Right atrial strain in atrial fibrillation: the hidden side of the moon

Eleonora Ruscio¹Francesca Augusta Gabrielli¹Gaetano Pinnacchio^1*Francesco Raffaele Spera^2,3Federica Giordano^1,4Maria Lucia Narducci^1,5Gianluigi Bencardino¹Francesco Perna¹Filippo Crea^1,6Gemma Pelargonio^1,5

• ¹Department of Cardiovascular Sciences, Agostino Gemelli University Polyclinic (IRCCS), Rome, Lazio, Italy
• ²Department of Clinical and Molecular Medicine – Sapienza University, Rome, Italy
• ³Cardiology Department, Sant'Andrea University Hospital, Rome, Sicily, Italy
• ⁴Cardiothoracic Department, University Hospital Santa Maria della Misericordia, Udine, Italy
• ⁵Cardiology Institute, Catholic University of Sacred Heart, Rome, Italy
• ⁶Center of Excellence of Cardiovascular Sciences, Ospedale Isola Tiberina - Gemelli Isola, Rome, Italy

Introduction: Left atrial (LA) remodelling in atrial fibrillation (AF) is well studied, whereas right atrial (RA) alterations remain poorly characterized. This study evaluates bi-atrial strain dynamics in AF patients undergoing catheter ablation (CA).Methods: A total of 56 consecutive patients undergoing AF ablation were prospectively evaluated using speckle-tracking echocardiography and electrophysiological study before and after CA (median follow-up: 7±3 months). A control group of 32 individuals undergoing CA for paroxysmal atrioventricular nodal reentrant tachycardia, without structural heart disease, was included for comparison. Results: Compared to controls, AF patients exhibited significantly lower RA strain parameters (RA strain, pRASr: 22.1±12.6% vs. 29.8±12.7%, p=0.009) and greater RA mechanical dispersion (SD-regional-RA-TTP-N: 0.048±0.015 vs 0.038±0.009, p=0.020). Patients with persistent AF demonstrated a more pronounced RA dysfunction than those with paroxysmal AF (pRASr: 15.9±11.7% vs 24.8±12.1%, p=0.017; SD-regional-RA-TTP-N: 0.062±0.030 vs 0.043±0.023, p=0.016), despite comparable LA strain values. RA function correlated with both LA strain and volume parameters, as well as with the extent of abnormal LA electroanatomical substrate (pRASr and pLASr: r=0.594, p<0.001; pRASr and low-voltage LA area: r=-0.316, p=0.018). Notably, RA parameters, rather than LA indices, were significantly reduced in patients with post-ablation AF recurrence (pRASr: 14.1±11.7% vs 24.6±13.5%, p=0.039; SD-regional-RA-TTP-N: 0.054±0.031 vs 0.032±0.010, p=0.002). However, the CHA2DS2-VASc score remained the sole independent predictor of AF recurrence (HR 1.47, CI 1.003-2.158, p=0.048). Conclusion: RA function, assessed through strain imaging, was progressively impaired in more severe AF subtypes, strongly correlating with bi-atrial mechanical and electroanatomical properties. Furthermore, RA function was associated with AF recurrence after catheter ablation, highlighting its potential prognostic value.