Left ventricular ejection time (LVET) is an important component in evaluating left ventricular performance. This measurement is usually made by measuring the timing of the transaortic valve flow velocity by continuous-wave Doppler. Although M-mode has also been used for measuring LVET, it has not been compared with the Doppler method. We tested the hypothesis that the M-mode-measured duration of aortic valve opening is comparable to Doppler-derived measurement of LVET by transesophageal echocardiography (TEE). Measurements were made in 31 patients undergoing nonaortic valve cardiac surgery. The timing of transaortic flow by continuous-wave Doppler was compared with the M-mode-derived timing of aortic valve opening. There was close correlation (Pearson correlation coefficient, r = 0.86; P < 0.0001) between M-mode and Doppler measurements. There was no significant difference between the two techniques by linearity tests (P > 0.1). Bland-Altman analysis showed no significant bias. We confirmed the hypothesis that M-mode-derived measurement of LVET is comparable to Doppler-derived measurement of LVET. M-mode may be an acceptable alternative to the Doppler method, especially when transvalvular velocity gradients cannot be readily obtained. M-mode is a simple, yet often underused, method of evaluating LVET during TEE.
IMPLICATIONS: Left ventricular ejection time is an important component of cardiac function assessment. Using transesophageal echocardiography, we found that the M-mode modality is comparable to Doppler assessment in determining ejection time and is a useful alternative when Doppler velocity gradients cannot be easily obtained.
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
Accepted for publication April 7, 2003.
Address correspondence and reprint requests to Madhav Swaminathan, MD, Department of Anesthesiology, Box 3094, Duke University Medical Center, Durham, NC 27710. Address e-mail to firstname.lastname@example.org.
Supported by the Cardiothoracic Division of the Department of Anesthesiology, Duke University Medical Center, Durham, NC.
Presented in part at the 76th Clinical and Scientific Congress of the International Anesthesia Research Society, San Diego, CA, March, 2002.