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Introduction. The "warm-up" effect in some patients with angina may represent ischaemic preconditioning. We investigated whether protection occurs against ischaemic left ventricular (LV) dysfunction and subsequent stunning. Methods. 16 patients (age 63±7y, 15 male) with 3-vessel coronary disease and normal resting LV function underwent 2 symptom-limited supine bicycle exercise tests 30min apart. Patients had practice tests and stopped antianginal medication. Equilibrium gated radionuclide ventriculography (RNV) was performed; regional ejection fractions (REFs) were calculated for 9 LV segments. Results. Exercise time and maximal ST depression were the same for each test, but the onset of angina was delayed by 1.7min during test 2, whilst a higher rate-pressure product was reached before angina or 1mm ST depression occurred (P < 0.01 for all). Heart rate and BP during equivalent RNV acquisitions were comparable between tests. LV segments whose REF fell during test 1 ("ischaemic") showed a reduced ischaemic response during test 2, with no increase in post-exercise stunning (Figure, left panel). "Nonischaemic" segments responded similarly to each test (Figure, right panel). (Graph Presented) Conclusion. Exercise-induced ischaemia causes immediate impairment and persistent stunning of some LV segments. With further exercise, dysfunction is less marked. This may represent ischaemic preconditioning.

Type

Journal article

Journal

Heart

Publication Date

01/05/1999

Volume

81