Pericardial diseases

Pericardial Anatomy - The Heart's Sac

• Structure: A fibro-serous, double-walled sac enclosing the heart.
  • Fibrous Pericardium: Tough, inelastic outer layer. Anchors the heart.
  • Serous Pericardium: Thin, double-layered membrane.
    • Parietal layer: Lines the inner surface of the fibrous pericardium.
    • Visceral layer (Epicardium): Adheres to the heart muscle.
• Pericardial Cavity: The potential space between the two serous layers. Contains 15-50 mL of ultrafiltrate for lubrication.

⭐ Clinical Pearl: The phrenic nerve (C3-C5) innervates the pericardium, causing referred pain to the trapezius ridge (shoulder) in pericarditis.

Acute Pericarditis - Fiery Friction Rub

• Etiology: Primarily idiopathic (viral, e.g., Coxsackie B), post-MI (early or Dressler syndrome), uremia, autoimmune (SLE), malignancy.
• Clinical Triad:
  • Chest Pain: Sharp, pleuritic, and postural-worsens when supine, improves by leaning forward.
  • Pericardial Friction Rub: High-pitched, scratchy sound best heard at the left sternal border; may be transient.
  • ECG Changes: Diffuse, concave ST-segment elevation and PR depression.
• Diagnostics:
  • ECG is key. Echocardiogram to assess for complications like pericardial effusion.
• Management:
  • NSAIDs (e.g., ibuprofen) and colchicine (reduces recurrence).
  • Corticosteroids for refractory cases or contraindications to NSAIDs.

⭐ PR-segment depression is the most specific ECG finding for acute pericarditis.

Effusion & Tamponade - Beck's Deadly Trio

• Pericardial Effusion: Abnormal fluid in the pericardial sac, impairing cardiac function.

  • Etiology: Often idiopathic/viral; also uremia, malignancy, post-MI (Dressler's).
  • Clinical: May be asymptomatic. Look for dyspnea, cough, distant heart sounds.
  • Diagnostics:
    • ECG: Low-voltage QRS, electrical alternans (swinging heart).
    • CXR: Enlarged, globular, "water-bottle" cardiac silhouette.
    • Echo: Gold standard for detection.

• Cardiac Tamponade: Life-threatening compression from a large/rapid effusion.

  • 📌 Beck's Triad: Hypotension + Jugular Venous Distension (JVD) + Muffled Heart Sounds.
  • Pulsus Paradoxus: Inspiratory systolic BP drop >10 mmHg.
  • Management: Urgent pericardiocentesis.

⭐ Echocardiography is key, showing right atrial and ventricular diastolic collapse-the most specific sign of tamponade.

Constrictive Pericarditis - Heart in a Cage

• Pathophysiology: Thickened, fibrotic, often calcified pericardium encases the heart, severely limiting diastolic filling.
• Etiologies: Idiopathic/viral, post-cardiac surgery, radiation therapy, tuberculosis.
• Clinical Signs:
  • Right heart failure signs dominate: ascites, peripheral edema, hepatomegaly.
  • Kussmaul's sign: Paradoxical ↑ in JVP with inspiration.
  • Pericardial knock: High-pitched early diastolic sound.
• Diagnosis:
  • Echocardiogram: Septal bounce, respiratory interventricular dependence.
  • Cardiac Cath: Equalization of diastolic pressures across all chambers; "dip-and-plateau" or square root sign in ventricular pressure tracings.

⭐ In constrictive pericarditis, ventricular diastolic pressures (RVEDP & LVEDP) are equalized and high, typically within 5 mmHg of each other.

High‑Yield Points - ⚡ Biggest Takeaways

• Acute pericarditis presents with pleuritic chest pain that improves when leaning forward, a friction rub, and diffuse ST-segment elevation.
• Cardiac Tamponade is marked by Beck's triad (hypotension, JVD, muffled heart sounds) and pulsus paradoxus (>10 mmHg SBP drop on inspiration).
• Constrictive Pericarditis features a pericardial knock, Kussmaul's sign (JVP ↑ on inspiration), and signs of right-sided heart failure.
• Electrical alternans on EKG is highly specific for a large pericardial effusion.
• Dressler syndrome is a delayed, post-MI autoimmune pericarditis.