Half of our CAD patients manifested diminution in PWA that was consistent with peripheral arterial vasoconstriction during the early phases of treadmill exercise. Such paradoxical vasoconstrictive responses were not observed in normal subjects and, therefore, they may represent generalized vascular pathology secondary to atherosclerosis.
Stress echocardiography yields prognostic information for risk stratification of patients with known or suspected ischemic heart disease. A normal stress echocardiographic study (peak WMSI = 1.0) confers a benign prognosis (0.9%/year cardiac event rate). Peak WMSI >1.7 and EF < or =45% are independent markers of patients at high risk of an adverse clinical outcome.
Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data.
Peripheral artery tonometry may be useful for improving the diagnosis of exercise-induced myocardial ischemia by both enhancing the sensitivity without impairing the specificity and increasing the percentage of definitive test results.
The destruction of the World Trade Center and associated terrorist activities of September 11, 2001 have spurred interest in understanding the medical consequences of terrorist activity. Currently, there is a paucity of data regarding this subject. Potential effects, however, can be garnered by studying the medical effects of other acute stressors, such as earthquakes, missile attacks, and the like. None of these stressors have been studied extensively, but there is enough data available concerning earthquakes to indicate that in some instances, the effects of the earthquake may last at least a period of weeks, if not months, following the earthquake. Since the World Trade Center attack was associated with a rise in post-traumatic stress syndrome and affective disorders afterwards, there is accordingly interest in both the acute and more prolonged health effects that could be engendered following terrorist attacks. Known pathophysiological effects of acute stress, whether produced in a laboratory environment or by studying naturally occurring acute stressors, include: the induction or potentiation of cardiac arrhythmias; the induction of myocardial ischemia in susceptible patients with underlying coronary artery disease; acute increases in arterial blood pressure with its ability to cause shear stress; the precipitation of worsening endothelial function and/or endothelial injury; coagulation abnormalities; and hemoconcentration. These all represent important areas for study following the occurrence of future terrorist activity. Based on existing epidemiological and pathophysiological data concerning the cardiac effects of acute life stressors, it would behoove physicians to closely monitor high-risk cardiac patients following future terrorist events. In addition, physician-scientists should be well prepared to use new epidemiological markers which could provide rapid information following future events, such as the evaluation of patients using pre-versus post-event serum markers or tracing records available among patients fitted with implantable cardiovertor-defibrillators.
SummaryBackground: Myocardial perfusion single-photon emission computed tomography (SPECT) permits assessment of stress perfusion and resting left ventricular (LV) function. Quantitative analysis of perfusion patterns among patients with LV dysfunction offers an opportunity for developing criteria to differentiate ischemic from nonischemic cardiomyopathy.Hypothesis: Quantitative assessment of SPECT may allow differentiation between ischemic and nonischemic cardiomyopathy.Methods: We evaluated 144 patients with LV ejection fraction ≤ 40%, divided into 63 patients with nonischemic and 81 with ischemic cardiomyopathy. Mean relative myocardial counts were obtained for regions drawn over defect and normal zones on rest and stress polar perfusion maps.Results: Multivariate logistic regression analysis of significant univariate SPECT predictors of ischemic cardiomyopathy revealed that the stress defect severity ratio (SDSR) was the best predictor of ischemic cardiomyopathy (p < 0.0001). By receiver operator characteristic (ROC) curve analysis, an SDSR of ≤ 45% optimized prediction of ischemic cardiomy-
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