[Diagnostic value of a two-dimensional echocardiographic score for left ventricular hypertrophy validated by the Imatron CT scan in familial hypertrophic cardiomyopathy]. / Valeur diagnostique d'un score echocardiographique bidimensionnel d'hypertrophie du ventricule gauche validé par scanner Imatron dans la cardiomyopathie hypertrophique familiale.

ABSTRACT

The aim of this study was to validate a two-dimensional echocardiographic score for left ventricular hypertrophy in familial hypertrophic cardiomyopathy (HCM) by fast CT scan and to study the diagnostic value by an indexed threshold value in affected and genotyped families in comparison with the classical diagnostic method of maximal wall thickness (E max). The study was performed successively in two patient groups with HCM. The echo/CT scan population comprised 26 patients. They underwent echocardiography and Imatron CT scanning. The E max and 2D echo score (sum of the thickness of 4 segments) were measured by echocardiography and compared to the left ventricular mass obtained by the CT method. The 2D echo score was closely correlated to the CT left ventricular mass (r = 0.85) with a higher correlation coefficient than the E max (r = 0.78). The echo/generic population comprised 109 genotyped adults with an identified mutation. The E max and 2D echo score were measured. The genotype was the reference for diagnosis. A theoretical value of the 2D echo score was determined in healthy individuals by a multiple linear regression model of ages, sex and body surface area. A threshold value for abnormality was established after analysis of the ROC. The sensitivity and specificity were 63% and 100% respectively for E max and 73% and 96% respectively for the indexed 2D echo score. The improvement in sensitivity was marked in young adults (< 50 years) with 69% for the indexed 2D echo score versus 54% for E max, p < 0.04. The authors conclude that the indexed 2D score has been validated as an index of hypertrophy by the Imatron CT and has a better diagnostic value than E max, especially in young adults. This echocardiographic criterion could be proposed as an alternative diagnostic sign for screening families.