Inflammation can involve any layer of the heart. The main conditions are pericarditis (outer sac), myocarditis (muscle), infective endocarditis (inner lining and valves), and rheumatic fever / rheumatic heart disease (an immune reaction that can involve all layers).

Pericarditis — inflammation of the pericardium, often with a small effusion.

• Causes: viral or idiopathic (most common in high-income countries), tuberculosis (important in endemic areas), bacterial infection, early post-MI pericarditis and post-MI/postpericardiotomy syndrome (days to weeks after MI or heart surgery), kidney failure (uremia), autoimmune disease, cancer, radiation
• Complications: pericardial effusion → cardiac tamponade, recurrent pericarditis, constrictive pericarditis (a thick, scarred pericardium that restricts filling)

Myocarditis — inflammation of the heart muscle, usually viral or post-viral; also autoimmune, drug-related, or (rarely) after mRNA COVID-19 vaccination, mostly in young males. It can cause heart failure, dysrhythmias, dilated cardiomyopathy, and sudden death.

Infective endocarditis (IE) — infection of the endocardium, usually on valves, forming vegetations (clumps of platelets, fibrin, and microorganisms). Pieces break off and embolize.

• Organisms: Staphylococcus aureus (now the most common; associated with injection drug use, intravascular devices, health care exposure), viridans group streptococci (mouth), enterococci
• Risk factors: prosthetic valve, previous IE, congenital heart disease, rheumatic or degenerative valve disease, injection drug use (often right-sided/tricuspid), intravascular catheters, hemodialysis, poor dental health

Rheumatic fever (RF) and rheumatic heart disease (RHD) — an autoimmune reaction 2–4 weeks after untreated group A streptococcal pharyngitis. Antibodies against the bacteria cross-react with heart, joint, skin, and brain tissue. Acute carditis mainly causes valvulitis (acute mitral regurgitation is typical). Repeated attacks cause scarring and fusion of the valve leaflets → chronic RHD, most characteristically mitral stenosis, often with mixed stenosis and regurgitation. The mitral valve is affected most often, then the aortic valve.

Pericarditis

• Sharp, pleuritic chest pain worse with deep breathing, coughing, and lying flat; relieved by sitting up and leaning forward; may radiate to the trapezius ridge
• Pericardial friction rub — scratchy, high-pitched sound; best heard at the left lower sternal border with the diaphragm while the client leans forward. It continues when the client holds the breath (a pleural rub stops)
• Low-grade fever, dyspnea, malaise

Myocarditis: recent viral illness, chest pain, fatigue, dyspnea, palpitations, signs of HF, dysrhythmias, syncope.

Infective endocarditis

• Fever (most common), chills, night sweats, fatigue, weight loss
• New or changed murmur
• Embolic and immune signs: splinter hemorrhages under nails, petechiae (conjunctiva, palate), Janeway lesions (painless red spots on palms/soles), Osler nodes (painful nodules on finger pads), Roth spots (retinal hemorrhages), splenomegaly, clubbing
• Embolic events: stroke, flank pain and hematuria (kidney), left upper quadrant pain (spleen), pulmonary emboli (right-sided IE)

Rheumatic fever — Jones criteria (evidence of recent strep infection plus 2 major, or 1 major + 2 minor)

The table shows the low-risk-population version. In moderate/high-risk settings (e.g., the Philippines), monoarthritis or polyarthralgia can count as a major criterion and echocardiography-detected (subclinical) carditis counts; minor criteria include monoarthralgia, fever ≥ 38 °C, and ESR ≥ 30 mm/h or CRP ≥ 3 mg/dL. Recurrent RF may be diagnosed with 3 minor criteria.

Pericarditis

• NSAID or high-dose aspirin plus colchicine is first-line. Colchicine for about 3 months after a first episode and at least 6 months for recurrences reduces recurrence; it is the last drug stopped
• Recurrent pericarditis with elevated CRP despite first-line therapy: interleukin-1 blockers (anakinra, rilonacept) are recommended before long-term steroids
• After MI, aspirin is preferred over other NSAIDs
• Corticosteroids are second-line (for contraindications to NSAIDs or specific causes) — they increase recurrence risk
• Treat the cause: antituberculous therapy for TB pericarditis; dialysis for uremic pericarditis
• Pericardiocentesis for tamponade (see Cardiac Tamponade topic); pericardiectomy for constriction
• Diuretics are not a treatment for pericarditis. If they are prescribed for coexisting heart failure, monitor serum potassium and volume status, because a loop diuretic causes hypokalemia and reduced preload can precipitate hypotension when a significant effusion is present

Myocarditis: supportive care, HF therapy when EF is reduced, rhythm monitoring, immunosuppression for specific types (e.g., giant cell, eosinophilic), mechanical support for fulminant cases. Paracetamol, aspirin, or NSAIDs may be used for symptoms in uncomplicated cases — use NSAIDs only as prescribed, as practice varies. Restrict strenuous exercise and competitive sports: ESC 2025 advises at least 1 month, then an individualized return based on symptoms, CRP, ECG, and imaging; US sports guidance commonly uses 3–6 months after myocarditis.

Infective endocarditis

• Prolonged IV antibiotics (usually 4–6 weeks) chosen by organism and valve type; a PICC line and outpatient parenteral therapy are common. Selected stable clients may step down to oral antibiotics per specialist decision
• Surgery for heart failure from valve destruction, abscess, uncontrolled infection, persistent bacteremia, fungal IE, or large vegetations with embolic risk
• Remove infected devices or catheters

Rheumatic fever / RHD

• Primary prevention: treat streptococcal pharyngitis promptly (penicillin or amoxicillin for 10 days)
• Treat acute RF: eradicate strep with penicillin; aspirin or NSAIDs for arthritis; HF treatment for carditis
• Secondary prophylaxis: benzathine penicillin G IM every 3–4 weeks (1.2 million units; 600,000 units for ≤ 27 kg [60 lb] per AHA — WHO 2024 uses < 30 kg) for years: RF without carditis — 5 years or until age 21; carditis without residual valve disease — 10 years or until 21; residual valve disease — 10 years or until age 40, sometimes lifelong (whichever is longer in each case). Oral penicillin is an alternative when injections are not possible
• Valve surgery or balloon mitral commissurotomy for advanced RHD

Drug safety

Listed in priority order.

1. Watch for tamponade in pericarditis — hypotension, JVD, muffled heart sounds, pulsus paradoxus; report immediately
2. Monitor for emboli in IE — neurologic checks, flank pain, hematuria, abdominal pain, limb ischemia, sudden dyspnea
3. Rhythm and hemodynamics — continuous ECG in myocarditis and severe IE; watch for HF (crackles, S₃, edema)
4. Antibiotic therapy in IE — collect cultures before the first dose; give doses on time; maintain IV line integrity and asepsis; assess for phlebitis, allergic reactions, nephrotoxicity, and ototoxicity; monitor drug levels and kidney function
5. Pain relief in pericarditis — position upright and leaning forward (over-bed table); give NSAIDs/colchicine as ordered
6. Rest and activity — rest during acute myocarditis and pericarditis to reduce cardiac workload; resume activity gradually
7. Fever management and nutrition during prolonged infection

• Pericarditis: finish the full colchicine course; report returning chest pain, breathlessness, or fainting; avoid strenuous exercise for at least 1 month and until symptoms resolve and inflammatory markers normalize
• Myocarditis: avoid competitive sports and strenuous exertion until cleared by the cardiologist (often 3–6 months)
• IE: complete the entire antibiotic course; PICC care; report fever, chills, or signs of stroke; regular dental care and daily oral hygiene; never share needles; tell dentists and providers about prior IE — it qualifies for prophylaxis before dental procedures
• Endocarditis prophylaxis is recommended only for high-risk clients (prosthetic valve or repair material, prior IE, certain congenital heart disease, transplant valvulopathy) before dental work involving the gums
• RF/RHD: never miss a penicillin injection; keep a card or record of dates; seek treatment for every sore throat with fever; family members with sore throat should be evaluated

• Pericarditis pain: sharp, pleuritic, relieved by sitting up and leaning forward
• Pericarditis hallmark: friction rub; ECG: diffuse ST elevation + PR depression
• Pericarditis treatment: NSAID/aspirin + colchicine; aspirin after MI
• Myocarditis: rest, monitor rhythm, restrict strenuous exercise until cleared
• IE: fever + new murmur; splinter hemorrhages, Janeway lesions, Osler nodes, Roth spots
• IE diagnosis: repeated positive blood cultures with typical organisms + echocardiographic vegetation; cultures before antibiotics
• IE treatment: 4–6 weeks of IV antibiotics — protect the line, watch nephrotoxicity and ototoxicity
• Prophylaxis before dental work only for high-risk clients (e.g., prosthetic valve)
• RF follows group A strep pharyngitis; mitral valve most affected; chronic RHD → mitral stenosis
• Secondary prevention: benzathine penicillin G every 3–4 weeks