An improved method for the quantitative analysis of M-mode echocardiograms.
A computer-assisted system is described which speeds and extends the quantitative interpretation of M-mode echocardiographic recordings. The system consists of a digitizing tablet, minicomputer, TV monitor and a hard copy device. M-mode echocardiograms are placed on the digitizing surface and traced using the digitizing pen. The entered signal includes the endocardial surfaces of the anterior and posterior left ventricular wall for at least one cycle, and two Q waves from a simultaneously recorded ECG to identify end diastole and heart rate. End systole is determined automatically as corresponding to the minimum LV dimension. Results of analysis include continuous plots of estimated volume and circumferential fiber shortening rate (CFSR) vs time. Determinations of special interest are also displayed: enddiastolic volume (EDV) and endsystolic volume (ESV), ejection fraction, cardiac output, mean and peak CFSR. M-mode echocardiograms obtained from 25 normal volunteers are used to evaluate the system. The standard error of the estimate of the computer-assisted system is comparable to the error between observers, furthermore the computer system adds no significant systematic or random error. Comparison between M-mode estimated volumes and angiographically determined values has been described previously and Sy - x here is significantly greater. The main advantages of this system are: 1. a continuous plot of estimated LV volume and CFSR is provided; 2. beat-to-beat analyses are facilitated; 3. the automatic determination of end systole removes possible errors in judgement made previously; 4. it is time saving when one considers the amount of data obtained. With these advantages and the generally satisfactory performance in the clinical trials, this system appears to have extended the clinical quantitative capabilities of M-mode echocardiograms.
D000293:Adolescent; D000328:Adult; D002648:Child; D003936:Diagnosis, Computer-Assisted; D004452:Echocardiography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male