How pericardial disease is tested on Step 1

Vignettes describe chest pain that changes with position, a hypotensive patient with distended neck veins after trauma or malignancy, or chronic right-sided congestion after radiation or TB.

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A slowly growing effusion can reach a liter without symptoms because the pericardium stretches. A rapid 150 mL of blood (trauma, ventricular rupture) can cause tamponade.

Acute pericarditis

Inflammation of the pericardial layers causes pain and a characteristic ECG.

Causes of pericarditisViral,idiopathicCoxsackie Bmost commonPost-MIDays (early) orweeks(Dressler)UremiaNo typical ECGchangesAutoimmuneSLE, RA,sclerodermaOtherTB, cancer,radiation,surgery
Causes. Dressler syndrome is an autoimmune pericarditis 2–10 weeks after MI or cardiac surgery.
FeaturePericarditisSTEMI
PainSharp, pleuritic, better sitting forwardPressure, not positional
ST elevationDiffuse, concave ("saddle-shaped")Regional, convex, with reciprocal depression
PR segmentDepressed (elevated in aVR)Usually normal
Q wavesAbsentMay develop
ExamFriction rub (up to three components)May have S4, new murmur

Treatment: NSAIDs (or aspirin after MI) plus colchicine for 3 months; avoid NSAIDs other than aspirin early after MI.

Cardiac tamponade

Fluid under pressure compresses all four chambers, limiting diastolic filling. Stroke volume and blood pressure fall.

EffusionPressure in afixed sac↓ FillingAll chamberscompressedEqualpressuresDiastolicpressuresequalizeSeptalshiftInspirationbows septumleftShockPulsusparadoxus,hypotension
Tamponade. On inspiration the expanding RV pushes the septum into the LV, so LV stroke volume and systolic pressure fall more than 10 mm Hg — pulsus paradoxus.
FindingExplanation
Beck triad: hypotension, JVD, muffled heart soundsLow output, high venous pressure, fluid around the heart
Pulsus paradoxus > 10 mm HgVentricular interdependence
Electrical alternansThe heart swings within the fluid
Low-voltage QRSFluid damps the signal
Echo: RA and RV diastolic collapsePericardial pressure exceeds chamber pressure

Treatment is urgent pericardiocentesis; give IV fluids and avoid diuretics, vasodilators, and positive-pressure ventilation if possible.

Constrictive pericarditis

Chronic inflammation leaves a thick, fibrotic, often calcified pericardium that stops the heart from filling in late diastole.

TamponadeFluid under pressureAcute or subacutePulsus paradoxus (prominent)Kussmaul sign usually absentNo pericardial knockTreat: pericardiocentesisConstrictive pericarditisRigid scarred pericardiumChronic (TB, radiation, surgery)Pulsus paradoxus less commonKussmaul sign presentPericardial knock in early diastoleTreat: pericardiectomyvs
Tamponade vs constriction. In constriction, early diastolic filling is rapid then stops abruptly — the pericardial knock and the "square root sign" on pressure tracings.

Clinical application

Trauma and malignancy are classic tamponade settings.

functions Worked example — the stabbing victim

A man with a stab wound to the left chest has blood pressure 78/50, distended neck veins, distant heart sounds, and a systolic pressure that drops 18 mm Hg on inspiration. Lungs are clear bilaterally and the trachea is midline. What is the diagnosis and treatment?

  1. Hypotension, JVD, and muffled heart sounds form Beck triad.
  2. A fall of more than 10 mm Hg on inspiration is pulsus paradoxus.
  3. Clear breath sounds and a midline trachea argue against tension pneumothorax, the main alternative.
  4. Rapid accumulation of blood in the pericardium explains tamponade from a small volume.

Answer. Traumatic cardiac tamponade. Treat with immediate pericardiocentesis or surgical drainage; IV fluids temporarily support preload.