Browsing by Subject "Dobutamine"

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    Evaluation of the anti-ischemic effects of D-ribose during dobutamine stress echocardiography: a pilot study
    (BioMed Central, 2009-02-07) Sawada, Stephen G.; Lewis, Stephen; Kovacs, Roxanne; Khouri, Samer; Gradus-Pizlo, Irmina; St Cyr, John A.; Feigenbaum, Harvey; Medicine, School of Medicine
    D-Ribose, a pentose sugar, has shown to improve myocardial high-energy phosphate stores depleted by ischemia. This study investigated the ability of D-Ribose with low dose dobutamine to improve the contractile response of viable myocardium to dobutamine and to assess the efficacy of D-ribose in reducing stress-induced ischemia. Twenty-six patients with ischemic cardiomyopathy completed a two-day, randomized, double blind crossover trial comparing the effects of D-Ribose and placebo on regional wall motion. On the first study day, either D-Ribose or placebo was infused for 4.5 hours. Low (5 and 10 μ/kg/min) and subsequently, high (up to 50 μ/kg/min) dose dobutamine echocardiography was then performed. On the second study day, patients crossed over to the alternative article for a similar 4.5 hours infusion time period and underwent a similar evaluation. The wall motion response during low dose dobutamine was the same with D-Ribose and placebo in 77% of segments (203/263, Kappa = 0.37). In segments with discordant responses, more segments improved with D-Ribose than with placebo (41 vs. 19 segments, p = 0.006). With high dose dobutamine infusion, the wall motion response (ischemia vs. no ischemia) was the same with D-Ribose and placebo in 83% of interpretable segments (301/363, kappa = 0.244). In segments with discordant responses, there were more ischemic segments with placebo compared to D-Ribose (36 vs. 26, p = 0.253). Nineteen patients developed ischemia during the dobutamine and placebo infusion and 13 patients had ischemia during dobutamine and D-ribose infusion (p = 0.109). D-Ribose improved contractile responses to dobutamine in viable myocardium with resting dysfunction but had no significant effect in reducing the frequency of stress-induced wall motion abnormalities.
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    Wall motion abnormalities with low-dose dobutamine predict a high risk of cardiac death in medically treated patients with ischemic cardiomyopathy
    (Wiley, 2009-07) Maskoun, Waddah; Mustafa, Nowwar; Mahenthiran, Jothiharan; Gradus‐Pizlo, Irmina; Kamalesh, Masoor; Feigenbaum, Harvey; Sawada, Stephen G.; Medicine, School of Medicine
    BACKGROUND: Severe and extensive coronary artery disease is the underlying cause of stress-induced wall motion abnormalities (SWMA) with low-dose (10 microg/kg/min) dobutamine suggesting that these abnormalities may identify those with poor outcome. HYPOTHESIS: We assessed the prognostic value of low-dose SWMA in medically treated patients with ischemic cardiomyopathy. METHODS: Low- and peak-dose dobutamine echocardiography was performed in 235 patients with ischemic cardiomyopathy (ejection fraction 31% +/- 8%) who were treated with medical therapy. The survival of patients with low-dose SWMA (n = 33) was compared with the survival of patients without ischemia (n = 85) and those with peak-dose SWMA (n = 117). RESULTS: There were 123 cardiac deaths (52%) during follow-up of 4.1 +/- 3.3 years. Multivariate predictors of cardiac death were age (p = 0.002, hazard ratio [HR]: 1.03), diabetes (p = 0.028, HR: 1.54), New York Heart Association (NYHA) class III, IV heart failure (p = 0.001, HR: 1.94), the presence of peak dose SWMA (p < 0.001, HR: 2.59), and low-dose SWMA (p = 0.005, HR: 2.28). Survival of patients without ischemia was significantly better than those with peak-dose SWMA (p < 0.0001) and those with low-dose SWMA (p = 0.001). The survival of patients with low-dose SWMA was the same as those with peak-dose SWMA (p = 0.89). CONCLUSIONS: Low-dose SWMA is an independent predictor of cardiac mortality in medically treated patients with ischemic cardiomyopathy. Patients with low-dose SWMA are at equivalent risk to those with peak-dose SWMA.