title: Exercise-induced prolongation of the infarct-related Q-waves as a marker of myocardial viability in the infarcted area.
abstract: OBJECTIVE
  It is known that exercise-induced ischemia in patients with coronary artery disease (CAD) may produce QRS prolongation in the surface electrocardiogram (ECG). To investigate the presence of exercise-induced Q-wave prolongation in patients with single-vessel CAD and Q-wave myocardial infarction (MI), in association with the presence of reversible perfusion defects during thallium scintigraphy in the infarcted area.
  
  
  METHODS
  107 consecutive patients (89 males, mean age 56+/-8 years) were evaluated. All patients underwent coronary arteriography, maximal treadmill exercise testing and thallium-201 scintigraphy. Q-wave duration was measured both before exercise testing and during maximal heart rate from 12-lead ECGs recorded with a paper speed of 50 mm/s.
  
  
  RESULTS
  Only 57 out of the 107 studied patients showed reversible perfusion defects in the infarcted area during thallium scintigraphy. Q-wave duration was significantly increased from the resting to the stress ECG (DeltaQ-wave duration) in patients with reversible perfusion defects in the infarcted areas (10+/-13 ms), but not in patients with fixed defects in the infarcted zone (-2.0+/-5 ms, p<0.01). The sensitivities and the specificities of Q-wave prolongation, ST segment elevation, and the combination of ST segment elevation with ST segment depression in the reciprocal leads for the detection of myocardial viability in the infarcted area were 82%, 48%, 29% and 88%, 50%, and 90%, respectively.
  
  
  CONCLUSIONS
  Exercise-induced Q-wave prolongation is demonstrated in those patients with single-vessel CAD and a recent MI who show reversible perfusion defects in thallium scintigraphy. Exercise-induced Q-wave prolongation was found to be a sensitive and specific ECG marker for the detection of myocardial viability in the infarcted area.
authors.affiliation: Department of Cardiology, University of Athens Medical School, Hippokration Hospital, Athens, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Michaelides
authors.forename: Polychronis
authors.initials: P
authors.lastname: Dilaveris
authors.forename: Zoi
authors.initials: Z
authors.lastname: Psomadaki
authors.forename: Athanasios
authors.initials: A
authors.lastname: Theoharis
authors.forename: George
authors.initials: G
authors.lastname: Andrikopoulos
authors.forename: Dimitris
authors.initials: D
authors.lastname: Richter
authors.forename: Maria-Niki
authors.initials: MN
authors.lastname: Aigyptiadou
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Stefanadis
authors.forename: George
authors.initials: G
authors.lastname: Tzannetis
authors.forename: Pavlos
authors.initials: P
authors.lastname: Toutouzas
mesh_terms: D000368:Aged; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes; D013997:Time Factors; D014022:Tissue Survival / Q000502:physiology*
chemical_list: D013794:Thallium Radioisotopes