The patient was a 51-year-old man with orthostatic hypotension. He had no history of diabetes mellitus, chronic kidney disease, the use of beta-blockers or over-the-counter medications. Chest X-ray indicated a small heart with a cardiothoracic ratio of 33% (Picture A). Transthoracic echocardiography showed a left ventricular mass index of 56.2 g/m2 and cardiac output of 4.3 L/min (Picture B). Although his blood pressure was 143/88 mmHg in the supine position, it declined to 57/34 mmHg after continuously standing for 1 minute (Picture C). His endocrine workup showed severely suppressed plasma renin activity (PRA) and serum aldosterone (aldo) levels despite him being in an upright position; aldo secretion was responsive to rapid adrenocorticotropic (ACTH) stimulation (Picture D). These results suggested that the function of the zona glomerulosa was preserved, while the renin-angiotensin-aldosterone system was suppressed. His symptoms were improved by wearing leg compression stockings and with the administration of oral fludrocortisone. “Small heart syndrome” is defined as a small heart shadow on chest X-ray with a cardiothoracic ratio of ≤42%, which indicates orthostatic intolerance (1). In such cases, the renin-aldosterone system is markedly downregulated despite a reduced cardiac output (2). Clinicians should be aware of small heart syndrome in patients with symptoms of orthostatic intolerance and hyporeninemic hypoaldosteronism.
Picture.
The authors state that they have no Conflict of Interest (COI).
References
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