April 22, 2026Journal of the American College of Cardiology33 citations
View Full PaperThe Natural History of Atrial Functional Mitral Regurgitation
Key Result
Mild-moderate to moderate atrial functional mitral regurgitation regressed more commonly (3.9 per 100 person-years) than it progressed (1.9 per 100 person-years), with neither affecting mortality.
Key Points
- This study aims to understand the incidence of left ventricular systolic dysfunction and the progression or regression of atrial functional mitral regurgitation in adults.
- Included 635 patients with atrial functional mitral regurgitation and left atrial volume index ≥40 mL/m2.
- Followed patients over a median of 2.2 years, assessing incidence of LVSD, progression, and regression of AFMR.
- Compared incident rates of LVSD with patients with no/mild AFMR, adjusting for age, sex, and comorbidities.
- Incidence rates per 100 person-years were 3.2 for LVSD, 1.9 for progression of AFMR, and 3.9 for regression.
- Regression of AFMR was more common than progression, but neither was associated with mortality.
- Independent risk factors for mortality included older age and higher estimated LV filling and pulmonary pressures.
Study Design
Type
Cohort (n=635)
Structured PICO
P
Population
635 adults with left atrial (LA) volume index ≥40 mL/m2, ≥mild-moderate atrial functional mitral regurgitation (AFMR), and follow-up echocardiogram. Median age 75 years, 51% female, 96% mild-moderate/moderate AFMR, 4% severe AFMR.
C
Comparator
Patients with no/mild AFMR matched on age, sex, comorbidities and ejection fraction (for LVSD incidence comparison)
O
Outcome
Incident left ventricular systolic dysfunction (LVSD) (ejection fraction <50% and ≥10% lower than baseline), progression of mild-moderate/moderate AFMR to severe, persistent regression of AFMR to no/trivial, and all-cause mortality
In patients with predominantly mild-moderate/moderate atrial functional mitral regurgitation, regression is more common than progression, and neither is associated with increased mortality or incident left ventricular systolic dysfunction over a median 2-year follow-up.
Main Result
p-value: p=0.52
Abstract
BACKGROUND The natural history of moderate/severe atrial functional mitral regurgitation (AFMR) is unknown. OBJECTIVES The authors sought to study the incidence of left ventricular (LV) systolic dysfunction (LVSD), progression or regression of ≥mild-moderate AFMR, and impact on mortality. METHODS Adults with left atrial (LA) volume index ≥40 mL/m2, ≥mild-moderate AFMR, and follow-up echocardiogram were followed for incident LVSD (ejection fraction <50% and ≥10% lower than baseline), progression of mild-moderate/moderate AFMR to severe, and persistent regression of AFMR to no/trivial. Relation of AFMR progression or regression as time-dependent covariates with all-cause mortality was studied. Incidence of LVSD was compared with patients with no/mild AFMR matched on age, sex, comorbidities and ejection fraction. Patients were followed until mitral intervention, myocardial infarction, or last follow-up. RESULTS A total of 635 patients (median age 75 years, 51% female, 96% mild-moderate/moderate AFMR, 4% severe AFMR) were included. Over a median 2.2 years (Q1-Q3: 1.0-4.3 years), incidence rates per 100 person-years were 3.2 for LVSD (P = 0.52 vs patients with no/mild AFMR), 1.9 for progression of AFMR, and 3.9 for regression. Female sex and larger LA volume index were independently associated with progression, whereas younger age, male sex, absent atrial fibrillation, and higher LA emptying fraction were independently associated with regression. Neither AFMR progression nor regression was independently associated with mortality. Instead, independent risk factors for mortality included older age, concentric LV geometry, and higher estimated LV filling and pulmonary pressures. CONCLUSIONS In patients with predominantly mild-moderate/moderate AFMR, regression of MR was more common than progression, but neither was associated with mortality. Instead, diastolic function abnormalities were more important. Over a median 2-year follow-up, LVSD risk was not increased.
Expert Takes2 quotes
1/2
“AFMR is neither primary mitral regurgitation (MR), which is a valve problem, nor the typical functional or secondary MR, which is ventricular in origin. Rather, it is functional MR of atrial origin. Patients with AFMR have not been studied separately in clinical trials, and literature about AFMR is sparse. As a result, there are no guidelines to advise physicians on how to approach this problem, which carries a poor prognosis.”
Serge Harb, Staff cardiologist, Cleveland Clinic Cardiovascular ImagingCleveland Clinicauto_pipelineView source
Cite This Study
Naser et al. (Mon,) conducted a cohort in Atrial functional mitral regurgitation (n=635). Observation of AFMR vs. Patients with no/mild AFMR was evaluated on Incident left ventricular systolic dysfunction (LVSD) (p=0.52). Mild-moderate to moderate atrial functional mitral regurgitation regressed more commonly (3.9 per 100 person-years) than it progressed (1.9 per 100 person-years), with neither affecting mortality.