Hyponatremia in Patients with Heart Failure beyond the Neurohormonal Activation Associated with Reduced Cardiac Output: A Holistic Approach

BACKGROUND: Heart failure (HF) is considered an epidemic disease with considerable morbidity, mortality, and immense healthcare costs. Electrolyte abnormalities are often encountered in patients with HF, posing a diagnostic and therapeutic challenge for clinicians. Hyponatremia affects up to one-third of HF patients and represents an unfavorable prognostic factor. SUMMARY: Low sodium levels in HF are mainly attributed to the neurohormonal activation secondary to decreased effective circulating volume. However, patients with HF often have several comorbidities which may cause or exacerbate the preexisting hyponatremia. Factors that provoke HF, such as alcohol overconsumption, may also be involved in hyponatremia development. Furthermore, drugs which are frequently prescribed to HF patients, especially diuretics, are potential culprits of hyponatremia and should always be addressed since their withdrawal may reverse hyponatremia. Despite the great prevalence and deleterious effects of hyponatremia in these patients, it is often overlooked and consequently undertreated. In this review, we present the mechanisms involved in the development of hyponatremia focusing on those besides neurohormonal activation. We also discuss the proper management of this electrolyte disorder which is frequently complex in patients with HF. KEY MESSAGES: Hyponatremia in patients with HF is not only the result of neurohormonal activation; several comorbidities and frequently used drugs should also be addressed. Hence, a holistic approach is required both for the diagnosis and optimal treatment.