Author + information
- Beth Ann Medford,
- Kristina Haugaa,
- Johan Bos,
- Angela Miller,
- Steve Ommen,
- Bernard Gersh,
- Jonathan Johnson,
- Frank Cetta,
- Benjamin Eidem and
- Patrick O'Leary
Hypertrophic cardiomyopathy (HCM) is marked by profound phenotypic and genotypic heterogeneity. Systolic anterior motion (SAM) of the anterior mitral leaflet is a classically described feature of HCM but its genetic predilection is unknown.
Our study cohort consisted of 213 (74 male, mean age 51 ± 167 years) consecutive, unrelated patients referred to Mayo Clinic for evaluation of HCM. All underwent genetic testing for myofilament/sarcomeric HCM (ACTC1, MYBPC3, MYH7, MYL2, MYL3, TNNC1, TNNI3, TNNT2, TPM1). Patients with either a positive genetic test or positive family history of HCM were classified as genetic HCM (G+ HCM) while those with a negative genetic test and a negative family history were called non-genetic HCM (G- HCM). Blinded to the patient's genetic classification, each echocardiogram was reviewed with particular attention to the maximum left ventricular wall thickness (MLVWT) and LV outflow tract obstruction (LVOTO), septal morphology, and presence of SAM.
Overall, 88 patients (41%) were either mutation positive or had a family history of HCM and therefore considered familial/genetic disease. Compared to G+ HCM patients, those with G- HCM were older at diagnosis (54 ± 16 vs. 47 ± 16 years, p = 0.001), had lower MLVWT (19 ± 5mm vs. 21 ± 5mm, p = 0.02), but had more LVOTO at rest (47 ± 47mmHg vs. 29 ± 41mmHg, p = 0.004). Notably, G-HCM patients were more likely to have the classic HCM finding of SAM compared to G+HCM patients [78/125 patients (62%) vs. 34/88 patients (39%), p=0.001]. Independent of the resting gradient and septal shape, presence of SAM, older age, and decreased MLVWT were predictors of G-HCM (SAM: OR 2.3879; 95%CI 1.5235-54.60.02, p=0.0011, Age: OR 1.03; 95%CI 1.01-1.05, p=0.0026, MLVWT: OR 0.93; 95%CI 0.88-0.98, p=0.01).
Independent of septal morphology and the degree of outflow tract obstruction, the presence of one of HCM's first described echocardiographic findings, SAM, is seen more commonly in HCM patients with a negative genetic test and no evidence for familial disease. This paradoxical observation raises the possibility that a subset of HCM may stem from a primary abnormality involving the mitral valve apparatus.
Moderated Poster Contributions
Poster Sessions, Expo North
Sunday, March 10, 2013, 3:45 p.m.-4:30 p.m.
Session Title: Congenital Cardiology Solutions: New Insights into Congenital Heart Disease in the Adult
Abstract Category: 12. Congenital Cardiology Solutions: Adult
Presentation Number: 1249M-137
- 2013 American College of Cardiology Foundation