Use of radionuclide angiography and an electrocardiographic stress test to diagnose multivessel disease after a first episode of uncomplicated myocardial infarction.

Abstract

SUMMARY Sixty consecutive patients who were symptom free 2-12 months after an uncomplicated acute myocardial infarction underwent maximal treadmill exercise testing, radionuclide angiography before and during submaximal bicycle stress test, and coronary angiography. The results of the non-invasive procedures were compared with those of coronary angiography. The sensitivity and specificity of electrocardiogram stress test for detection of multivessel disease were 40% and 77% respectively. Failure of left ventricular ejection fraction to increase at least 5% with exercise identified 20 of the 25 patients with multivessel disease (sensitivity 80%) and 23 of the 35 patients with no additional coronary antery stenosis (specificity 66%). In patients with anterior Q waves the sensitivity was 78% and the specificity 50%, whereas in the presence of inferior Q waves these values were 81% and 87% respectively. Loss of left ventricle synchronicity during effort, as indicated by failure of the standard deviation of the phases to decrease during exercise, demonstrated a radionuclide angiography sensitivity of 80% (77% for anterior myocardial infarction and 81% for inferior myocardial infarction) and a specificity of 50% (33% for anterior myocardial infarction and 64% for inferior myocardial infarction). When the test was considered to be positive if either the ejection fraction or the standard deviation of the phases criteria were positive, the sensitivity was 100% and specificity 46% (30% for anterior myocardial infarction and 65% for inferior myocardial infarction).It is concluded that in patients who are free from angina 2-12 months after an episode of uncomplicated myocardial infarction, a simple exercise electrocardiogram cannot be relied upon to detect residual ischaemia. An abnormal ejection fraction response or an increased standard deviation of the phases during exercise nuclear angiography or both identified all the patients with multivessel disease. None of the patients in whom radionuclide angiographic criteria were negative had multivessel disease.Several post-myocardial infarction risk stratification and the degree of electrical instability.'l In the first studies have identified three major variables related year after hospital discharge roughly 5%-10% of to subsequent coronary events: the extent of myo-patients will die, 6% will experience a new episode cardial damage, residual coronary artery disease, of non-fatal myocardial infarction, and 16% will develop angina.4-6 Contrast ventriculography and coronary angiography have been widely used toRequests for reprints to Professor A Brusca, Divisione Univer-evaluate the left ventricular function and the extent sitaria di Cardiologia,

Relative power of clinical, exercise test, and angiographic variables in predicting clinical outcome after myocardial infarction: the Newham and Tower Hamlets study.

“…A positive exercise test was defined as the development of (a) angina pectoris; (b) horizontal or downsloping ST depression > 1 mm, 80 ms after the J point; (c) an inappropriate blood pressure response defined as failure of the systolic blood pressure to rise 10 mm Hg or more, or, having risen, to fall again by 10 mm Hg or more (the latter finding had to be confirmed immediately the patient stopped exercising); (d) inability to complete the exercise test because of severe dyspnoea, fatigue, or ataxia; (e) increase in the frequency of ventricular extrasystoles of >6 greater than the count on the pre-exercise 379 electrocardiogram or development of ventricular triplets. GROUP UNDERGOING CARDIAC CATHETERISATION (GROUP 3) Cardiac catheterisation was performed at a median of 21 (interquartile range, [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] days after infarction in patients with a positive exercise test. One hundred and thirty nine patients (53% of group 2) were defined as having a positive exercise test but 16 of these patients did not undergo catheterisation for the following reasons: (a) four died before cardiac catheterisation; (b) five refused cardiac catheterisation; (c) four had exercise tests erroneously reported as "negative" (in each case an inappropriate blood pressure response had been overlooked) and were not therefore put forward for catheterisation; (d) three because of administrative error.…”