Angiographic assessment of left ventricular function
In patients with coronary heart disease, the ventriculogram provides important data about the size, shape, and ejection pattern of the left ventricle. Studies of the motion of individual segments of the myocardium can provide information about local disturbances in contraction (asynergy) as well as information about the residual contractile pattern of normal zones of the ventricle. Approximately 35% of patients referred for assessment of clinical coronary artery disease show a normal ventricular contraction pattern at rest. The remaining 65% demonstrate some type of resting left ventricular asynergy. Results of previous studies have indicated that these abnormalities most commonly occur in patients who had myocardial infarction, but asynergy can also occur without evidence of infarction. The patterns may range from the classic well-demarcated bulging left ventricular aneurysm to various types and degrees of abnormal motion of a segment of the heart without change in overall contour. Asynergic segments may be dyskinetic, akinetic, or hypokinetic, and the area may be composed of muscle or scar or both. A disturbed temporal sequence of contraction (asynchrony) may also be observed.
One might hypothesize that the pattern of ventricular contraction that is normal at rest could be disrupted during acute ischemia, at which time segmental or global wall motion may abruptly become abnormal. This has been observed experimentally in animals. In man, wall motion may be studied during stress known to precipitate ischemia (such as tachycardia induced by rapid atrial pacing). The demonstration of a new asynergic zone on ventriculogram under such conditions suggests . . .