Cardiovascular magnetic resonance of mitral valve length in hypertrophic cardiomyopathy.
Previous data suggest that mitral valve leaflets are elongated in hypertrophic cardiomyopathy (HCM), and mitral valve leaflet elongation may constitute a primary phenotypic expression of HCM. Our objective was to measure the length of mitral valve leaflets by cardiovascular magnetic resonance (CMR) in subjects with HCM caused by a Finnish founder mutation in the myosin-binding protein C gene (MYBPC3-Q1061X), carriers of the same mutation without left ventricular hypertrophy, as well as in unselected consecutive patients with HCM, and respective controls.



Anterior mitral valve leaflet (AML) and posterior mitral valve leaflet (PML) lengths were measured by CMR in 47 subjects with the Q1061X mutation in the gene encoding MYBPC3 and in 20 healthy relatives without the mutation. In addition, mitral valve leaflet lengths were measured by CMR in 80 consecutive non-genotyped patients with HCM in CMR and 71 age- and gender-matched healthy subjects.



Of the subjects with the MYBPC-Q1016X mutation, 32 had left ventricular hypertrophy (LVH, LV maximal wall thickness ≥ 13 mm in CMR) and 15 had no hypertrophy. PML was longer in patients with the MYBPC3-Q1061X mutation and LVH than in controls of the MYBPC group (12.8 ± 2.8 vs 10.6 ± 1.9 mm, P = 0.013), but the difference between the groups was not statistically significant when PML was indexed for BSA (P = 0.066), or when PML length was adjusted for BSA, age, gender, LV mass and ejection fraction (P = 0.195). There was no significant difference in the PML length in mutation carriers without LVH and controls (11.1 ± 3.4 vs 10.6 ± 1.9, P = 0.52). We found no difference in AML lengths between the MYBPC mutation carriers with or without hypertrophy and controls. In 80 consecutive non-genotyped patients with HCM, there was no difference either in AML or PML lengths in subjects with HCM compared to respective control subjects.



In subjects with HCM caused by the Q1061X mutation in the MYBPC3 gene, the posterior mitral valve leaflets may be elongated, but mitral valve elongation does not constitute primary phenotypic expression of the disease. Instead, elongated mitral valve leaflets seem to be associated with body size and left ventricular remodeling.
Department of Radiology, Kuopio University Hospital, Kuopio, Finland.
Mika
M
Tarkiainen
Department of Radiology, Kuopio University Hospital, Kuopio, Finland.|University of Eastern Finland, Kuopio, Finland.
Petri
P
Sipola
Heart and Lung Center, Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
Mikko
M
Jalanko
Heart and Lung Center, Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
Tiina
T
Heliö
Heart and Lung Center, Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland.
Mika
M
Laine
HUS Medical Imaging Center, Clinical Physiology and Nuclear Medicine, Hyvinkää Hospital, Hyvinkää, Finland.
Vesa
V
Järvinen
University of Eastern Finland, Kuopio, Finland.
Kaisu
K
Häyrinen
Department of Radiology, Helsinki University Central Hospital, Helsinki, Finland.
Kirsi
K
Lauerma
Centre for Medicine and Clinical Research, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland. Johanna.Kuusisto@kuh.fi.
Johanna
J
Kuusisto
D000293:Adolescent; D000328:Adult; D049628:Body Size; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000235:genetics / Q000503:physiopathology; D002352:Carrier Proteins / Q000235:genetics; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D005260:Female; D005387:Finland; D020022:Genetic Predisposition to Disease; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging* / Q000235:genetics / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009154:Mutation; D010641:Phenotype; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling; D055815:Young Adult; D000099163:Myosin Binding Protein C
D002352:Carrier Proteins; D000099163:Myosin Binding Protein C
Cardiomyopathy; Cardiovascular magnetic resonance; Hypertrophic; Mitral valve