Which medical term describes the thickening of the heart muscle that can obstruct blood flow?

The correct term that describes the thickening of the heart muscle, which can obstruct blood flow, is cardiomyopathy. This condition involves the abnormal thickening of the heart muscle, particularly in the left ventricle, which can lead to obstructive issues. When the heart muscle becomes overly thickened, it can impede the heart's ability to pump blood effectively, causing symptoms like shortness of breath and chest pain, especially during physical exertion.

The other terms refer to different heart-related conditions. Arrhythmia pertains to irregular heartbeats, which can be due to various causes but does not specifically describe thickening of the heart muscle. Myocarditis is the inflammation of the heart muscle, often due to infection, and does not imply the structural change characterized by thickening. Endocarditis involves inflammation of the inner lining of the heart chambers and valves, usually related to infection, rather than a change in the thickness of the heart muscle itself. Understanding these different conditions helps in recognizing their distinct characteristics and implications for heart health.