Morphologic classification of hypertrophic cardiomyopathy with myocardial single photon emission tomography. Comparison to echocardiographic classification

Introduction and objectives. The aim of this study was to compare different morphologic types of hypertrophic cardiomyopathy obtained by single photon emission tomography to those obtained by echocardiogram. Material y methods. in 76 (64%) out of 119 patients with hypertrophic cardi omyopathy the echocardiogram permitted an optimal visualization of all left ventricular segments in the short axis view and consequent classification to one of the six morphological types: type I (septal anterior hypertrophy) , type II (septal anterior and septal posterior hypertrophy), type III (sep tal and antero-lateral hypertrophy), type IV (antero-lateral and/or septal posterior hypertrophy), type V (concentric hypertrophy) and type VI (apical hypertrophy). Without knowledge of echo data, two experienced observers in cluded the short axis of single photon emission tomography images at rest ( Tc-99m-tetrofosmin) to one of those types. Results. Global concordance between echocardiogram and single photon emissi on tomography was 75%. Type III was the most frequent both in echo (76%) an d in single photon emission tomography (74%) and type III produced the majo rity of discrepancies. SPET identified 4 patients with a predominant septal and inferior hypertrophy, that did not correspond to any of the 6 types of echocardiographic classification and had been previously classified as typ e III by echo in 3 cases and as type V in 1 case. Conclusion. There was agreement between echo and single photon emission tom ography in the morphological classification of most of the patients (75%) w ith hypertrophic cardiomyopathy. Nevertheless, some discrepancies were obse rved for the type III echocardiogram.