biomarkers. Two control patients, matched by age and gender, were assigned to each case: one with previous SARS-CoV-2 infection without PCS (group 2) and one without prior SARS-CoV-2 infection (group 3). Results IST or POTS criteria were met in 34 out of the 200 PCS patients (17%). The mean age was 39 ± 10 years, with 29 women (91%). The interval from the index COVID-19 disease to the PCS diagnosis was 71 ± 17 days, with a majority of patients (n = 29,85%) not requiring hospital admission during the acute phase. At physical examination, the mean heart rate was 96 ± 3bpm at supine and 112 ± 17bpm at the upright position, with 8 patients fulfilling diagnostic criteria of POTS. No underlying structural heart disease, pro-inflammatory state, myocyte injury or hypoxia were identified among our patient population. The 6MWT showed a significantly diminished exercise capacity with a 59% of the estimated distance after adjustment by age, sex and body mass index; an impaired quality of life was also identified, as suggested by a median MLFHQ total score of 67 out of 105 points. The 24-hour Holter showed an increase in HR predominantly during daytime in group 1 (mean daytime HR of 94 ± 3bpm), an altered heart rate variability with a decrease in time domain parameters [PNN50 4 ± 4 in group 1 (vs. 11 ± 9 in group 2 and 18 ± 9 in group 3; p