Archive for the ‘Ischemia’ Category

Symptoms of Patients With Silent Ischemia as Detected by Thallium Stress Testing: ConclusionIn contrast to these findings, in a study similar to ours, dyspnea was reported to be more frequent in those individuals with a positive thallium stress test who did not have chest pains. However, in that study, dyspnea was reported in the context of it being a test-limiting symptom and, therefore, the absence of chest pains might have produced a bias for other test endpoints, such as dyspnea. In our study, subjects were able to report and quantify any symptoms irrespective of the examiner’s reason for stopping the test, thereby providing a more reliable assessment of symptoms. canadian family pharmacy online

The lack of specificity of dyspnea as a symptom is well recognized. Dyspnea has been found to relate poorly to objective markers of cardiopulmonary disability. Nevertheless, cardiac dysfunction, particularly as evidenced by left ventricular diastolic indices, precedes other indications of myocardial ischemia. Our study suggests that, in general, within the time required for such changes to become evident as dyspnea, perhaps by producing stiffening of the lung, other determinants for stopping the test have already become manifest. Although dyspnea may lack specificity on stress testing, or even as an “anginal equivalent,” its importance as a presenting symptom for other myocardial ischemic syndromes, such as in pulmonary edema or myocardial infarction, is clear.
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As shown in Table 4, scores for breathlessness were the same for the two groups. When this variable was dichotomized, 78 percent in the silent ischemia group reported this symptom in comparison to 84 percent in the angina group, p=NS. Indeed, a lack of specificity for breathlessness was evident for the entire cohort: both the average score for breathlessness (1.5 ±0.1) and the percentage reporting this symptom was the same for those with myocardial ischemia (80 percent) as for those having a negative thallium stress test (83 percent), p=NS. By contrast, chest pains were reported by 23 percent of individuals with myocardial ischemia on the thallium stress test, but in only 10 percent of those having a negative test, p=0.006.
Table 5 compares the evidence for coronary disease in both groups. The percentages having a history of myocardial infarction, myocardial infarction within 30 days of testing, Q-wave on the ECG, or coronary angiographic-confirmed disease were not different. Although only 38 of the 294 patients had coronary angiograms, the percentage of those with silent ischemia, 24 percent, having this procedure was comparable to those with angina, 35 percent, p=NS.
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Symptoms of Patients With Silent Ischemia as Detected by Thallium Stress Testing: ResultsOne hundred thirty-six patients of the cohort of 294 satisfied criteria for myocardial ischemia. Forty-three (32 percent) of those having a positive test had pains (chest, back, arm, and/or jaw), the angina group, whereas 93 (68 percent) did not have this symptom, the silent ischemia group. As shown in Table 1, groups were similar for clinical characteristics: age, gender, and coronary risk factor distribution were comparable. However, the anginal history was different for the groups. Individuals having angina on the test were more likely to have had a history of chest pain with activity (Table 2). Except for a higher average monthly use of nitroglycerin in the angina group, treatment for the two groups was similar (Table 2). Even when the use of antianginal drugs, exclusive of nitroglycerin, was considered as a single variable, no difference was evident (angina group: 81 percent vs 74 percent, p=0.42).
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Blood pressure was measured by mercury sphygmomanometry at the end of each 3-min stage, at intermediate intervals when indicated, at peak exercise, and at 1-min intervals during recovery. The ST segment deviation during exercise (that is, horizontal or downsloping depression or rarely elevation) was measured as the difference between the resting and peak exercise ST depression measured 0.08 s after the J point, expressed in millivolts. A positive response, according to conventional criteria, consisted >1.0 mV of horizontal or downsloping depression at any time during the test or the recovery phase of the test. Individuals with a left bundle branch block pattern, receiving digoxin, or those not meeting criteria for a positive test yet not achieving >85 percent of maximal predicted heart rate were considered to have had a nondiagnostic ECG response.
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Symptoms of Patients With Silent Ischemia as Detected by Thallium Stress Testing: MethodThe occurrence of myocardial ischemia without chest pains has been referred to as silent (myocardial) ischemia. Because myocardial ischemia produces a complex array of hemodynamic and neurohu-moral effects, even when pain is not experienced, nonanginal symptoms might be expected. Previous studies of silent ischemia have focused on the significance, mechanisms, and prognostic implications of this disorder.” It would be of interest to know also whether individuals with myocardial ischemia not having chest pains experience other sensations that might serve as surrogate warnings. Symptoms resulting from myocardial ischemia not perceived as angina pectoris could be termed “anginal equivalents.” Patients undergoing stress testing might be a suitable cohort for identifying “anginal equivalents’ The purpose of this study was to determine the symptoms of individuals who have evidence of myocardial ischemia but do not experience chest, arm, back, or jaw pains. In this study, myocardial ischemia was denoted by scintigraphic or electrocardiographic changes occurring on thallium stress testing. Symptoms occurring during the test were assessed by a questionnaire completed by the patient immediately following cessation of the study. www.mycanadianpharmacy.com

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