MELAS Syndrome with Cardiac Involvement: A Multimodality Imaging Approach

Abstract

A 49-year-old man presented with chest pain, dyspnea, and lactic acidosis. Left ventricular hypertrophy and myocardial fibrosis were detected. The sequencing of mitochondrial genome (mtDNA) revealed the presence of A to G mtDNA point mutation at position 3243 (m.3243A>G) in tRNA^Leu(UUR) gene. Diagnosis of cardiac involvement in a patient with Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes syndrome (MELAS) was made. Due to increased risk of sudden cardiac death, cardioverter defibrillator was implanted.

Figure 1

(a) Electrocardiogram showing short PR interval and left ventricular (LV) hypertrophy. (b) Echocardiogram showing concentric, nonobstructive LV hypertrophy.

Figure 2

Color-coded (a1–a6) and merged gray-scale (b1–b6) late-enhancement Dual-Energy CT perfusion maps in four-chamber (a1, b1), two-chamber (a2, b2), and short-axis views from base to apex (a3–a6 and b3–b6, resp.) showing the left ventricular (LV) hypertrophy and diffuse, patchy, nonischemic (predominantly intramural), late-enhancement (arrows). T2-STIR MRI imaging (c1–c6) and phase sensitive T1-weighted inversion recovery late-enhancement MRI images (d1–d6) in four-chamber (c1, d1), two-chamber (c2, d2), and short-axis views from base to apex (c3–c6 and d3–d6, resp.) demonstrated diffuse, patchy, nonischemic (predominantly intramural) myocardial edema and late-enhancement consistent with necrosis/fibrosis with a high level of concordance with Dual-Energy CT. (e) Sequence chromatograph of the tRNA ^Leu(UUR) region flanking the m.3243A>G mutation (arrow) in blood sample from the proband and in a wild type sample (Ctr). (f) PCR-Restriction Fragment Length Polymorphism analysis showed the variable mutant load in patient's peripheral tissues. B: blood; U: urine; H: hair; S: saliva.