Initial case was received from the literature article on 18 June 2014. The following verbatim from the article abstract: Learning objective 1: Recognize that myopericarditis may rarely be observed after immunization. Learning Objective 2: Weigh risks and benefits of invasive procedures such as cardiac angiography, particularly if alternatives are available. Case: A previously health 28-year-old man presented with 1 day of sudden onset severe substernal chest pain, not associated with inspiration and improved by leaning forward. Three days prior he had received a single intramuscular Tdap vaccine, and 2 days prior developed tactile fevers and myalgias. Vital signs and clinical exam were normal. He denied sick contacts, any history of vaccine reactions, or any cardiac risk factors apart from a 10-pack-year tobacco history. EKG showed diffuse up sloping ST segment elevations. Laboratory studies revealed WBC 13.3/ mm3, troponin 9.1 ng/mL, creatinine kinase 372 IU/L, and C-reactive protein 79.3 mg/L. Two-dimensional echocardiography showed normal left ventricle size and function and no effusion. His symptoms were thought consistent with pericarditis and he was started on high dose aspirin and colchicine. Overnight he was febrile to 38.1C, his troponin up trended to 30.5 ng/mL, and his chest pain persisted. Cardiac catheterization showed normal coronary arteries. Several hours later he developed worsening chest pain and new, marked ST elevations in leads I, AVL, and V1-V6. Repeat angiography showed a newly dissected and occluded LAD, which was stented with restoration of TIMI 3 flow. He was discharged with an ejection fraction of 45 % on colchicine, clopidogrel, and aspirin. An infectious workup including Coxsackie B, echovirus, and adenovirus was ultimately negative, as were antinuclear antibody and rheumatoid factor. He represented several times over the next few months with atypical chest pain but normal cardiac enzymes and CRP. He underwent an exercise treadmill test-myoview and was able to exercise 10 min without EKG changes. Nuclear imaging showed a medium to large partially reversible perfusion defect in the apex and anteroseptal wall, but repeat catheterization showed a patent LAD stent and distal vasospasm. He was treated for vasospasm with isosorbide mononitrate and diltiazem. Discussion: Most cases of myopericarditis result from viral infection, although other pathogens, drugs, hypersensitivity, and autoimmune disorders are occasionally implicated. Cardiovascular complications due to vaccination are rare. Only two case reports of myopericarditis after Tdap vaccination exist, and of 20 million doses distributed from 2005 to 2007, three cases were reported postlicensure safety surveillance. While it is impossible to definitely exclude a viral etiology for this case, negative viral serologies and absence of symptoms prior to vaccination make it less likely. While early post- vaccination prodrome favors a hypersensitivity reaction, hypersensitivity myocarditis is usually a retrospective, circumstantial diagnosis. The diagnostic accuracy of endomyocardial biopsy remains poor and was not indicated. Coronary angiography may be performed if there is significant uncertainty as to whether the clinical picture reflects acute coronary syndrome versus myopericarditis. Cardiac MRI has been shown to be highly sensitive (76 %) and specific (96 %) alternative for myocarditis detection and differentiation from infarction. However, it is not available in many resource-limited settings, including the hospital to which this patient presented.