Review Question - QID 217780

This patient who presents with a high-pitched and harsh holosystolic murmur that is best heard at the lower left sternal border most likely has a ventricular septal defect. These patients will have increased right ventricular pressure due to direct communication and shunting of blood from the left side of the heart.

Ventricular septal defects are congenital defects resulting in an opening in the interventricular septum of the heart. This results in left-to-right shunting of blood in the heart, causing increased pulmonary blood flow and alterations in pulmonary vasculature. Over time, this can result in pulmonary hypertension with severe ventricular septal defects. Unlike patients with normal cardiac anatomy, who typically have far lower pressures in the right side of the heart compared to the left, patients with ventricular septal defects will have relatively increased right-sided pressures, which, over time can even exceed left-sided pressures. When this occurs, the shunting of blood reverses to go from right to left, which is a condition known as Eisenmenger syndrome.

Moller et al. studied the pressure response of the right ventricle in patients who were born with ventricular septal defects. They found that over 1/3 of adolescents had an abnormally high right ventricular pressure response during exercise.

Spicer et al. described the pathophysiology of ventricular septal defects. This disease presents with an isolated early increase in right ventricular pressure.

Incorrect Answers:
Answer 1: Decreased right and decreased left ventricular pressures can occur in patients with heart failure with reduced ejection fraction. These patients have decreased myocardial contractility causing hypoperfusion of end organs. Patients will present with peripheral edema and dyspnea on exertion.

Answer 2: Decreased right and increased left ventricular pressures are atypical of any disease process because almost all increases in left-sided pressures would also be propagated through the pulmonary vasculature back to the right side of the heart as well. In normal patients left sided ventricular pressure is higher than right sided ventricular pressure.

Answer 3: Increased right and decreased left ventricular pressures can occur in patients with total anomalous pulmonary venous return. These patients have an abnormal return of blood from the lungs to the right side of the heart. These patients present with neonatal cyanosis.

Answer 4: Increased right and increased left ventricular pressures can occur in patients with chronic hypertension. These patients require increased pressures in order to overcome increases in peripheral vascular resistance. These patients may have headaches or be asymptomatic.

Bullet Summary:
Ventricular septal defects lead to increased right-sided ventricular pressures due to the anomalous connection between the right and left sides of the heart.