Hypertrophic cardiomyopathy in a patient with secondary hypoparathyroidism: A case report

Dilated cardiomyopathy in patients with hypoparathyroidism: A narrative review

Background

Hypoparathyroidism is a rare endocrine disorder characterized by low blood calcium levels, elevated phosphorus levels, and insufficient parathyroid hormone production. It can lead to dilated cardiomyopathy (DCM), a cardiac condition characterized by enlarged ventricles and reduced heart function. This review aims to explore the relationship between hypoparathyroidism and DCM, the impact of calcium on cardiac function, and the potential for DCM reversal with calcium supplementation.

Methods

A comprehensive literature search was conducted using PubMed, Google Scholar, and relevant keywords and Mesh terms. Case reports evaluating dilated cardiomyopathy in patients with Hypoparathyroidism were included in the study. Additionally, references cited in each study were carefully examined to identify relevant reports. The cases included in the review were analyzed, and common cardiac manifestations, diagnostic approaches, and management were identified.

Results

DCM in hypoparathyroidism presents with symptoms of heart failure, reduced ejection fraction, and impaired left ventricular function. Laboratory tests show low serum calcium levels and elevated phosphate levels. Prompt diagnosis and treatment with calcium and vitamin D supplementation can lead to improvements in cardiac function.

Conclusion

Hypoparathyroidism-induced DCM is reversible with timely calcium and vitamin D supplementation. Patient compliance with prescribed medications and supplements is crucial to prevent and manage cardiac complications. Regular follow-up check-ups and monitoring of calcium levels can aid in early detection and improve patient outcomes. Educating patients about the importance of treatment adherence can significantly reduce the risk of developing DCM and other cardiac symptoms associated with hypoparathyroidism. Routine follow-up of DCM among patients with endocrine disorders is recommended.

Phosphate toxicity and SERCA2a dysfunction in sudden cardiac arrest

Almost half of the people who die from sudden cardiac arrest have no detectable heart disease. Among children and young adults, the cause of approximately one-third of deaths from sudden cardiac arrest remains unexplained after thorough examination. Sudden cardiac arrest and related sudden cardiac death are attributed to dysfunctional cardiac ion-channels. The present perspective paper proposes a pathophysiological mechanism by which phosphate toxicity from cellular accumulation of dysregulated inorganic phosphate interferes with normal calcium handling in the heart, leading to sudden cardiac arrest. During cardiac muscle relaxation following contraction, SERCA2a pumps actively transport calcium ions into the sarcoplasmic reticulum, powered by ATP hydrolysis that produces ADP and inorganic phosphate end products. Reviewed evidence supports the proposal that end-product inhibition of SERCA2a occurs as increasing levels of inorganic phosphate drive up phosphate toxicity and bring cardiac function to a sudden and unexpected halt. The paper concludes that end-product inhibition from ATP hydrolysis is the mediating factor in the association of sudden cardiac arrest with phosphate toxicity. However, current technology lacks the ability to directly measure this pathophysiological mechanism in active myocardium, and further research is needed to confirm phosphate toxicity as a risk factor in individuals with sudden cardiac arrest. Moreover, phosphate toxicity may be reduced through modification of dietary phosphate intake, with potential for employing low-phosphate dietary interventions to reduce the risk of sudden cardiac arrest.