BETA-BLOCKADE IN CONGESTIVE-HEART-FAILURE - PERSISTENT ADVERSE HEMODYNAMIC-EFFECTS DURING CHRONIC TREATMENT WITH SUBSEQUENT DOSES

Objective-To determine whether the acute adverse haemodynamic effects of beta blockade in patients with congestive heart failure persist dur ing chronic treatment. Design-Sequential haemodynamic evaluation of he art failure patients at baseline and after three months of continuous treatment with the beta(1) selective antagonist metoprolol. Setting-Ca rdiac care unit in university hospital. Patients-26 patients with mode rate to severe congestive heart failure (New York Heart Association gr ade II to IV) and background treatment with digoxin, diuretics, and an giotensin converting enzyme inhibitors, and with a left ventricular ej ection fraction < 25%. Methods-Baseline variables included a six minut e walk, maximum oxygen consumption, and right heart catheterisation. A ll patients received metoprolol 6.25 mg orally twice daily initially a nd the dose was gradually increased to a target of 50 mg twice daily. Haemodynamic measurements were repeated after three months of treatmen t, both before (trough) and after drug readministration. Results-Long term metoprolol had functional, exercise, and haemodynamic benefits. I t produced decreases in heart rate, pulmonary capillary wedge pressure , and systemic vascular resistance, and increases in cardiac index, st roke volume index, and stroke work index. However, when full dose meto prolol was readministered during chronic treatment, there was a reduct ion in cardiac index (from 2.8 (SD 0.46) to 2.3 (0.38) 1/min/m(2), p < < 0.001) and stroke work index (from 31.4 (11.1) to 26.6 (10.0) g.m/m( 2), p < 0.001) and an increase in systemic vascular resistance (from 9 43 (192) to 1160 (219) dyn.s.cm(-5), p << 0.001). Conclusions-Adverse haemodynamic effects of beta blockers in heart failure persist during chronic treatment, as shown by worsening haemodynamic indices with sub sequent doses.