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
    • Congestive Heart Failure (CHF) (see Congestive Heart Failure, [[Congestive Heart Failure]])

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
  • Hypoxemia (see Hypoxemia, [[Hypoxemia]])

---

References

• xxx