Background

In the last years, cardiologist increasingly recognize “atrial functional mitral regurgitation” (AFMR) frequently associated with heart failure with persevered ejection fraction (HFpEF) and atrial fibrillation. In AFMR, left ventricular size and systolic function are typically normal, whereas isolated mitral annular dilatation and inadequate leaflet adaption are considered as culprit. Until now, there are only scarce data on the mechanisms and prevalence of AFMR, and no study assessed the prevalence and mechanisms of dynamic MR in this cohort yet.

Purpose

To assess prevalence and predictors of exercise-induced changes in MR during handgrip exercise in patients with AFMR.

Methods

We enrolled consecutive patients with AFMR and at least mild severity that underwent echocardiography at rest and during three minutes of handgrip exercise according to a standardized protocol. Assessment of MR was performed according to current guidelines. In all patients, additional comprehensive assessment of mitral valve characteristics (e.g. mitral annulus diameter, leaflet lengths, jet location) was performed.

Results

We identified 84 patients (19%) with AFMR out of 445 patients that underwent echocardiography at rest and during handgrip exercise. Mean age was 78±7 years, 58% were female and 94% had atrial fibrillation. Mean modified H₂FpEF Score was 5.7±1.0, and 65% of patients revealed a score ³6 points (demonstrating a probability for having HFpEF >90%). Median NT-proBNP was 1639 (1043-2908) ng/l, and median eGFR was 55 (40-76) ml/min/1.73m². Mean left ventricular ejection fraction was 58±8%, mean systolic artery pressure was 43±13 mmHg and half of patients (52%) showed concomitant moderate or severe tricuspid regurgitation. At rest, MR severity was graded as mild in 67% of patients, moderate MR in 23% and severe in 11% of patients. Handgrip exercise led to an increase in at least one grade in MR severity in 19 patients (23%), while 8 patients (10%) experienced a decrease of MR severity (Fig. 1). Eight patients (10%) of those with non-severe MR at rest, developed severe MR during handgrip exercise (Fig. 1). According to a pre-defined cutoff of increase in effective regurgitant orifice area (EROA) ³10 mm² during exercise, 27% of patients revealed dynamic MR, irrespective of the severity of MR at rest. The leaflet-to-annulus ratio was the onliest predictor of dynamic MR (increase in EROA ³10 mm² during handgrip exercise)(OR 4.692 (0.936 to 8.962); p=0.005)(Fig. 1).

Conclusion(s)

In patients with AFMR, handgrip echocardiography unmasks marked exercise-induced increases of MR severity in every third patient independent of the severity of MR at rest. Inadequate leaflet adaption assessed by the leaflet-to-annulus ratio is associated with exercise-induced increases in MR severity. Future studies need to address the prognostic importance of exercise testing in patients with AFMR.

Figure 1. Figure 1A) gives an overview of the distribution of MR severity at rest and during handgrip exercise. Figure 1B) shows leaflet-to-annulus ratio in patients with (red) and without (blue) dynamic MR during handgrip exercise.