Supracristal Ventricular Septal Defect Clinical Presentation

Updated: Aug 31, 2015
  • Author: Ira H Gessner, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Presentation

History

In patients with supracristal ventricular septal defects (VSDs), symptoms and severity are a function of the size of the defect, the relative systemic and pulmonary vascular resistances, and the presence of associated abnormalities. Symptoms may range from severe congestive failure and cardiogenic shock in patients with large conal defects and left heart obstruction to complete absence of symptoms in patients with small, isolated defects.

Exercise intolerance and dyspnea suggest progressive aortic insufficiency, although early detection and treatment for valve insufficiency should obviate any significant symptoms.

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Physical Examination

Congestive heart failure does not occur in the patient with an isolated, small supracristal ventricular septal defect (VSD). General examination findings consist of a long harsh systolic murmur and no signs of respiratory distress or growth failure. Infants with larger defects, especially those associated with significant left ventricular outflow obstruction (eg, doubly committed subarterial defect with interrupted aortic arch), may present as early as the first week of life with profound congestive heart failure and cardiogenic shock as the ductus arteriosus closes. Infants with only a large left-to-right shunt usually develop symptoms before the second month of life.

The murmur of an isolated, small supracristal VSD is similar to that of other types of small VSDs. While it may be loudest in the third left intercostal space (ie, more superior than other VSDs), it begins with the first heart sound and has a similar harsh, noisy quality. As with other types, a large defect may produce no murmur from the defect itself. In this case, a murmur may result from turbulent flow through the pulmonic valve, thus becoming crescendo-decrescendo in character. This murmur may radiate laterally and posteriorly because of shunt flow directed into the branch pulmonary arteries. [14]

Second heart sound findings depend on volume of shunt flow as well as pulmonary artery pressure and resistance. With a small shunt, the second heart sound splits and varies normally with respiration, and the pulmonary component is normal in intensity. With a large shunt, and elevated pulmonary artery pressure, the pulmonary component of S2 increases in intensity. Intensity of this sound is further increased if pulmonary resistance is increased, in which case the splitting interval of S2 is decreased. With a large left-to-right shunt, one should hear a short, low-frequency, middiastolic apical murmur due to increased flow across the mitral valve. With significantly elevated pulmonary vascular resistance, shunt flow decreases and this diastolic murmur does not occur.

When a patient is known to have a supracristal VSD, physical examination should focus on whether aortic valve insufficiency is present. Blood pressure must be carefully evaluated for pulse pressure (ie, the difference between systolic and diastolic blood pressures) and pulse amplitude, as these increase with increasing aortic valve insufficiency unless heart failure also occurs. With significant aortic valve insufficiency, the aortic component of S2 decreases in intensity. If left ventricular end diastolic pressure increases, left atrial pressure increases, thus causing an increase in intensity of the pulmonic component of S2. Aortic valve insufficiency causes a high-pitched diastolic murmur beginning with the aortic component of the second heart sound. It is best heard along the left sternal border, usually in the third left intercostal space at the sternal edge.

The combined systolic and diastolic murmurs of supracristal VSD with aortic valve insufficiency may be likened to the sound of sawing wood. This systolic-diastolic murmur combination should not be misinterpreted as a continuous murmur (eg, patent ductus arteriosus, arteriovenous malformation or fistula). Significant aortic valve insufficiency may cause a late diastolic murmur at the apex resulting from atrial contraction augmenting late ventricular filling. This is the Austin Flint murmur.

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