Non-ischemic Cardiomyopathies - Cases
Hideki Koike, MD, PhD
Researcher
MHIF
MINNEAPOLIS, Minnesota, United States
Hideki Koike, MD, PhD
Researcher
MHIF
MINNEAPOLIS, Minnesota, United States
Amr Idris, MD
MD
Minneapolis Heart Institute at Abbott Northwestern Hospital, United States
Victor cheng, MD
Cardiologist
Minneapolis Heart Institute at Abbott Northwestern Hospital, United States
Jana Lindberg, RT
Cardiovascular Special Imaging Coordinator
Minneapolis Heart Institute at Abbott Northwestern Hospital
Minneapolis, Minnesota, United States
John Sukumar Aluru, MB
Researcher
MHIF, United States
Erik B. Schelbert, MD
Cardiologist
Minneapolis Heart Institute at Abbott Northwestern Hospital
Saint Paul, Minnesota, United States
Hirotomo Sato, MD, PhD
Researcher
MHIF, United States
Miho Fukui, MD, PhD
Researcher
MHIF
Minneapolis, Minnesota, United States
Elizabeth Z Grey, MD
Cardiologist
Minneapolis Heart Institute at Abbott Northwestern Hospital, United States
Jay Sengupta, MD
Cardiologist
Minneapolis Heart Institute at Abbott Northwestern Hospital, United States
John Lesser, MD
Cardiologist
Minneapolis Heart Institute at Abbott Northwestern Hospital
Minneapolis, Minnesota, United States
Joao Cavalcante, MD
Director, Cardiac MRI and Structural CT Labs
Minneapolis Heart Institute at Abbott Northwestern Hospital
Minneapolis, Minnesota, United States
A previously healthy 19-year-old female with a family history of myocarditis in her twin sister presented with chest pain. Electrocardiogram (EKG) showed sinus tachycardia with no ischemic changes. Markedly elevated troponin I (9.7 ng/ml, normal < 0.034 ng/ml) prompted echocardiography which showed normal left ventricular (LV) size and LV ejection fraction (LVEF=60%). COVID-19 testing was negative. Coronary computed tomography angiography (CTA) excluded coronary artery disease.
Diagnostic Techniques and Their Most Important Findings:
The cardiovascular magnetic resonance (CMR) was performed at 1.5T Siemens Aera using a standard clinical protocol including cine imaging, T1, T2, ECV mapping, and late gadolinium enhancement (LGE). CMR revealed normal left ventricular size, borderline LV systolic function (LVEF=54%), and normal right ventricular size and function (RVEF=61%). Pre-contrast myocardial signal elevation was seen on T2 (Panel A, T2 > 55 msec) and T1 mapping (Panel B, T1 > 1050 msec), with edema predominantly involving the mid septum. LGE imaging showed a ring-like non-ischemic pattern involving the subepicardial and mid-myocardial in the mid and apical anterior, septum, and inferior segments (Panel C). Myocardial extracellular volume was very high (46%, normal: 24-28%, Panel D). All those findings supported non-ischemic myocardial injury in a pattern consistent with myocarditis. Premature ventricular contractions and non-sustained ventricular tachycardia were seen on a cardiac monitor for which the beta-blocker was uptitrated. Because of her family history of myocarditis, the genetic counseling referral and testing panel were obtained with the identification of a missense mutation variant in the desmoplakin (DSP) gene which is associated with dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Family member genetic screening and primary prevention of sudden cardiac death with subcutaneous ICD implantation were discussed. Subsequent CMR, 3 months after initial presentation, revealed myocardial edema resolution and established myocardial fibrosis (Panel E).
Learning Points from this Case:
This case highlights the uncommon differential diagnosis of acute myocarditis, which can be the initial manifestation of DSP cardiomyopathy. While the management of myocarditis secondary to DSP cardiomyopathy is not fully agreed upon, chest pain symptoms, along with troponin elevation and remarkable CMR findings should prompt the consideration for this entity. In this case, the CMR imaging protocol for myocarditis with use of myocardial maps and LGE was crucial not only for the diagnosis but potential follow-up.