Mild hypertension in patients with suspected dilated cardiomyopathy: cause or consequence?

This study was undertaken to clarify the relationship between mild transient hypertension and dilated cardiomyopathy. Fifty-five patients were studied: group 1--controls (12 patients), group 2--hypertensives without clinical evidence of heart failure (14 patients), group 3--patients with hypertensive heart failure and diastolic blood pressure above 100 mmHg (10 patients), group 4--patients with possible dilated cardiomyopathy with mild hypertension, i.e. diastolic blood pressure of 90-100 mmHg (8 patients), group 5--patients with dilated cardiomyopathy and normal blood pressure (11 patients). The haemodynamic status and cardiac contractility indices were measured in each patient on admission, using M-mode echocardiography. Serum sodium and potassium as well as the urinary sodium, potassium and vanillyl mandelic acid excretions were also measured. The stroke volume, cardiac output and cardiac index fell with heart failure, but much more remarkably in group 4. The peripheral vascular resistance was higher in groups 2, 3 and 4 than in groups 1 and 5; so also were the aortic diameter, left posterior wall thickness and left ventricular mass. The plasma volume, aldosterone and cortisol levels were higher and the urinary sodium and potassium excretion lower in patients with heart failure (groups 3, 4 and 5). It is concluded that the raised blood pressure found in some patients suspected to have dilated cardiomyopathy is not due to the haemodynamic and biochemical changes that occur in heart failure. Such patients are 'chronic' hypertensives with hypertensive heart failure. Their presenting blood pressure is low because of their markedly reduced cardiac output.