Functional Mitral Regurgitation in Heart Failure

Mitral regurgitation severity at left ventricular assist device implantation is associated with distinct myocardial transcriptomic signatures

OBJECTIVES

We examined for differences in pre-left ventricular assist device (LVAD) implantation myocardial transcriptome signatures among patients with different degrees of mitral regurgitation (MR).

METHODS

Between January 2018 and October 2019, we collected left ventricular (LV) cores during durable LVAD implantation (n = 72). A retrospective chart review was performed. Total RNA was isolated from LV cores and used to construct cDNA sequence libraries. The libraries were sequenced with the NovaSeq system, and data were quantified using Kallisto. Gene Set Enrichment Analysis (GSEA) and Gene Ontology analyses were performed, with a false discovery rate <0.05 considered significant.

RESULTS

Comparing patients with preoperative mild or less MR (n = 30) and those with moderate-severe MR (n = 42), the moderate-severe MR group weighted less (P = .004) and had more tricuspid valve repairs (P = .043), without differences in demographics or comorbidities. We then compared both groups with a group of human donor hearts without heart failure (n = 8). Compared with the donor hearts, there were 3985 differentially expressed genes (DEGs) for mild or less MR and 4587 DEGs for moderate-severe MR. Specifically altered genes included 448 DEGs for specific for mild or less MR and 1050 DEGs for moderate-severe MR. On GSEA, common regulated genes showed increased immune gene expression and reduced expression of contraction and energetic genes. Of the 1050 genes specific for moderate-severe MR, there were additional up-regulated genes related to inflammation and reduced expression of genes related to cellular proliferation.

CONCLUSIONS

Patients undergoing durable LVAD implantation with moderate-severe MR had increased activation of genes related to inflammation and reduction of cellular proliferation genes. This may have important implications for myocardial recovery.

Occlusion of the os of the left coronary artery by dysplastic aortic valve tissue presenting as progressive mitral insufficiency and cardiac arrest

Mitral regurgitation in the neonatal period is relatively rare. It can be secondary to a congenital malformation of the valve apparatus or mitral valve dysfunction and deformation secondary to myocardial dysfunction or volume load of the left ventricle. Less commonly, it can be due to coronary artery abnormalities leading to mitral valve papillary muscle ischaemia and subsequent dysfunction. Such coronary artery abnormalities include anomalous left coronary artery from pulmonary artery, left main coronary artery atresia, or a thromboembolic phenomenon. In this study, we describe a newborn with a dysplastic aortic valve causing obstruction of the os of the left coronary artery leading to progressive mitral insufficiency.

Efficacy of Electrical Cardioversion in Relation to Occurrence and Type of Functional Mitral Regurgitation in Patients with Atrial Fibrillation

Background: Recent studies have changed the perception of rhythm control in the treatment of atrial fibrillation (AF). Functional mitral regurgitation (fMR) can be both a cause and a consequence of AF and may influence rhythm restoration procedures. Materials and methods: A retrospective analysis included 182 consecutive patients with AF on optimal medical therapy (OMT) undergoing electrical cardioversion (CVE). Based on transthoracic echocardiography, the study group was divided into 20 (11%) patients without mitral regurgitation (MR) and 132 (82%) with fMR 77 (58%) with atrial fMR (afMR; left ventricle ejection fraction (LVEF) ≥ 50%, left atrial (LA) dilatation) and 55 (42%) and with ventricular fMR (vfMR; LVEF < 50%). Patients with severe and organic MR were excluded from the study. Results: vfMR patients had a greater incidence of kidney failure (p = 0.01) and coronary heart disease (p = 0.02); more frequent use of diuretics during hospitalization (p < 0.01); greater LA diameter and area (p < 0.01; p < 0.01) than afMR patients. CVE efficiency was high in all four groups (84−95%). The presence and type of fMR did not affect the efficacy of CVE (p = 0.2; p = 0.9) and did not require the use of more energy (p = 0.4; p = 0.8). The independent predictor of successful CVE was the amount of white blood cells (OR 0.74, p < 0.05). Conclusions: Efficacy of CVE is high among AF patients on OMT regardless of the incidence and type of fMR. Subclinical inflammation should be excluded before elective CVE because it may decrease its efficacy.