Myocarditis — viva

Stem

Practice viva. The examiner asks how you would confirm and manage suspected myocarditis in a young adult with chest pain and raised troponin, and works through terminology, diagnostic criteria, biopsy, risk, treatment rows, arrhythmia and return to sport.^[1]

Branch A — What do you call it?

Examiner: What is IMPS, and what are myopericarditis and perimyocarditis?^[1]

Strong answer:

• ESC 2025 introduces inflammatory myopericardial syndrome (IMPS) as an umbrella term during the initial diagnostic process until a final diagnosis is made.^[1]
• In ESC 2025 Table 3, myopericarditis is predominant pericarditis and perimyocarditis is predominant myocarditis; both footnotes describe definite criteria for pericarditis with elevated biomarkers of myocardial injury, without or with newly developed LV impairment respectively.^[1]
• Complicated myocarditis is acute myocarditis with ≥1 of LVEF <50% on echocardiogram, sustained ventricular arrhythmias, advanced heart block, heart failure or cardiogenic shock (ESC 2025 Table 3).^[1]

Follow-up: How does the ACC 2024 pathway stage it?^[5]

• As consensus, without classes: A at-risk, B asymptomatic, C symptomatic and D advanced myocarditis; patients can move from higher to lower stages.^[5]

Branch B — How do you confirm it?

Examiner: Troponin is raised and coronary angiography is normal. What next?^[1]

Strong answer:

• ESC 2025 recommends CMR in patients with the clinical suspicion of myocarditis, using the updated Lake Louise criteria (Class I, Level B).^[1]
• The updated criteria rest on at least one T2-based criterion plus ideally one T1-based criterion; both increase specificity, and one alone can support possible myocarditis in an appropriate clinical scenario, with less specificity (ESC 2025).^[1]
• ESC 2025 Table 4: definite myocarditis is a clinical presentation with a CMR- or EMB-proven result; CMR-proven is 2 out of 2 updated criteria, uncertain is 1 out of 2.^[1]
• The diagnostic accuracy of CMR is higher if performed early, best within the first 2 weeks (ESC 2025).^[1]

Follow-up: When would you biopsy?^[1]

• ESC 2025 recommends EMB in high-risk myocarditis and/or haemodynamic instability, and/or in intermediate-risk myocarditis not responding to conventional therapy, to detect a specific histologic subtype and assess viral genome (Class I, Level C).^[1]
• In suspected giant-cell myocarditis it is recommended for unexplained new-onset HF of up to 2 weeks with a normal or dilated LV and new ventricular arrhythmias, second- or third-degree AV block, or failure to respond to usual care within 1 to 2 weeks (ESC 2025, Class I, Level C).^[1]
• Complication rates range from 0.6% to 5%, up to 26% in fulminant cases on MCS (ESC 2025).^[1]
• Immunohistology: ≥14 leucocytes/mm² with T lymphocytes ≥7 cells/mm² has been considered the cut-off for the diagnosis of myocarditis (ESC 2025), although these criteria have been questioned by cardiopathologists.^[1]

Branch C — How sick is the patient?

Examiner: How do you stratify risk?^[1]

Strong answer:

• ESC 2025 Table 7, myocarditis row, high risk: acute HF/cardiogenic shock, dyspnoea NYHA III–IV refractory to medical therapy, cardiac arrest/syncope, VF/sustained VT, high-level AV block; on imaging, newly reduced LVEF (<40%) or extensive LGE. Its footnote a, printed on cardiac arrest/syncope, VF/sustained VT, high-level AV block, newly reduced LVEF (<40%) and extensive LGE on CMR, says these criteria do not lead directly towards EMB; in these scenarios it is a case-by-case decision depending on the suspected underlying cause.^[1]
• Intermediate: new/progressive dyspnoea, non-sustained ventricular arrhythmias, persistent release or relapsing troponin; on imaging, newly mildly reduced LVEF (41%–49%) and/or WMA, or preserved LVEF (≥50%) and LGE ≥2 segments on CMR.^[1]
• Low: stable symptoms or oligosymptomatic; on imaging, preserved LVEF (≥50%) without LGE or limited LGE (<2 segments) on CMR.^[1]
• Admission is recommended for moderate- to high-risk myocarditis (Class I, Level C) and should be considered for low-risk myocarditis (Class IIa, Level C) (ESC 2025).^[1]

Branch D — Treatment

Examiner: What does ESC 2025 say about steroids?^[1]

Strong answer:

• Routine immunosuppressive therapy is not recommended in acute myocarditis with preserved LV function because no outcome benefit has been shown (ESC 2025, Class III, Level C).^[1]
• Corticosteroids should be considered in fulminant, non-infectious forms to stabilize the patients (ESC 2025, Class IIa, Level C), and may be considered in acute myocarditis with impaired LVEF refractory to standard HF therapy (ESC 2025, Class IIb, Level C).^[1]
• In acute cardiac and systemic virus infection, immunosuppressive therapy must be avoided.^[1]
• Combined immunosuppressive therapy is recommended in diagnosed giant-cell myocarditis (ESC 2025, Class I, Level C).^[1]

Follow-up: And the heart failure?^[1]

• Adherence to the ESC HF guidelines is recommended in myocarditis with LV systolic dysfunction and/or HF (ESC 2025, Class I, Level C), and HF therapy should be considered for at least 6 months after complete LV recovery (Class IIa, Level C).^[1]
• ESC 2026 HF: empirical foundational medical therapy for HFrEF in myocarditis with HFrEF.^[2]
• With haemodynamic compromise, a timely Shock Team discussion is recommended (Class I, Level C), and with cardiogenic shock or acute decompensation in chronic myocarditis, temporary MCS should be considered (Class IIa, Level C) (ESC 2025).^[1]

Branch E — Arrhythmia

Examiner: He has sustained VT on day 3. Does he need an ICD?^[1]

Strong answer:

• ESC 2025: in acute myocarditis with sustained VA (VT/VF) in the acute phase, ICD implantation may be considered (Class IIb, Level C); a WCD for 3–6 months should be considered as a bridge to recovery (Class IIa, Level C).^[1]
• It is generally accepted to wait 3–6 months after an acute episode to evaluate the need for an ICD (ESC 2025).^[1]
• In non-active myocarditis, ESC 2025 recommends ICD implantation for haemodynamically not-tolerated sustained VT to prevent SCD (Class I, Level C) and says it should be considered for haemodynamically tolerated sustained VT to prevent SCD (Class IIa, Level C).^[1]
• The ESC 2022 row that an ICD before hospital discharge should be considered for haemodynamically not-tolerated sustained VT or VF during the acute phase (Class IIa, Level C) is dated history beside the ESC 2025 row saying it may be considered for sustained VA in the acute phase (Class IIb, Level C).^[4][1]

Branch F — Sport

Examiner: He plays competitive football. When can he return?^[1]

Strong answer:

• ESC 2025: restriction of physical exercise until remission, for at least 1 month, is recommended in athletes and non-athletes after IMPS, using an individualized approach (Class I, Level C).^[1]
• ESC 2025 remission: full regression of symptoms with normal laboratory results and investigations, including CMR evidence of active inflammation; additional testing (e.g. exercise testing and Holter monitoring) is recommended in myocarditis to detect clinical remission.^[1]
• The ACC 2024 ECDP (consensus; it notes the literature is limited) suggests resuming exercise 3 to 6 months after myocarditis if symptoms have resolved and the patient is asymptomatic, with CMR (stage D or at least medium-risk stage C) or transthoracic echocardiography (low-risk stage C), a 24-hour ECG and an exercise test all unremarkable.^[5]
• In competitive athletes with myocarditis and preserved LV function, the AHA/ACC 2025 sports statement says return to competitive sports participation can be considered 4 to 6 weeks after complete resolution of symptoms if all its criteria are met. The criteria are inflammation or oedema resolved (CMR T2 signal or serum biomarkers) and no clinically relevant arrhythmias on ambulatory ECG monitoring and exercise testing.^[7]