The authors conclude “ECG changes are similar in patients with DMD regardless of presence of DCM. The most common findings are short PR interval and RVH. Prominent Q waves in leads II, III, aVF, V5, and V6 are more likely”. Therefore, in DMD, ECG changes are not-specifically present in patients with DCM. The short PR interval deserves attention as poorly outlined in the clinical evaluation as potential ECG marker of myocardial involvement in DYS-related phenotypes. Whether a short PR could constitute an ECG marker of mild BMD with DCM and X-DCM associated with Dystrophin defects could be matter of joint evaluation in our working group. Prominent Q waves are better known ECG markers: Q waves in the lateral leads seem to be much more common than in the inferior leads.
fAlthough in DMD ECG changes do not discriminate patients with and without DCM (2), the ECG changes may assume the role of Dystrophin-related disease markers in male patients with DCM. When flanked by increased sCPK, both with and without clinical signs and symptoms of overt myopathy, and X-linked recessive inheritance, ECG changes may contribute to suspect a Dystrophin-related DCM. Patients with DYS gene defects commonly seen first by cardiologists are unlikely to be affected by DMD, which is a paediatric diagnosis, well clinically recognised. BMD patients without DCM are also unlikely to reach the cardiologic attention before the myologic diagnosis.
The possible differential diagnosis as X-linked DCM could be with Barth syndrome, which is a paediatric disease, and is characterised by left ventricular non-compaction, granulocytopenia, methylglutaconic aciduria, hypocholesterolemia, mild increased sCPK and myopthy, and growth deficiency. Ventricular arrhythmia may develop later on the course of the disease (up to 43% of patients with ≥11 years of age). In Barth syndrome ECG changes are present in 58% of the cases (3).
Additional X-linked DCM diseases include Emery-Dreifuss Muscle Dystrophy (EMDM) caused by defects of emerin: patients with EDMD frequently show conduction defects and rare develop DCM. Other X-linked cardiomyopathies, such as Danon, Anderson Fabry Disease typically show HCM phenotypes making unlikely the need for differential diagnosis with DYS-associated DCM.
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