Second- and third-generation beta-blocking drugs in chronic heart failure

The left-ventricular (LV) functional, hemodynamic, and antiadrenergic effects of metoprolol, bucindolol, and carvedilol have been compared in three concurrent placebo-controlled clinical trials in patients with symptomatic idiopathic dilated cardiomyopathy. All three drugs were well tolerated, all produced at least moderate degrees of β-blockade as assessed by reduction in exercise heart rate, and all increased the left-ventricular ejection fraction. Compared with the β_1-selective, second-generation compound metoprolol, the third-generation compounds bucindolol and carvedilol lowered indices of adrenergic activity and tended to improve LV function to a greater extent. In patients with chronic heart failure there may be important therapeutic response differences between second- and third-generation beta-blocking agents.