Scintigraphic characterization of Q wave and non-Q-wave acute myocardial infarction.

This study examines the scintigraphic features of patients in Killip class I or II after acute myocardial infarction (AMI) with relation to ECG changes. The 41 consecutively studied patients (23 men and 18 women) with first AMI were divided into two groups: group 1 (n = 25) had Q wave AMI, and group 2 (n = 16) had non-Q wave AMI. Rest thallium-201 myocardial scintigrams and radionuclide ventriculograms were obtained 10 days (mean) after AMI. The thallium images were divided into 15 segments in three projections and assessed qualitatively and quantitatively. Fixed perfusion defects were present in at least one segment in 23 patients (92%) in group 1 and in eight patients (50%) in group 2 (p = 0.007). All but one patient in group 1 (4%) and three patients in group 2 (19%) had perfusion defects (fixed or reversible). The number of segments with perfusion defects was 5.6 +/- 2.6 in group 1 and 2.9 +/- 2.3 in group 2 (p = 0.002); the peak creatine kinase was 1280 +/- 880 Units/L in group 1 and 360 +/- 340 Units/L in group 2 (p less than 0.001); the left ventricular ejection fraction was 38 +/- 14% in group 1 vs 43 +/- 15% in group 2 (p = NS). Thus fixed perfusion defects are present in 92% of patients with Q waves and in 50% of patients with no Q waves.