Right atrial strain: the hidden proof of bi-atrial cardiomyopathy in AF patients?

Abstract Background Although assessment of left atrium (LA) abnormalities has been extensively studied in atrial fibrillation (AF), structural and functional changes in the right atrium (RA) have remained almost unexplored in this context. Purpose We investigated the role of bi-atrial strain in patients with AF undergoing catheter ablation (CA). Methods Fifty-six consecutive patients undergoing catheter ablation of AF were prospectively studied with speckle-tracking echocardiography and electrophysiological study, before and after CA (median follow-up: 7±3 months). A group of 32 subjects undergoing CA of paroxysmal atrioventricular node-reentrant tachycardia, without structural heart disease, served as control group. Results Patients with AF had worse LA, but also RA strain indexes compared to controls [RA strain parameters: peak RAS reservoir (pRASr): 22.1±12.6 vs 29.8±12.7%, p=0.009; RA dispersion: SD-regional-RA-time-to-peak (SD-regional-RA-TTP): 0.048±0.015 vs 0.038±0.009, p=0.020)]. Patients with persistent AF showed similar LA strain values, but worse RA strain indexes, compared to patients with paroxysmal AF (pRASr: 24.8±12.1 vs 15.9±11.7%,p=0.017; SD-regional-RA-TTP:0.043±0.023 vs 0.062±0.030, p=0.016). RA function showed a significant relation with both LA strain and volume indexes and with abnormal LA electroanatomical substrate (pRASr and pLASr, Pearson correlation: r 0.594, p< 0.001; pRASr and low-voltage LA area: -0.316, p=0.018). RA, but not LA, parameters were found significantly reduced in patients with AF recurrence post-CA compared to those who maintain sinus rhythm (pRASr: 14.1±11.7 vs 24.6±13.5, p=0.039; SD-regional-RA-TTP: 0.054±0.031 vs 0.032±0.010, p=0.002), while the only independent clinical predictor of AF recurrence remained cardiovascular risk profile (CHA2DS2 VASc Score: HR 1.47,CI 1.003-2.158, p= 0.048). Conclusion RA function, as assessed by strain imaging, resulted progressively impaired in worse subtypes of AF, showing a strong correlation with bi-atrial mechanical and electroanatomical parameters, and associated with AF recurrences post-ablation.Graphical Abstract