1. Utility of Cardiac MRI in Diagnosing Fabry’s Cardiomyopathy
Ankita Tirath1, Arun Nagabandi, MD2, Gyanendra K.Sharma, MD2, Jayanth H. Keshavamurthy3
1Medical College of Georgia at Augusta University, 2Division of Cardiology, 3Department of Radiology and Imaging,
Augusta University Medical Center, Augusta, GA
Background
Results of CMR
Conclusions
Fabry’s disease is an X-linked lysosomal storage disorder with reported incidence of 1:40,000, caused by deficiency of the enzyme alpha-galactosidase A. This results in accumulation of intracellular globotriaosylceramide in various tissues throughout the body
In males, Fabry’s disease is diagnosed by measurement of the activity of the alpha-galactosidase A enzyme in leukocytes or plasma. In female carriers, analysis of the gene for mutations is required
Greater than 50% of patients with Fabry’s disease have cardiac manifestations, most commonly concentric left ventricular hypertrophy (LVH), malignant arrhythmias and infiltrative cardiomyopathy
The gold standard to demonstrate myocardial fibrosis is late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR)
Typically, the basal and mid segments of anterolateral and inferolateral left ventricular walls develop myocardial fibrosis with sparing of the subendocardium
Clinical manifestations of Fabry’s disease can be cutaneous, corneal, cardiac, renal, or neurologic.
Cardiovascular manifestations include left and right ventricular hypertrophy, aortic and mitral regurgitation, conduction defects, coronary artery disease, and aortic root dilation.
The most common pattern of hypertrophy is concentric, with asymmetric septal hypertrophy occurring in only 5% of cases. Hypertrophy is likely due to deposition of glycolipid, hypertrophy of individual myocytes, and interstitial remodeling. Deposition of glycolipid in the electrical conduction pathway of the heart can result in arrhythmias.
CMR with LGE involving the basal and mid segments of anterolateral and inferolateral walls with sparing of the subendocardium is diagnostic
Fabry disease should be considered in patients with unexplained LVH, because early diagnosis and enzyme replacement can improve the course of disease. Fabry’s should be excluded in patients with diagnosis of hypertrophic cardiomyopathy, as approximately 2-5% of these patients have Fabry’s disease. A
Major Teaching Points
CMR has specific findings in Fabry’s cardiomyopathy and is diagnostic of the condition.
An indirect way to screen for regional myocardial fibrosis is functional strain rate imaging by echocardiography.
Early diagnosis and treatment with enzyme replacement can alter the course and slow down overall progression of the disease. B
Fig.1 Cardiac MRI - Short axis view – (A) LV with mesocardial fibrosis of inferolateral wall and (B) concentric LVH, characteristic of Fabry’s disease
Case Presentation
A 52 year old white male presented to the ED with worsening shortness of breath and swelling in his hands for 4 days. He was in moderate respiratory distress and on exam had elevated JVP, crackles in lungs, normal heart sounds, and edema of hands and feet. His labs were significant only for elevated BNP (502 pg/mL) and troponin I (0.149 ng/mL).  
Chest x-ray showed pulmonary edema
Electrocardiography showed sinus rhythm with no abnormalities
Echocardiography showed ejection fraction of 55-60% with a restrictive left ventricular filling pattern
Left heart catheterization revealed non-obstructive coronaries
Cardiac MRI for further investigation revealed increased myocardial mass, severe concentric LVH, and LGE in a pattern suggestive of Fabry’s cardiomyopathy
Use of CMR in Evaluation of LVH
References
Fabry’s disease: Approximately half of patients have LGE localized to the mid-myocardial portion of the basal inferolateral wall, with sparing of the subendocardium
Hypertrophic Cardiomyopathy (HCM): Heterogeneous patterns, usually involving segments that are most hypertrophied
Cardiac Amyloidosis: Approximately 70% with pattern of global subendocardial gadolinium enhancement; often involves both atria and ventricles
Cardiac Sarcoidosis: Enhancement at right ventricular septum is very specific; enhancement is typically subepicardial or mid‐myocardial
Gersh BJ, Maron BJ, Bonow RO, et al ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Thorac Cardiovasc Surg. 2011;142(6):e
Watanabe E, Kimura F, Nakajima T, et al. Late gadolinium enhancement in cardiac sarcoidosis: characteristic magnetic resonance findings and relationship with left ventricular function. J Thorac Imaging. 2013;28:60–66
De cobelli F, Esposito A, Belloni E, et al. Delayed-enhanced cardiac MRI for differentiation of Fabry's disease from symmetric hypertrophic cardiomyopathy. AJR Am J Roentgenol. 2009;192(3):W
Seydelmann N, Wanner C, Störk S, Ertl G, Weidemann F. Fabry disease and the heart. Best Pract Res Clin Endocrinol Metab. 2015;29(2):
Azour L, Jacobi AH, Cham MD. The Heart of the Matter: Cardiac Imaging of Sarcoidosis. Society of Thoracic Radiology (STR), presented March 13‐16, 2016. 
Acknowledgements
I would like to thank Dr. Sharma, Dr. Nagabandi, and Dr. Keshavamurthy for their support. I would also like to thank the Medical College of Georgia at Augusta University for supporting me in my medical education.