Interatrial conduction block – the phantom menace for patients with severe COVID 19?

Abstract SARS-CoV-2 is responsible for a worldwide pandemic, which has caused nearly 7 million of deaths. The effective treatment of COVID-19 is dependent on multipular risk factors, which are still under clinical research. The presence of interatrial block (IAB) could have an influence on the pulmonary circulation which can contribute to the severity of the disease. Our aim was to prove the IAB results in atrial asynchronous contraction which may contribute to the hemodynamic disorders or higher pressure in pulmonary circulation, and worse prognosis in COVID 19. The study included 50 patients (25F, 26M), aged 69,5+/-13,1 years, under hospitalization due to COVID 19. The study groups were divided dependent on the P wave morphology. 6 patients with AF were excluded from the study. All qualified patients required oxygen therapy (at least HFNO) and pharmacological treatment against SARS-CoV-2 related pneumonia. The clinical data included assessment of lungs lesions (CT scan), the lowest measured pO2/fiO2, and the comorbidities. The P wave was measured at 200mm/s, x265. The ECHO included EF, assessment of mitral regurgitation, LA strain, LA volume, the parameters of PVs regurgitation flow. We found that the normal P wave morphology was connected to the higher survival rate (p=0.019) while the full Bachmann bundle block (A-IAB) presented the opposite tendency (p=0,037). LV EF was another relevant variable in this regard (p=0.006). Among statistically relevant comorbidities we can enumerate HF (p=0.033) and arterial hypertension (p=0.006) from which suffered all patients who died in our research group. Interestingly, PACS and LA strain conduit did not correlate with survival. Similarly, the parameters of PVs reverse flow didn’t reveal the correlation with survival. Concluding, the presence of IAB (especially in the form of A-IAB), results in asynchronous LA contraction, which may constitute a risk factor in the course of COVID-19.