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Current guidelines for the investigation of patients with chest pain suggestive of myocardial ischaemia recommend that they have objective confirmation of the diagnosis. Although an exercise stress test (EST) is neither 100% sensitive nor specific for the diagnosis of coronary artery disease, it remains the most frequently used test for the evaluation of patients with suspected ischaemic heart disease, and is an important predictor of prognosis. 1 2
Although infrequent, exercise-induced ST-segment elevation (STE) is most commonly seen in patients who have had a prior myocardial infarction (MI), and in this cohort the phenomenon does not necessarily reflect reversible ischaemia but is associated with lower left ventricular ejection fraction, left ventricular wall motion abnormalities at rest and an adverse prognosis. 3 4 5 For patients without a prior history of MI or pathological Q waves on the electrocardiogram (ECG), exercise-induced STE is rare. In previous small studies this finding has been attributed to coronary artery spasm 6 7 8 or severe coronary artery stenosis. 9 10 The finding of exercise-induced STE, although uncommon, may be of greater diagnostic significance for ischaemic heart disease than previously recognised. The aim of this study was to identify patients with exercise-induced STE without prior history or electrocardiographic evidence of MI. We also sought to assess outcomes of these patients up to 9 years from diagnosis.
Patients and methods
Between January 1998 and December 2005 all patients undergoing ESTs in our department had the details of the test recorded on a computerised database. All patients without prior history of MI or pathological Q waves (defined as [= or >, slanted]25% of the height of the partner R wave and/or >0.04 s in width and >2 mm in depth) on the resting ECG, who had an EST, were identified. Within this cohort those who developed STE during exercise or in the recovery phase were selected for further analysis. STE was defined as ST-segment elevation on the ECG of [= or >, slanted]1 mm in two or more contiguous leads and in three or more consecutive beats. The ST segment was measured 0.08 s after the J point
The presence and duration of STE were retrospectively verified. All exercise electrocardiograms were standard recordings.
In all cases following the stress test the STE...