In Response:
We wish to thank Dr Pérez-Riera et al for their interest in our article1 and for their thoughtful comments. They rightly point out that 4 additional 12-lead ECG features in Figure are relevant to the ECG characteristics of left-dominant arrhythmogenic cardiomyopathy.
Cardiac computed tomography revealed low-attenuation areas and magnetic resonance imaging showed late gadolinium enhancement areas on the mid myocardial septum and subepicardial anterior-lateral left ventricular myocardium, consistent with fibrofatty infiltration. We agree with their opinion because the characteristic ECG features and origin of the premature ventricular complexes correspond to the distribution of fibrofatty infiltration, including the subepicardial lateral lesion.
A genetic analysis revealed heterozygous pathogenic mutations in the DSP (desmoplakin gene) and MYBPC3(myosin-binding protein C gene). Recently, variable clinical expressions of both arrhythmogenic cardiomyopathy and hypertrophic cardiomyopathy have been reported in members of an Italian family who carried heterozygous mutations in DSP and MYBPC3.2 Among the 4 clinically evaluated double heterozygotes for the mutations in DSP and MYBPC3, 2 were diagnosed with arrhythmogenic cardiomyopathy and 2 with hypertrophic cardiomyopathy.
In our case, the clinical phenotype was left-dominant arrhythmogenic cardiomyopathy, but the histological findings from the endomyocardial biopsy showed unique features. The histological findings suggested that the fibrofatty replacement and intercalated disc remodeling were associated with the DSP mutation. The findings also suggested that the hypertrophy and disarrangement of the myocytes were associated with the MYBPC3 mutation. The combined effects of the 2 gene mutations possibly represent a novel pathophysiological mechanism of left-dominant arrhythmogenic cardiomyopathy.
Disclosures
None.
References
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