Right atrial strain predicts death risk in atrial fibrillation valve disease

Atrial functional tricuspid regurgitation, a leaky heart valve driven not by damaged leaflets but by the relentless stretching of the heart’s upper chambers in atrial fibrillation, has long been an enigma for cardiologists. The finding, published in Echo Research & Practice, suggests that right atrial deformation imaging could become a valuable tool for identifying which patients with this increasingly recognised condition are at highest risk.

The research team, led by Jawza Aldakhil and Sanjeev Bhattacharyya, screened consecutive patients with atrial fibrillation who underwent transthoracic echocardiography between January 2017 and June 2025. To qualify for the atrial functional tricuspid regurgitation cohort, patients needed significant right atrial remodelling, defined as a right atrial area greater than 25 square centimetres, together with at least moderate functional tricuspid regurgitation, while excluding anyone with primary valve disease, cardiomyopathy, congenital heart disease, device-related valve problems, right ventricular dilatation or more than mild right ventricular systolic dysfunction. Patients with atrial fibrillation but only mild, trivial or no regurgitation served as controls. In total, 152 patients were analysed: 120 with atrial functional tricuspid regurgitation and 32 controls.

The echocardiographic picture that emerged was one of profound biatrial remodelling. Compared with controls, patients with the condition had larger left atrial diameter (4.6 versus 3.9 centimetres), greater indexed left atrial volume (64 versus 44 millilitres per square metre) and larger right atrial area (27 versus 22 square centimetres). Markers of right-sided haemodynamic burden were also elevated, including higher tricuspid regurgitation jet velocity (2.9 versus 2.1 metres per second), higher estimated right atrial pressure and higher pulmonary artery systolic pressure (41 versus 26 millimetres of mercury). Notably, conventional measures of biventricular systolic function, including left ventricular ejection fraction, right ventricular fractional area change and TAPSE, were preserved, reinforcing the idea that this is fundamentally a disease of the atria rather than the pumping chambers.

Strain analysis, performed offline with vendor-specific speckle-tracking software by an observer blinded to clinical outcomes, added a functional dimension to these structural changes. Right ventricular longitudinal strain was mildly impaired in the regurgitation group (-16 versus -19 percent), and right atrial reservoir strain was markedly reduced (10 versus 16 percent). Reproducibility of the right atrial strain measurement was excellent, with an intra-class correlation coefficient of 0.97. Because most patients were in atrial fibrillation, the investigators minimised beat-to-beat variability using an index-beat method, selecting cardiac cycles with similar preceding R-R intervals, or averaging over three comparable cycles when rhythm irregularity made that impossible.

Follow-up extended to a median of 6.3 years, during which 63 deaths occurred in the overall study population, 53 of them among patients with atrial functional tricuspid regurgitation, equivalent to 44 percent of that group. Kaplan-Meier analysis showed numerically lower survival in the regurgitation group, although the difference did not reach statistical significance (log-rank p = 0.059), and atrial functional tricuspid regurgitation itself carried a numerically higher but non-significant hazard of death on univariable analysis (HR 1.89, 95% CI 0.96 to 3.72). Mortality data were drawn from the NHS Spine Personal Demographics Service, a national registry that captures deaths occurring both inside and outside the treating institution.

The prognostic analysis focused on the 120 patients with the condition. In univariable Cox regression, older age (HR 1.02 per year, 95% CI 1.00 to 1.04), higher tricuspid regurgitation jet velocity (HR 1.59, 95% CI 1.07 to 2.35) and lower right atrial reservoir strain (HR 0.90 per one-percentage-point change, 95% CI 0.84 to 0.96) were each significantly associated with mortality. Diabetes, smoking, heart failure history, diuretic use, right ventricular fractional area change, right ventricular longitudinal strain, right atrial area and female sex showed no significant association. After multivariable adjustment for age, sex and jet velocity, right atrial reservoir strain remained the only independent predictor of death, with an adjusted hazard ratio of 0.88 per percentage point (95% CI 0.81 to 0.95, p < 0.001).

A crucial secondary analysis addressed whether concomitant mitral regurgitation, present in 57 percent of the cohort, was driving the result. Among the 51 patients with isolated atrial functional tricuspid regurgitation and no mitral regurgitation, lower right atrial reservoir strain remained associated with worse survival, with an adjusted hazard ratio of 0.86 (95% CI 0.77 to 0.96, p = 0.005), closely mirroring the estimate in the full cohort. The authors note that the wider confidence interval in this smaller subgroup reflects reduced precision rather than a weaker effect, although they caution that a contribution from atrial functional mitral regurgitation cannot be formally excluded without an interaction analysis.

Mechanistically, the authors interpret reduced right atrial reservoir strain as a window into advanced atrial cardiomyopathy. Impaired atrial strain has previously been linked to atrial fibrosis and adverse remodelling in atrial fibrillation populations, and the marked reduction observed here likely reflects diminished atrial compliance. A stiff, poorly compliant right atrium cannot accommodate venous return effectively, potentially contributing to systemic venous congestion and progressive right-sided heart failure physiology. Consistent with this, patients showed higher pulmonary pressures and mildly impaired right ventricular deformation despite preserved conventional right ventricular systolic parameters, hinting at early right-sided functional changes that standard echocardiographic measures may miss.

The clinical implications are framed carefully. Current assessment of atrial functional tricuspid regurgitation relies mainly on regurgitation severity and conventional echocardiographic parameters, which the authors argue may not capture the full extent of underlying atrial disease. As transcatheter tricuspid valve therapies evolve, better phenotypic characterisation and risk stratification will matter more, and right atrial deformation imaging may offer additional insight, particularly in patients whose conventional right ventricular systolic function appears preserved. The authors also raise, without endorsing, the speculative question of whether drugs that influence atrial remodelling, such as SGLT2 inhibitors, which a recent meta-analysis linked to lower atrial fibrillation incidence, might alter the natural history of the condition; they emphasise this remains unestablished and requires prospective testing.

Important limitations temper the conclusions. This was a retrospective, single-centre study vulnerable to selection bias; strain analysis used a single vendor-specific platform, limiting generalisability; the beat-selection method was not recorded for each study; and data on diuretic dose, renal function and natriuretic peptides were unavailable, so residual confounding by baseline heart failure severity cannot be excluded. Only all-cause mortality was captured, leaving open whether the association is driven by cardiovascular causes specifically. The survival sample was modest, and the authors describe their findings as hypothesis-generating until confirmed in larger prospective cohorts.

Subject of Research: Echocardiographic predictors of mortality in atrial functional tricuspid regurgitation associated with atrial fibrillation

Article Title: Determinants of outcome in atrial functional tricuspid regurgitation

Article References: Aldakhil, J., Patel, K., Badiani, S., Petersen, S. E., Lloyd, G., & Bhattacharyya, S. (2026). Determinants of outcome in atrial functional tricuspid regurgitation. Echo Research & Practice, 13(1), Article 38. https://doi.org/10.1186/s44156-026-00140-4

Image Credits: AI Generated

DOI: 10.1186/s44156-026-00140-4

Keywords: atrial fibrillation, tricuspid regurgitation, right atrial strain, echocardiography, mortality, speckle-tracking, atrial remodelling, risk stratification, heart failure, cardiac imaging, Determinants, outcome