Comparison of MPEG digital video with super VHS tape for diagnostic echocardiographic readings.

BACKGROUND: Digital recording of echocardiographic studies is on the clinical horizon. However, full digital capture of complete echocardiographic studies in traditional video format is impractical, given current storage capacity and network bandwidth. To overcome these constraints, we evaluated the diagnostic image quality of digital video by using MPEG (Motion Picture Experts Group) compression. METHODS AND RESULTS: Fifty-eight complete, consecutive studies were recorded simultaneously with the use of MPEG-1 and sVHS videotape. Each matched MPEG and sVHS study pair was reviewed by two from a total of six readers, and findings were recorded with the use of a detailed, computerized reporting tool. Intrareader and interreader discrepancies were characterized as major or minor and analyzed in total and for specific subgroups of findings (left and right ventricular parameters, valvular insufficiency, and left ventricular regional wall motion). Intrareader discrepancies were reviewed by a consensus panel for agreement with either MPEG or sVHS findings. There was an exact concordance between MPEG and sVHS readings in 83% of findings. The majority of discrepancies were minor, with major discrepancies in only 2.7% of findings. There was no difference in the rate of consensus panel agreement with MPEG or sVHS for instances of intrareader discrepancy, either in total or for any subgroup of findings. Interreader discrepancy rates were nearly identical for both MPEG and sVHS. CONCLUSIONS: MPEG-1 digital video is equivalent to sVHS videotape for diagnostic echocardiography. MPEG increases the range of practical options for digital echocardiography and offers, for the first time, the advantages of digital recording in a familiar video format.

Ethanol-induced coronary vasodilation in patients with and without coronary artery disease.

To assess the influence of ethanol on coronary arterial blood flow and dimensions, we measured coronary sinus blood flow in 35 subjects (23 men and 12 women, aged 38 to 69 years; (29 with and 6 without coronary artery disease) before and during a 15- to 30-minute intracoronary infusion of (1) 5% dextrose in water (n = 15, controls) or (2) 5% dextrose in water (n = 20). In the controls heart rate, arterial pressure, and coronary sinus blood flow were unchanged. In those receiving ethanol at a rate that produced a concentration in coronary sinus blood of 285 +/- 102 (mean +/- SD) mg/dl, heart rate-systolic arterial pressure product was unchanged; coronary sinus blood flow rose 27 +/- 36%, and coronary vascular resistance fell 17 +/- 22% (p less than 0.05 in comparison to baseline); arterial-coronary sinus oxygen content difference fell (p less than 0.05), and epicardial coronary arterial dimensions were unchanged. Thus intracoronary ethanol increases coronary blood flow and decreases resistance without inducing a change in epicardial coronary dimensions, suggesting that its effect results from dilatation of the intramyocardial resistance vessels.