USEFULNESS OF RADIONUCLIDE VENTRICULOGRAPHY DURING TRANSESOPHAGEAL ATRIAL-PACING IN THE DIAGNOSIS OF CORONARY-ARTERY DISEASE

Radionuclide ventriculography before, during, and after atrial transes ophageal pacing was carried out in 15 patients with suspected coronary artery disease (CAD) and without myocardial infarction. All patients underwent coronary angiography. Ten patients (group 1) had a coronary lesion > 50% on at least one of the main coronary arteries. Five patie nts (group 2) had normal coronary arteries. Radionuclide left ventricu lar ejection fraction (LVEF) before pacing was 56 +/-3% in group 1 and 59 +/-3% in group 2 (NS). Radionuclide ventriculography during pacing was 45 +/-4% in group 1 (P < 0.0001 vs basal in group 1) and 45 +/-6% in group 2 (P < 0.01 vs basal in group 2, NS vs group 1 during pacing ). Immediate postpacing ejection fraction did not differ in the two gr oups and was identical to the prepacing value. A quantitative regional wall motion analysis was performed in 105 segments. Regional radionuc lide ventriculography was calculated in each segment as follows: end-d iastolic counts - end-systolic counts/end-diastolic counts. The relati ve decrease in regional LVEF during pacing was more important in the 3 9 segments related to a narrowed vessel than in the 66 segments relate d to normal coronary artery (32 +/- 13% vs 13 +/- 10%, P < 0.0001). A more than 20% relative decrease in at least one segment during pacing occurred in 10 patients in group 1 (sensitivity 100%) and in 2 patient s in group 2 (specificity 60%). In conclusion, global radionuclide ven triculography during transesophageal atrial pacing decreases in patien ts with and without CAD. In contrast, regional wall motion abnormaliti es during pacing are more important in segments related to a narrowed coronary artery and can be proposed for patients unable to exercise as an alternative to pharmacologic stress test in the diagnosis of CAD.