Impediments to Heart Transplantation in Adults With MELAS:m.3243A>G Cardiomyopathy

The new 2023 ESC guidelines for the management of cardiomyopathies: a guiding path for cardiologist decisions

In the ESC 2023 guidelines, cardiomyopathies are conservatively defined as 'myocardial disorders in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease, and congenital heart disease sufficient to cause the observed myocardial abnormality'. They are morpho-functionally classified as hypertrophic, dilated, restrictive, and arrhythmogenic right ventricular cardiomyopathy with the addition of the left ventricular non-dilated cardiomyopathy that describes intermediate phenotypes not fulfilling standard disease definitions despite the presence of myocardial disease on cardiac imaging or tissue analysis. The new ESC guidelines provide 'a guide to the diagnostic approach to cardiomyopathies, highlight general evaluation and management issues, and signpost the reader to the relevant evidence base for the recommendations'. The recommendations and suggestions included in the document provide the tools to build up pathways tailored to specific cardiomyopathy (phenotype and cause) and define therapeutic indications, including target therapies where possible. The impact is on clinical cardiology, where disease-specific care paths can be assisted by the guidelines, and on genetics, both clinics and testing, where deep phenotyping and participated multi-disciplinary evaluation provide a unique tool for validating the pathogenicity of variants. The role of endomyocardial biopsy remains underexploited and confined to particular forms of restrictive cardiomyopathy, myocarditis, and amyloidosis. New research and development will be needed to cover the gaps between science and clinics. Finally, the opening up to disciplines such as bioinformatics, bioengineering, mathematics, and physics will support clinical cardiologists in the best governance of the novel artificial intelligence-assisted resources.

A Case Report of a Clinically Suspected Diagnosis of Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes (MELAS) Syndrome With Cardiac Impairment

This case report presents a description of a hypertrophic left ventricle with reduced ejection fraction in a man in his mid-twenties with clinical, radiologic, and biochemical features of a rare syndrome called mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). A literature review of this uncommon syndrome and MELAS cardiomyopathy has been conducted.

Late-onset MELAS syndrome in a 46-year-old man with initial symptom of chest tightness: a case report

Background

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) syndrome is a rare mitochondrial disorder caused by mutations in mitochondrial DNA, resulting in impaired energy production and affecting multiple organs. We present a suspected MELAS syndrome case with the initial symptom of chest tightness.

Case summary

A 46-year-old man sought medical attention due to progressively worsening chest tightness during physical activity. He had been receiving treatment for type 2 diabetes for 15 years. One year ago, he presented with symptoms of hearing impairment. Transthoracic echocardiography revealed increased thickness of the left ventricular wall. Serum protein electrophoresis showed no evidence of light-chain amyloidosis, and the 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid scan showed no definite uptake in the heart muscle. The patient's head magnetic resonance imaging (MRI) indicated lacunar infarcts. The lactate threshold test was positive. The biopsy of the skeletal muscle showed broken red fibre infiltration on modified Gomori trichrome staining, and electron microscopy revealed signs of mitochondrial cardiomyopathy, including mild mitochondrial swelling, lipid accumulation, and myofibril damage. A whole-exome genetic test was used to detect the m.3243A>G mutation in the MT-TL1 gene. Based on these findings, MELAS syndrome was the most probable diagnosis.

Discussion

The patient presented with chest tightness in adulthood, without any accompanying psychoneurological symptoms. However, the patient presented with other symptoms, including diabetes mellitus, hearing loss, abnormal lactate levels, ischaemic lesions on head MRI, and left ventricular hypertrophy. By identifying a mutation in the MT-TL1 gene and conducting a muscle biopsy, the diagnosis of MELAS syndrome was definitively confirmed.