© 2001 European Society of Cardiology
Exercise-induced ST-elevation is related to left ventricular dysfunction but not to myocardial viability in patients with healed myocardial infarction
a GIE de Médecine Nucléaire, Centre Henri Becquerel et CHU de Rouen 1 rue d'Amiens, 76038 Rouen Cedex, France
b Service de Cardiologie, Hopital Charles Nicolle CHU de Rouen, Rouen, France
* Corresponding author. Tel.: +33-232-08-2258; fax: +33-232-08-2550. E-mail address: alain.manrique{at}rouen.fnclcc.fr (A. Manrique).
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Abstract |
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Background: Exercise-induced ST-segment elevation was proposed as a marker of myocardial viability after a recent myocardial infarction.
Aims: The aim of this study was to evaluate whether exercise-induced ST segment elevation is related to viability or to left ventricular dysfunction in patients with history of old Q wave myocardial infarction.
Methods: Fifty patients (43 men, age 57±11 years) were studied 31±49 months after a Q wave myocardial infarction. They all underwent stress, reinjection-redistribution, and late redistribution Tl-201 SPECT, completed by equilibrium radionuclide angiography. Viability was defined by defect reversibility or significant (>60%) persistent Tl-201 uptake in dyssinergic segments on late redistribution SPECT. Relative post-exercise and reinjection-redistribution LV volumes were calculated using validated software (QGS).
Results: Twenty-one out of 50 patients (42%, G1) had significant stress-induced ST-elevation (>1 mm 80 ms after J point in at least 2 ECG leads with Q wave), and 29/50 (58%, G2) did not. Seventeen out of 50 patients (34%) demonstrated myocardial viability on late redistribution scan. The diagnostic accuracy of exercise-induced ST-elevation was only 52% for viability assessment. Significant LVEF reduction and increased relative LV volumes were observed in G1 compared to G2 (LVEF: 39±10% vs. 49±11%, P=0.003; post-stress LV volume: 134±98 ml vs. 81±41 ml, P<0.02; reinjection-redistribution LV volume: 123±86 ml vs. 79±40 ml; P<0.02). Perfusion defects were similar in G1 and G2 (post-exercise: 38±12% vs. 37±14%, ns; reinjection-redistribution: 31±11% vs. 30±11%, ns; late redistribution: 30±10% vs. 28±11%, ns).
Conclusion: These results suggest that, in patients with history of myocardial infarction, exercise-induced ST-segment elevation is not related to persistent myocardial viability but is associated to left ventricular dysfunction.
Key Words: ST segment • Single photon emission tomography • Left ventricular function • Viability
Received November 10, 2000; Accepted May 28, 2001