Atrial functional mitral regurgitation in cardiology and cardiac surgery

Figures

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  Figure 1. AFMR vs. VFMR: echocardiographic diagnostic deployment and pathogenesis (2,3) [adapted with permission from Nappi (3)]. Top: the following examples illustrate the normal, AFMR, and VFMR echocardiographic and color Doppler findings. In a normal mitral valve, the leaflets exhibit a concavity oriented towards the left ventricle (red arrow). In both AFMR and FMR, the mitral valve is straightened, and its concavity is lost due to tethering of the leaflets. In AFMR, this occurs as a result of severe enlargement of the LA and mitral annulus, which flattens the mitral valve leaflets. In VFMR, the enlarged left ventricle with global or regional systolic dysfunction, in conjunction with displacement of the papillary muscles, results in valve tethering. The mitral annulus and LA exhibit variable degrees of enlargement in VFMR. In AFMR, the mitral valve coaptation is typically not displaced apically, in contrast to VFMR. Bottom: a downward trend in the pathogenetic mechanism is illustrated. In AFMR, the initial pathogenetic mechanism is an elevated LA pressure, which subsequently induces severe enlargement of the LA and mitral annulus, accompanied by flattening of the mitral valve leaflets.…

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  Figure 2. Left: in instances of extensive left atrial remodeling, the posterior mitral annulus is observed to be pulled towards the epicardial surface of the posterior left ventricular basal wall. This phenomenon results in the posterior mitral leaflet being pulled, which in turn increases the annulopapillary distance. This ultimately leads to the development of AF-related leaflet tethering and an off-center eccentric mitral regurgitant jet. [adapted with permission from Silbiger (21)]. Right: top TEE displays a substantially enlarged LA cavity with no MV leaflet pathology and a regular LV. The bottom TEE reveals pronounced AFMR (21,24-39). AF, atrial fibrillation; LA, left atrium; LV, left ventricle; MV, mitral valve; PM, papillary muscle; A, anterior; P, posterior; TEE, transesophageal echocardiogram; AFMR, atrial functional mitral regurgitation.

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  Figure 3. The echocardiographic images from a patient with AFMR caused by atrial fibrillation. (A) It is important to note that the mitral leaflets are confined to the annular plane (arrows). (B) There is a centrally directed MR jet. RA, right atrium; LA, left atrium; V; ventricle; MR, mitral regurgitation; AFMR, atrial functional mitral regurgitation.

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  Figure 4. Outline the diagnostic criteria for the distinction between isolated AFMR and VFMR (45) [adapted with permission from Nappi (3)]. A schematic representation of the heart, illustrating the differences between AFMR and VFMR, is presented. The modified cardiac schematic rendering for AFMR and VFMR demonstrates notable distinctions that are influenced by the systolic phase (early, mid, or end-systole) of dimension assessment, particularly if not normalized. Additionally, gender plays a significant role, with significant differences observed between men and women. *, usually associated with giant left atrium. AF; atrial fibrillation; AFMR, atrial functional mitral regurgitation; CAD; coronary artery disease; HFpEF; heart failure with preserved ejection fraction; LA, left atrium; LV, left ventricle; MR, mitral regurgitation; PML, posterior mitral leaflet; VFMR, ventriculogenic functional mitral regurgitation.

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  Figure 5. Clinical evaluation and diagnosis flowchart for AFMR [adapted with permission from Nappi (3)]. For detailed explanation and references see text. AF, atrial fibrillation; AFMR, atrial functional mitral regurgitation; AHA/ACC, American Heart association/American College of Cardiology; ESC, European Society of Cardiologists; FU, follow-up; GDMT, guideline-directed medical therapy; HFpEF, heart failure with preserved ejection fraction; LA, left atrium; LV, left ventricle; MR, mitral regurgitation; PML, posterior mitral leaflet; TEE, transoesophageal echocardiography; TTE, transthoracic echocardiography.