Sources of subjective variability in the assessment of left ventricular regional wall motion from contrast ventriculograms.

Intraobserver and interobserver variability in the subjective interpretation of angiographic regional wall motion was quantitated in 135 contrast left ventriculograms showing a wide range of normal and abnormal cardiac function, and the effects of rating-scale complexity and myocardial regional differences were examined. Three experienced observers separately graded endocardial motion on a 6-point scale (0 = normal to 5 = dyskinesia) in each of 5 regions. Scores were also tabulated on a 3-point scale and as normal or abnormal. Average intraobserver agreement (2 evaluations per observer) was 68% using the 6-point scale, 86% using the 3-point scale and 90% for normal/abnormal. Interobserver agreement (3 observers) was 47% for exact agreement using the 6-point scale, 75% using the 3-point scale and 80% for normal/abnormal. Interobserver agreement was 84% within a range of 1 wall motion grade on the 6-point scale. Subjectively normal wall motion was most frequent in the 2 basal segments and least frequent in the apical and anterolateral segments. Disagreements were most frequent in the latter 2 segments, but when normal segments were excluded, these interregional differences disappeared. Thus, intraobserver and interobserver agreement is higher than previously reported, and may exceed 80%. Variability depends on whether regional wall motion is normal, but is also affected by the complexity of the rating scale. The distinctions implied by a 6-point subjective rating scale are probably not reliable, but variability is greatly reduced by use of a simplified scoring system.