Copyright © Italian Federation of Cardiology. Unauthorized reproduction of this article is prohibited. Influence of dynamic obstruction and hypertrophy location on diastolic function in hypertrophic cardiomyopathy Gustavo Avegliano a,b , J. Pablo Costabel a , Marina Huguet c , Jorge Thierer a , Marcelo Trivi a , Tobon-Gomez Catalina b,c , Mario Petit d , Bart Bijnens b,e , Alejandro Frangi b,e and Ricardo Ronderos a Background Hypertrophic cardiomyopathy (HCM) is a disease with marked genetic and phenotypic heterogeneity. It is well known that obstructive septal forms of this disease entail worse clinical outcome compared with nonobstructive septal and apical forms. The objective of this study was to analyze the differences in left ventricular diastolic function in different subgroups of HCMs and to assess the influence of the location of myocardial hypertrophy and the presence of dynamic obstruction on impairment of diastolic function and its correlation with the clinical status. Methods We studied 86 patients with HCM; 27 with the obstructive asymmetric septal type (OAS), 37 with the nonobstructive asymmetric septal type (NOAS) and 22 with apical hypertrophic cardiomyopathy (ApHCM). Patients underwent conventional and tissue Doppler echocardiography and were assessed applying the latest recommendations regarding diastolic dysfunction. Cardiac magnetic resonance was used to study the various morphologic subtypes and quantify left ventricular mass (LVM). Results The early diastolic annular velocity (e 0 ) was significantly lower in OAS with a median of 5 cm/s compared with NOAS with 7 cm/s and ApHCM with 7.5 cm/s (P U 0.0002), and the E/e 0 ratio was 8.5 in ApHCM, 10 in NOAS and 14 in OAS (P U 0.0001); no significant differences were found in LVM or maximal wall thickness. Conclusion In HCM, the location of left ventricular hypertrophy and the presence of dynamic obstruction affect the degree of diastolic dysfunction; impairment is greater in patients with the OAS type, and markedly less in patients with apical involvement. J Cardiovasc Med 2014, 15:207–213 Keywords: cardiomyopathy hypertrophic, echocardiography, magnetic resonance imaging a Cardiac Imaging Department, Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina, b Center for Computational Imaging and Simulation Technologies in Biomedicine, Universitat Pompeu Fabra, c Cetir Sant Jordi, d Centro Cardiovascular Sant Jordi and e Institucio ´ Catalana de Recerca i Estudis Avanc ¸ats, Barcelona, Spain Correspondence to Gustavo Pablo Avegliano, MD, Cardiovascular Ultrasound Laboratory, Instituto Cardiovascular de Buenos Aires, Blanco Encalada 1543, 1428, Buenos Aires, Argentina Tel: +54 11 47877500; fax: +54 11 47877500; e-mail: avegliano@gmail.com Received 15 January 2013 Revised 4 May 2013 Accepted 15 May 2013 Introduction Hypertrophic cardiomyopathy (HCM) is a disease with marked genetic and phenotypic heterogeneity, 1–3 resulting in a variable clinical presentation, course and prognosis. It is well known that obstructive forms present with worse clinical outcome than the nonobstructive forms of the disease. 4,5 Also, the clinical outcome of patients with the apical form is generally more benign than for those with septal forms. 6,7 Despite such findings, it is yet unclear whether these different clinical expressions are associated with different degrees of impairment in diastolic function. The goal of this study was to assess the differences in diastolic function between patients with obstructive asy- metric septal (OAS) hypertrophic cardiomyopathy, non- obstructive asymmetric septal (NOAS) hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy (ApHCM). Methods Study population From January 2006 until July 2008, we prospectively studied 99 patients with HCM referred to the Cardiac Imaging Department of the Instituto Cardiovascular de Buenos Aires (Argentina) and the Centro Cardiovascular Sant Jordi (Barcelona, Spain). The diagnosis of HCM was based on the presence of myocardial hypertrophy in the absence of local or systemic etiologies. 8–10 Morphological types were defined by cardiac magnetic resonance (CMR) and Doppler echocardiography. Using cardiac magnetic resonance, a septal asymmetric HCM was defined by a ventricular septum at least 15 mm in thick- ness and a septum/inferolateral wall thickness ratio at least 1.5. 8,9 ApHCM was defined by a wall thickness of at least 15 mm in the apical segments, and an apical to basal segments ratio of at least 1.5. 6 NOAS was defined when left ventricular outflow tract gradient was less than Original article 1558-2027 ß 2014 Italian Federation of Cardiology DOI:10.2459/JCM.0b013e3283638093