[Direct measurement of papillary muscle dynamics in the intact canine left ventricle during acute coronary occlusion (author's transl)].

UNLABELLED

The functions of the normal and ischemic papillary muscle in the intact canine heart were studied using an ultrasonic transit time method. Miniaturized piezoelectric crystals (1.5-2 mm 0) were implanted during extracorporeal circulation into the root and tip of the anterior and posterior papillary muscle of the left ventricle.

RESULTS

1. Phasic changes of left ventricular geometry during the heart cycle determine the dynamic pattern of papillary muscle movements. 2. The amplitude and velocity of papillary muscle length is directly related to those of myocardial wall segments. 3. Experimental ischemia induces total dysfunction of the papillary muscle within seconds. 4. Despite total muscle dysfunction no mitral insufficiency occured.