ECHOCARDIOGRAPHIC FOURIER PHASE AND AMPLITUDE IMAGING FOR QUANTIFICATION OF ISCHEMIC REGIONAL WALL ASYNERGY - AN EXPERIMENTAL-STUDY USING CORONARY MICROEMBOLIZATION IN DOGS

Objectives. This study investigated whether echocardiographic Fourier phase and amplitude imaging can be used to evaluate ischemia related r egional wall asynergy. Background. Because myocardial ischemia delays the onset and peak of endocardial inward motion and reduces its magnit ude, Fourier phase and amplitude analysis of twe-dimensional echocardi ograms may be used to evaluate regional wall motion abnormalities obje ctively by analyzing temporal sequence and magnitude of endocardial mo tion. Methods. Digital cine loops of left ventricular long- and short- axis views were obtained in six anesthetized dogs at baseline and 1 to 30 min after coronary microembolization and were mathematically trans formed using a first-harmonic Fourier algorithm to obtain phase angles and amplitudes of endocardial segments. Mean phase angles and amplitu des were compared with visual wall motion analysis based on a scoring system and quantitative analysis based on segmental fractional area sh ortening derived from planimetry. Results. Microembolization delayed s egmental phase angles by 47 +/- 44 degrees in mild to moderate hypokin esia (fractional shortening [mean +/- SD] 41 +/- 13%) and by 77 +/- 63 degrees in severe hypokinesia (fractional shortening 13 +/- 5%) and r educed segmental amplitudes from 80 +/- 36 gray level intensity at bas eline to 53 +/- 34 in segments developing mild to moderate hypokinesia , and from 93 +/- 36 to 35 +/- 28 gray level intensity in segments dev eloping severe hypokinesia. Shifts in segmental phase angles correlate d better with dynamic shifts in segmental fractional area shortening t han did changes in wall motion score (r = -0.65 vs. r = 0.52, p < 0.00 1). Conclusions. Echocardiographic Fourier phase imaging can be used t o evaluate ischemia-related regional wall asynergy, displaying contrac tion sequence and magnitude in a simple, objective format.