Effects of intravenous metoprolol by two injection methods on atrial fibrillation and rapid ventricular rates complicated with heart failure

Objective To explore the effectiveness and safety of intravenous metoprolol by two injection methods in treatment for patients of atrial fibrillation anti rapid ventricular rates complicated with heart failure.Methods Patients of atrial fibrillation and rapid ventricular rates complicated with heart failure were administrated regular drug therapy for their heart failure,and then they were observed for half an hour.If their ventricular rates were above 100 beats/min and blood pressure equal to or above 100/60 mm Hg (1 mm Hg=0.133 kPa),they were randomly divided into three groups,the first one administrated with metoprolol 10 mg by minipump in an hour,the second one administrated with metoprolol 5 mg in 10 minutes by direct injection,and repeated by 5 mg 10 minutes later if their heart beats were still above 100 beats/min and blood pressure equal to or above 100/60 mm Hg,and the third one administrated with normal saline as control group.As either ventricular rates were equal to or lower than 60 beats/min or blood pressure lower than 90/60 mm Hg,drug administration would be terminated.Symptoms,physical signs, heart rate,blood pressure,rale on auscultation of the chest,parameters of haemodynamics,serum levels of brain natrium peptide (BNP) and atrial natrium peptide (ANP) were observed at 0 h and 1 h after drug injection.Results Clinical symptoms and physical signs of heart failure were improved significantly,heart rates and serum levels of BNP (F=15.929,14.534,all P0.01) decreased significantly after infection in both groups with intravenous metoprolol,as compared with those in control group (F=5.011,4.559,all P0.01),but difference in blood pressure between the two groups with intravenous metoprolol and the control group did not reach statistical significance.Cardiac index (CI),cardiac output (CO),stroke index (SI),stroke volume (SV) and left ventricular ejection time (LVET) of noninvasive parameters of cardiac functions in the first group with minipump injection of metoprolol all increased significantly,as compared with those in control group (F=4.435,4.726,3.965,3.450,5.966,all P0.05),but no similar effects in the second group with direct injection of metoprolol were found.Conclusion Intravenous metoprolol either by minipump or direct injection were both effective and safe for the management of rapid ventricular rates in patients of atrial fibrillation complicated with heart failure,but more haemodynamically effective with minipump injection.