Validation of the myocardial performance index by echocardiography in mice: a noninvasive measure of left ventricular function.
BACKGROUND
The myocardial performance index (MPI) is a Doppler-based measure of left ventricular (LV) function. It is noninvasive, independent of LV shape, and does not require dimensional measurements. However, it has never been validated in mice.


METHODS
A total of 29 anesthetized mice with LV pressure catheters underwent echocardiography (2-dimensional, M-mode, and Doppler) at baseline and during manipulations of beta-adrenergic tone, temperature, preload, and afterload. The maximum derivative of LV pressure with respect to time (dP/dt(max)) was compared with MPI, fractional shortening (FS), mean velocity of circumferential fiber shortening, and the FS/MPI ratio.


RESULTS
MPI (baseline 0.44 +/- 0.07) correlated strongly with dP/dt(max) (R = -.779, P <.001), as did FS and mean velocity of circumferential fiber shortening. MPI differed significantly with contractility, preload, and afterload manipulation. FS/MPI showed the best correlation with dP/dt(max).


CONCLUSIONS
MPI strongly correlates with dP/dt(max) over a range of hemodynamic conditions in mice. It can be used as a noninvasive index of LV function in this species.
Broberg
Craig S
CS
Divisions of Cardiology, Oregon Health and Science University, Portland, Oregon 97221, USA.
Pantely
George A
GA
Barber
Brent J
BJ
Mack
Gordon K
GK
Lee
Kathryn
K
Thigpen
Timothy
T
Davis
Lowell E
LE
Sahn
David
D
Hohimer
A Roger
AR
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D004280:Dobutamine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D015150:Echocardiography, Doppler; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D051379:Mice; D023421:Models, Animal; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D009206:Myocardium / Q000737:chemistry*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011433:Propranolol / Q000008:administration & dosage; D013223:Statistics as Topic; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D004280:Dobutamine; D011433:Propranolol