Overview
Definition:
Myocarditis is an inflammation of the heart muscle (myocardium), most commonly caused by viral infections, but can also be triggered by autoimmune disorders, toxins, or drugs
In pediatric athletes, it presents a significant risk due to the potential for arrhythmias and sudden cardiac death during physical exertion.
Epidemiology:
The incidence of myocarditis in children is estimated to be between 1-2 per 100,000 person-years
Viral etiologies are most common, with enteroviruses (e.g., Coxsackie B) and adenoviruses being frequent culprits
While rare, it is a leading cause of non-ischemic cardiomyopathy and sudden cardiac death in young athletes.
Clinical Significance:
Myocarditis in pediatric athletes poses a critical challenge for clinicians, requiring careful diagnosis and management to prevent long-term sequelae such as dilated cardiomyopathy or fatal arrhythmias
Appropriate return-to-play (RTP) guidelines are paramount to ensure the safety of these young individuals and mitigate the risk of exercise-induced cardiac events.
Clinical Presentation
Symptoms:
Chest pain, which may be pleuritic or mimic ischemic pain
Dyspnea, especially with exertion
Palpitations or irregular heartbeat
Syncope or near-syncope
Fatigue and malaise
Fever or symptoms of preceding viral illness (e.g., URI)
Exercise intolerance.
Signs:
Tachycardia disproportionate to fever or exertion
Gallop rhythm (S3, S4)
Murmurs of mitral or tricuspid regurgitation
Signs of heart failure (e.g., elevated JVP, hepatomegaly, peripheral edema)
Hypotension
Arrhythmias on ECG or telemetry
Friction rub in some cases.
Diagnostic Criteria:
Diagnosis is often based on a combination of clinical suspicion, electrocardiographic findings, cardiac enzyme elevation, cardiac imaging, and sometimes endomyocardial biopsy
Current guidelines (e.g., from the American Heart Association, European Society of Cardiology) emphasize a stepwise diagnostic approach to confirm the diagnosis and assess severity.
Diagnostic Approach
History Taking:
Detailed history of recent viral illness
Nature and timing of cardiac symptoms
Family history of sudden cardiac death or cardiomyopathy
Current training regimen and intensity
Use of any medications or supplements
Red flags include exertional chest pain, syncope, and significant dyspnea.
Physical Examination:
Thorough cardiovascular examination including vital signs, cardiac auscultation for murmurs, gallops, and rubs
Assessment for peripheral edema, jugular venous distension, and hepatomegaly
Neurological assessment to rule out other causes of syncope
Evaluation for signs of systemic illness.
Investigations:
Electrocardiogram (ECG): May show ST-segment and T-wave abnormalities, conduction delays, or arrhythmias
Cardiac biomarkers: Elevated troponin I or T levels indicate myocardial injury
Echocardiogram: Assesses ventricular function, wall motion abnormalities, chamber size, and effusion
Cardiac MRI (CMR): Gold standard for diagnosing myocarditis, demonstrating inflammation (ed1ema) and late gadolinium enhancement indicating myocardial scarring
Endomyocardial biopsy: Historically used but now reserved for selected cases due to invasiveness and sampling variability
Viral PCR panels from blood/stool/CSF may identify specific pathogens.
Differential Diagnosis:
Pericarditis (often presents with pleuritic chest pain, friction rub, and ST elevation in limb leads
ECG changes differ from myocarditis)
Arrhythmogenic cardiomyopathy (AC)
Hypertrophic cardiomyopathy (HCM)
Viral-induced non-specific ST-T wave changes
Myocardial contusion
Drug-induced cardiomyopathy.
Management
Initial Management:
Rest is the cornerstone of initial treatment, with complete cessation of athletic activity
Hospitalization is indicated for symptomatic patients, those with significant arrhythmias, heart failure, or hemodynamic instability
Supportive care for heart failure symptoms (e.g., diuretics, ACE inhibitors, beta-blockers) and arrhythmias.
Medical Management:
Primary treatment focuses on supportive care and addressing the underlying cause
For suspected viral myocarditis, no specific antiviral therapy is generally indicated unless a treatable pathogen is identified (e.g., CMV)
Immunomodulatory therapy (e.g., corticosteroids, IVIG) may be considered in selected cases of giant cell myocarditis or eosinophilic myocarditis, but its role in typical viral myocarditis is controversial and generally not recommended
Beta-blockers and ACE inhibitors are used cautiously to manage ventricular dysfunction and prevent adverse remodeling, especially once inflammation has subsided.
Surgical Management:
Surgical interventions are generally not indicated for acute myocarditis itself but may be required for complications such as severe heart failure requiring mechanical circulatory support (e.g., ECMO, VAD) or cardiac transplantation in end-stage disease
Arrhythmia management may include implantable cardioverter-defibrillators (ICDs) for patients at high risk of sudden cardiac death.
Supportive Care:
Strict physical rest is crucial
Monitoring of heart rate, rhythm, blood pressure, and oxygen saturation
Fluid management to prevent overload
Pain control for pleuritic chest pain
Nutritional support as needed
Psychological support for the athlete and family during the recovery period.
Return To Play Criteria
Initial Activity Restriction:
Complete cessation of all competitive and recreational sports for a minimum of 3 to 6 months from symptom onset or diagnosis
This period allows for myocardial recovery and reduces the risk of re-injury or exacerbation
Absolute rest is advised initially.
Assessment For Rtp:
Following the initial rest period, a comprehensive cardiovascular evaluation is necessary
This includes a symptom-free period, normal or stable ventricular function on echocardiography, absence of significant arrhythmias on Holter monitoring (24-48 hours), and absence of myocardial scar on CMR if performed and indicated
Myocardial enzymes should be normalized
A thorough clinical assessment by a cardiologist experienced in sports cardiology is essential.
Graded Return Protocol:
If cleared, RTP begins with a graded exercise protocol
This involves gradually increasing the intensity and duration of activity over several weeks, with careful monitoring for any recurrence of symptoms or arrhythmias
Return to full competition is only permitted after successful completion of the graded program without adverse events.
Long Term Follow Up:
Even after successful return to play, long-term follow-up with a cardiologist is recommended
This includes annual clinical assessments, ECGs, and potentially repeat echocardiography to monitor for late complications such as dilated cardiomyopathy or persistent arrhythmias
Continued vigilance for any recurrent symptoms is vital.
Complications
Early Complications:
Acute heart failure
Life-threatening arrhythmias (e.g., ventricular tachycardia, fibrillation)
Myocardial rupture
Pericardial effusion and tamponade
Stroke due to mural thrombus formation.
Late Complications:
Dilated cardiomyopathy
Chronic heart failure
Persistent arrhythmias
Sudden cardiac death
Myocardial scarring leading to reduced contractility.
Prevention Strategies:
Prompt diagnosis and appropriate management
Strict adherence to activity restrictions and RTP guidelines
Careful risk stratification for arrhythmias and ICD implantation when indicated
Early recognition and management of heart failure
Long-term cardiovascular monitoring.
Key Points
Exam Focus:
DNB/NEET SS exams frequently test the diagnostic criteria, differential diagnosis, and crucially, the return-to-play guidelines for myocarditis in athletes
Understanding the risk stratification and the stepwise approach to clearing athletes is vital.
Clinical Pearls:
Always suspect myocarditis in a young athlete presenting with exertional chest pain, syncope, or unexplained fatigue
Remember that a normal ECG does not rule out myocarditis
Cardiac MRI is invaluable for assessing myocardial inflammation and fibrosis, guiding RTP decisions.
Common Mistakes:
Premature return to play without adequate recovery or thorough evaluation
Underestimating the severity of myocarditis and its potential for fatal arrhythmias
Relying solely on ECG or biomarkers for RTP clearance without comprehensive assessment
Inconsistent application of evidence-based RTP guidelines.