Postural orthostatic tachycardia syndrome associated with post-acute covid-19 syndrome is not mediated through smaller hearts or contractile dysfunction

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Swedish Heart-Lung foundation Swedish Research Council Introduction Post-acute covid-19 syndrome (PACS) is a novel condition with persistent symptoms affecting different organs. We have previously reported postural orthostatic tachycardia syndrome (POTS) as one important long-term complication. The pathophysiological mechanisms behind PACS and associated POTS are largely unknown. It has previously been suggested that POTS patients have a smaller left ventricular mass (LVM) and volume contributing to the persistent symptoms of tachycardia, however it is currently unknown if these pathophysiological mechanisms are similar in PACS associated POTS. Furthermore, it has been shown that global longitudinal strain (GLS) and global circumferential strain (GCS) are more sensitive measures of contractile function compared to ejection fraction, however it is also currently unknown if GLS and GCS differs between PACS patients with and without POTS. Purpose To elucidate if patients with PACS associated POTS have a lower LVM compared to PACS without POTS, and if GLS and GCS differ between the groups. Methods In total, 31 patients that had suffered a mild SARS-CoV-2 infection diagnosed with PACS according to the WHO criteria were enrolled in this prospective cohort study. POTS was verified by head-up tilt test; 16 patients (age 40±10 years, 94% women) were POTS positive whereas 15 (45±11 years, 93% women) were POTS negative. All patients underwent cardiac magnetic resonance imaging, and global longitudinal strain (GLS) and global circumferential strain (GCS) were calculated. Results There were no differences between the groups with regards to left ventricular dimensions or mass, Table 1. There were no differences in GLS and GCS between the two groups (GLS: PACS and POTS positive -18±2% vs PACS and POTS negative -19±2%, p=0.53; GCS: PACS and POTS positive -17±3% vs PACS and POTS negative -19±3%, p=0.16), Figure 1. Conclusions PACS-related POTS is not associated with contractile dysfunction nor differences in cardiac geometrics, providing mechanistic insights in the pathophysiology of PACS associated POTS. Other specific pathophysiological mechanisms that underlie POTS associated with PACS needs to be established.