Is 2D speckle tracking echocardiography useful for detecting and monitoring myocardial dysfunction in adult m.3243A>G carriers? - a retrospective pilot study

Chronological change of left ventricular global longitudinal strain in patients with maternally inherited diabetes and deafness: A case series

RATIONALE

Maternally inherited diabetes and deafness (MIDD) is a rare genetic disorder arising from mitochondrial DNA mutations, characterized by a combination of diabetes mellitus and sensorineural deafness. It is known that MIDD patients with cardiomyopathy have a poor prognosis, but there are no established guidelines for the diagnosis and follow-up of cardiomyopathy in MIDD patients.

PATIENT CONCERNS

Patient 1 was a 48-year-old woman who visited the hospital with cardiomegaly and had been taking oral hypoglycemic agents for 8 years. Patient 2 was a 21-year-old man, the son of patient 1, who visited the hospital for genetic screening. Patient 2 was also diagnosed diabetes mellitus 2 years ago.

DIAGNOSIS

Patient 1 was found to have restrictive cardiomyopathy on echocardiography and underwent endomyocardial biopsy and genetic testing to determine the etiology. The m.3243A>G mutation was confirmed and she was diagnosed with MIDD accompanied with diabetes and hearing loss. Additionally, patient 2 had m.3243 A>G mutation and was diagnosed with MIDD due to diabetes and hearing loss.

INTERVENTIONS

Because MIDD does not have a specific treatment, patient 1 took ubidecarenone (coenzyme Q10), acetylcarnitine, and multivitamin along with the treatment for diabetes control and heart failure. Patient 2 was taking ubidecarenone (coenzyme Q10), acetylcarnitine, and multivitamin along with treatment for diabetes.

OUTCOMES

She subsequently underwent routine transthoracic echocardiography, and a progressive decline in global longitudinal strain (GLS) was first observed, followed by a worsening of the patient's clinical situation. Patient 2 had concentric remodeling and decreased GLS. On periodic echocardiography, GLS decreased at a very slow rate, and the patient's clinical course was stable.

LESSONS

The findings of this report contribute to the understanding of the clinical course of MIDD-associated cardiomyopathy and highlight the potential of GLS as a sensitive marker for disease progression.

Screening and prevalence of cardiac abnormalities on electro- and echocardiography in a large cohort of patients with mitochondrial disease

BACKGROUND

In patients with primary mitochondrial disease (MD), screening with electrocardiogram (ECG) and transthoracic echocardiography (TTE) is warranted according to current guidelines as structural cardiac abnormalities are frequent. This study aims to evaluate the cardiac phenotype of a large Dutch cohort of patients with MD and investigates whether ECG alone is sufficient for predicting structural cardiac abnormalities on TTE.

METHODS

In this retrospective cohort study, genetically confirmed MD patients >18 years old with an available ECG and TTE were included. Newcastle Mitochondrial Disease Scale for Adults (NMDAS) scores were assessed. ECG's were evaluated for rhythm and conduction disorders, voltage criteria for left ventricular hypertrophy (LVH) and repolarization disorders. Echocardiographic evaluation included left and right ventricular volumes and function, and presence of LVH or concentric remodeling.

RESULTS

In total, 200 MD patients were included with a median age of 45 years (IQR; 37-57) of whom 36% were male. Of all MD patients, 35% had abnormalities on ECG and 61% on TTE. Most frequent structural cardiac abnormalities on TTE were: global longitudinal strain > - 18% (54%), concentric remodeling (27%) and left ventricular (LV) ejection fraction <52% (14%). Patients with maternally inherited diabetes and deafness (MIDD) and mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) had the highest prevalence of ECG abnormalities (50% and 47%). TTE abnormalities were most prevalent in patients with MIDD (75%), followed by mitochondrial myopathy (MM) (55%), MELAS (47%) and Mitochondrial Epilepsy and Ragged Red Fibers (MERRF) (47%). MD patients with a high disease severity (NMDAS ≥21) had a higher prevalence of ECG abnormalities (44%, p = 0.039) and structural cardiac abnormalities (72%, p = 0.004) compared to patients with a NMDAS score of 11-20 and ≤ 10 (ECG: 34% and 19%; TTE: 63% and 39%). ECG abnormalities had a positive predictive value of 74% and a negative predictive value of 53% for structural cardiac abnormalities on TTE.

CONCLUSION

MD patients frequently have cardiac involvement especially patients with MIDD, MELAS or high NMDAS score. ECG as sole screening parameter is insufficient to detect structural cardiac abnormalities.