Hyponatremia is a very common electrolyte abnormality, associated with poor short- and long-term outcomes in patients with heart failure (HF). Two opposite processes can result in hyponatremia in this setting: Volume overload with dilutional hypervolemic hyponatremia from congestion, and hypovolemic hyponatremia from excessive use of natriuretics. These two conditions require different therapeutic approaches. While sodium in the form of normal saline can be lifesaving in the second case, the same treatment would exacerbate hyponatremia in the first case. Hypervolemic hyponatremia in HF patients is multifactorial and occurs mainly due to the persistent release of arginine vasopressin (AVP) in the setting of ineffective renal perfusion secondary to low cardiac output. Fluid restriction and loop diuretics remain mainstay treatments for hypervolemic/ dilutional hyponatremia in patients with HF. In recent years, a few strategies, such as AVP antagonists (Tolvaptan, Conivaptan, and Lixivaptan), and hypertonic saline in addition to loop diuretics, have been proposed as potentially promising treatment options for this condition. This review aimed to summarize the current literature on pathogenesis and management of hyponatremia in patients with HF.

Background The impact of sex in patients with chronic coronary syndrome (CCS) has been widely reported, but little is known about the influence of sex on the risk of new-onset HF in patients with CCS. Objectives We aimed to examine sex-related differences and new-onset heart failure (HF) risk in patients with known or suspected CCS undergoing vasodilator stress cardiac magnetic resonance (CMR). Methods We prospectively evaluated 5,899 consecutive HF-free patients submitted to stress CMR for known or suspected CCS. Ischemic burden (number of segments with stress-induced perfusion deficit) and left ventricular ejection fraction (LVEF) were assessed by CMR. The association between sex and new-onset HF (including outpatient diagnosis or acute HF hospitalization) was evaluated using a Cox proportional-hazards regression model adjusted for competing events (death, myocardial infarction, and non-CMR-related revascularization). Results A total of 2,289 (38.8%) patients were women, and 539 (9.1%) underwent CMR-related revascularization. During a median follow-up of 4.5 years, 610 (10.3%) patients died, 191 (3.2%) suffered a myocardial infarction, 420 (7.1%) underwent CMR-non-related revascularization, and 314 (5.3%) developed new-onset HF. Unadjusted new-onset HF rates were higher in women than in men (1.25 vs 0.83 per 100 person/years, p=0.002) (Figure 1). After comprehensive multivariate adjustment, women showed an increased risk of new-onset HF (HR=1.61, 95% CI: 1.21–2.13, p=0.001). Compared with men, the risk of new-onset HF was higher in women with LVEF >53%. Conclusions Compared with men, women with CCS are at a higher risk of new-onset HF. Further studies are needed to unravel the mechanisms behind these sex-related differences. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III and Fondo Europeo de Desarrollo Regional (FEDER) Figure 1