Turk Kardiyol Dern Ars. 2006; 34(6): 346-351

The effect of beta-blocker therapy on left ventricular systolic functions and functional capacity in patients with heart failure: a comparison between metoprolol succinate and carvedilol

Şakir ARSLAN¹, Mustafa Kemal EROL¹, Engin BOZKURT², Fuat GÜNDOĞDU¹, Hanifi Yekta GÜRLERTOP¹, Hüseyin ŞENOCAK^1
1Atatürk University Medical Faculty, Department of Cardiology, ERZURUM
²Atatürk Education Hospital, Department of Cardiology, ANKARA

OBJECTIVES
We evaluated the effect of metoprolol succinate or carvedilol given in addition to conventional treatment on left ventricular systolic functions and effort capacity in patients with heart failure.

STUDY DESIGN
The study included 33 patients (6 females, 27 males; mean age 60±10 years) with mild to moderate heart failure (NYHA functional class II-III). Following six weeks of standard treatment, the patients were randomized to receive carvedilol or metoprolol succinate, whose initial doses were 3.125 mg twice daily and 25 mg daily, with weekly increments to target doses of 50 mg/day and 100 mg/day, respectively. The patients were assessed by the six-minute walk test and transthoracic echocardiography prior to, and after three months of, beta-blocker treatment.

RESULTS
Compared with pretreatment values, resting heart rate and systolic blood pressure showed significant decreases after beta-blocker treatment (carvedilol, p<0.001; metoprolol, p<0.05). Decrease in diastolic pressure was significant only in the metoprolol group (p<0.01). In both groups, systolic and diastolic diameters and end volumes showed significant decreases, and ejection fraction showed a significant increase. There was a dramatic increase in the walking distance in both groups (p<0.001) associated with significantly decreased heart rate and symptom scores which were more notable in the carvedilol group. However, none of the improvements obtained by beta-blocker treatment differed significantly between the two groups (p>0.05).

CONCLUSION
Our findings show that metoprolol succinate and carvedilol provide similar but significant improvements in left ventricular systolic functions and effort capacity of patients with mild to moderate heart failure.

Keywords: Adrenergic beta-antagonists, carbazoles/therapeutic use; exercise test; heart failure, congestive/drug therapy; metoprolol/therapeutic use; ventricular function, left

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