Effects of atrial pacing stress test on ultrasonic integrated backscatter cyclic variations in normal subjects and in patients with coronary artery disease.

AIMS To evaluate the effects of acute, atrial pacing-induced, reversible myocardial ischaemia on myocardial thickening and integrated backscatter cyclic variations in patients with or without coronary artery disease. METHODS AND RESULTS Thirty-six patients with suspected coronary artery disease underwent transoesophageal echocardiography with simultaneous atrial pacing, and coronary angiography. In myocardial segments not related to a significantly narrowed coronary artery, both from patients with and without coronary artery disease, thickening and integrated backscatter cyclic variations were not reduced at peak pacing. In segments related to a significantly narrowed coronary artery, thickening decreased at peak pacing, was still reduced at pacing interruption and recovered at 2 min, while backscatter cyclic variations, blunted at peak pacing, immediately recovered after pacing interruption. CONCLUSION During stress-induced myocardial ischaemia, backscatter cyclic variations are blunted and thickening reduced. Returning to baseline, pre-atrial pacing values occur more rapidly in backscatter cyclic variations than when thickening takes place. Evaluation of stress-induced alterations in backscatter cyclic variations may aid in the identification of ischaemia-induced regional left ventricular functional impairment and, hence, in coronary artery disease diagnosis.