Stress-Induced Wall Motion Abnormalities with Low-Dose Dobutamine Infusion Indicate the Presence of Severe Disease and Vulnerable Myocardium
ABSTRACT Patients with left ventricular (LV) systolic dysfunction due to coronary artery disease (CAD) may develop stress-induced wall motion abnormalities (SWMA) with low-dose (10 microg/kg/min) dobutamine infusion. The clinical significance of low-dose SWMA is unknown.
We investigated the clinical, hemodynamic and angiographic correlates of low-dose SWMA in patients with chronic ischemic LV systolic dysfunction.
Seventy patients with chronic ischemic LV systolic dysfunction who had dobutamine stress echocardiography were studied. Clinical, hemodynamic, and angiographic parameters at rest and low-dose were compared between 38 patients (mean ejection fraction (EF) of 30 +/- 8%) with low-dose SWMA and 32 patients (EF 30 +/- 11%) without low-dose SWMA.
Multivariate analysis showed that the number of coronary territories with severe disease (stenosis > or =70%)(P = 0.001, RR = 6.3) was an independent predictor of low-dose SWMA. An increasing number of collateral vessels protected patients from low-dose SWMA (P = 0.011, RR = 0.25). A higher resting heart rate was a negative predictor of low-dose SWMA (P = 0.015, RR = 0.92) but no other hemodynamic variables were predictors. In the patients with low-dose SMA, regions with low-dose SWMA were more likely to be supplied by vessels with severe disease than regions without low-dose SWMA (92% vs 58%, P < 0.001).
In patients with ischemic LV systolic dysfunction, the extent of severe disease and a lower numbers of collaterals predict the occurrence of low-dose SWMA. Low-dose SWMA is a highly specific marker for severe disease.
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ABSTRACT: Numerous studies in children with anaphylaxis and (suspected) cutaneous, food, drug and insect allergy have been published in 2009. It is not possible to summarize these studies in 250 words. The reader is invited to “have a glance” at the conclusions of this article before an “enjoyable” reading of this “What's new in pediatric allergology in 2009?”.Revue Française d Allergologie 10/2011; 51(6):576-598. DOI:10.1016/j.reval.2011.09.005 · 0.22 Impact Factor
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ABSTRACT: Introduction and objectives To investigate negative contractile responses in the left ventricle during lowdose dobutamine (LDD) gated single-photon emission computed tomography (SPECT) in patients with ischemic cardiomyopathy. Methods Sixty-eight consecutive patients (mean age, 60±11 years; 7 male) with ischemic cardiomyopathy (i.e., left ventricular ejection fraction [LVEF] ≤40%) were evaluated using gated-SPECT at rest and during LDD infusion. Associations between a negative contractile reserve (i.e., a ≥1-grade improvement in wall thickening score with LDD infusion) and scintigraphic viability criteria and coronary angiography findings were analyzed. Results Some 42.6% (29/68) of patients had a negative contractile reserve in one or more segments. In 14.7% (n=10), the LVEF decreased by ≥4% with LDD. These patients had more segments with a negative contractile reserve (2.8±2.5 vs. 0.87±0.40; P=.042), and the cut-off value on receiver operating characteristic curve analysis was ≥2 segments with a negative contractile reserve (sensitivity 70%, specificity 74%, positive likelihood ratio 2.71, negative likelihood ratio 0.40). Some 94% (74/79) of segments with a negative contractile reserve were in viable myocardium (i.e. normal or viable on scintigraphy). Twelve of 17 segments with akinesia or severe hypokinesia and a negative contractile reserve satisfied scintigraphic viability criteria, with the majority (10/12) lying in territories supplied by a patent coronary artery. Conclusions A negative contractile reserve was not uncommon in patients with ischemic cardiomyopathy and was associated with a general decrease in left ventricular systolic function. It was observed mainly in myocardial segments that appeared viable on scintigraphy and were supplied by a patent coronary artery.Revista Espa de Cardiologia 02/2010; 63(2):181-189. DOI:10.1016/S0300-8932(10)70036-1 · 3.34 Impact Factor
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ABSTRACT: Introduction and objectives The objective of this study was to use low-dose dobutamine (LDD) gated single-photon emission computed tomography (SPECT) to evaluate segmental thickening of the left ventricle (LV) and its relationship with changes in ejection fraction (EF) and ventricular volumes in patients with ischemic cardiomyopathy. Methods This prospective multicenter study involved 89 patients with ischemic cardiomyopathy (i.e., EF ≤40%) who underwent LDD gated-SPECT at rest. The LV was divided into 17 segments and systolic thickening was assessed in a total of 1513 segments during LDD infusion. Results A significant increase in LVEF (33.2% vs. 30.8%; P<.001) was observed during LDD infusion and occurred at the expense of a reduction in end-systolic volume (130.5 mL vs. 136.4 mL; P=.005). The increase in EF was ≥5% in 33.7% of patients, while the EF decreased by ≥5% in 5.6% of patients. With LDD infusion, both an improvement in ≥3 segments with severely decreased baseline thickening (odds ratio [OR] = 18.3; 95% confidence interval [CI], 5.3-63) and an improvement in ≥10 segments with mild-to-moderate alterations in baseline thickening (OR = 4.53; 95% CI, 1.26-16.16) were associated with a ≥5% increase in LVEF. Conclusions During the assessment of global left ventricular contractile reserve by LDD gated-SPECT, attention should be paid not only to the behavior of segments with severely decreased baseline thickening, which are generally regarded as indicating viability, but also to segments with mild-to-moderate alterations and to those in which thickening decreases.Revista Espa de Cardiologia 10/2008; 61(10):1061-1069. DOI:10.1157/13126046 · 3.34 Impact Factor