Final answer:
Dilated cardiomyopathy involves enlargement and weakening of the heart's ventricles, whereas pressure overload hypertrophy involves thickening of the heart muscle due to increased resistance, such as in the left ventricle overcoming systemic circuit resistance.
Step-by-step explanation:
Dilated cardiomyopathy (CM) and pressure overload hypertrophy are two different responses of the heart muscle to different types of stress. Dilated CM is characterized by an enlargement of the heart's ventricles and thinning of the heart muscle, causing the heart to be weaker and less able to pump blood efficiently. On the other hand, pressure overload hypertrophy occurs when the heart muscle thickens in response to increased resistance that it must overcome to pump blood, as is the case with the left ventricle which must generate much greater pressure to overcome resistance in the systemic circuit. Therefore, the myocardium in the left ventricle is significantly thicker compared to the right ventricle. Both conditions can affect the heart's ability to pump blood, but they do so in different ways and require different treatment strategies.