Cardiac changes in uraemia and their possible relationship to cardiovascular instability on dialysis

In the past, cardiac changes in renal failure have commonly been ascribed to hypertension and poorly specified toxic effects ('uraemic cardiomyopathy'). Our recent experimental and clinical studies suggest (a) that cardiac hypertrophy can be dissociated from hypertension and that blood pressures may have only a permissive role, (b) that experimental uraemia is associated with specific activation of pericytes and intermyocardiocytic fibrosis. Cardiac hypertrophy not correlated with elevated blood pressure, and intermyocardiocytic fibrosis not observed in similarly hypertensive non-uraemic patients, have recently been documented in dialysis patients. The implications of these findings may be (a) electrical instability and predisposition to a sudden cardiac death and (b) diastolic cardiac malfunction with impaired LV filling and predisposition to dialysis hypotension. Some evidence for the latter possibility is provided.