A new, simple and accurate method for determining ejection fraction by Doppler echocardiography.
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Резюме
OBJECTIVE
To evaluate the feasibility, accuracy and reproducibility of a new and simple method for determining ejection fraction by Doppler echocardiography. This method should theoretically be less influenced by the distortions of left ventricular geometry caused by prior myocardial infarction.
METHODS
Two groups of patients (total 114) were evaluated independently at the Quebec and Ottawa Heart Institutes (60 and 54 patients, respectively). All were referred for radionuclide angiography performed within 24 h of the echocardiogram. Regional asynergy was present in 59% of Quebec patients and 37% of Ottawa patients. The new method for calculating ejection fraction consisted of dividing Doppler derived stroke volume in the left ventricular outflow tract by left ventricular end-diastolic volume calculated by Teichholz's formula; for comparison, ejection fraction was also measured by single plane area length or multiple disc planimetry as well as by the Quinones method at the Quebec Heart Institute.
RESULTS
Feasibility of the new method was 97% in Quebec and 100% in Ottawa. Compared with radionuclide angiography, the correlation coefficient for the new method was 0.92 (standard error of estimate [SEE] = 7.3) in Quebec compared with 0.88 (SEE = 8.5 and 8.1) for both the Quinones and single plane area length methods, and 0.84 (SEE = 12.0) in Ottawa compared with 0.77 (SEE = 10.9) for the single plane multiple disc method. Correlations in patients with regional asynergy were 0.90 in Quebec and 0.75 in Ottawa compared with 0.81 and 0.54 with planimetry. Correlation coefficients for interobserver variability in 12 patients were 0.97 with the new method compared with 0.83 with the Quinones method and 0.85 with single plane planimetry.
CONCLUSIONS
This new and simple method is feasible, accurate and reproducible even in patients with regional asynergy. Provided there is no significant mitral regurgitation, it is a time-saving alternative for the routine evaluation of ejection fraction by Doppler echocardiography.
