الفهرس 
CARDIOMYOPATHCARDIOMYOPATHYOnly 14 pages are availabe for public view
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Abstract
Differentiating between ischemic and non-ischemic etiology of left ventricular dysfunction has important clinical and therapeutic implications in patients with chronic heart failure. Several non-invasive techniques (i.e. echocardiography, dobutamine echocardiography, thallium-scintigraphy, positron emission tomography, magnetic resonance) have been proposed to establish the etiology of left ventricular dysfunction, but the results are controversial and the optimal strategy remains unsettled (Plewka et al., 2005).
The aim of this work is to study the potential role of tissue Doppler parameters using dobutamine stress echocardiography in identifying the ischemic etiology in patients with dilated cardiomyopathy. The patients were selected from the cardiology clinic and department of Ain Shams University Hospitals.
• The current study included (30) Patients with chronic heart failure (ischemic and non-ischemic) all with globally reduced contractility (EF<40%), and excluded Patients with Severely decompensated heart failure (NYHA class IV), Patients with cardiogenic shock, myocardial infarction (<3 months), unstable angina (<1 month), structural valve disease, ventricular tachycardia or atrial fibrillation.
• All patients were subjected to careful history taking, general examination and cardiac examination. with special interest to determine the risk factors for CAD as hypertension, diabetes mellitus, smoking, dyslipidemia and positive family history of ischemic heart disease, resting twelve-lead surface ECG, echo Doppler study to determine EF% using modified Simpson’s rule, Dobutamine stress echocardiography, tissue Doppler echocardiography and coronary angiography.
o Dobutamine stress echocardiography was performed: dobutamine was started at a dose of 5ug/kg body weight /minute and the dose was increasing every 3min. as 10, 20, 30, 40, till reaching 85% of maximal age-predicted heart rate according to age, (MAPHR = 220 - age). Patients who did not achieve 85% of maximal age-predicted heart rate were given 1 mg atropine in increments of 0.25 mg until the target heart rate was achieved.
o The standard views were the parasternal long axis, parasternal short axis view, apical 4-chamber view, apical 2-chamber view and apical long axis view.
o Tissue Doppler imaging was done using the echocardiographic Vivid 5 machine, to assess systolic and diastolic function of the left ventricle by measuring tissue Doppler velocities at mitral annulus, using pulsed-wave tissue Doppler myocardial velocity.
o Assessment of long axis function by TDI: tissue Doppler velocities were measured in standard views, apical 4-chamber view, apical 2-chamber view and apical long axis view to assess the septal, anterior, inferior, lateral, anteroseptal and posteroseptal points on mitral annulus. In those 6 positions we recorded the peak systolic velocity (Sm), peak early diastolic velocity (Em), and peak atrial systolic velocity (Am). Average measurements of 3 consecutive cardiac cycles were recorded.
These measurements were recorded at rest, and reevaluated at peak dobutamine stress, and then we calculate the mean (Sm) wave, (Em) wave, and (Am) wave velocities of the 6 mitral annular sites.