ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT
ATRIAL SEPTAL DEFECT (ASD)
Most common is ostium secundum ASD, located at mid interatrial septum. Ostium primum ASDs (e.g., typical of Down syndrome) appear at lower atrial septum and are associated with abnormal development of atrioventricular (AV) valves, especially a cleft appearance of the mitral valve. Sinus venosus type defects do not actually involve the atrial septum, but rather represent a defect localized between a right pulmonary vein and the junction of the superior vena cava or inferior vena cava with the right atrium (RA). Physiologically such defects mimic ASDs.
History
When discovered in adulthood, usually asymptomatic until third or fourth decades, when exercise intolerance, dyspnea, and palpitations may occur. Onset of symptoms may be associated with development of pulmonary hypertension (PHT) (see below).
Physical Examination
Wide, fixed splitting of S2, systolic murmur from flow across pulmonic valve, possible diastolic flow rumble across tricuspid valve, prominent jugular venous v wave.
ECG
Incomplete RBBB (rSR’ in right precordial leads) common. Left-axis deviation frequently present with ostium primum defect. Ectopic atrial pacemaker or first degree AV block occur in sinus venosus defects.
CXR
Increased pulmonary vascular markings, prominence of RA, RV, and main pulmonary artery (LA enlargement not usually present).
Echocardiogram
RA, RV, and pulmonary artery enlargement; Doppler shows abnormal transatrial flow. Echo contrast (agitated saline injection into peripheral systemic vein) may visualize transatrial shunt.
Treatment: Atrial Septal Defect
Treatment: Atrial Septal Defect
In the absence of contraindications an ASD with a significant pulmonary-to-systemic flow (Qp/Qs) ratio (≥1.5:1.0) with right heart enlargement should be considered for surgical or percutaneous transcatheter closure. Closure is usually contraindicated with significant PHT and is not undertaken for small defects with trivial left-to-right shunt flow.
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Citation
Kasper, Dennis L., et al., editors. "ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT." Harrison's Manual of Medicine, 19th ed., McGraw Hill Inc., 2017. harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623305/all/ACYANOTIC_CONGENITAL_HEART_LESIONS_WITH_LEFT_TO_RIGHT_SHUNT.
ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT. In: Kasper DLD, Fauci ASA, Hauser SLS, et al, eds. Harrison's Manual of Medicine. McGraw Hill Inc.; 2017. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623305/all/ACYANOTIC_CONGENITAL_HEART_LESIONS_WITH_LEFT_TO_RIGHT_SHUNT. Accessed September 14, 2024.
ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT. (2017). In Kasper, D. L., Fauci, A. S., Hauser, S. L., Longo, D. L., Jameson, J. L., & Loscalzo, J. (Eds.), Harrison's Manual of Medicine (19th ed.). McGraw Hill Inc.. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623305/all/ACYANOTIC_CONGENITAL_HEART_LESIONS_WITH_LEFT_TO_RIGHT_SHUNT
ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT [Internet]. In: Kasper DLD, Fauci ASA, Hauser SLS, Longo DLD, Jameson JLJ, Loscalzo JJ, editors. Harrison's Manual of Medicine. McGraw Hill Inc.; 2017. [cited 2024 September 14]. Available from: https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623305/all/ACYANOTIC_CONGENITAL_HEART_LESIONS_WITH_LEFT_TO_RIGHT_SHUNT.
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