Left ventricular function and beta-blockade in chronic ischaemic heart failure. Double-blind, cross-over study of propranolol and penbutolol using non-invasive techniques.

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Abstract
From an original group of 32 male post-infarction patients treated with digoxin for presumed cardiac failure, 8 patients were recruited for the present study by means of a single-blind evaluation of the patients'' clinical need for continued treatment with digoxin. Dyspnea on effort as recorded on a standardized questionnaire was used to define failure of the left ventricle. To be recruited to the present study the functional class (New York Heart Association) of the patients had to deteriorate at least 1 full class while on placebo instead of digoxin. During a subsequent double-blind, crossover phase digoxin was kept constant and additional treatment with 160 mg propranolol or 40 mg penbutolol twice daily was given. Each patient received the 2 .beta.-blockers for 2 wk each separated by an intermediate 4-wk placebo period. Cardiac function was investigated using ECG, apexcardiography, phonocardiography, echocardiography and pulse curves from the carotid artery, jugular bulb and liver before and at the end of each treatment period. Well-preserved systolic function was indicated before .beta.-blockade despite the history and symptoms, and despite several indices of cardiac damage such as pronounced ischemic ECG abnormalities and large and hypertrophied hearts (X-ray and echo). Many variables reflected impaired diastolic function. During .beta.-blockade no signs of impaired cardiac function emerged. Diastolic filling properties were enhanced which contributed to the performance of the left ventricle during systole. No differences between propranolol and penbutolol were shown.