What important renal function is affected by heart failure?

Heart failure can significantly impact renal function, particularly through its effects on electrolyte balance. In heart failure, reduced cardiac output leads to poor renal perfusion and activation of neurohormonal systems such as the renin-angiotensin-aldosterone system (RAAS). This activation prompts the kidneys to retain sodium and water in an attempt to increase blood volume and improve perfusion, but it can also lead to imbalance in electrolytes like potassium, sodium, and magnesium.

Furthermore, in heart failure, congestion occurs due to fluid overload, which can alter the distribution and elimination of electrolytes. For instance, excess fluid may contribute to dilutional hyponatremia (low sodium concentration in the blood). The kidneys' response to these imbalances is crucial for maintaining homeostasis, and when their function is impaired due to heart failure, it can lead to significant clinical consequences.

While protein synthesis, glucose metabolism, and acid-base balance are also important renal functions that can be influenced by heart disease, the most direct and prominent impact of heart failure on kidney function is through the disruption of electrolyte balance. This makes electrolyte management a critical part of treating patients with heart failure, highlighting why this aspect is chosen as the key renal function affected in such cases.