Ventricular Septal Defect
Definition
Abnormal opening in the interventricular septum
Types
- Membranous (most common)
- Muscular (may be multiple)
- Subvalvular (atrioventricular canal, posterior, inlet)
- Supracristal (subpulmonic)
Shunt
- Left-to-right
Cardiac Auscultation
- Systolic murmur, heard best along the left sternal border
Electrocardiogram
- Left atrial enlargement
- Left ventricular enlargement
Chest X-ray
- Cardiomegaly (due to left atrial, left ventricular, and pulmonary artery enlargement).
Cardiac Catheterization
- An oxygen step-up should be noted in the right ventricle.
Treatment
- Await spontaneous closure in small defects
- Surgical patch when Qp/Qs shunt is > 1.5:1
M-Mode
- Left atrial enlargement
- Left ventricular enlargement
- Left ventricular volume overload (left ventricular enlargement with hyperkinetic wall motion)
- Tricuspid valve systolic flutter
- Pulmonic valve systolic flutter
2-D
- Parastemal long-axis and short-axis views are best for membranous and supracristal ventricular septal defects
- Parasternal long-axis and short-axis views are best for muscular ventricular septal defects
- Apical four-chamber with a posterior tilt is best to visualize atrioventricular canal ventricular septal defect
Doppler
- Color flow Doppler is extremely helpful
- PW and CW Doppler may be used when color flow Doppler is not available
- Determine Qp/Qs
- Determine systemic and pulmonary artery pressure
Postoperative
- Determine whether a shunt remains
Assessment of VSD size
Small VSD
- Large systolic pressure difference
- Small left to right shunt
- Normal right sided pressures
Moderate VSD
- <50% of aorta
- Systolic pressure difference ≥15 mm Hg
- Predominant L->R shunt , R->L in isovolumic relaxation
- Volume overload of LA, LV and LVH
Large VSD
- RV systolic pressure > 80% of LVSP
- Bidirectional shunt
- VSD ≥50% aortic size