Myocarditis

• Myocardial inflammation in the absence of ischaemia
• Often associated with pericarditis , termed myopericarditis
• The estimated incidence of myocarditis was 22 per 100,000 people, or approximately 1.5 million cases in the 2013 world population.
• occurs more commonly in males than in females.
• Myocarditis and/or pericarditis have been reported as rare side effects after COVID-19 vaccines particularly in young males aged 16-40 years. Cases have also rarely been reported in children
• Usually a benign disease without serious long-term complications
• In the acute setting can cause arrhythmias, cardiac failure, cardiogenic shock and death
• May result in delayed dilated cardiomyopathy

CAUSES (HIGAAP)

• hypersensitivity
• infectious/infiltrative (haemochromatosis or amyloidosis)
• giant cell myocarditis
• autoimmune (SLE, polymyositis, scleroderma, sarcoid)
• active viral (Coxsackie B, HIV)
• post viral (lymphocytic) – (rheumatic fever)
• mRNA Covid19 Vaccine

ASSESSMENT

HISTORY

• chest pain – is usually associated with concomitant pericarditis. However, myocarditis can mimic myocardial ischemia and/or infarction both clinically and on the electrocardiogram
• SOB
• palpitations
• fever
• malaise
• arthralgias
• fatigue and decreased exercise capacity

EXAMINATION

• fever
• tachycardia
• signs of fluid overload – increased jugular venous pressure, hepatomegaly, and peripheral edema
• direct evidence of cardiac dysfunction in symptomatic patients.
  • S3 and occasionally S4 gallops are important signs of impaired ventricular function, particularly when biventricular acute myocardial involvement results in systemic and pulmonary congestion.
  • If the right or left ventricular dilatation is severe, auscultation may reveal murmurs of functional mitral or tricuspid insufficiency.
• A pericardial friction rub and effusion may become evident in some patients with myopericarditis 
• cardiogenic shock

INVESTIGATIONS

• elevated ESR, cardiac biomarkers, rheumatological markers
• Serology:
  • enterovirus PCR/serology, parvovirus B19 PCR/serology, HHV6 PCR/serology, echovirus PCR/serology, coxsackie virus PCR/serology
  • HIV
  • HCV
• rheumatic fever: ASOT
• lupus screen. coeliac disease screen. anti-myosin antibodies. anti beta-1 adrenoreceptor antibodies
• quantiferon gold for TB
• ECG: sinus tachycardia, non-specific ST elevation, TW changes
• Chest Xray: The heart size on chest radiograph varies from normal to cardiomegaly with or without pulmonary vascular congestion and pleural effusions 

MANAGEMENT

• treatment of HF
  • low sodium diet
  • cautious diuresis as needed
  • ACE inhibitors
  • Beta blockers
  • intraaortic balloon pump/temporary LV assist device for  intractable or when cardiogenic shock does not respond to medical therapy
• treatment of arrhythmia
  • SVT – rate control therapy and antiarrhythmic therapy
  • Sustained ventricular arrhythmias  – urgent cardioversion
  • Recurrent arrhythmias – antiarrhythmic drugs
  • Symptomatic nonsustained ventricular tachycardia – antiarrhythmic drugs
• in select cases, anticoagulation (Thromboembolic complications can occur when HF is severe or protracted)
  • Symptomatic HF with an LVEF below 20.
  • Minimal risk factors for hemorrhage.
  • A stable hemodynamic profile without evidence of liver synthetic dysfunction.
• Alcohol restriction
  • to at most one alcoholic drink per day, since heavy alcohol intake may enhance the severity of the myocarditis
• avoidance of exercise
  • reduce the work of the heart during the acute phase of myocarditis, especially when there is fever, active systemic infection, or HF
• NSAIDs  — In animal models of myocarditis, nonsteroidal antiinflammatory drugs (NSAIDs) are not effective. To the contrary, they may actually enhance the myocarditic process and increase mortality.