Early exercise testing after treatment with thrombolytic drugs for acute myocardial infarction: importance of reciprocal ST segment depression.

OBJECTIVE

To investigate the clinical importance of reciprocal ST depression induced by exercise testing early after acute myocardial infarction in patients treated with thrombolysis.

DESIGN

Prospective observational study.

SETTING

District general hospital in London.

SUBJECTS

202 patients (170 men) aged 33-69 with acute myocardial infarction treated with thrombolysis.

MAIN OUTCOME MEASURES

All patients underwent exercise testing and coronary arteriography. ST depression induced by exercise was classified as either reciprocal (associated with ST elevation) or isolated (occurring on its own). The relation between reciprocal ST depression and the following end points was studied: characteristics of the infarct, left ventricular ejection fraction, extent of coronary artery disease on arteriography, and presence of angina induced by exercise.

RESULTS

Reciprocal ST depression occurred almost exclusively in Q wave infarctions and was associated with a lower overall ejection fraction than isolated ST depression. It tended to be associated with persistent occlusion of the coronary artery related to the infarct and did not indicate remote ischaemia due to multivessel coronary disease. Unlike isolated ST depression, reciprocal ST depression was not associated with angina induced by exercise.

CONCLUSIONS

Reciprocal ST depression induced by exercise is usually associated with extensive Q wave infarctions and persistent occlusion of the artery related to the infarct. It does not seem to indicate reversible ischaemia and should not be used as a non-invasive marker of multivessel disease in the assessment of requirements for further investigation soon after acute myocardial infarction.