Ep 167 Myocarditis – A Diagnostic Challenge

In this Part 2 of our two-part series on pericarditis and myocarditis, Anton is again joined by Dr. Walter Himmel and Dr. Paul Dorian. They answer such questions as: Why does myocarditis often present a diagnostic challenge? What are the range of ECG findings in myocarditis? Does a negative high sensitivity troponin or CRP rule out myocarditis? What is the role of PoCUS in the diagnosis and prognosis of myocarditis? When should we consider myocarditis or pericarditis in patients with recent COVID-19 infection or COVID mRNA vaccination, and which of these patients require workups? and more... Podcast production, sound design & editing by Anton Helman Written Summary and blog post by Kate Dillon, edited by Anton Helman March, 2022 Cite this podcast as: Helman, A. Episode 168 Myocarditis - A Diagnostic Challenge. Emergency Medicine Cases. March, 2022. https://emergencymedicinecases.com/myocarditis. Accessed [date] Go to part 1 of this 2-part podcast on pericarditis and myocarditis Why does myocarditis often present a diagnostic challenge? The reason that myocarditis presents a diagnostic challenge is that clinical findings are nonspecific and the breadth of presentations is wide, ranging from subclinical disease to fulminant heart failure, a variety of dysrhythmias and cardiogenic shock. The definitive diagnosis is made by cardiac MRI. It is important to remember that myocarditis is just one of the many cardiomyopathies that include dilated, hypertrophic and restrictive cardiomyopathies. The many presentations of acute myocarditis: * ACS-like or pleuritic chest pain (from associated pericarditis) * Unexplained new onset or worsening heart failure * Unexplained dysrhythmia (palpitations, syncope) * Unexplained cardiogenic shock A European multicenter study found that the most common presenting symptoms of myocarditis were dyspnea (71.7%), non-specific chest pain (31.9%), dysrhythmic events (17.9%) and pericardial effusion or systolic separation of the pericardium (14.2%). Consider myocarditis in: * Patients presenting with signs or symptoms of viral illness or sepsis + cardiac symptoms * Patients with new or worsening heart failure without risk factors for coronary artery disease * Patients whose presentation is not quite fitting the typical presentations for dysrhythmias, heart failure, ACS or sepsis Discriminating sepsis from early cardiogenic shock secondary to myocarditis is challenging during the early stages of workup and treatment, as myocarditis may present with features of both. A preliminary diagnosis of myocarditis may be made if there is 1+ clinical presentation and 1+ diagnostic criteria from different categories (suspicion is higher with higher number of fulfilled criteria) in the absence of: * Angiographically detectable CAD * Known pre-existing cardiovascular disease or extra-cardiac causes that could explain the syndrome (valve disease, congenital heart disease, etc.). Ancillary features supporting the diagnosis of myocarditis: * Fever >38C at presentation or within the preceding 30 days with or without evidence of respiratory or GI infection * Peripartum period * Previous clinically suspected or definite myocarditis * Personal or family history of allergic asthma, other types of allergies, or extracardiac autoimmune disease * Family history of dilated cardiomyopathy (DCM) or myocarditis In the subacute presentation of myocarditis patients may present with unexplained fatigue and dysrhythmias such as VPBs, non-sustained VT.