Physiological Adaptation Q 34

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In which of the following types of cardiomyopathy does cardiac output remain normal?

  

     A. Obliterative

     B. Restrictive

     C. Dilated

     D. Hypertrophic

    

    

Correct Answer: D. Hypertrophic

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Hypertrophic cardiomyopathy (HCM) is a condition in which there is severe ventricular hypertrophy and poor diastolic filling. It is an autosomal dominant condition wherein the heart muscles asymmetrically increase in size and mass along the septum. The increase in the thickness of heart muscles reduces the size of the cavities of the ventricles, causing them to take a longer time to relax after systole. Cardiac output isn’t affected by hypertrophic cardiomyopathy because the ventricle’s size remains relatively unchanged.

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Options A and B: Restrictive cardiomyopathy (RCM) is wherein the heart walls are rigid, causing a restrictive stretching and filling of blood properly. Restrictive and obliterative cardiomyopathy are the same.

Option C: Dilated cardiomyopathy (DCM) is when the left ventricle is enlarged and weakened, causing a decrease in the ability to pump blood (decreased cardiac output). It is the most common type of cardiomyopathy and commonly leads to progressive heart failure. The cause of DCM can be idiopathic, or it can result from inflammatory processes like myocarditis or cytotoxic agents like alcohol and certain neoplastic drugs.

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