Echocardiographic Score Index Research Articles

Value of low dose dobutamine Doppler tissue imaging for detecting hibernating myocardium.

In order to assess the value of Doppler tissue imaging (DTI) in detecting viable hibernating myocardium, 20 patients with coronary artery disease and chronic left ventricular dysfunction underwent low dose dobutamine stress echocardiography and low dose dobutamine stress DTI. The results showed that among the 100 asynergic segments, 35 segments showed improvement after dobutamine infusion (group H) and no changes were observed in the remaining 65 segments (group N). The left ventricular echocardiographic score index decreased from 1.60 +/- 0.35 to 1.44 +/- 0.36 (n = 20, P < 0.01). During low dose dobutamine stress DTI, there was no difference in the values of velocity of S wave (V.) before dobutamine infusion between two groups. However, after dobutamine infusion, the values of Vs and VR in group H were significantly higher than those in group N (Vs: 10.1 +/- 3.0 cm/s vs 7.3 +/- 2.2 cm/s, P < 0.01; VR: 60% +/- 41% vs 25% +/- 32%, P < 0.001), 95.7% asynergic myocardial segments with VR < or = 0 had no viability while 86% asynergic segments with VR > 80% were viable myocardium. It is concluded that the different reactions to dobutamine stress between hibernating and necrosis myocardium could be showed by DTI and it is more clinically significant when VR < or = 0 and VR > 80%.

906-64 Doppler Tissue Imaging of Left Ventricular Myocardium — Initial Results During Pharmacologic Stress

The new technique of Doppler tissue imaging (DTI) theoretically has the potential to quantify regional myocardial function. To determine the pattern of normal and ischemic LV contraction and relaxation during pharmacologic stress we studied DTI during a Dobutamin stress test (incremental steps from 5 up to 40 mcg/kg/min per 5’) in 18 patients with suspected ischemic heart disease using coronary angiography (CA) and conventional stress echocardiography (SE) for reference. We used a conventional ultrasound equipment (Acuson 128 XP) with software modifications which allowed also the display of myocardial regional velocities by colour Doppler (CD) and by the pulsed Doppler mode. Velocity patterns were analyzed in representative regions for each vascular bed as for peak velocities of contraction (V c ) and relaxation (V R ) and were compared to the echocardiographic score index in a 14 segment model. DTI images in CD and pulsed wave Doppler could be obtained in all patients. The analysis of 2-dimensional CD images gave similar morphological regional information as SE. Analysis, however, proved difficult in the presence of high heart rates due to low frame rates. In the 7 patients without coronary artery disease, there was a significant increase of V C (9.3 ± 4.1 to 13.1 ± 5.3 cm/s) and V R (-10.4 ± 2.6 to -148 ± 4.2 cm/s) during peak stress (p &lt; 0.01). In infarcted beds, V c and V R were low both before and during peak stress. In regions supplied by an artery with &lt; 50% stenosis, V R more than V c decreased during peak stress. Sensitivity for the diagnosis of coronary artery disease was 81% using SE and 92% using DTI. DTI provides quantification of regional LV contraction and relaxation and thus augments ultrasound stress studies.

Low-dose dobutamine in patients with acute myocardial infarction identifies viable but not contractile myocardium and predicts the magnitude of improvement in wall motion abnormalities in response to coronary revascularization

To assess the effects of coronary revascularization on viable but noncontractile myocardium, we examined 21 patients with a documented anterior acute myocardial infarction who had a significant improvement in wall motion abnormality evaluated by two-dimensional echocardiography in the infarct-related artery in response to low-dose dobutamine infusion. All patients had a significant residual stenosis in the infarct-related artery. In response to low-dose dobutamine, there was a marked improvement in contractility in the infarct-related area segments and this was reflected by a decrease in echocardiographic score index from 1.5 ± 0.15 to 1.09 ± 0.08 ( p = 0.0001). Of these 21 patients, 13 underwent successful revascularization: 10 had percutaneous transluminal coronary angioplasty (PTCA) and three had coronary artery bypass grafts (CABG) (group I). Eight patients received medical therapy only (group II). At 40 ± 15 days of follow-up, both groups had improvement in their segmental wall motion abnormalities. However, the improvement in group I was greater than that in group II, 1.1 ± 0.13 and 1.35 ± 0.1, respectively ( p = 0.0002). We conclude that: (1) low-dose dobutamine infusion may identify viable but noncontractile myocardium in patients with acute myocardial infarction and (2) in these patients revascularization causes a greater improvement in left ventricular function over time when compared with a nonrevascularized group.

Identification of viable myocardium by echocardiography during dobutamine infusion in patients with myocardial infarction after thrombolytic therapy: Comparison with positron emission tomography

To assess the presence of viable myocardium salvaged by coronary artery reperfusion, 17 patients with acute anterior myocardial infarction were studied. Each received intravenous thrombolysis within the first 3 h of symptoms and underwent two-dimensional echocardiography before and during dobutamine infusion (10 μg/kg per min) 7 ± 4 days after admission and positron emission tomography 9 ± 5 days after admission. Echocardiography and positron emission tomography were again performed 9 ± 7 months later. Six comparable segments specific for the territory of the left anterior descending artery were selected for comparison of the two techniques. Wall thickening was evaluated by using an echocardiographic score index. Segmental perfusion and glucose uptake were measured and normalized to the peak activity. A ratio of glucose uptake to perfusion was calculated for each segment.Concordant interpretation of the two techniques was found in 79% of affected segments for both acute and follow-up studies. Positron emission tomography revealed the presence of viable myocardium in 11 patients (group 1); perfusion was within normal limits in 5 of these (group 1A). Myocardial thickening improved with dobutamine infusion in these five patients, the echocardiographic score index decreasing from 12 ± 2 at rest to 7.8 ± 1.3 during dobutamine infusion (p = 0.003). Functional recovery was demonstrated in all five patients (follow-up score index 7.4 ± 1.7). Six patients exhibited decreased perfusion but an abnormally high glucose to perfusion ratio (group 1B); their score index improved with dobutamine from 14.8 ± 2.2 to 12 ± 2.1 (p = 0.05), but late functional recovery was found in only one of the six patients (mean follow-up score index in group 1B 16 ± 1.7). In the six remaining patients in whom no viable myocardium was detected with positron emission tomography (group 2), the echocardiographic score index did not change with dobutamine (15 ± 0.9 to 14.7 ± 0.8, p = NS) and there was no functional recovery (follow-up score index 15.5 ± 1.0).Echocardiography during dobutamine infusion is a promising method to unmask viable myocardium in acute myocardial infarction. Early recovery of perfusion in the area at risk is associated with a good functional outcome, whereas a high glucose to perfusion ratio indicates jeopardized myocardium that frequently loses viability.

Relative prognostic value of clinical, biochemical, echocardiographic and haemodynamic variables in predicting in-hospital and one-year cardiac mortality after acute myocardial infarction.

This study examined the relative value of clinical, biochemical, echocardiographic and haemodynamic variables, obtained early after acute myocardial infarction in predicting in-hospital and one-year cardiac mortality in 66 consecutive patients. Clinical examination and cross-section echocardiography were obtained in all 66 patients. An echocardiographic score index was calculated by grading wall motion from 0 to 5 in each of 16 left ventricular segments. Right-sided cardiac catheterization was performed soon after admission in 51 patients. Cardiac enzymes were measured every fourth hour in all patients and peak levels were identified in 55. During the follow-up of one year, 14 patients died of cardiac causes, seven of them during hospital stay; three patients died of a non-cardiac cause and were excluded from analysis. The echocardiographic score index was the best predictor of cardiac death and survival (chi 2 = 35), followed by Killip class on admission (chi 2 = 22), stroke volume index (chi 2 = 17) and a biochemical risk index (chi 2 = 11). Stepwise logistic discriminant analysis performed in the patients in whom all variables were obtained resulted in three independent prognostic variables: the echocardiographic score index, systemic vascular resistance at the time of catheterization and the development of infarct expansion. High- and low-risk patients are well identified by echocardiography in the acute phase of myocardial infarction.