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electrocardiagram-of-acute-pericarditis

Electrocardiogram of acute pericarditis. By Lecturio


Definition of Pericarditis

Pericarditis occurs when the pericardium, the visceral sac that covers the heart, experiences inflammation. Pericarditis has many etiologies including infection, autoimmune disease, uremia, radiation, surgery, and myocardial infarction.

The pericardium has 2 parts and 3 layers. The fibrous pericardium is the outer layer and is composed of connective tissue. The serous pericardium is composed of 2 layers: the visceral pericardium attached to the outermost layer of the heart – the epicardium, and the parietal pericardium that lines the inside of the pericardial sac. The parietal pericardium is fused to the fibrous pericardium. The pericardial cavity between the visceral and pericardial layers is filled with serous fluid.

Epidemiology of Acute Pericarditis

Spread of acute pericarditis

Acute pericarditis is diagnosed in about 1 in 1000 hospital admissions. It is more common in adults than in children. Uremic pericarditis is seen in patients with chronic renal failure. Purulent pericarditis (pericarditis with pus in the pericardial space, as a result of bacterial infection) has become rare in the developed world with the regular use of antibiotics but is still common in the developing world.

Etiology of Acute Pericarditis

Causes of acute pericarditis

There are many causes of acute pericardial inflammation:

Viral infection
Bacterial infection
  • Tuberculosis*
  • Streptococcus species
  • Pseudomonas
  • Staphylococcus species
Fungal infection
  • Histoplasma
  • Blastomyces
  • Coccidioides
  • Aspergillus
Autoimmune disease
Renal failure
  • Uremia
Cardiovascular disease
Cancer
Medication
  • Penicillin
  • Cromolyn sodium
Open heart surgery and trauma  –
Irradiation
  • Iatrogenic to cancer treatment of the chest
Idiopathic*  –

The most common causes of acute pericarditis

Pathology and Pathophysiology of Acute Pericarditis

The pericardium has 4 functions: it restricts the heart and prevents excess dilation, produces a chamber at a negative pressure that aids in atrial filling, provides a frictionless environment, and isolates the heart from the rest of the body.

Inflamed pericardium shows a polymorphonuclear infiltrate on microscopy, as well as vascularization. Inflammatory signaling may stimulate the release of fluid that could result in effusion or fibrinous reactants that could result in a constrictive complication. Tuberculosis, sarcoidosis, or fungal infections will show a granulomatous reaction with multinucleated giant cells and epithelioid cells on microscopy. The accumulation of urea, a metabolic toxin, in the pericardial space results in inflammation of the parietal and visceral layers.

Symptoms of Acute Pericarditis

Acute pericarditis is characterized by the following signs and symptoms:

  • Persistent substernal chest pain that radiates to the trapezius or to the neck, which is improved by leaning forward and worsened by lying supine, coughing, or inhalation
  • Symptoms of the underlying disease
  • Auscultation: friction rub between the visceral and parietal layers
  • ECG: concave ST-segment elevations in all leads except V1 and PR elevation in aVR
  • Other symptoms: dry cough, fatigue, fever

Note: Some symptoms of pericarditis are similar to those seen in acute coronary syndrome but are distinguishable because the symptoms of pericarditis change with body position.

electrocardiagram-of-acute-pericarditis

Image: Electrocardiogram of acute pericarditis. By Lecturio

Diagnosis of Acute Pericarditis

Diagnosis is based on abnormal findings on ECG (see above) with a history of chest pain that changes with body position. Elevated BUN or creatinine is present in the case of uremia. Positive blood culture indicates an infectious etiology. A retrospective diagnosis can be made on autopsy if pericardial adhesions are found. Chest X-ray is necessary to rule out effusion.

Differential Diagnoses of Acute Pericarditis

Therapy of Acute Pericarditis

Treatment of acute pericarditis

Generally, administration of oxygen, monitoring via ECG, and serial blood pressure evaluations are required. Further, myocardial infarction should be ruled out via ECG, and cardiac enzymes (troponin, CK-MB, LDH) should be assessed. Pain should be treated with morphine. Other treatments depend on the etiology.

  • Treat with NSAIDs such as aspirin.
  • Adjuvant therapy consists of colchicine.

In addition, the underlying condition should be addressed:

  • Antibiotics should be used to treat tuberculosis or other bacterial etiologies
  • Dialysis is required if uremia is present

Progression and Prognosis of Acute Pericarditis

Hospitalization for hemodynamically stable patients with normal laboratory results is rarely necessary.

Viral and idiopathic pericarditis are often uncomplicated and self-limiting. Post-myocardial infarction pericarditis is usually indicative of a large infarct and is associated with increased mortality. Purulent pericarditis is associated with 40% mortality while tuberculous pericarditis accounts for about 50% mortality. Uremic pericarditis has a much lower mortality rate.

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