Septal dyskinesia in the left ventricle is detected frequently in many pati
ents after open-heart surgery. The present study was designed to determine
whether the antegrade delivery of cardioplegic solution to the regional wal
l categorized in echocardiography is homogeneous, and whether the distribut
ion to the septal wall differs from that to the lateral wall in the absence
of coronary artery disease. To assess these hypotheses quantitatively, rad
ioactive microspheres were mixed into the cardioplegic solution and infused
by an antegrade method in eight normal pigs. The cardioplegic distribution
to the septal wall was significantly less than to the lateral wall close t
o the base of the left ventricle (P<0.05). Therefore, antegrade perfusion o
f cardioplegic solution was non-uniformly distributed to the regional and t
ransmural wall of normal pig hearts. Absence of functional correlation was
a limitation of this study. However, these findings suggest that inadequate
protection of the ventricular septum by antegrade cardioplegia might be an
explanation for the abnormalities of septal wall motion after open-heart s
urgery.