Hyponatremia in heart failure: revisiting pathophysiology and therapeutic strategies

Hyponatremia is frequently encountered in patients with heart failure (HF), and its association with adverse outcomes is well-established in this population. While hyponatremia is an independent marker for severity of HF, it is not certain whether it has a causal impact on the progression of the disease. There are no universally accepted consensus guidelines regarding therapeutic strategies for HF-associated hyponatremia and volume overload; current societal guidelines do not address management of this complication. Whereas thiazide diuretics are known to induce or worsen hyponatremia in this setting through a number of mechanisms, loop diuretics can be considered a readily available first-line pharmacologic therapy. Consistent with pathophysiology of the disease and mechanisms of action of loop diuretics, available clinical evidence supports such an approach provided that patients can be closely monitored. Use of vasopressin receptor antagonists is an emerging therapeutic strategy in this setting, and the efficacy of these agents has so far been shown in a number of clinical studies. These agents can be reserved for patients with HF in whom initial appropriate loop diuretic therapy fails to improve serum sodium levels.