Laboratory test Diffuse ST elevation in a young male due to myocarditis /<unk>  An ECG showing<unk> . Note the ST elevation in multiple leads with slight reciprocal ST depression in aVR. Laboratory values can show increased urea (BUN), or increased blood creatinine in cases of uremic<unk> . Generally, however, laboratory values are normal, but if there is a concurrent myocardial infarction (heart attack) or great stress to the heart, laboratory values may show increased cardiac markers like Troponin (I, T), CK-MB, Myoglobin, and LDH1 (lactase dehydrogenase isotype 1). The preferred initial diagnostic testing is the ECG, which may demonstrate a 12-lead electrocardiogram with diffuse, non-specific, concave ("saddle-shaped"), ST-segment elevations in all leads except aVR and V1 and PR-segment depression possible in any lead except aVR; sinus tachycardia, and low-voltage QRS complexes can also be seen if there is subsymptomatic levels of pericardial effusion. The PR depression is often seen early in the process as the thin atria are affected more easily than the ventricles by the inflammatory process of the pericardium. Since the mid-19th century, retrospective diagnosis of<unk>  has been made upon the finding of adhesions of the pericardium. When<unk>  is diagnosed clinically, the underlying cause is often never known; it may be discovered in only 16–22 percent of people with acute<unk> . Imaging File:PericardialeffusionUS.Ultrasounds showing a pericardial effusion in someone with<unk>  File:PericardialeffusionCXR.A pericardial effusion as seen on CXR in someone with<unk>  On MRI T2-weighted spin-echo images, inflamed pericardium will show high signal intensity. Late gadolinium contrast will show uptake of contrast by the inflamed pericardium. Normal pericardium will not show any contrast enhancement. Classification<unk>  can be classified according to the composition of the fluid that accumulates around the heart. Types of<unk>  include the following: * serous * purulent * fibrinous * caseous * hemorrhagic Acute vs. chronic Depending on the time of presentation and duration,<unk>  is divided into "acute" and "chronic" forms. Acute<unk>  is more common than chronic<unk> , and can occur as a complication of infections, immunologic conditions, or even as a result of a heart attack (myocardial infarction), as Dressler's syndrome. Chronic<unk>  however is less common, a form of which is constrictive<unk> . The following is the clinical classification of acute vs. chronic: * Clinically: Acute (6 months)
Pericarditis
Myocardial infarction
Carditis
Pleurisy
Myopericarditis
Precordial catch syndrome
Constrictive pericarditis
Myocarditis