Improved echocardiographic evaluation of the closed-chest canine: methods and anatomic observations

This report describes an improved and convenient method of obtaining echocardiograms from the precordial surface of the closed-chest conscious dog. All major cardiac structures were identified using contrast echocardiography. Anatomic relations and the orientation of cardiac structures to the ultrasound transducer in the position of study were established by postmortem examinations. Good quality echocardiograms were obtained from nine of 11 conscious dogs. Highly significant correlations were found when comparing left ventricular systolic time intervals measured from simultaneous echo and pressure recordings. This method has advantages over other echo techniques; namely, elimination of surgical intervention, displacement of interfering lung tissue, and wider field available for study with a minimum of reverberation artifact. The ability to obtain echocardiograms from the chronic experimental dog under physiologic conditioins might provide new and improved applications of echocardiography for the evaluation of human cardiac disorders.