Dynamic change of mitral regurgitation after myocardial reverse remodelling: a case report

Abstract

Background: Chronic mitral regurgitation can be primary (degenerative) or secondary (functional); each has its own aetiology, treatment approach, and prognosis. A combination of the two types of regurgitation can lead to unexpected haemodynamic changes.

Case summary: A 72-year-old woman presented to our hospital with dyspnoea on exertion, moist cough, and orthopnoea. At admission, transthoracic echocardiography (TTE) findings revealed severely reduced left ventricular ejection fraction, dilation of the left ventricle and left atrium, mild mitral regurgitation with prolapse of the posterior leaflet, and bilateral leaflet tethering. She was diagnosed with idiopathic cardiomyopathy with mild mitral regurgitation. After compensation of heart failure, angiotensin-receptor blocker and beta-blocker treatment were initiated, and the dose was subsequently titrated. At 7 months after initiating medical therapy, TTE showed significant improvement of the left ventricular ejection fraction, disappearance of left ventricular dilation (reverse remodelling), and mitral valve tethering. However, posterior leaflet prolapse became apparent, and mitral regurgitation blowing became more severe. Chordal lengthening, leaflet thickening, and degeneration were observed, but there were no ruptured chordae. Successful surgical repair of the mitral and tricuspid valves was performed.

Discussion: In this unusual mitral regurgitation case, the regurgitation worsened following an improvement of cardiac function due to the loss of tethering from a reduction of the left ventricular diameter and an increase in closing force by increasing the left ventricular contractile force. Eventually, mitral regurgitation prolapse became apparent. Therefore, we should consider that reverse remodelling may exacerbate mitral regurgitation.

Keywords: Case report; Mitral regurgitation; Mitral valve tethering; Myocardial reverse remodelling; Prolapse.

Figure 1

Transthoracic echocardiogram on admission presenting (A) left ventricular dilation, tethering of both leaflets, and posterior leaflet prolapse; (B) a mild mitral regurgitation jet; (C) the grey-scale four-chamber view; and (D) the colour Doppler imaging four-chamber view.

Figure 2

The transthoracic echocardiogram after 7 months of medical therapy showing (A) that ejection fraction improved to 64%, left ventricular volume reduced, and anterior leaflet tethering disappeared compared with the corresponding in the acute phase. Posterior leaflet prolapse worsened; (B) mitral regurgitation was exacerbated; (C) the grey-scale four-chamber view; and (D) the colour Doppler imaging four-chamber view.

Figure 3

Transoesophageal echocardiography showing (A) P2 prolapse, (B) the mitral regurgitation jet blowing from the same site on colour Doppler imaging, (C) three-dimensional imaging from the left atrial side showing P2–P3 prolapse, and (D) colour Doppler imaging showing the severe mitral regurgitation jet from the prolapse part shifting to the front of the left atrium.

Figure 4

Schematic representation of the proposed mechanism of the patient’s heart activity. (A) In the acute phase, the closing force to the mitral valve was weakened, and the tethering force increased. As a result, the gap of the mitral leaflets decreased, and mitral regurgitation jet was attenuated. (B) After reverse remodelling, the closing force was enhanced, and the tethering force decreased. Accordingly, prolapse of posterior leaflet and exacerbation of mitral regurgitation were observed.