Clinical Cases Cardiomegaly

Clinical Case

Mr. Westbrook, a 60-year-old male, has suffered from hypertension for 20 years. As his primary care physician, you gave him a prescription for Lisinopril (an ACE inhibitor), though he states, "I don't take it as often as I should." He has not requested a refill for quite a while, so you begin to wonder if he even takes it at all.

1. Given his long history of uncontrolled hypertension, what would you expect a Chest XR or CT to reveal about the appearance of his heart?
   
   
   1. Left ventricular hypertrophy
      
      
2. What is one possible consequence of prolonged chronic hypertension and left ventricular hypertrophy?
   
   
   1. Left-sided heart failure: With chronic high blood pressure, the heart must work harder to maintain cardiac output. As a result of this process, the left ventricular wall grows very thick (muscular) in order to compensate for the increased afterload. As the workload increases, the heart may not be able to maintain an ejection fraction (EF) close to 60%, instead ejecting a smaller stroke volume. The remaining blood in the left ventricle can eventually cause it to dilate. When dilation is extensive and myocytes are increasingly stretched, decreased overlap between actin and myosin filaments causes weak contraction. This progression may eventually result in left-sided heart failure, causing fluid backflow into the lungs (pulmonary congestion), which can lead to pulmonary edema.
      
      
3. How might Mr. Westbrook present to the clinic if he reached the point of left-sided heart failure?
   
   
   1. Dyspnea (shortness of breath), paroxysmal nocturnal dyspnea (attacks of severe SOB/coughing while sleeping), orthopnea (SOB when lying flat, due to redistribution of fluid within the lungs), and crackles in lungs.
      
      
4. Which tests are commonly used to diagnose heart failure?
   
   
   1. BNP- BNP is released from the ventricles in response to stretch (dilation). This can be used to estimate the severity of the heart failure, as well as the success of therapy.
      
      
   2. Echocardiogram - This is used for definitive diagnosis of heart failure.
      
      
   3. ECGs, X-ray/CT/MRI, and stress tests may also be of value.
      
      
5. Right-sided heart failure is often caused by left-sided heart failure. Why might this occur?
   
   
   1. Blood flow occurs due to a pressure gradient between two spaces. Decreased forward perfusion out of the lungs (from left heart failure) causes pressure to build up in the pulmonary arteries. Thus, the gradient between the right ventricle and pulmonary arteries decreases. This can result in right ventricular hypertrophy, dilation, and eventual right-sided heart failure. Features of right-sided heart failure include jugular venous distension, hepatosplenomegaly, and pitting edema in the extremities. Each of these is caused by buildup of fluid in the systemic veins.
      
      
6. What is the name of right-sided heart failure caused by a primary lung condition?
   
   
   1. Cor pulmonale
      
      

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