Assessment of cardiac function using global and regional left ventricular endomyocardial and epimyocardial peak systolic strain and strain rate in healthy Labrador retriever dogs.

Speckle tracking echocardiography (STE) is based on tracking of natural acoustic myocardial markers. The study aimed at quantifying global and regional endomyocardial and epimyocardial left ventricular longitudinal, circumferential and radial peak systolic strain and strain rate, including feasibility and variability; and assessing synchronicity and torsion, in healthy dogs. Cineloops were acquired from left apical 4-chamber, basal and apical right parasternal short-axis views in 22 healthy Labrador retrievers. A general epimyocardial to endomyocardial strain gradient was found. Strain was higher at apex compared to base. A strain longitudinal base to apex gradient was found. Left ventricular synchronicity could be assessed in all dogs and torsion in 1/3. Short axis apical view had highest variability. Dog and operator contributed most to overall variance. In conclusion, STE allows assessment of myocardial function in healthy Labrador retrievers. A longitudinal base to apex gradient was found and a new synchronicity index for use in dogs was introduced.