Comparison of the Therapeutic Effects of the Beta-Blocking Agent Bisoprolol and the Calcium-Blocking Agent Diltiazem in Patients With Heart Failure Due to Dilated Cardiomyopathy

Abstract

Beta-blocking agents reduce mortality and improve symptoms in patients with dilated cardiomyopathy (DCM). There have been reports that diltiazem, a calcium-blocking agent, is also effective in such patients. We prospectively compared the effects of the beta-blocking agent bisoprolol with those of the calcium-blocking agent diltiazem in 18 patients (11 males and 7 females, age 14 to 68) with DCM. The 18 patients, (10 in New York Heart Association functional class III and 8 in class IV) were randomly assigned to 2 groups. Bisoprolol was administered as the first drug in 10 patients and diltiazem was administered in 8. Cross-over to bisoprolol was also performed in 3 patients. At the end of the study, among the 13 patients who had been given bisoprolol, 9 showed a good response (efficacy rate: 69%). In contrast, only 3 of the 8 patients who received diltiazem showed a good response (efficacy rate: 37.5%). Among the patients in NYHA class III, all 7 (100%) who were treated with bisoprolol responded but only 2 of the 4 (50%) treated with diltiazem responded (p < 0.05). Among the patients in class IV, 2 of 6 (33%) responded to bisoprolol and 1 of 4 (25%) responded to diltiazem (not significant). These results suggest that diltiazem, like bisoprolol, has a beneficial effect in patients with DCM, with a greater effect in class III patients. However, we conclude that diltiazem should usually be used as a second choice to improve heart failure in DCM, and as the first medication only in those with contraindications to beta-blocking agents.

Effect of Beta-Blocker Treatment in Dilated Cardiomyopathy With Bradyarrhythmias

“…4 However, some studies have revealed that betablockers with ISA have no beneficial effect in patients with severe heart failure although they improve the clinical condition in mildly symptomatic patients. [9][10][11][12][13] The mechanism of the beneficial effect of beta-blocker treatment for heart failure remains unclear, but suppression of circulating cathecholamines leading to myocardial toxicity and myocardial dysfunction, restoration of -1-receptor downregulation and improvement of myocardial metabolism due to a reduction of heart rate and oxygen consumption have been postulated as possible mechanisms. 16 In a trial using various beta-blockers for heart failure, Swedberg et al indicated that alprenolol, nonselective and with ISA, caused deterioration in heart failure or provoked heart failure death, and had to be replaced by metoprolol without ISA for a beneficial effect.…”