Treatment in Dilated Cardiomyopathy : with special emphasis on beta-adrenergic receptor blockade and angiotensin-converting enzyme inhibition

Sammanfattning: Dilated cardiomyopathy (DCM) is a heart muscle disease of unknown origin, characterised by ventricular dilatation and impairment of systolic function. The basic treattnent is medical, according to different pharmacological principles. Evaluation of the severity of the disease and the effects of medication are important for optimal management.Fifty-four patients (42 male and 12 female) with DCM were randomized to receive treatment with either a beta-adrenergic receptor blocker (metoprolol) or an angiotensin-converting enzyme (ACE) inhibitor (captopril). Almost all patients had a history of congestive heart failure and were therefore treated with furosemide. Baseline characteristics and the effects of therapy were studied by invasive haemodynamics, echocardiography, neurohormonal function, heart rate variability and quality of life evaluation.There were favourable effects on left ventricular (LV) function with both drugs but metoprolol seemed to be superior to captopril in improving LV stroke volume and reducing LV filling pressure. There was a reduction in both systolic and diastolic dimensions and the non-invasive findings were in accordance with invasive results. Neurohormonal activation was less than expected and the levels of plasma renin activity and angiotensin II were within the normal range while the levels of atrial natriuretic peptide were increased. Urinary excretion of Aldosterone was reduced with both metoprolol and captopril therapy, but treatment with petoprolol reduced the level of ANP during exercise.Both drugs increased heart rate variability but petoprolol was superior to captopril in increasing totaol power and power in the low and very low frequency.Quality of life was assessed by a disease-specific questionnaire and wsa improved in the dimension "emotion" in both groups during treatment. In the captopril group there were also improvements in total score and in the dimension "physical activity". Improvements in quality of life dimensions, however, did not correlate to improvement in LV function.In conclusion both metoprolol and captopril were well tolerated. There were effects of beta-adrenergic receptor blockade on LV performance that were not obtained, at least not equally, during therapy with ACE inhibitor. Itreatment of patients with DCM should therefore include a beta-receptor blocker. Carefully performed, non-invasive methods can be used to evaluate the effects of therapy.