**Introduction/Hypothesis:**
Background: Arrhythmogenic cardiomyopathy (ACM) is characterized by fibroadipose replacement of the myocardium due to genetic defects in cardiac desmosome proteins. Clinical manifestations of ACM include arrhythmias, heart failure, and myocarditis. The acute phase of the disease often involves chest pain and signs of myonecrosis without evidence of coronary artery disease. This case explores the use of cardiac MRI in the diagnosis of acute phase ACM.

**Methods**
Case Presentation: A 47-year-old female presented to Mayo Clinic FL emergency room with complaints of sharp pleuritic chest pain that improved with leaning forward, dyspnea, orthopnea, and progressively worsening bilateral leg swelling following a recent viral illness. Pertinent medical history included arrhythmogenic cardiomyopathy with recurrent myopericarditis, inducible VF status post ICD placement 10 months prior, and fibromuscular dysplasia. Previous genetic testing revealed pathologic desmoplakin variant and variant of uncertain significance in the desmin gene. The patient was hemodynamically stable. EKG showed normal sinus rhythm with nonspecific ST changes. Serial troponins peaked at 48, then down trended. NT-proBNP and CXR were unremarkable. D-dimer was elevated, but CTA was negative for pulmonary embolism and there was no DVT on lower extremity ultrasound. ICD interrogation showed no events. Coronary CTA was negative for spontaneous coronary artery dissection and significant coronary artery disease. A transthoracic echocardiogram demonstrated increased LV wall thickness to cavity ratio, grade 1/3 LV diastolic dysfunction, preserved EF of 65%, collapsible IVC, no regional wall motion abnormalities, and no pericardial effusion. The patient continued to have moderate chest discomfort despite normal leukocyte count, CRP and ESR. Given her symptoms and elevated troponins without coronary disease, there was high suspicion for a recurrent episode of myocarditis, prompting a cardiac MRI. T1 images showed a thin mid-myocardial stripe of late gadolinium enhancement along the basal to mid-inferoseptal left ventricular wall similar to her previous cardiac MRI one year prior. There was also mild asymmetric hypertrophy of the basal septum of the left ventricle. T2 images were not available to differentiate acute and chronic myocarditis or prior scar. Nonetheless, her increase in troponin from baseline and new clinical symptoms suggested an acute flare of myocarditis. Artifact from her ICD limited full pericardial visualization, making the MRI less reliable in evaluating for pericarditis. The patient’s overall findings and clinical picture were most consistent with myocarditis possibly triggered by her viral illness. She was given colchicine 0.6 mg daily. She continued to experience pleuritic chest discomfort and decreased exertional capacity, so a trial of prednisone with slow taper was pursued with clinical improvement.

**Results**
Cardiac MRI T1 and SSFP images from July 2023 and August 2024 are attached.

**Conclusion**
Decision-making: Myocarditis was suspected based on clinical picture. Cardiac MRI can support the diagnosis; however, limitations can reduce sensitivity. Clinical picture and improvement with therapies can enhance diagnosis accuracy.
Conclusion: Cardiac MRI is considered highly diagnostic of acute myocarditis in symptomatic patients with normal inflammatory markers and elevated troponins. Other acute cardiac pathologies were excluded with several cardiac imaging modalities, but evidence of a nonischemic pattern on cardiac MRI and her acute symptoms played a key role in suggesting myocarditis in this patient with ACM. However, interpretation of cardiac MRI in patients with ACM can be challenging because of issues differentiating baseline cardiomyopathy-related late gadolinium enhancement, residual scar from prior myocarditis, and acute myocarditis. Essentially, it is important to rely on the patient’s clinical presentation to guide management in such cases.
References:
Aquaro GD, Ghebru Habtemicael Y, Camastra G, Monti L, Dellegrottaglie S, Moro C, Lanzillo C, Scatteia A, Di Roma M, Pontone G, Perazzolo Marra M, Barison A, Di Bella G; “Cardiac Magnetic Resonance” Working Group of the Italian Society of Cardiology. Prognostic value of repeating cardiac magnetic resonance in patients with acute myocarditis. J Am Coll Cardiol. 2019 Nov 19;74(20):2439-2448.
Aquaro, G.D., Perfetti, M., Camastra, G., Monti, L., Dellegrpttaglie, S., et al. Cardiac MR with late gadolinium enhancement in acute myocarditis with preserved systolic function: ITAMY study. J Am Coll Cardiol. 2017;70(16):1977.
Brandão M, Bariani R, Rigato I, Bauce B. Desmoplakin cardiomyopathy: Comprehensive review of an increasingly recognized entity. J Clin Med. 2023 Apr 3;12(7):2660
De Cobelli, F., Pieroni, M., Chimenti, C., Belloni, E., et al. Delayed gadolinium-enhanced cardiac magnetic resonance in patients with chronic myocarditis presenting with heart failure or recurrent arrythmias. J Am Coll Cardiol. 2009 Mar 31;53(13):1138-45.
Ghawanmeh, M., Frances, B., Kerai, A., Patel, P., et al. Management of recurrent myocarditis due to desmoplakin cardiomyopathy. JACC Case Rep. 2022;4(1):59-62.
Mahrholdt H, Goedecke C, Wagner A, Meinhardt G, Athanasiadis A, Vogelsberg H, Fritz P, Klingel K, Kandolf R, Sechtem U. Cardiovascular magnetic resonance assessment of human myocarditis: A comparison to histology and molecular pathology. Circulation. 2004 Mar 16;109(10):1250-8.
Martens, P, Cooper, L, & Tang, W. Diagnostic approach for suspected acute myocarditis: Considerations for standardization and broadening clinical spectrum. Journal of the American Heart Assocation. 2023;12(17).
Mistrulli, R., Micolonghi, Follesa, F., Fabiani, M., et al. The role of genetic testing in suspected fulminant myocarditis: A case report. Molecular Genetics and Metabolism Reports. 2023;37(101000).
Patriki, D., Gresser E., Manka, R.,Emmert, M.Y., Luscher, L.F., Heidecker, B. (2018). Approximation of the incidence of myocarditis by systematic screening with cardiac magnetic resonance imaging. JACC Heart Fail. 2018;6(7):573.
Rezaei Bookani K, Minga I, Wodskow J, Harris J, Gordon R, Sarswat N, Pursnani A. A case series of desmoplakin cardiomyopathy: a mimic of viral myocarditis. Eur Heart J Case Rep. 2022 Aug 16;6(8):ytac341.
Varrenti, M., Preda, A., Frontera, A., Baroni, M., Gigli, L., Vargiu, S., Colombo, G., Carbonaro M, Paolucci M, Giordano F, Guarracini F, Mazzone P. Arrhythmogenic cardiomyopathy: Definition, classification and arrhythmic risk stratification. J Clin Med. 2024 Jan 14;13(2):456.



**Introduction/Hypothesis:**
**Background:** Arrhythmogenic cardiomyopathy (ACM) is characterized by fibroadipose replacement of the myocardium due to genetic defects in cardiac desmosome proteins. Clinical manifestations of ACM include arrhythmias, heart failure, and myocarditis. The acute phase of the disease often involves chest pain and signs of myonecrosis without evidence of coronary artery disease. This case explores the use of cardiac MRI in the diagnosis of acute phase ACM.

**Methods**
**Case Presentation:** A 47-year-old female presented to Mayo Clinic FL emergency room with complaints of sharp pleuritic chest pain that improved with leaning forward, dyspnea, orthopnea, and progressively worsening bilateral leg swelling following a recent viral illness. Pertinent medical history included arrhythmogenic cardiomyopathy with recurrent myopericarditis, inducible VF status post ICD placement 10 months prior, and fibromuscular dysplasia. Previous genetic testing revealed pathologic desmoplakin variant and variant of uncertain significance in the desmin gene. The patient was hemodynamically stable. EKG showed normal sinus rhythm with nonspecific ST changes. Serial troponins peaked at 48, then down trended. NT-proBNP and CXR were unremarkable. D-dimer was elevated, but CTA was negative for pulmonary embolism and there was no DVT on lower extremity ultrasound. ICD interrogation showed no events. Coronary CTA was negative for spontaneous coronary artery dissection and significant coronary artery disease. A transthoracic echocardiogram demonstrated increased LV wall thickness to cavity ratio, grade 1/3 LV diastolic dysfunction, preserved EF of 65%, collapsible IVC, no regional wall motion abnormalities, and no pericardial effusion. The patient continued to have moderate chest discomfort despite normal leukocyte count, CRP and ESR. Given her symptoms and elevated troponins without coronary disease, there was high suspicion for a recurrent episode of myocarditis, prompting a cardiac MRI. T1 images showed a thin mid-myocardial stripe of late gadolinium enhancement along the basal to mid-inferoseptal left ventricular wall similar to her previous cardiac MRI one year prior. There was also mild asymmetric hypertrophy of the basal septum of the left ventricle. T2 images were not available to differentiate acute and chronic myocarditis or prior scar. Nonetheless, her increase in troponin from baseline and new clinical symptoms suggested an acute flare of myocarditis. Artifact from her ICD limited full pericardial visualization, making the MRI less reliable in evaluating for pericarditis. The patient’s overall findings and clinical picture were most consistent with myocarditis possibly triggered by her viral illness. She was given colchicine 0.6 mg daily. She continued to experience pleuritic chest discomfort and decreased exertional capacity, so a trial of prednisone with slow taper was pursued with clinical improvement.

**Results**
Cardiac MRI T1 and SSFP images from July 2023 and August 2024 are attached.

**Conclusion**
**Decision-making:** Myocarditis was suspected based on clinical picture. Cardiac MRI can support the diagnosis; however, limitations can reduce sensitivity. Clinical picture and improvement with therapies can enhance diagnosis accuracy.
**Conclusion:** Cardiac MRI is considered highly diagnostic of acute myocarditis in symptomatic patients with normal inflammatory markers and elevated troponins. Other acute cardiac pathologies were excluded with several cardiac imaging modalities, but evidence of a nonischemic pattern on cardiac MRI and her acute symptoms played a key role in suggesting myocarditis in this patient with ACM. However, interpretation of cardiac MRI in patients with ACM can be challenging because of issues differentiating baseline cardiomyopathy-related late gadolinium enhancement, residual scar from prior myocarditis, and acute myocarditis. Essentially, it is important to rely on the patient’s clinical presentation to guide management in such cases.
**References:**
1. Aquaro GD, Ghebru Habtemicael Y, Camastra G, Monti L, Dellegrottaglie S, Moro C, Lanzillo C, Scatteia A, Di Roma M, Pontone G, Perazzolo Marra M, Barison A, Di Bella G; “Cardiac Magnetic Resonance” Working Group of the Italian Society of Cardiology. Prognostic value of repeating cardiac magnetic resonance in patients with acute myocarditis. _J Am Coll Cardiol._ 2019 Nov 19;74(20):2439-2448.
2. Aquaro, G.D., Perfetti, M., Camastra, G., Monti, L., Dellegrpttaglie, S., et al. Cardiac MR with late gadolinium enhancement in acute myocarditis with preserved systolic function: ITAMY study. _J Am Coll Cardiol_. 2017;70(16):1977.
3. Brandão M, Bariani R, Rigato I, Bauce B. Desmoplakin cardiomyopathy: Comprehensive review of an increasingly recognized entity. _J Clin Med._ 2023 Apr 3;12(7):2660
4. De Cobelli, F., Pieroni, M., Chimenti, C., Belloni, E., et al. Delayed gadolinium-enhanced cardiac magnetic resonance in patients with chronic myocarditis presenting with heart failure or recurrent arrythmias. _J Am Coll Cardiol._ 2009 Mar 31;53(13):1138-45.
5. Ghawanmeh, M., Frances, B., Kerai, A., Patel, P., et al. Management of recurrent myocarditis due to desmoplakin cardiomyopathy. _JACC Case Rep_. 2022;4(1):59-62.
6. Mahrholdt H, Goedecke C, Wagner A, Meinhardt G, Athanasiadis A, Vogelsberg H, Fritz P, Klingel K, Kandolf R, Sechtem U. Cardiovascular magnetic resonance assessment of human myocarditis: A comparison to histology and molecular pathology. _Circulation_. 2004 Mar 16;109(10):1250-8.
7. Martens, P, Cooper, L, & Tang, W. Diagnostic approach for suspected acute myocarditis: Considerations for standardization and broadening clinical spectrum. _Journal of the American Heart Assocation._ 2023;12(17).
8. Mistrulli, R., Micolonghi, Follesa, F., Fabiani, M., et al. The role of genetic testing in suspected fulminant myocarditis: A case report. _Molecular Genetics and Metabolism Reports_. 2023;37(101000).
9. Patriki, D., Gresser E., Manka, R.,Emmert, M.Y., Luscher, L.F., Heidecker, B. (2018). Approximation of the incidence of myocarditis by systematic screening with cardiac magnetic resonance imaging. _JACC Heart Fail_. 2018;6(7):573.
10. Rezaei Bookani K, Minga I, Wodskow J, Harris J, Gordon R, Sarswat N, Pursnani A. A case series of desmoplakin cardiomyopathy: a mimic of viral myocarditis. _Eur Heart J Case Rep_. 2022 Aug 16;6(8):ytac341.
11. Varrenti, M., Preda, A., Frontera, A., Baroni, M., Gigli, L., Vargiu, S., Colombo, G., Carbonaro M, Paolucci M, Giordano F, Guarracini F, Mazzone P. Arrhythmogenic cardiomyopathy: Definition, classification and arrhythmic risk stratification. _J Clin Med_. 2024 Jan 14;13(2):456.



Equivocal Cardiac MRI In Myopericarditis In A Patient With Arrhythmogenic Cardiomyopathy

This course will explore basic and cutting-edge imaging techniques to improve patient care and hone individual skills in performance and interpretation of echocardiography, nuclear cardiology, cardiac computed tomography, and cardiovascular magnetic resonance imaging. Days will reinforce how cardiovascular imaging may improve comprehension in ischemic heart disease, structural heart disease, cardiomyopathies, and heart failure. Experts will utilize novel techniques to reinforce key topics including taped interventional cases and a strong emphasis on case presentations.