Echocardiographic Assessment of Cardiomyopathy in Pediatric Oncology Associated with Increased Cardiac Output Due to the Influence of the Tumor Process: Pheochromocytoma/Paraganglioma, Neuroblastoma (Literature Review with Clinical Observations)

Abstract

The condition of increased cardiac output is a state in which, in response to various pathological causes, there is a pathological activation of the renin-angiotensin-aldosterone and sympathetic-adrenal systems, which overall creates a multifaceted, increased load on the heart, ultimately leading to heart failure. The cause of this condition may be arteriovenous pathological shunts, among which arteriovenous dural fistulas in glomus tumors (intracranial paragangliomas) occupy a special place. An arteriovenous fistula is a direct connection between an artery and a vein bypassing the capillary bed, creating a massive shunt from the high-pressure system to the low-pressure system, triggering a pathophysiological chain. In addition, activation of the renin-angiotensin-aldosterone and sympathetic-adrenal systems and direct myocardial damage can be caused by elevated levels of catecholamines in the blood in cases of adrenal paraganglioma (pheochromocytoma) and neuroblastoma. The condition of increased cardiac output is more often described in the literature using examples of clinical cases in adults, with significantly less literature data available in pediatric practice.