PLACEBO-CONTROLLED, CROSSOVER, DOUBLE-BLIND-STUDY OF DIGITALIS IN PATIENTS WITH DILATED CARDIOMYOPATHY IN SINUS RHYTHM

Because of the conflicting results from studies examining the usefulne ss of digitalis in patients with dilated cardiomyopathy (DCM) in sinus rhythm, a prospective, double-blind, crossover, placebo-controlled tr ial was performed in 13 such patients. After a 28-day washout period, patients received 8 days of betamethyl digoxin and 8 days of matched p lacebo in random sequence. Clinical response was assessed objectively by exercise performance with the use of respiratory gas-exchange analy sis and contractility value determined by echocardiography (Suga index ) before and after drug administration. The patients, acting as their own controls, were followed up at 6 months and 1 year. Eight patients responded satisfactorily to digitalis, a response maintained during fo llow-up; 5 patients had a poor or no response, and the drug was withdr awn. Improvements in oxygen consumption and work capacity in the 8 pat ients were linked either to an increase in the contractility indices o r to an enhanced ventilation:perfusion ratio, as reflected in a reduct ion of physiologic dead space. The 8 responders had a cardiac volume l ess than 1050 mL/m(2) and a relatively better prognosis than the 5 non responders (cardiac volume >1050 mL/m(2)). Four patients with a Suga i ndex of 1.3 or higher were considered responders to digitalis therapy, whereas 9 patients with an index lower than 1.3 had a controversial a nd variable response. Indices of cardiac contractility and measurement s of cardiac volume can help to determine response to digitalis therap y, but DCM continues to be a diagnostic challenge for clinicians.