OBJECTIVETo evaluate the value of low-dose adenosine echocardiography (LDAE) for detection of myocardial viability in patients with acute myocardial infarction (MI).

METHODSThirty-six patients underwent LDAE within 3 - 10 days after onset of first acute MI before (n = 4) or after (n = 32) percutaneous coronary intervention. A 17-segment semi-quantitative scoring model was adopted. Wall motion improvement derived from two dimensional images at follow-up (2 - 3 months after acute MI) comparing baseline before adenosine infusion was used as gold criteria for myocardial viability.

RESULTSLow-dose adenosine slightly increased heart rates [(70.7 +/- 10.8) beats/min vs. (78.1 +/- 10.9) beats /min, P < 0.01] and also significantly reduced left ventricular endsystolic volume [(30.4 +/- 1.9) ml vs. (20.1 +/- 9.3) ml, P < 0.01] and increased ejection fraction (62.6% +/- 10.4% vs. 74.7% +/- 9.8%, P < 0.01). The sensitivity, specificity, diagnostic accuracy, positive and negative prective values of LDAE for identification of viable myocardium were 90.3%, 80.8%, 86.0%, 84.8% and 87.5%, respectively. Incidence of mild adverse reaction during LDAE was 38.9% (14/36). LDAE at dose of 100 microgxkg(-1)xmin(-1) was ideal in terms of balanced sensitivity and specificity for detecting viable myocardium without increasing the adverse effects compared to lower doses.

CONCLUSIONSLDAE (100 microgxkg(-1)xmin(-1)) has excellent sensitivity and specificity for detecting viable myocardium in acute MI with only minimal adverse effects.

Adenosine ; Dobutamine ; administration & dosage ; Echocardiography ; Humans ; Myocardial Infarction ; Myocardium

OBJECTIVETo evaluate the safety and efficiency of the dobutamine stress echocardiography in patients with hypertrophic cardiomyopathy and estimate the difference between provokable obstruction and resting obstruction in these patients.

METHODSEchocardiography was performed in 22 patients with HCM (LVOTPG < 50 mm Hg at rest, 1 mm Hg = 0.133 kPa) at rest and at the end point of dobutamine stress. Dobutamine was administered via an infusion pump, starting at a dose of 5 microg x min(-1) x kg(-1) and increasing every 5 minutes by 5 microg x min(-1) x kg(-1) till the maximum dose of 20 microg x min(-1) x kg(-1). Fifty-seven patients with HCM (LVOTPG > 50 mm Hg at rest) were also studied at rest.

RESULTSIn these 22 patients, the mean maximum velocity of LVOT was 5.39 +/- 1.60 m/s, the mean maximum LVOTPG was 125.7 +/- 62.4 mm Hg at the end point of dobutamine stress and the mean dose of dobutamine was 13.90 +/- 6.85 microg x min(-1)xkg(-1). Sixteen patients evidenced positive stress results at the end point of dobutamine stress. The main difference between the provokable obstruction and resting obstruction was that in provokable obstruction patients, the SAM positive patients were fewer and the proportion of Maron II patients was higher (50%).

CONCLUSIONSDobutamine stress echocardiography was a safe and sensitive way for detecting patients with hypertrophic cardiomyopathy. Provokable obstruction patients had fewer SAM and higher proportion of Maron II.

Adult ; Cardiomyopathy, Hypertrophic ; diagnosis ; diagnostic imaging ; Dobutamine ; administration & dosage ; Echocardiography, Stress ; methods ; Female ; Humans ; Male ; Middle Aged

OBJECTIVETo compare the efficacy and safety of intravenous levosimendan and dobutamine in patients with decompensated heart failure refractory to conventional medications.

METHODSPatients were recruited into this multicentre, randomised, positive-controlled and parallel-group study to receive either levosimendan or dobutamine therapy. In the levosimendan group, an initial loading dose of levosimendan of 12 microg x kg was infused over 10 min, followed by a continuous infusion of 0.1 microg x kg(-1) x min(-1) for 1 h and then 0.2 microg x kg(-1) x min(-1) for 23 h. In the control group, dobutamine was infused for 1 h at an initial dose of 2 microg x kg(-1) x min(-1) without a loading dose, followed by a continuous infusion of 4 microg x kg(-1) x min(-1) for 23 h. Hemodynamic responses at 24 h were evaluated by echocardiography (in both groups) and Swan-Gans catheter (in the levosimendan group). Clinical assessment was performed to evaluate efficacy and safety of the medications.

RESULTSA total of 225 patients from 12 medical centers were evaluated; 119 assigned to levosimendan and 106 assigned to dobutamine group. The effectiveness rate was 31.9% (38 patients) in the levosimendan group and 17.9% (19 patients) in the dobutamine group (P < 0.01). At 24 h, left ventricular ejection fraction (LVEF) was improved by 6. 4% in the levosimendan group, compared with 4.6% in the dobutamine group (P > 0.05). Stroke volume (SV) was increased by 11.1 ml in the levosimendan group and 2.8 ml in the dobutamine group respectively (P < 0.05). Dyspnea and clinical manifestations improvements were more significant in levosimendan therapy group compared to dobutamine group. There were less adverse effects including hypokalemia, hypotension and ventricular premature beats in the levosimendan group than in the dobutamine group (P < 0.05).

CONCLUSIONLevosimendan was well tolerated and superior to dobutamine for patients with decompensated heart failure refractory to conventional medications.

Aged ; Cardiotonic Agents ; administration & dosage ; therapeutic use ; Dobutamine ; administration & dosage ; therapeutic use ; Female ; Heart Failure ; drug therapy ; Humans ; Hydrazones ; administration & dosage ; therapeutic use ; Injections, Intravenous ; Male ; Middle Aged ; Pyridazines ; administration & dosage ; therapeutic use ; Treatment Outcome

PURPOSE: Functional mitral regurgitation (FMR) and myocardial dyssynchrony commonly occur in patients with dilated cardiomyopathy (DCM). The aim of this study was to elucidate changes in FMR in relation to those in left ventricular (LV) dyssynchrony as well as geometric parameters of the mitral valve (MV) in DCM patients during dobutamine infusion. MATERIALS AND METHODS: Twenty-nine DCM patients (M:F=15:14; age: 62+/-15 yrs) with FMR underwent echocardiography at baseline and during peak dose (30 or 40 ug/min) of dobutamine infusion. Using 2D echocardiography, LV end-diastolic volume, end-systolic volume (LVESV), ejection fraction (EF), and effective regurgitant orifice area (ERO) were estimated. Dyssynchrony indices (DIs), defined as the standard deviation of time interval-to-peak myocardial systolic contraction of eight LV segments, were measured. Using the multi-planar reconstructive mode from commercially available 3D image analysis software, MV tenting area (MVTa) was measured. All geometrical measurements were corrected (c) by the height of each patient. RESULTS: During dobutamine infusion, EF (28+/-8% vs. 39+/-11%, p=0.001) improved along with significant decrease in cLVESV (80.1+/-35.2 mm3/m vs. 60.4+/-31.1 mm3/m, p=0.001); cMVTa (1.28+/-0.48 cm2/m vs. 0.79+/-0.33 cm2/m, p=0.001) was significantly reduced; and DI (1.31+/-0.51 vs. 1.58+/-0.68, p=0.025) showed significant increase. Despite significant deterioration of LV dyssynchrony during dobutamine infusion, ERO (0.16+/-0.09 cm2 vs. 0.09+/-0.08 cm2, p=0.001) significantly improved. On multivariate analysis, DeltacMVTa and DeltaEF were found to be the strongest independent determinants of DeltaERO (R2=0.443, p=0.001). CONCLUSION: Rather than LV dyssynchrony, MV geometry determined by LV geometry and systolic pressure, which represents the MV closing force, may be the primary determinant of MR severity.
Aged ; Dobutamine/administration & dosage/*pharmacology ; Echocardiography ; Female ; Humans ; Male ; Middle Aged ; Mitral Valve/*anatomy & histology/drug effects/*physiopathology ; Mitral Valve Insufficiency/*physiopathology ; Ventricular Dysfunction, Left/*physiopathology

Brief ischemic episodes that induce myocardial and coronary endothelial dysfunction may alter the responses to inotropic drugs. To determine the effects of inotropic drugs in stunned myocardium, the coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and regional mechanical function in response to intracoronary dobutamine, epinephrine, amrinone, and calcium chloride (CaCl2) were measured before (normal) and 30 min after a 15-min-period occlusion of the left anterior descending artery (stunned) in an open-chest canine model. Percent segment shortening (%SS) and post-systolic shortening (%PSS) were determined. Myocardial extraction of oxygen (EO2) and lactate (E(lac)) was calculated. The inotropic drugs increased %SS, CBF, and MVO2 in normal myocardium. Epinephrine and amrinone decreased, while dobutamine and CaCl2 did not affect EO2. The ischemia and reperfusion itself significantly reduced %SS and E(lac), and increased %PSS. In stunned myocardium, the responses to inotropic drugs were not significantly altered, except that they progressively reduced %PSS and epinephrine did not affect EO2. These findings indicate that a brief episode of ischemia does not affect the mechanical and metabolic coronary flow responses to inotropic drugs, although it abolishes direct vasodilator responses to epinephrine.
Amrinone/administration and dosage ; Animals ; Calcium Chloride/administration and dosage ; Cardiotonic Agents/*administration and dosage ; Comparative Study ; Dobutamine/administration and dosage ; Dogs ; Dose-Response Relationship, Drug ; Epinephrine/administration and dosage ; Female ; Male ; Myocardial Contraction/*drug effects ; Myocardial Stunning/*drug therapy/etiology/*physiopathology ; Oxidation-Reduction/drug effects ; Oxygen Consumption/*drug effects ; Reperfusion Injury/complications/*drug therapy/*physiopathology ; Treatment Outcome