Exercise-induced ST-elevation is related to left ventricular dysfunction but not to myocardial viability in patients with healed myocardial infarction.
BACKGROUND
Exercise-induced ST-segment elevation was proposed as a marker of myocardial viability after a recent myocardial infarction.


OBJECTIVE
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).


CONCLUSIONS
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.
Manrique
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A
GIE de Médecine Nucléaire, Centre Henri Becquerel et CHU de Rouen, 1 rue d'Amiens, 76038 Cedex, Rouen, France. alain.manrique@rouen.fnclcc.fr
Koning
R
R
Hitzel
A
A
Cribier
A
A
Véra
P
P
D000368:Aged; D000704:Analysis of Variance; D020820:Dyskinesias / Q000150:complications / Q000000981:diagnostic imaging; D015716:Electrocardiography, Ambulatory; D015444:Exercise; D005080:Exercise Test; D005260:Female; D005328:Fetal Viability / Q000502:physiology*; D005602:France; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010477:Perfusion; D011237:Predictive Value of Tests; D011875:Radionuclide Angiography; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D013794:Thallium Radioisotopes; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*
D013794:Thallium Radioisotopes