Using isoproterenol stress echocardiography to predict the response to carvedilol in patients with dilated cardiomyopathy

Left Ventricular Ejection Fraction and Fractional Shortening are Useful for the Prediction of the Therapeutic Response to Metoprolol in Children with Vasovagal Syncope

The objective of this manuscript was to explore if left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) could predict the efficacy of metoprolol therapy on vasovagal syncope (VVS) in children. Forty-nine children, including 30 with VVS and 19 gender- and age-matched healthy controls, were included in the study. Metoprolol was prescribed to the VVS subjects. The clinical data were obtained during follow-up at 2 and 6 months. The results showed that LVEF and LVFS of responders were significantly higher than those of non-responders both at the 2-month follow-up (LVEF: 72.5 ± 3.2% vs. 64.6 ± 3.4%; LVFS: 40.9 ± 2.3% vs. 34.9 ± 2.9%), and at the 6-month follow-up (LVEF: 72.8 ± 2.8% vs. 65.5 ± 4.6%; LVFS: 41.1 ± 1.9% vs. 35.8 ± 3.6%). The receiver operating characteristic curve (ROC) analysis demonstrated that 70.5% as a cutoff value of baseline LVEF yielded a sensitivity of 80% and a specificity of 100% in predicting the therapeutic effectiveness of metoprolol at 2 months. For baseline LVFS, 38.5% as a cutoff value yielded a sensitivity of 90% and a specificity of 90%. At the 6-month follow-up, the ROC analysis demonstrated that 70.5% as a cutoff value of baseline LVEF yielded a sensitivity of 81.3% and a specificity of 88.9% in the prediction of metoprolol efficacy. For baseline LVFS, 37.5% as a cutoff value yielded a sensitivity of 93.8% and a specificity of 66.7%. In conclusion, baseline LVEF and LVFS might be useful predictors of the efficacy of β-blocker therapy on VVS in children.

Comparative effects of carvedilol and losartan alone and in combination for preventing left ventricular remodeling after acute myocardial infarction in rats

It has been verified that losartan has beneficial effects on ventricular remodeling (VRM) after acute myocardial infarction (AMI), but the effects of carvedilol alone or in combination with losartan on this condition have not been defined. The present study used rats to compare the effects of carvedilol and losartan alone and in combination for preventing VRM after AMI. After ligation of the left coronary artery, 100 surviving female Sprague-Dawley rats were randomly assigned to 1 of 4 groups: (1) AMI control (n=25), (2) carvedilol (Car, 1 mg x kg(-1) x day(-1)) (n=25), (3) losartan (Los, 3 mg x kg(-1) x day (-1)) (n=25), and (4) Car (1 mg x kg (-1). day(-1)) + Los (3 mg x kg(-1) x day (-1)) (n=25). A sham-operated group (n=17) was also randomly selected. Drugs were administered by gastric gavage for 4 weeks. After hemodynamic studies, the hearts were fixed and analyzed pathologically. Exclusive of the rats that had died or had an infarct size <35% or >55%, complete data were obtained for 65 rats, comprising AMI control (n=13), Car (n=12), Los (n=13), combination (n=14), and sham (n=13) groups. There were no significant differences in the size of infarct among the 4 AMI groups (45.8 approximately 46.7%, all p>0.05). Compared with the sham group, left ventricular (LV) end-diastolic pressure (LVEDP), volume (LVV), weight (LVW) and septal thickness (STh) were all significantly increased (all p<0.001), whereas +/-dp/dt was significantly decreased (both p<0.001) in the AMI group. In comparison with the AMI group, LVEDP, LVV, LVW and STh were all significantly decreased (LVEDP: 12.7+/-2.3, 9.7+/-2.8, and 8.6+/-3.5 mmHg vs 20.6+/-2.7 mmHg, all p<0.001; LVV: 0.74+/-0.07, 0.76+/-0.07, and 0.70+/-0.09 ml vs 0.86+/-0.05 ml, all p<0.05; LVW: 668.4+/-52.0, 702.6+/-45.4, and 683.9+/-67.7 mg vs 787.3+/-76.7 mg, p<0.05 approximately 0.001; STh: 1.57+/-0.05, 1.48+/-0.07, and 1.46+/-0.07 mm vs 1.71+/-0.04 mm, all p<0.05), whereas +/-dp/dt was significantly increased (all p<0.05) in the Car, Los, and combination groups, with LVEDP decreasing more in both Los and the combination groups than in the Car group alone (p<0.05) and STh decreasing more in the combination group than in the Car group alone (p<0.05). Carvedilol and losartan alone and in combination all prevent VRM after AMI in rats, with almost equivalent effect.

Use of thallium-201 myocardial scintigraphy for the prediction of the response to beta-blocker therapy in patients with dilated cardiomyopathy

This study was performed to evaluate whether thallium-201 myocardial scintigraphy (Tl-201) and iodine-123-metaiodobenzylguanidine (MIBG) myocardial scintigraphy could predict the usefulness of beta-blocker therapy in patients with dilated cardiomyopathy (DCM). Tl-201 and MIBG were performed in 47 patients before beta-blocker therapy. Patients were classified into group A, if their cardiac function improved, and group B, whose function remained unchanged. Two types of extent score (ES) by Tl-201 were proposed to quantitate myocardial damage, mean-2SD (ES-2) and mean-3SD (ES-3). The ES difference between ES-2 and ES-3 was calculated, and according to ES and ES difference, DCM cases were classified into 3 groups: mild-defect type (mild-type), moderate-defect type (moderate-type) and severe-defect type (severe-type). The heart-to-mediastinum (H/M) MIBG uptake ratio was evaluated, and the percent washout ratio of myocardial MIBG was obtained from these data. Group A comprised 18 mild-type, 14 moderate-type and 1 severe-type cases, and group B comprised 5 mild-type, 4 moderate-type and 5 severe-type cases. A significant relation was observed between the defect type on Tl-201 and the response to beta-blocker therapy (p=0.0090). Both H/M MIBG uptake ratios and washout ratio were not significantly different in the 2 groups. Tl-201 may be useful for predicting the response to beta-blocker therapy in patients with DCM.