Summary.  Literature review shows that elevated serum creatinine (or diminished creatinine clearance) is frequent in patients with heart failure (40%) and prognostically bad as it indicates an independently manifold increased mortality. In addition, even renal function worsening during hospitalization (increase in serum creatinine by approximately 30 micromol/L or higher) is not a rare finding (every 4 patients with heart failure) and is an independent marker of bad outcome. The pathophysiological mechanisms involved are numerous: dehydration (including the overdiuresis-induced one), the worsening of cardiac function (including negative inotropes), too much of vasodilatation (drug-induced, i.e. Amlodipine), nephrotoxic drugs, etc. Due to methodological reasons, large heart failure trials have not included enough patients with diminished renal function, as far more of them can be found in "real-life" conditions (epidemiologically). Thus, conclusions of large trials have not proved fully applicable but should be made so by means of trials including a representative number of patients suffering from both cardiac and renal failure. In our country, the knowledge on the issue of decreased renal function in heart failure patients is far from satisfactory, which necessitates further education. Drugs and their doses should be carefully selected and adjusted to individual findings, nephrotoxic medicaments should be avoided, and all useful drugs should be administered. Each of the five basic drugs (beta blockers, ACE inhibitors, spironolactone, aspirin, statins) for heart insufficiency (primarily induced by ischemic heart disease) seems to improve prognosis (including. life span prolongation) even in patients with diminished renal function.
Key words: Congestive heart failure, renal function worsening, pathophysiological mechanisms, drugs