Key result
A miniaturized conductance system yielded mean left ventricular volumes similar to flow probe and echocardiography in mice, though individual values did not correlate and saline altered hemodynamics.
Why the study?
Does miniaturized conductance technology accurately measure left ventricular volume in mice compared to echocardiography, flow probe, and ultrasonic crystals?
Does miniaturized conductance technology accurately measure left ventricular volume in mice compared to echocardiography, flow probe, and ultrasonic crystals?
Miniaturized conductance technology provides mean left ventricular volume measurements similar to echocardiography and flow probes in mice, but individual values do not correlate and the hypertonic saline calibration method alters hemodynamics.
Caution warranted for individual murine LV volume measurements by conductance; leaves open need for refined calibration in small-animal models.
The application of left ventricular pressure-volume analysis to transgenic mice to characterize the cardiac phenotype has been problematic due to the small size of the mouse heart and the rapid heartbeat. Conductance technology has been miniaturized for the mouse and can solve this problem. However, there has been no validation of this technique. Accordingly, we performed echocardiography followed by simultaneous ultrasonic crystals, flow probe, and conductance studies in 18 CD-1 mice. Raw conductance volumes were corrected for an inhomogenous electrical field (alpha) and parallel conductance (G(pi)) yielding a stroke volume of 14.1 +/- 3.7 microliter/beat, end-diastolic volume of 20.8 +/- 6.5 microliter, and end-systolic volume of 9.0 +/- 5.8 microliter. The mean conductance volumes were no different from those derived by flow probe and echocardiography but did differ from ultrasonic crystals. G(pi) was determined to be 14.9 +/- 8.7 microliter. However, hypertonic saline altered dimension and pressure in the mouse left ventricle. Although G(pi) can be determined by the hypertonic saline method, saline altered hemodynamics, questioning its validity in the mouse. Although mean measures of absolute volume may be similar among different techniques, individual values did not correlate.
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Feldman et al. (2000) studied CD-1 mice (n=18). Conductance system vs. Echocardiography, ultrasonic crystals, and flow probe was evaluated on Left ventricular volume. A miniaturized conductance system yielded mean left ventricular volumes similar to flow probe and echocardiography in mice, though individual values did not correlate and saline altered hemodynamics.
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