The patient was referred for cardiac magnetic resonance imaging (MRI) to evaluate for myocarditis. Cardiac MRI ( Fig. 1 ) was performed on a 3-T scanner [Magnetom Vida, Siemens Healthcare] six days after the second dose of vaccine. Cine images showed normal left ventricular function. Short axis (A) and four-chamber long axis (B) post-contrast inversion recovery images showed subepicardial late gadolinium enhancement in the anterolateral wall of the mid and apical left ventricle. Short axis native T1 (C) and T2 (E) maps showed corresponding increased T1 (1450–1550 ms; normal: 1100–1300) and T2 (54–60 ms; normal: 40–50) signal intensity, respectively. Measured T1 (D) and T2 (F) values of the normal intraventricular septum was 1200–1300 and 43–46 ms, respectively. Per the 2018 Lake-Louise criteria, these findings are diagnostic of myocarditis.A respiratory viral panel was performed and was negative.

Magnetic Resonance Imaging of Case 1. Post contrast magnitude inversion recovery (MAG-IR) images in short axis (A) and four-chamber long axis (B) views show subepicardial enhancement in the anterolateral wall of the mid ventricle and apex (arrowheads). Native T1 map shows corresponding abnormality (arrowheads in C) with elevated values (D) in the anterolateral wall as compared to the interventricular septum. T2 mapping also showed abnormality in this region (arrows in E) with elevated values (F) when compared to the interventricular septum.

Fig. 1 Magnetic Resonance Imaging of Case 1. Post contrast magnitude inversion recovery (MAG-IR) images in short axis (A) and four-chamber long axis (B) views show subepicardial enhancement in the anterolateral wall of the mid ventricle and apex (arrowheads). Native T1 map shows corresponding abnormality (arrowheads in C) with elevated values (D) in the anterolateral wall as compared to the interventricular septum. T2 mapping also showed abnormality in this region (arrows in E) with elevated values (F) when compared to the interventricular septum.

A previously healthy 25-year-old man presents to the hospital after receiving the second dose of the mRNA-1273 SARS-CoV-2 immunization (Moderna). On the first day after the second dose the patient developed subjective fever and chills. Six hours after the onset of fevers, the patient noticed substernal chest pain and as result reported to the hospital. His physical examination revealed a fever of 39.1 °C, blood pressure of 129/75 mmHg, pulse of 76 bpm, a respiratory rate of 20, and oxygen saturation of 98% on room air. An electrocardiogram (ECG) revealed diffuse mild concave ST elevations with no reciprocal changes. Initial laboratory evaluation showed an elevated troponin I of 14 ng/mL (normal <0.032 ng/mL), an elevated C-reactive protein (CRP) of 25 ng/mL (normal 0–0.5 ng/mL), and erythrocyte sedimentation rate (ESR) of 25 mm/h (normal <15 mm/h). Nasopharyngeal SARS-CoV-2 PCR was performed twice and was negative; the patient also denies any history of infection with COVID-19. The patient was admitted and underwent coronary angiography that showed normal coronary arteries. An echocardiogram showed normal function and no significant valvular disease; ejection fraction was 55%. Troponin levels continued to rise, peaking at 20.4 ng/mL on hospital day 2 and declined to 9.5 ng/mL by the time of discharge on the morning of hospital day 3, at which point his chest pain had resolved.

2.2 Case 2

A 21-year-old woman with no underlying health conditions presents as a transfer from an outside hospital for chest pain. The patient received the second dose of the mRNA-1273 SARS-CoV-2 immunization (Moderna) vaccine and developed lightheadedness the next day while exercising, such that she was unable to complete her usual exercise routine. Two days after the vaccine, the patient developed sharp retrosternal chest pain that radiated to her left jaw and woke her up from sleep for which she presented to an outside hospital. Her vital signs were normal with a temperature of 36.5 °C, blood pressure of 110/70 mmHg, heart rate of 70 bpm, respiratory rate of 18, and oxygen saturation of 99% on room air. Initial ECG showed diffuse, mild concave ST elevations and PR depressions without reciprocal changes. Her initial laboratory results showed an elevated troponin I of 2.3 ng/mL (normal <0.3 ng/mL), and elevated D-Dimer of 640 ng/mL (normal <500 ng/mL), an ESR of 7 mm/h (normal 1–20 mm/h), and a CRP of 8 ng/mL (normal <10 ng/mL). A nasopharyngeal SARS-CoV-2 PCR was negative and the patient denies past history of infection with COVID-19. The patient reported a family history of long QT syndrome in three of her siblings and her mother for which she has received work-up consisting of echocardiography, a stress test, and genetic testing 4 years prior, all of which were negative; the patient's QT and QTc at the time of presentation were 384 and 428 ms, respectively.

A CT pulmonary angiogram performed to exclude pulmonary embolism was negative. The coronary arteries were visualized on the CT and appeared normal with no abnormal course or origin. A transthoracic echocardiogram showed a mildly reduced LVEF of 50% with no wall motion abnormalities or significant valvular disease.

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Schaarschmidt F.

Stehning C.

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Bunck A.C. A systematic evaluation of three different cardiac T2-mapping sequences at 1.5 and 3T in healthy volunteers. [7] Ferreira V.M.

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et al. Comparison of original and 2018 Lake Louise criteria for diagnosis of acute myocarditis: results of a validation cohort. Fig. 2 Magnetic Resonance Imaging of Case 2. Post-contrast magnitude inversion recovery (MAG-IR) (A) and phase sensitive inversion recovery (PSIR) (B) images in short axis views show subepicardial enhancement in the inferolateral wall at the base (arrowheads). Native T1 map shows corresponding abnormality (arrowheads in C) with elevated values (D) in the inferolateral wall as compared to the interventricular septum. T2 mapping also showed abnormality in this region (arrows in E) with elevated values (F) when compared to the interventricular septum. Repeat testing showed the troponin I had increased to 4.4 ng/mL. A CMR ( Fig. 2 ) was performed on a 1.5-T scanner [Magnetom Vida, Siemens Healthcare] four days after the second dose to evaluate for possible myocarditis. Cine images revealed normal left ventricular size and function. Short-axis post-contrast images (A) showed subepicardial enhancement in the inferolateral wall at the base. T1 (B) and T2 (D) maps showed corresponding elevated values of 1200 ms for T1 (normal 950–1050 ms), as opposed to 950–980 for the septal wall (C), and 59–63 ms for T2 (normal 45–55 ms) as opposed to 44–48 ms for the septal wall (E). Per the 2018 Lake-Louise criteria, these findings are diagnostic of myocarditis.A respiratory viral panel was also performed on this patient and was negative.

The patient's symptoms resolved the next day and her troponin declined to 1.3 ng/mL. The patient improved clinically and was discharged home on metoprolol.