UNASSIGNED: Glycogen storage disease (GSD) type Ⅲa is a rare autosomal recessive disorder resulting in the accumulation of abnormally structured glycogen in the liver, skeletal muscle, and cardiac muscle. Cardiovascular magnetic resonance (CMR) tissue characteristics in GSD have rarely been reported.
UNASSIGNED: We report a 24-year-old male patient suffering from recurrent palpitation and atypical chest pain for 5 years with suspected hypertrophic cardiomyopathy. Laboratory tests revealed an elevated creatine kinase, and physical exam revealed hepatosplenomegaly. Cardiovascular magnetic resonance demonstrated asymmetrical massive left ventricular hypertrophy with a maximal thickness of 34.6 mm in the septum. In the regions with focal late gadolinium enhancement (LGE) in the anterior septum, both native T1 and extracellular volume (ECV) are elevated. However, in the LGE-negative regions of the myocardium, native T1 was elevated without elevation in ECV (septum, 22.7%; free wall, 20.9%). Whole exome sequencing revealed a novel pathogenic homozygous nonsense variant of the AGL gene (c.4284 T > G, p. Tyr1428*), confirming the diagnosis of the patients as GSD type Ⅲa.
UNASSIGNED: This case showed increased diffuse native T1 but not ECV on CMR in LGE-negative myocardium in GSD, which indicates that the T1 value is increased with an accumulation of glycogen in the myocardium, but the ECV space was not expanded in this process. Genetic testing should be obtained in severe LV hypertrophy when multi-organ involvement is present, and myocardial tissue characterization is discrepant between T1 elevation and normal ECV to consider glycogen storage disorder.

Danon disease (DD) is an exceptionally uncommon X-linked dominant lysosomal glycogen storage disorder characterized by pronounced ventricular hypertrophy and cardiac insufficiency. The timely identification of cardiac impairment in individuals with DD holds significant clinical importance.
We present a case of Danon Disease in a three-generation pedigree from Anhui Province, China. Clinical features and laboratory data were collected and analyzed for a 16-year-old male proband (III-1) and two affected female family members (II-2 and II-3). The proband exhibited Wolf-Parkinson-White syndrome, hypertrophic cardiomyopathy, abnormal cognitive function, and muscle weakness. Gene sequencing confirmed a mutation (c.963G > A) in the LAMP-2 gene.
Patients with DD may present both dilated and hypertrophic cardiomyopathy. Comprehensive myocardial tissue characterization by MRI plays a key role in the diagnosis of the disease.

UNASSIGNED: Acute myocarditis is commonly associated with viral infections, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Myocarditis following mRNA COVID-19 vaccination has also been reported, however this is rare and usually resolves within days or weeks. We present a case of acute myocarditis reported after vaccination with mRNA-1273 COVID-19 vaccine (Moderna) diagnosed using cardiac magnetic resonance imaging (CMR). This report describes the utility of CMR in the diagnosis and follow-up of such patients using parameters which could suggest the clinical course of myocarditis.
UNASSIGNED: A 23-year-old male presented in the emergency department with complaints of chest pain radiating to the left arm following vaccination with the second dose of COVID-19 mRNA-1273 vaccine (Moderna). Patient\'s history revealed an incidence of myocarditis in the past. CMR showed a mid-range left ventricular ejection fraction (38%) and subepicardial late gadolinium enhancement (LGE) in the inferolateral and apical myocardial segments with diffuse elevation of native T1 mapping relaxation times in all myocardial segments. The patient was admitted briefly in the intensive care unit and after a favorable clinical course was discharged from the hospital in stable condition. A follow-up CMR after 3 months revealed normalization of LVEF (57%) and native T1- times in most segments. Scarred myocardium reflecting chronic myocarditis continued to show elevated T1 times.
UNASSIGNED: Our patient presenting with acute myocarditis after recent COVID-19 mRNA vaccination reported a favorable clinical course. CMR revealed increased T1 mapping relaxation times diffusely spread across the myocardium and an impairment of the left ventricular function (LVEF) during the acute phase. However, the LVEF as well as the T1 times normalized at follow-up in all segments except for myocardium affected by chronic myocarditis.

UNASSIGNED: Danon disease is an X-linked dominant disorder with defects in the lysosome-associated membrane protein 2 (LAMP2) gene and is characterized histologically by intracellular autophagic vacuoles in skeletal and cardiac muscles. Cardiac magnetic resonance (CMR) T1 mapping potentially allows to differentiate intracellular and extracellular cardiac abnormalities with a combination of native T1 value and extracellular volume (ECV) fraction.
UNASSIGNED: We assessed CMR T1 mapping in two Danon disease patients (a 22-year-old man and his 48-year-old mother), who had a LAMP2 c.864G>A p. Val288Val mutation, and two blood relatives without Danon disease (his 47-year-old maternal aunt and 49-year-old father). The male patient underwent a left ventricular (LV) assist device implantation at 15 months after the image acquisition because he was inotrope dependent (INTERMACS profile 3) and had no noticeable psychological or musculoskeletal symptoms. His mother was in New York Heart Association Class II with mildly reduced LV ejection fraction (46%). The Danon group showed late gadolinium enhancement (LGE) in the anterior and posterolateral LV walls. In the interventricular wall, where evident LGE was not noted, the Danon group had high native T1 value, compared with the T1 value in the non-Danon group, and normal ECV fraction. Cardiac biopsy from the interventricular wall showed intracytoplasmic autophagic vacuoles, which are characteristics of Danon disease.
UNASSIGNED: This characteristic pattern of high native T1 and normal ECV fraction in the areas without LGE, which may reflect the existence of intracytoplasmic autophagic vacuoles, may support the differential diagnosis of Danon disease from other cardiomyopathies.

BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder due to mutations in the gene encoding for alpha-galactosidase A, with subsequent accumulation of complex sphingolipids in multiple organs, including the heart. Female heterozygotes can develop cardiac involvement although this is usually milder and slower to progress compared with male hemizygotes.
METHODS: A 71-year-old woman with two separate pathological Fabry mutations (N215S, C202R; compound heterozygote) presented with progressive cardiac involvement despite enzyme replacement therapy (ERT) with Replagal, as demonstrated by troponin elevation and cardiovascular magnetic resonance (CMR) findings: moderate segmental left ventricular dysfunction with wall thinning, low myocardial native T1, and extensive late gadolinium enhancement with co-located increased T2.
CONCLUSIONS: We report for the first time, a detailed cardiac phenotype using CMR in a compound heterozygote Fabry patient with progressive cardiac involvement despite ERT.