John is a 35-year-old nurse who had rheumatic fever as a child. He noticed a per

Question

John is a 35-year-old nurse who had rheumatic fever as a child. He noticed a persistent tachycardia and light-headedness. Chest x-rays showed an enlarged left atrium and left ventricle. ECG analysis showed atrial fibrillation and mild pulmonary congestion. Cardiac evaluation resulted in the following information:

Cardiac output (CO)                        3.4 L/min

Blood pressure (BP)                       100/58 mm Hg

Left atrial pressure (LAP)                16 mm Hg

Right ventricular pressure (RVP)     44/8 mm Hg

Heart sounds revealed valvular regurgitation.

1.Deduce which A-V valve is incompetent, thus allowing the regurgitation.

2.Using anatomical terms, describe the location at which this valvular disorder could best be heard.

3.Which heart sound would be pronounced and lengthened?

4.If the other AV valve were incompetent instead of this one, would the CO, BP, LAP, and RVP be different?

5.If so, how? What are the causes of the tachycardia, light-headedness, and mild pulmonary congestion?

Explanation / Answer

1.The A-V valve that is incompetent, allowing the regurgitation, is the mitral valve.

2.This valvular disorder could best be heard at the left midclavicular line at the fifth intercostal space.

3.The first heart sound would be pronounced and lengthened for mitral incompetence.

4.If the tricuspid valve were incompetent instead of the mitral valve, the LAP and RVP would be different. They both would be normal or near normal.

5.The tachycardia is a reflex response (sympathetic) to the lowered systemic blood pressure. The light-headedness is from reduced blood pressure (100/58). The mild pulmonary congestion is due to regurgitation of blood through the mitral valve from the left ventricle into the left atrium during left ventricular contraction. This "reverse flow" through the incompetent mitral valve elevates the left atrial pressure and increases the pulmonary capillary pressure, resulting in fluid accumulation in the lungs (pulmonary congestion).

Related Questions

Navigate

• Browse (All)
• Browse J
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.