A rare case of dystrophic calcifications in the heart

A 77-year-old male with history of hypertension and diabetes mellitus presented with complaints of easy fatiguability on taking a flight of few steps. Previously, he was detected with valvular heart disease before undergoing orthopedic surgery in 2018. The patient also had atrial fibrillation since 2019. 

Transthoracic echocardiography (Fig 1) revealed an echogenic mass in IVS (interventricular septum) measuring 2.6 x 2.1 cm with posterior acoustic shadowing along with concentric left ventricular hypertrophy. Chest radiograph (Fig 2) showed moderate cardiomegaly. Cardiac MRI (magnetic resonance imaging) (Fig 3a-d) revealed tubular focal circumscribed lesions appearing hypointense on T2 weighted images (WI) showing absence of late gadolinium enhancement seen in basal part of IVS with involvement of adjacent cardiac skeleton i.e. mitral valve and aortic root. Correlative CT (Fig 4) confirms the findings

Our case demonstrates dystrophic calcification in heart based on clinical history and imaging findings. History of valvular heart disease and atrial fibrillation favours local tissue damage. Imaging reveals focal and circumscribed foci as opposed to diffuse and amorphous calcifications seen in metastatic variety. Also, serum calcium and parathyroid levels were normal.

Background

Cardiac calcifications are broadly classified into dystrophic and metastatic calcifications (see table 1 for differences).

Dystrophic calcification occurs as sequelae of local tissue damage leading to concentration of calcium ions within membrane-bound vesicles and subsequent crystallization resulting in intracellular and/or extracellular deposits. The most common aetiology is myocardial infarction. Other causes include trauma, infection, inflammation and neoplasm. [1] Freundlich IM et al. demonstrated that dystrophic calcifications occur in 8% of infarctions more than 6 years. [2]

Metastatic calcification is a systemic manifestation secondary to disturbances in calcium homeostasis from various causes such as renal failure, bone pathologies, hyperparathyroidism and vitamin D-related disorders. [3] In patients with hyperparathyroidism, metastatic calcification has been noted without serum calcium abnormalities, suggesting the role of parathyroid hormone that drives calcium into the cells. [3]

Clinical perspective

Myocardial calcifications can extend to involve the aortic and mitral annulus.[4] It can cause sudden cardiac death, focal wall motion abnormalities, arrhythmias and restrictive physiology in severe cases. [5,6]

Imaging perspective

Radiographs may detect dense calcifications, however localization may not possible. Echocardiography shows echogenic foci with posterior acoustic shadowing. Dense shadowing may limit the examination. Computed tomography (CT) scan is the gold standard modality. On cardiac MRI, calcification appear as non-enhancing hypointense deposits on both T1 and T2 weighted images showing intense blooming on susceptibility-weighted images. Both CT and cardiac MRI can localize calcifications, however MRI also provides functional parameters.

Dystrophic calcifications are usually focal and linear. Myocardial infarctions result in thin curvilinear calcifications at the periphery of infarct and may show isolated papillary muscle calcifications. [7,8] Calcifications associated with rheumatic heart disease often involve mitral valve. [4]

Infectious and inflammatory processes can result in circumferential linear or diffuse globular deposits. Calcifications from pericarditis commonly affect the right heart and atrioventricular groove with sparing of the apex.[9]

In contrast, metastatic calcifications can be dense or faint but are diffuse, globular or amorphous.[7] Metastatic calcifications may decrease over time with correction of underlying abnormality.[3] Concomitant calcifications in other parts of body favour metastatic calcification.

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