STUDY OF MYOCARDIAL INFARCT REMODELING BY SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHIC IMAGING

Left ventricular (LV) remodeling after Q-wave anterior acute myocardia l infarction (AMI) was examined with single-photon emission computed t omographic thallium imaging, initial (after adenosine infusion) and 4- hour delayed reinjection images were obtained in 34 patients aged 65 1 2 years. Short-axis slices from the delayed images were quantitatively analyzed by measuring the outer and inner diameters, and wall thickne ss. The results were compared with those in a group of normal subjects . The outer diameter was greater in patients than in normal subjects a t the apical, mid- and basal levels (all p < 0.01); the average outer diameter was 16.9 +/- 1.9 mm in patients, and 12.2 +/- 1.3 mm in norma l subjects (p < 0.001). Similarly, the inner diameter was greater in p atients than in normal subjects at the 3 levels (all p < 0.05); the av erage inner diameter was 6.5 +/- 1.8 mm in patients, and 4.7 +/- 1.3 m m in normal subjects (p < 0.01). Wall thickness was greater in patient s than in normal subjects (5.2 +/- 0.5 vs 3.8 +/- 0.5 mm; p < 0.0001). There were significant correlations between LV dilation and time elap sed (in weeks) since AMI (r = 0.57; p < 0.005), and the size of the pe rfusion abnormality (r = 0.44; p < 0.03). Thus, LV dilation occurs aft er Q-wave anterior AMI, and is related to infarct size and duration. T hese changes can be studied by single-photon emission computed tomogra phic thallium imaging.