PMC9887669_01
Serial chest radiography. Serial progression of cardiomegaly is observed. The presence of a dual-chamber pacemaker is noted.
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A chest radiography revealed that her heart size increased progressively over the past 2 years (Figure 1). Although common mutations known to cause dilated cardiomyopathy, such as those in TTN, LMNA, MYH7, and TNNT2, were not found in next-generation sequencing, the m.3243A > G heterozygote mutation of the MT-TL1 gene was confirmed by Sanger sequencing (see Supplementary material online, Figure S1).
Histologic findings of the myocardium of the right ventricle obtained by endomyocardial biopsy. (A) Haematoxylin and eosin staining: hypertrophy of myocytes (black arrows) is observed; (B) Electron microscopy: a disarrangement of mitochondrial cristae (red asterisks) is observed.
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Haematoxylin-eosin staining showed hypertrophy of myocytes (Figure 2A), and an electron microscopy revealed a disarrangement of mitochondrial cristae (Figure 2B), which were compatible with mitochondrial cardiomyopathy; Congo red staining was negative.