Abstract 16699: Deformation Patterns Differ in Genotype-Positive Patients with Hypertrophic Cardiomyopathy
Objective: Echocardiographic strain imaging with 2-dimensional speckle tracking is an emerging tool for defining cardiac function and pre-clinical cardiac hypertrophy. In hypertrophic cardiomyopathy (HCM), a reverse septal contour is a strong predictor of mutation-positive sarcomeric HCM. We hypothesized that left ventricular deformation patterns would differ based upon genotype in a large cohort of patients with HCM.
Methods: 131 patients (42 male, 55 ± 15 yrs) with clinically diagnosed HCM underwent comprehensive transthoracic echocardiography inclusive of left ventricular strain imaging and septal contour. Longitudinal peak systolic strain was assessed from 17 left ventricular myocardial segments. Blinded to echocardiographic results, all patients underwent comprehensive genotyping for 9 myofilament HCM-associated genes.
Results: Genotyping revealed that 51 out of 131 patients (39%) were mutation positive for sarcomeric/myofilament-HCM (genotype-positive; GP). Global peak systolic longitudinal strain did not significantly differ between GP and HCM patients lacking a mutation (genotype-negative; GN). However, regional strain was lower in GP patients in the mid inferoseptal (-12 vs -15; p=0.004), basal anteroseptal (-9 vs -11; p=0.04) and basal inferoseptal segments (-10 vs -13; p=0.002) compared to GN patients. Strain patterns in reverse-curve, GP HCM patients differed significantly from GN patients with sigmoidal curvature in multiple segments (mid anteroseptal, p=0.012, mid inferoseptal <0.0001, mid inferior p=0.02, basal anterior p=0.02, basal anteroseptal p=0.003, and basal inferoseptal p=0.003) as well as for averaged mid septal strain (p=0.002), averaged basal septal strain (p=0.02), and averaged global strain (p=0.02).
Conclusions: While global peak longitudinal systolic strain did not differ between all HCM patients with or without an HCM mutation, significant regional strain differences were noted in GP patients, more pronounced when comparing differing septal morphologies. Analysis of deformation patterns has potential to further enhance the pre-genetic test probability of identifying the patient with mutation-positive sarcomeric/myofilament-HCM.
- © 2012 by American Heart Association, Inc.