Developmental Pathophysiology, Develop. Physiol., Dr. D. Penney
Table 4.16 - Characteristics of Ventricular Septal Defects (the most common heart defect).
- Tiny crevice size to 50 - 60% of aortic diameter; orifice of defect limits maximal flow such that RV pressure doesn't reach systemic.
- Blood shunted across defect proportional to defect size; flow from LV to RV occurs throughout systole giving a pansystolic murmur.
- O2 step-up seen in RV relative to RA; increase proportional to extent of shunt flow.
- Pulmonary blood flow increases; increase in lung vascularity is seen on X-ray.
- X-ray, ECG & echocardiography determine degree of enlargement.
Altered pressures and saturation -
| Normal|| small VSD|
|PA||20/5 (12)||25/10 (17)|
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