Beta-blockers without partial agonist activity are now considered to be strategic therapy for patients with chronic heart failure, but many issues remain to be clarified. The objective of the double-blind, randomized, placebo-controlled cardiac insufficiency talinolol study (CITAS) is to assess efficacy and safety of talinolol - a selective beta-1 adrenoreceptor blocker - in patients with ischemic and non-ischemic heart failure. The primary end-point refers to the influence of talinolol on exercise capacity, evaluated by 6-min walking-test. Secondary end-points consist of left ventricular function, cardiovascular and all-cause mortality, hospitalizations, quality of life, combined clinical end-points and adverse events. There were enrolled 294 patients with stable heart failure in NYHA class II-IV, LVEF <40%, receiving diuretics, ACE-inhibitors and optionally nitrates and digoxin. Talinolol was titrated up to 100 mg/day (one arm) or to 150 mg/d (the other arm), starting with 12.5 mg daily. Enrollment began in November 1997 and the last visit will be in December 2000.