MyocarditisMANAGEMENT

CARDIOVASCULAR PRESENTATIONS · 12 SECTIONS

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579 items

☷ Legend

01Approach to the Critical Patient/attcp74

Immediate priorities

›High-risk myocarditis states

›Cardiogenic shock

›SCAI shock stage C to E framework

›Malignant arrhythmia

›Sustained VT

›VF

›High-grade AV block

›Fulminant myocarditis phenotype

›Rapid onset heart failure within 2 weeks of viral-like illness

›Severe hemodynamic compromise despite limited time course

›Myopericarditis with tamponade concern

›Hypotension with elevated JVP and muffled heart sounds

›Monitoring and access

›Continuous ECG monitoring

›Defibrillator pads in place for unstable rhythm risk

›Two large-bore IV lines

›Central access if vasoactive infusion anticipated

›Arterial line if shock or vasoactive titration

›MAP target per perfusion and lactate trend

›Time-critical tests

›12-lead ECG within 10 minutes for chest pain equivalent

›STEMI pathway activation if criteria met

›High-sensitivity troponin serial strategy

›Dynamic change supports acute myocardial injury

›Point-of-care ultrasound focused cardiac exam

›LV systolic function estimate

›RV size and function estimate

›Pericardial effusion with tamponade physiology

›Immediate escalation triggers

›If shock with suspected myocarditis, early cardiology and ICU

›Mechanical circulatory support capability discussion

›If sustained VT or VF, ACLS with reversible cause workup

›Consider myocarditis as non-ischemic trigger

›If high-grade AV block with instability, transcutaneous pacing

›Transition to transvenous pacing if persistent

Hemodynamic goals

›Perfusion targets

›MAP at least 65 mmHg for most adults

›Higher target if chronic hypertension or ongoing ischemia concern

›Urine output at least 0.5 mL/kg/hour

›Trend with creatinine and lactate

›Lactate downtrend over 2 to 6 hours

›Persistent elevation suggests inadequate flow or sepsis overlap

›Ventilation and oxygenation targets

›SpO2 92 to 96 percent for most

›Avoid hyperoxia when stable

›If ABG obtained, PaO2 adequate for clinical state

›Use mmHg for PaO2 and PaCO2 reporting

›Fluid strategy

›Cautious bolus approach if pulmonary edema risk

›Small aliquots 250 mL with reassessment

›Early diuresis if congestion with preserved perfusion

›Loop diuretic strategy in treatment section

Risk stratification and pathway

›ACC myocarditis pathway concepts

›Classic presentation clusters

›Chest pain syndrome mimicking ACS

›New or worsening heart failure or shock

›Arrhythmia or conduction disease

›Etiology categories

›Viral or post-viral

›Autoimmune or inflammatory

›Hypersensitivity or eosinophilic

›Giant cell

›Sarcoid

›Immune checkpoint inhibitor myocarditis

›Admission level-of-care triggers

›ICU level of care criteria

›Vasoactive support requirement

›Rising lactate or escalating oxygen requirement

›Sustained ventricular arrhythmia

›High-grade AV block

›Stepdown criteria

›Stable vitals without vasoactive support

›No malignant rhythm and stable conduction

›No rapid biomarker rise after initial evaluation

02History/hx62

Presentation patterns

›Symptom clusters

›Chest pain

›Pleuritic component suggests pericardial involvement

›Pressure-like pain overlaps with ACS

›Dyspnea

›Orthopnea

›PND

›Palpitations or syncope

›Pre-syncope with exertion suggests arrhythmia risk

›Systemic symptoms

›Viral prodrome 1 to 2 weeks prior

›Fever or myalgias

›Time course

›Abrupt onset within days

›Fulminant phenotype consideration

›Subacute progression over weeks

›Inflammatory cardiomyopathy overlap

›Recurrent episodes

›Autoimmune or sarcoid consideration

Risk factors and exposures

›Infectious exposures

›Recent upper respiratory infection

›Household contacts

›Recent gastroenteritis

›Dehydration and tachycardia confounders

›Tick exposure

›Lyme carditis with AV block differential

›Travel or zoonotic exposure

›Chagas consideration with appropriate geography

›Medication and toxin exposures

›Immune checkpoint inhibitors

›Time since initiation within first 3 months common risk window

›New antibiotics or anticonvulsants

›Hypersensitivity myocarditis signal

›Cocaine or stimulants

›Demand ischemia and coronary vasospasm confounders

›Autoimmune and inflammatory history

›Known autoimmune disease

›SLE

›IBD

›Sarcoidosis history

›Prior pulmonary or skin involvement

›Cardiac history

›Prior myocarditis

›Prior MRI findings and EF recovery

›Cardiomyopathy or heart failure

›Baseline EF and meds

›Family history sudden cardiac death

›Inherited arrhythmia overlap possibility

Red flags

›High-risk symptoms

›Syncope

›Exertional syncope concern

›Resting dyspnea

›Rapid progression within 24 to 48 hours

›Persistent chest pain with rising troponin

›Coronary disease exclusion priority

›Neurologic symptoms

›Embolic stroke concern with LV thrombus

›Immunocompromised state

›Transplant recipient

›Opportunistic infections

›Active malignancy on therapy

›ICI myocarditis and overlap syndromes

03Physical Exam/exam48

General and hemodynamics

›Vitals and perfusion

›Tachycardia

›Disproportionate to fever or pain raises concern

›Hypotension

›Narrow pulse pressure supports low output

›Fever

›Sepsis overlap and infectious myocarditis consideration

›Cool extremities

›Delayed capillary refill

›Respiratory status

›Work of breathing

›Accessory muscle use

›Hypoxemia

›Pulmonary edema vs pneumonia differentiation

›Volume assessment

›Elevated JVP

›RV involvement possibility

›Peripheral edema

›New onset suggests decompensated HF

Cardiovascular and systemic findings

›Cardiac exam

›S3 gallop

›LV dysfunction marker

›New murmur

›Functional MR with LV dilation

›Pericardial friction rub

›Myopericarditis support

›Pulmonary exam

›Crackles

›Congestion support

›Wheeze

›Cardiac asthma possibility

›Signs of systemic inflammation

›Rash

›Hypersensitivity or autoimmune clue

›Urticaria or facial swelling

›Drug reaction overlap

›Neurologic and embolic signs

›Focal neurologic deficit

›Embolic event concern

›Painful cool limb

›Peripheral embolus concern

PITFALLS

›Common exam traps

›Normal exam despite significant myocardial inflammation

›Early disease with preserved EF

›Attribution of tachycardia to anxiety alone

›Persistent sinus tachycardia as myocarditis clue

›Over-reliance on absence of chest pain

›Heart failure or arrhythmia-first presentations common

04Differential Diagnosis/ddx28

Life-threatening causes of chest pain or shock

›Ischemic and vascular

›Acute coronary syndrome ICD-10 I21 to I22

›Troponin elevation overlap

›Aortic dissection ICD-10 I71.0

›Pulse deficit or neurologic deficits

›Pulmonary embolism ICD-10 I26

›RV strain and troponin overlap

›Cardiopulmonary emergencies

›Cardiac tamponade ICD-10 I31.4

›Effusion and pulsus paradoxus

›Sepsis with myocardial dysfunction ICD-10 A41

›Lactate elevation with distributive pattern

›Massive GI bleed with demand ischemia

›Anemia and tachycardia driver

Mimics and related cardiac conditions

›Pericarditis ICD-10 I30

›PR depression and diffuse ST elevation pattern

›Troponin mild elevation in myopericarditis

›Stress cardiomyopathy ICD-10 I51.81

›Triggering stressor and typical echo pattern

›Acute decompensated heart failure ICD-10 I50.9

›Chronic HF features and known low EF

›Arrhythmogenic disorders

›SVT related demand ischemia

›Brugada or inherited channelopathy

›Cardiac sarcoidosis SNOMED CT sarcoidosis of heart

›Conduction disease and ventricular arrhythmia pattern

›Lyme carditis ICD-10 A69.23

›Fluctuating AV block and exposure history

05Laboratory Tests/lt50

Core ED labs

›Acute myocardial injury and heart failure markers

›High-sensitivity troponin I or T serial testing

›Rise and fall pattern supports acute injury

›Normal value does not exclude myocarditis

›BNP or NT-proBNP

›Elevation supports myocardial stress and HF

›Baseline safety labs for therapy

›Electrolytes with magnesium

›Potassium goal at least 4.0 mmol/L for arrhythmia reduction

›Magnesium goal at least 1.0 mmol/L for arrhythmia reduction

›Creatinine and eGFR

›Contrast and medication dosing implications

›AST and ALT

›Congestive hepatopathy vs systemic illness

›Inflammation and infection screen

›CBC with differential

›Eosinophilia suggests eosinophilic myocarditis

›CRP

›Trend supports inflammatory activity

›ESR

›Supportive but non-specific

›Shock and perfusion labs

›Lactate

›Serial downtrend target

›VBG or ABG if respiratory failure or shock

›pH and PaCO2 in mmHg for ventilatory status

Targeted etiologic labs

›Infectious testing guided by presentation

›Blood cultures for fever or sepsis physiology

›Prior to antibiotics if possible

›Respiratory viral PCR when viral syndrome present

›Management impact limited for most viruses

›HIV testing when risk factors present

›Opportunistic infection and cardiomyopathy overlap

›Lyme serology when exposure and AV block pattern present

›Two-tier approach per local guidance

›Autoimmune and inflammatory testing when suspected

›ANA and ENA when systemic autoimmune features

›Supports rheumatologic evaluation

›ACE level and chest imaging correlation for sarcoid context

›Low specificity and supportive only

PITFALLS and interpretation limits

›Troponin limitations

›Degree of elevation poorly correlates with severity

›Fulminant cases can have variable values

›Troponin elevation non-specific

›ACS exclusion still required when presentation fits

›Viral serologies pitfalls

›Routine viral antibody panels low utility

›False positives and delayed results

›PCR positivity does not confirm myocarditis etiology

›Association rather than proof

06Diagnostic Tests/dt75

Scoring Systems

›Shock and heart failure staging tools

›SCAI shock staging

›Stage A at risk

›Stage B beginning shock

›Stage C classic shock

›Stage D deteriorating

›Stage E extremis

›NYHA functional class

›Class I no limitation

›Class II mild limitation

›Class III marked limitation

›Class IV symptoms at rest

›ACC AHA heart failure stages

›Stage A risk only

›Stage B structural disease without symptoms

›Stage C symptomatic structural disease

›Stage D advanced refractory

›Myocarditis risk features in ACC ECDP framework

›High-risk clinical features

›Hemodynamic instability

›Syncope

›Sustained ventricular arrhythmia

›High-risk test features

›Reduced LVEF on echo

›High-grade AV block on ECG

MRI

›Cardiac MRI role

›Tissue characterization for myocardial inflammation

›Edema assessment with T2-based techniques

›Non-ischemic injury assessment with T1-based techniques

›Revised Lake Louise criteria 2018 summary

›At least one T2-based marker

›At least one T1-based marker

›MRI findings supporting myocarditis

›T2-based markers

›Regional myocardial edema on T2-weighted imaging

›Elevated T2 mapping values

›T1-based markers

›LGE in non-ischemic distribution

›Elevated native T1 mapping values

›Elevated extracellular volume fraction

›MRI limitations and contraindications

›Early disease with negative MRI possible

›Repeat imaging if high suspicion and evolving course

›Hemodynamic instability limits feasibility

›Stabilize first and consider alternative diagnostics

›Gadolinium contraindication in severe renal failure context

›Use non-contrast protocols when needed

›Coronary evaluation when ACS cannot be excluded

›Coronary CT angiography in low to intermediate risk with stable vitals

›Alternative to invasive angiography in selected patients

›Invasive coronary angiography in high-risk ACS presentation

›ST elevation or refractory chest pain

›Alternative CT pathways by presentation

›CT pulmonary angiography for PE concern

›RV strain and hypoxemia pattern

›CT aorta for dissection concern

›Tearing pain or pulse deficit

Ultrasound (or US)

›Point-of-care echocardiography

›LV systolic function

›Global hypokinesis supports myocarditis pattern

›RV assessment

›RV dilation suggests PE or RV myocarditis involvement

›Pericardial effusion

›Tamponade physiology evaluation

›IVC size and collapsibility

›Volume status support for resuscitation choices

›Formal transthoracic echocardiography

›LVEF quantification

›Baseline for prognosis and therapy

›Regional wall motion assessment

›Focal abnormalities overlap with ACS

›Valvular function

›Functional MR with LV dilation

›Intracardiac thrombus evaluation

›Anticoagulation implications

07Disposition/dispo28

Admission and transfer criteria

›ICU admission criteria

›Cardiogenic shock or vasoactive support requirement

›Consider VA-ECMO capable center if escalating

›Sustained VT or VF

›Antiarrhythmic infusion or repeated cardioversion

›High-grade AV block

›Temporary pacing requirement

›Rapidly rising troponin with hemodynamic change

›Ongoing ischemia exclusion and myocarditis monitoring

›Stepdown or monitored bed criteria

›Suspected myocarditis with stable vitals

›Continuous telemetry for 24 to 48 hours

›Mild LV dysfunction without shock

›Guideline-directed HF therapy initiation

›Transfer criteria

›Need for mechanical circulatory support

›Impella or VA-ECMO capability

›Suspected giant cell myocarditis or ICI myocarditis

›Advanced HF and immunosuppression expertise

Discharge criteria for selected low-risk patients

›Low-risk outpatient pathway

›Normal vitals and no arrhythmia on monitoring period

›No syncope history in event

›Preserved LV function on echo

›No pericardial effusion with tamponade physiology

›Troponin stable or downtrending

›No dynamic ECG ischemic changes

›Reliable follow-up within 72 hours

›Cardiology or rapid access clinic

08Treatment/t103

Supportive and heart failure management

›General principles

›Activity restriction during acute phase

›Avoid competitive sports and intense exercise

›Volume management

›Loop diuretic for congestion with stable perfusion

›Loop diuretics

›Furosemide IV 20 to 40 mg

›If diuretic naive and mild congestion

›Re-dose based on urine output response

›If on chronic loop diuretic

›Initial IV dose at least equivalent to home total daily dose

›Electrolyte monitoring every 6 to 12 hours

›Potassium and magnesium replacement targets

›Guideline-directed medical therapy when stable

›ACE inhibitor or ARB

›Initiate when euvolemic and SBP adequate

›Beta blocker

›Avoid initiation during acute decompensated HF or shock

›Initiate after stabilization with improving congestion

›Mineralocorticoid receptor antagonist

›Consider when LVEF reduced and potassium under 5.0 mmol/L

›SGLT2 inhibitor

›Consider in stable HFrEF without severe hypotension

Cardiogenic shock and fulminant myocarditis

›Vasoactive strategy

›Norepinephrine infusion initiation for hypotension

›Start 0.05 to 0.1 mcg/kg/min

›Titrate every 2 to 5 minutes to MAP target

›Typical range 0.05 to 1 mcg/kg/min

›Escalate with perfusion markers and lactate trend

›Inotrope for low output with adequate BP

›Dobutamine infusion initiation

›Start 2.5 to 5 mcg/kg/min

›Titrate to cardiac output and perfusion

›Max commonly 20 mcg/kg/min

›Monitor for tachyarrhythmia

›Milrinone infusion alternative

›Start 0.125 to 0.25 mcg/kg/min

›Avoid bolus in hypotension

›Renal dose adjustment needed

›Hypotension risk monitoring

›Mechanical circulatory support concepts

›Indications

›Refractory shock despite vasoactive escalation

›Persistent lactate elevation with end-organ injury

›Options

›VA-ECMO for profound biventricular failure

›Consider LV unloading strategy per center protocol

›Impella for predominant LV failure

›Hemolysis monitoring

›IABP selected scenarios

›Limited support compared with VA-ECMO

›Respiratory support

›Noninvasive ventilation for pulmonary edema

›CPAP or BiPAP if mentation intact

›Intubation strategy in shock

›Hemodynamic optimization prior to induction

›Post-intubation hypotension anticipation

Arrhythmias and conduction disease

›Ventricular tachyarrhythmias

›Amiodarone IV bolus and infusion

›Bolus 150 mg over 10 minutes

›Repeat bolus for recurrent VT as needed

›Infusion 1 mg/min for 6 hours

›Then 0.5 mg/min maintenance

›Lidocaine IV alternative

›Bolus 1 to 1.5 mg/kg

›Repeat 0.5 to 0.75 mg/kg every 5 to 10 minutes

›Max total 3 mg/kg

›Infusion 1 to 4 mg/min after bolus

›Bradyarrhythmia and AV block

›Atropine IV for symptomatic bradycardia

›1 mg IV

›Repeat every 3 to 5 minutes

›Max 3 mg

›Prepare pacing if ineffective

›Transcutaneous pacing

›Bridge to transvenous pacing when persistent

›Transvenous pacing

›High-grade AV block with instability

›Atrial fibrillation or flutter

›Rate control strategy when stable

›Beta blocker deferral in acute decompensated HF

›Amiodarone for rate control when LV dysfunction and hypotension

›Anticoagulation decision

›CHA2DS2-VASc framework

›Bleeding risk and hemodynamic stability

Etiology-directed immunotherapy

›Endomyocardial biopsy driven therapy concepts

›Giant cell myocarditis

›High-dose corticosteroid plus additional immunosuppression per specialist

›Eosinophilic myocarditis

›Corticosteroid therapy consideration after infection exclusion

›Cardiac sarcoidosis

›Corticosteroid therapy with steroid-sparing agents per specialist

›Immune checkpoint inhibitor myocarditis

›Immediate ICI hold coordination with oncology

›High-dose corticosteroid early per specialty pathways

›Steroid-refractory escalation

›Additional immunosuppressants per expert consultation

Myopericarditis pain control

›Analgesia strategy

›Acetaminophen

›650 to 1000 mg PO or IV every 6 to 8 hours

›NSAID caution

›Avoid routine NSAIDs in isolated myocarditis due to theoretical harm

›Use in pericarditis-dominant syndrome per cardiology guidance

09Special Populations/sp38

Pregnancy

›Diagnostic considerations

›Pregnancy physiologic dyspnea confounder

›Lower threshold for echo if symptoms progressive

›PE overlap risk in pregnancy

›Imaging choice balance with maternal risk

›Medication considerations

›ACE inhibitor and ARB contraindicated in pregnancy

›Use pregnancy-safe HF regimen per obstetric medicine and cardiology

›Anticoagulation approach

›LMWH preferred when anticoagulation indicated

›Disposition considerations

›Maternal fetal medicine involvement for moderate to severe disease

›Delivery planning if late gestation and unstable

Geriatric

›Atypical presentations

›Heart failure symptoms without viral prodrome

›Higher coronary disease probability

›Delirium as low perfusion marker

›Early lactate and perfusion assessment

›Medication safety

›Higher hypotension risk with GDMT initiation

›Slower titration and close monitoring

›Renal function fluctuation

›Dose adjustment for diuretics and milrinone

Pediatrics

›Presentation patterns

›Poor feeding and lethargy in infants

›Tachycardia out of proportion clue

›Abdominal pain and vomiting in older children

›Misdiagnosis risk as gastroenteritis

›Diagnostic considerations

›Echocardiography early in suspected cases

›Coronary anomaly consideration in chest pain differential

›MRI feasibility challenges

›Sedation risk and availability limitations

›Treatment considerations

›Weight-based vasoactive dosing per pediatric critical care

›Early PICU involvement for fulminant cases

›IVIG consideration in selected pediatric myocarditis pathways

›Specialist-directed due to mixed evidence

10Background/b39

Epidemiology

›Disease frequency and burden

›Myocarditis as an important cause of sudden cardiac death in younger populations

›Risk highest with active inflammation and ventricular arrhythmia

›Viral etiologies common in high-income settings

›Exact pathogen often unconfirmed without biopsy

›Coding and terminology

›ICD-10 acute myocarditis I40

›I40.0 infectious myocarditis

›I40.1 isolated myocarditis

›I40.8 other acute myocarditis

›I40.9 acute myocarditis unspecified

›ICD-10 myocarditis unspecified I51.4

›Chronic or unspecified clinical context

›SNOMED CT myocarditis disorder concept

›Use for clinical terminology mapping

Pathophysiology

›Core mechanisms

›Myocardial inflammation with myocyte injury

›Direct pathogen injury in some cases

›Immune-mediated injury in many cases

›Electrical instability pathways

›Inflammatory scar and edema as arrhythmogenic substrate

›Hemodynamic failure pathways

›Reduced contractility leading to low output and congestion

›Phenotypes

›Acute myocarditis

›Chest pain and biomarker elevation

›Fulminant myocarditis

›Rapid onset severe HF and shock

›Inflammatory cardiomyopathy

›Persistent inflammation with chronic LV dysfunction

Therapeutic Considerations

›Evidence and guideline themes

›Supportive care as foundation

›HF therapy and shock management principles

›Etiology-directed immunosuppression in selected biopsy-proven subtypes

›Giant cell and eosinophilic forms as key examples

›Exercise restriction after acute myocarditis

›Return-to-play decisions guided by symptom resolution and testing

›ACC ECDP myocarditis guidance

›Structured diagnostic pathway and risk stratification approach

11Patient Discharge Instructions/pdi25

Copy discharge instructions

›Diagnosis explanation

›Suspected myocarditis

›Heart muscle inflammation that can affect rhythm and pumping

›Activity

›No strenuous exercise or competitive sports until cleared

›Light daily activity only if symptoms allow

›Medications

›Take prescribed heart medications exactly as directed

›Do not stop beta blockers or ACE inhibitors without clinician guidance

›Follow-up

›Cardiology follow-up within 72 hours to 1 week

›Repeat testing plan for echo and labs as arranged

›Return to ED immediately for red flags

›Worsening chest pain

›Pain at rest or lasting more than 10 minutes

›Trouble breathing

›New shortness of breath at rest or waking at night

›Fainting or near-fainting

›Especially with palpitations

›Rapid or irregular heartbeat

›Persistent palpitations or heart rate over 120 at rest

›New leg swelling or sudden weight gain

›Weight gain over 2 kg in 2 days

›Fever with feeling very unwell

›Possible infection or worsening inflammation

12References/r9

Guidelines and consensus

›ACC Expert Consensus Decision Pathway on Diagnosis and Management of Myocarditis 2024

›ACC Ten Points to Remember summary 2024

›JACC Scientific Expert Panel updated Lake Louise Criteria 2018

›Revised CMR criteria requiring at least one T1-based and one T2-based marker

›ESC Working Group position statement on myocarditis 2013

›Criteria for clinically suspected myocarditis and biopsy guidance

›Review literature on myocarditis management updates 2024

›Synthesis of ESC 2021 to 2022 guideline era changes

›Source file link

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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