Related Experiment Video
Updated: Jan 24, 2026
Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model
Published on: August 8, 2022
Identification of Myocardial Disarray in Patients With Hypertrophic Cardiomyopathy and Ventricular Arrhythmias
Rina Ariga1, Elizabeth M Tunnicliffe1, Sanjay G Manohar2
1Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.
Insights
Fractional anisotropy (FA) measured by diffusion tensor cardiac magnetic resonance (DT-CMR) imaging is reduced in hypertrophic cardiomyopathy (HCM), indicating myocardial disarray. This reduced FA is linked to a higher risk of ventricular arrhythmia in HCM patients.
Area of Science:
- Cardiovascular Imaging
- Cardiac Electrophysiology
- Medical Physics
Background:
- Myocardial disarray is a key factor in fatal arrhythmias within hypertrophic cardiomyopathy (HCM).
- Diffusion tensor cardiac magnetic resonance (DT-CMR) imaging, specifically fractional anisotropy (FA), can noninvasively assess cardiac microstructural abnormalities like disarray by mapping water diffusion along muscle fibers.
Purpose of the Study:
- To evaluate FA as a noninvasive in vivo biomarker for HCM myoarchitecture.
- To determine the association between FA and ventricular arrhythmia in HCM patients.
Main Methods:
- Fifty HCM patients and 30 healthy controls underwent DT-CMR, cine, late gadolinium enhancement (LGE), and extracellular volume (ECV) imaging at 3-T.
- Diastolic FA was measured and compared between HCM patients and controls.
- The relationship between FA, LGE, ECV, and ventricular arrhythmia was analyzed.
Main Results:
- HCM patients exhibited significantly reduced diastolic FA compared to controls (0.49 ± 0.05 vs. 0.52 ± 0.03; p=0.0005).
- Reduced FA in HCM correlated with LGE and ECV, suggesting fibrosis contributes to lower FA.
- Lower FA in hypertrophied segments was observed in HCM patients with ventricular arrhythmia (0.41 ± 0.03 vs. 0.46 ± 0.06; p=0.007).
- A 0.05 decrease in FA increased the odds of ventricular arrhythmia by 2.5 (p=0.015), independent of LGE, ECV, and wall thickness.
Conclusions:
- DT-CMR assessment of left ventricular myoarchitecture using FA aligns with histological findings of disarray and fibrosis in HCM.
- Reduced diastolic FA in HCM is associated with ventricular arrhythmia and likely reflects myocardial disarray.
- Diastolic FA may serve as an early in vivo marker of disarray and an independent risk factor for ventricular arrhythmia in HCM.
Background:
Myocardial disarray is a likely focus for fatal arrhythmia in hypertrophic cardiomyopathy (HCM). This microstructural abnormality can be inferred by mapping the preferential diffusion of water along cardiac muscle fibers using diffusion tensor cardiac magnetic resonance (DT-CMR) imaging. Fractional anisotropy (FA) quantifies directionality of diffusion in 3 dimensions. The authors hypothesized that FA would be reduced in HCM due to disarray and fibrosis that may represent the anatomic substrate for ventricular arrhythmia.
Objectives:
This study sought to assess FA as a noninvasive in vivo biomarker of HCM myoarchitecture and its association with ventricular arrhythmia.
Methods:
A total of 50 HCM patients (47 ± 15 years of age, 77% male) and 30 healthy control subjects (46 ± 16 years of age, 70% male) underwent DT-CMR in diastole, cine, late gadolinium enhancement (LGE), and extracellular volume (ECV) imaging at 3-T.
Results:
Diastolic FA was reduced in HCM compared with control subjects (0.49 ± 0.05 vs. 0.52 ± 0.03; p = 0.0005). Control subjects had a mid-wall ring of high FA. In HCM, this ring was disrupted by reduced FA, consistent with published histology demonstrating that disarray and fibrosis invade circumferentially aligned mid-wall myocytes. LGE and ECV were significant predictors of FA, in line with fibrosis contributing to low FA. Yet FA adjusted for LGE and ECV remained reduced in HCM (p = 0.028). FA in the hypertrophied segment was reduced in HCM patients with ventricular arrhythmia compared to patients without (n = 15; 0.41 ± 0.03 vs. 0.46 ± 0.06; p = 0.007). A decrease in FA of 0.05 increased odds of ventricular arrhythmia by 2.5 (95% confidence interval: 1.2 to 5.3; p = 0.015) in HCM and remained significant even after correcting for LGE, ECV, and wall thickness (p = 0.036).
Conclusions:
DT-CMR assessment of left ventricular myoarchitecture matched patterns reported previously on histology. Low diastolic FA in HCM was associated with ventricular arrhythmia and is likely to represent disarray after accounting for fibrosis. The authors propose that diastolic FA could be the first in vivo marker of disarray in HCM and a potential independent risk factor.
More Related Videos
12:09Patient-specific Modeling of the Heart: Estimation of Ventricular Fiber Orientations
Published on: January 8, 2013
18:11A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis
Published on: December 28, 2012
Related Concept Videos
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
01:16ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism,...
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:29Cardiomyopathy IV: Restrictive Cardiomyopathy
01:28Mechanism of Cardiac Arrhythmias