LEFT-VENTRICULAR MIDWALL DYNAMICS IN THE RIGHT ANTERIOR OBLIQUE PROJECTION IN INTACT UNANESTHETIZED MAN

The presence of nonuniform, asymmetric, asynergic left ventricular contraction is usually taken as indicative of segmental disease. In order to assess the uniformity, symmetry, and synergy of left ventricular contraction in patients with normal left ventricular function, the authors measured the dynamics of implanted radiopaque midwall markers silhouetting the left ventricle in the 30 degree right anterior oblique projection in eight patients post-cardiac surgery having normal left ventricular volumes, ejection fraction, heart rate, cardiac output, circumferential fiber shortening velocity and subjectively normal wall motion in all left ventricular regions. The data are consistent with myocardial fiber distribution and orientation in the wall of the heart and the location of the papillary muscles relative to the 30 degree right anterior oblique view of the left ventricle. It is concluded that contraction can be nonuniform, asymmetric, and asynergic even in the left ventricle with normal function.