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, reversib le myocardial ischaemia on myocardial thickening and integrated backsc atter cyclic variations in patients with or without coronary artery di sease. Methods and results Thirty-six patients with suspected coronary artery disease underwent transoesophageal echocardiography with simul taneous atrial pacing, and coronary angiography. In myocardial segment s not related to a significantly narrowed coronary artery, both from p atients with and without coronary artery disease, thickening and integ rated backscatter cyclic variations were not reduced al peak pacing. I n segments related to a significantly narrowed coronary artery, thicke ning decreased at peak pacing, was still reduced at pacing interruptio n and recovered at 2 min, while backscatter cyclic variations, blunted at peak pacing, immediately recovered after pacing interruption. Conc lusion During stress-induced myocardial ischaemia, backscatter cyclic variations are blunted and thickening reduced. Returning to baseline, pre-atrial pacing values occur mote rapidly in backscatter cyclic vari ations than when thickening takes place. Evaluation of stress-induced alterations in backscatter cyclic variations may aid in the identifica tion of ischaemia-induced regional left ventricular functional impairm ent and, hence, in coronary artery disease diagnosis.