Systematic assessment in patients with dilated cardiomyopathy phenotype 

We thank Antonopoulos¹ and colleagues for their interest in our recent publication (in print). We agree that cardiovascular magnetic resonance imaging (CMR) adds incremental value in the assessment of patients with ventricular dysfunction, where the type and extent of scar can inform diagnosis and prognosis. We also agree that diagnosis of idiopathic dilated cardiomyopathy (DCM) should be made after careful consideration of the aetiology ventricular dysfunction; it is our approach to consider both acquired (including inflammatory) and inherited causes in all patients. This systematic approach was applied in this case and included detailed clinical history, blood, and imaging tests (echocardiography, CT coronary angiography, and CMR), followed by a multidisciplinary team discussion.²

There was no parenchymal lung disease, significant lymphadenopathy, or any systemic features to suggest sarcoid, although isolated cardiac sarcoidosis could not be fully excluded based on non-invasive assessment alone. The phenotype was not typical for endomyocardial fibrosis or eosinophilic granulomatosis with polyangiitis. In particular, there was no history of travel to endemic areas, nor of asthma, and there was no eosinophilia over the preceding 10 years, though the eosinophil count can be normal in the chronic stages. Autoimmune panel was negative, and typical CMR features including ventricular cavity amputation were absent.^3,4 Inherited cardiac conditions, some of which can present as inflammatory heart disease, were also considered, but contemporary DCM genetic panel was negative.

The patient reported low exercise tolerance since secondary school, and the clinical impression was of a chronic disease of unknown aetiology. The extensive heterogenous scarring in combination with both severe ventricular dysfunction and pulmonary hypertension suggested an adverse prognosis with little chance of reversibility from standard heart failure medication. Although risk benefit analysis of endomyocardial biopsy was undertaken, it was felt to have a limited role in the management of our case. The extent of scar contributed to our decision to implant a subcutaneous implantable cardioverter defibrillator at an early stage and to refer for cardiac transplant assessment.

Since publication of our case, the patient has received an orthotopic heart transplant. Histology from the explanted heart reported ‘replacement fibrosis with myocyte damage’ which appears to be lymphocyte mediated (with CD3+T cells and CD68+ macrophage on immunostaining) suggesting a chronic inflammatory condition. There was no evidence of vasculitis or granuloma. Viral polymerase chain reaction was not performed. The clinical diagnosis remains ‘idiopathic DCM’.

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Author notes