BackgroundThe effects of focal hypertrophy on geometry of the left ventricle and systolic function have not been studied in patients with hypertrophic cardiomyopathy (HCM), despite the fact that the former is the most prominent disease characteristic. The aim of our study was to analyze systolic function over ventricle geometry, generating a functional index made from left ventricle end diastolic dimension (LVEDD) divided by end diastolic thickness of the region with maximal extent of hypertrophy and interventricular septum.Material/MethodsOur hospital database of cardiac magnetic resonance was screened for HCM. Geometric functional index (GFI) was calculated for LVEDD over maximal end diastolic thickness (MaxEDT) giving GFI-M, while LVEDD over interventricular septum was expressed as GFI-I. There were 55 consecutive patients with HCM.ResultsThere were 43 males (78.2%) and 12 females (21.8%). The mean age was 52.3±16.7 years (range: 15.5–76.4 years). A significant difference of GFI was found for preserved versus impaired systolic function of the left ventricle (preserved systolic function); GFI-M 2.28±0.60 versus 3.66±0.50 (p<0.001), and GFI-I 2.75±0.88 versus 3.81±0.87 (p<0.001), respectively. Diagnostic value was tested using receiver operating curve (ROC) analyzes, with GFI-M area under curve (AUC)=0.959 (95% CI: 0.868–0.994); (p<0.001) and GFI-I-AUC=0.847 (0.724–0.930); (p<0.001). GFI-M was superior to GFI-I for appraisal of left ventricle systolic dysfunction in HCM; ΔAUC=0.112 (0.018–0.207); (p=0.020).ConclusionsGFI is a simple tool, with high sensitivity and specificity for detecting impairment of systolic function in patients with HCM. Further studies would be necessary to investigate its clinical and prognostic impacts, as well as reproducibility with prospective validation.

LITERATURE 1.Murphy RT, Thaman R, Blanes JG, Ward D, Sevdalis E, Papra E, et al. Natural history and familial characteristics of isolated left ventricular noncompaction. Eur Heart J. Hypertrophic cardiomyopathy (HCM) and left ventricular noncompaction (LVNC) are both genetically determined and familial diseases. Hypertrophic cardiomyopathy (HCM) is defined as hypertrophy of the myocardium more than 1.5cm, without another identifiable cause, such as long-standing hypertension, amyloidosis, aortic stenosis, glycogen storage disease. Many of the mutations associated with HCM involve the cardiac sarcomeric proteins and include actin, myosin, or troponin component of the sarcomere and it is most frequently transmitted as an autosomal dominant trait. Left ventricular noncompaction is a rare congenital cardiomyopathy which is characterized by the presence of a thin, compacted epicardial layer and a non-compacted thicker endocardial layer of myocardium, with prominent trabeculation and deep recesses communicating with the cavity of the left ventricle. The cause of the disorder has been identified as mutations in genes associated with the mitochondrial function, like G4.5 which encodes the protein tafazzin, genes related with the cytoskeleton, like those of alpha-dystrobrevin or dystrophin, genes that code proteins of the Z line of the sarcomere, like LDB3, which codes the protein Cypher/ZASP, genes of the internal nuclear membrane proteins (LMNA, which encodes lamin A/C) and even genes that code sarcomeric proteins like cardiac alpha-actin and the beta-myosin heavy chain and cardiac troponin T. The clinical picture of both diseases, HCM and LVNC, varies from mild forms until severe forms with heart failure and complex ventricular arrhythmias. LVNC and HCM may appear as overlapping entities. Cases of patients sharing both the LVNC and HCM phenotypes have been already published, and it is speculated that mutations in sarcomere protein genes known to cause hypertrophic cardiomyopathy and dilated cardiomyopathy may be associated with left ventricular noncompaction. 1-5 In our case report, we are presenting patient with clear overlapping pheenotyp for LVNC and HCM, using the imaging method cardiac MRI.

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