Clinical usefulness of radiopaque markers in left ventricular function

Restoration of coronary blood flow following successful bypass surgery would be expected to lead to improvement of regional contraction. Several methods have been described for the quantitative assessment of regional or segmental left ventricular wall motion from the left ventriculogram. All methods need a reference point as a basis for their coordinate systems or to compensate for movement of the patient relative to the film camera. Morphological abnormalities such as aneurysms or akinetic areas influence the location of the reference point, resulting in artifacts when measuring wall motion. Localized abnormalities of contraction are not always reflected in “overall” measurements. Akinesis and/or dyskinesis of one or more segments can occur in the presence of normal end diastolic volume or ejection fraction. Such overall parameters will, however, gradually go into pathological ranges with an increase in the number of abnormally contracting segments. Another approach to the quantification of local wall motion uses radiopaque markers. In this study marker pairs are implanted during bypass surgery in the area of newly perfused regions as well as in control regions. Sequential cineradiograms at 50 fr. per second were made at intervals over a period of one year. It was found that direct traumatic effects of the surgical intervention overwhelm the expected improvement of myocardial function in the first three postoperative months. At present the quantitative approach to segmental cardiac function is mainly one of image analysis in one or two preselected planes. Subjective visual interpretation of these images should be replaced by objective data analysis.