Intracardiac and Extracardiac Shunt

Intracardiac Shunt

Atrial Septal Defect (ASD) (see Atrial Septal Defect, [[Atrial Septal Defect]])

  • L->R Shunt: normal direction of shunting in absence of pulmonary hypertension
    • Diagnosis
      • Echocardiogram:
      • Swan: step-up in SaO2 from venous SaO2 to right atrium
  • R->L Shunt: occurs in cases with pulmonary hypertension
    • Diagnosis
      • Echocardiogram: bubble study (injection of agitated saline injected into vein) reveals shunt, with rapid appearance of bubbles on left side of heart
      • Swan:
    • Clinical
      • Hypoxemia (see Hypoxemia, [[Hypoxemia]]): due to blood bypassing pulmonary circulation

Patent Foramen Ovale (PFO) (see Patent Foramen Ovale, [[Patent Foramen Ovale]])

  • L->R Shunt: normal direction of shunting in absence of pulmonary hypertension
    • Diagnosis
      • Echocardiogram
      • Swan: step-up in SaO2 from venous SaO2 to right atrium
  • R->L Shunt: occurs in cases with pulmonary hypertension
    • Diagnosis
      • Echocardiogram: bubble study (injection of agitated saline injected into vein) reveals shunt, with rapid appearance of bubbles on left side of heart
      • Swan:
    • Clinical
      • Hypoxemia (see Hypoxemia, [[Hypoxemia]]): due to blood bypassing pulmonary circulation

Ruptured Sinus of Valsalva Aneurysm (see Sinus of Valsalva Aneurysm, [[Sinus of Valsalva Aneurysm]])

  • L->R Shunt: in cases with rupture into right atrium or right ventricle
    • Diagnosis
      • Echocardiogram:
      • Swan:
    • Clinical
      • Dyspnea (see Dyspnea, [[Dyspnea]]): most common manifestation
      • xxx
  • L->L Shunt: in cases with rupture into left ventricle
    • Diagnosis
      • Echocardiogram:
      • Swan:
    • Clinical

Ventricular Septal Defect (VSD)/Ventricular Septal Rupture (see Ventricular Septal Defect, [[Ventricular Septal Defect]] and Ventricular Septal Rupture, [[Ventricular Septal Rupture]])

  • L->R Shunt: normal direction of shunting in absence of pulmonary hypertension
    • Diagnosis
      • Echocardiogram:
      • Swan: step-up in SaO2 from venous right atrium to right ventricle
  • R->L Shunt: occurs in cases with pulmonary hypertension
    • Diagnosis
      • Echocardiogram: bubble study (injection of agitated saline injected into vein) reveals shunt, with rapid appearance of bubbles on left side of heart
      • Swan:
    • Clinical
      • Hypoxemia (see Hypoxemia, [[Hypoxemia]]): due to blood bypassing pulmonary circulation

Extracardiac Shunt

Hepatopulmonary Syndrome (see Hepatopulmonary Syndrome, [[Hepatopulmonary Syndrome]])

  • Diagnosis
    • Echocardiogram: bubble study (injection of agitated saline injected into vein) reveals shunt, with delayed appearance of bubbles (after 3-6 cardiac cycles) on left side of heart
  • Clinical

References

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