What is a common consequence of dilated cardiomyopathy?

Dilated cardiomyopathy is characterized by the enlargement and weakening of the heart's chambers, particularly the left ventricle. This condition leads to a significant reduction in the heart's ability to pump blood effectively, resulting in a decreased ejection fraction. The ejection fraction is a measurement of the percentage of blood that is pumped out of the heart with each contraction. In dilated cardiomyopathy, the mechanical function of the heart is compromised due to the dilation of the ventricular chambers, which affects the overall cardiac output and can result in symptoms such as fatigue and shortness of breath.

In contrast, options that suggest an increased heart rate or thickened chambers do not typically occur in dilated cardiomyopathy; the condition is more closely associated with chamber enlargement rather than hypertrophy, which refers to thickening of the heart muscle. A normal heart size is also inconsistent with dilated cardiomyopathy, as the defining feature is the dilation of the heart chambers. Therefore, the reduction in ejection fraction is a key consequence of this condition, making it the correct choice.