Constrictive Pericarditis and Cardiac Tamponade

Constrictive Pericarditis

Etiology

• • Common causes: Idiopathic or viral (chronic or recurrent), following cardiac surgery (postcardiotomy), post acute MI, following radiation therapy.

  • Less common causes: Autoimmune connective tissue disorders, ESRD, uremia, post-infectious (tuberculous or purulent), malignancy (breast, lung, lymphoma), trauma, drug induced, asbestosis, and sarcoidosis

Pathophysiology:

• • Pericardium is a fibrous sac containing pericardial space (visceral and parietal layers) which is normally filled with 15 - 50 mL of fluid.

  • In chronic inflammation the pericardial layers become thickened, calcified; the pericardial space is obliterated and the pericardium becomes noncompliant.

  • Impairment of cardiac filling occur due to external constraints, leading to equalization of pressures in all four cardiac chambers.

H & P:

• • Insidious, gradual. Fatigue, exercise intolerance, venous congestion.

  • Features of right sided HF: LE edema, hepatomegaly, ascites, JVD. Increased JVP with prominent y descent (opening of the tricuspid valve in diastole with rapid emptying of the right atrium). Kussmaul's sign (JVP does not decrease upon inspiration, and on the contrary rises). Pericardial knock (early, loud, high-pitched S3)

DDx:

Cardiac Tamponade: is a clinical diagnosis and a medical emergency

Etiology

• • More likely causes: idiopathic pericarditis, infection (bacterial, including mycobacterial, fungal, and viral, including HIV); neoplasm (lymphoma, breast)

  • Less likely causes: Postcardiotomy, autoimmune connective tissue disorder, uremia, trauma, radiation, MI (subacute), drugs (hydralazine, INH, procainamide, phenytoin), hypothyroidism.

Pathophysiology:

• • Fluid accumulation in pericardial space leading to increase in the pericardial pressure.

  • The rate of accumulation of fluid, compliance of the pericadium, and the amount of fluid determines the rapidity of onset of cardiac tamponade. A rapid accumulation of fluid (trauma, perforation during PCI), of a small volume of fluid can raise the pericardial pressure significantly. Slow accumulation causes pericardium to stretch and a large amount of fluid can accumulate under lower pressure.

  • Tamponde occurs when the pressure in the pericardial space is sufficiently high enough to hinder cardiac filling, resulting in a decrease in cardiac output.

H & P

• • Beck's triad: Elevated JVP, hypotension, and distant heart sounds

  • Fatigue, dyspnea, anxiety, presyncope, chest discmfort, abdominal fullness, slowed sensorium, and a vague sense of being "uncomfortable" patients often feel more comfortable sitting forward.

  • Puslus paradoxus > 10 mm Hg, JVD, diminished heart sounds, tachycardia, hypotension, and signs of shock.

  • ECG is low voltage, tachycardia, electrical alternans (due to swinging of the heart within the pericardium)

  • TTE: First-line diagnostic test to diagnose effusion and evaluate its hemodynamic significance. Check location of effusion, width of fluid rim around the heart.

    • Significant effusion suggestive of hemodynamic compromise:

      • Dilated, incompressible IVC

      • Significant variation in tricuspid and mitral inflow velocities

      • Early diastolic collapse of right ventricle and collapse of the right atrium (during ventricular diastole)

      • Circumferential effusion

  • TEE is helpful when TTE images are poor, or suspicion for loculated effusion (especially at atrial level following cardiac surgery)

  • CT and MRI helpful to assess the anatomical location of the effusion (especially at loculated). Avoided in unstable patient.

  • Right heart catheterization: not usually necessary, but used for hemodynamic assessement to show equalization of atrial and ventricular diastolic pressure.

Tx:

• • Limited role for medical therapy. IVF, no diuretics, nitrates, or any other preload reducing agents. Do not slow resting sinus tachycardia; compensates to maintain cardiac output in the setting of a reduced stroke volume (from reduced diastolic filling), BB and CCB to slow heart rate must be avoided.

• In intubation for respiratory distress or before the fluid is drained, make sure the volume is replete and a pericardiocentesis needle is immediately available before any sedatives are given (a patient in particularly "severe tamponade" can arrest with the preload reduction from sedation)

• Surgical: pericardial window.

Tx:

• • Medical therapy is limited: diuretics, low salt diet. Pts with constriction often have a resting sinus tachycardia to maintain cardiac output in the setting of a reduced stroke volume (from reduced diastolic filling), BB and CCB to slow heart rate must be avoided.

  • Surgical pericardiectomy is the only definitive treatment.