The influence of interatrial conduction disorders on atrial mechanical function - atrial strain and pulmonary veins reversal flow

The physiologic activation of left atrium (LA) happens via Bachmann bundle which is major for the proper functioning of the heart. In 1979 Bayes de Luna described the interatrial blocks (IABs), which impair the mechanism of AV synchrony. Our aim was to evaluate the LA mechanics using LA strain in normal and impaired interatrial conduction, regarding the retrograde flow in the pulmonary veins (PV). The study included 51 patients (25F,26M; 69,5+/-13,1 years), with SARS-CoV-2(+), and related symptoms. 6 patients with persistent AF were excluded from the study. All participants underwent clinical evaluation, ECG (200mm/s, x256), echocardiography (EF, mitral regurgitation, LA volume, global and regional strain, PV reversal flow). We found a statistic dependency between LA global strain and P-wave morphology, MR, HF, AFP. There was no clear correlation between the PV reversal flow and LA strain. The mean P wave duration was correlated with its morphology. The correlations between the P-wave morphology and hypertension, overweight, AFP were also observed. Concluding, LA mechanics are negatively influenced by IABs. LA global strain is independently correlated with P wave duration, EF and MR. The examination with regional LA strain is a potentially good technique for assessing LA mechanics and is complementary to precise electrocardiography.