[Effects of carvedilol (beta 1, beta 2, alpha 1 bloker) on refractory congestive heart failure]

The effect of beta-adrenergic receptor antagonism in cardiac sympathetic neuronal remodeling in patients with heart failure

BACKGROUND

beta-adrenergic receptor antagonism with drugs like carvedilol slows the progression of heart failure by an undefined mechanism. (123)I-metaiodobenzylguanidine (MIBG) is an analog of norepinephrine used to study cardiac sympathetic function.

METHODS AND RESULTS

In this double-blind randomized, placebo-controlled study, we used MIBG imaging to evaluate the effect of carvedilol (n=15) or placebo (n=7) on neuronal norepinephrine reuptake in patients with heart failure due to idiopathic dilated cardiomyopathy, with LVEF less than 35% and functional class II or III. The drug was begun at 6.25 mg b.i.d. and titrated up to 25 mg t.i.d, as tolerated. Thorax planar scintigraphy images were obtained 15 min (Initial) and 4 h (Late) after MIBG injection at baseline (t(0)) as well as 2 months (t(1)) and 6 months (t(2)) after drug initiation. The multifarious statistical technique of profile analysis was applied and p< or =0.05 was considered significant. The heart/mediastinum MIBG uptake (H/M ratio) was calculated from these images. On the Initial images, the H/M ratio was 1.64+/-0.24 (t(0)), 1.71+/-0.21 (t(1)), and 1.87+/-0.34 (t(2)) in the carvedilol group and 1.68+/-0.42 (t(0)), 1.81+/-0.45 (t(1)), and 1.69+/-0.44 (t(2)) in controls (p=0.0455). On the Late images, the H/M ratio was 1.39+/-0.24 (t(0)), 1.53+/-0.23 (t(1)), and 1.64+/-0.36 (t(2)) in the carvedilol group, and 1.49+/-0.45 (t(0)), 1.53+/-0.47 (t(1)), and 1.47+/-0.41 (t(2)) in controls (p=0.0513).

CONCLUSION

Compared with placebo, the addition of carvedilol to existing heart failure treatment incites the reverse remodeling of cardiac sympathetic nervous system function.

Delisting of infants and children from the heart transplantation waiting list after carvedilol treatment

OBJECTIVES

We performed a prospective, randomized, double-blind, placebo-controlled study of carvedilol effects in children with severe, chronic heart failure (HF), despite the use of conventional therapy.

BACKGROUND

Little is known about the effects of carvedilol in youngsters with chronic HF and severe left ventricular (LV) dysfunction.

METHODS

We conducted a double-blind, placebo-controlled study of 22 consecutive children with severe LV dysfunction. The children had chronic HF and left ventricular ejection fraction (LVEF) <30%. Patients were randomly assigned to receive either placebo (8 patients) or the beta-blocker carvedilol (14 patients) at 0.01 mg/kg/day titrated up to 0.2 mg/kg/day, followed-up for six months.

RESULTS

During the follow-up and the up-titration period in the carvedilol group, four patients died and one underwent heart transplantation. In patients receiving carvedilol evaluated after six months, a significant increase occurred in LVEF, from 17.8% (95% confidence interval [CI], 14.1 to 21.4%) to 34.6% (95% CI, 25.2 to 44.0%); p = 0.001. Modified New York Heart Association (NYHA) functional class improved in nine patients taken off the transplant waiting list. All nine patients were alive at follow-up. In the placebo group, during the six-month follow-up, two patients died, and two underwent heart transplantation. Four patients persisted with HF symptoms (NYHA functional class IV). No significant change occurred in LVEF or fractional shortening.

CONCLUSIONS

Carvedilol added to standard therapy may reduce HF progression and improve cardiac function, allowing some youngsters to be removed from the heart transplantation waiting list.