USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

Eccentric left ventricular hypertrophy (LVH) is primarily a response to volume overload. This condition occurs when there is an increase in the volume of blood within the ventricle, prompting the heart muscle to adapt by increasing in size. A common scenario causing this volume overload is valvular heart disease, such as aortic regurgitation or mitral regurgitation, where the heart has to handle more blood than normal. In response, the walls of the left ventricle stretch and thicken, leading to the characteristic eccentric remodeling.

While other conditions like dilated cardiomyopathy or myocardial infarction can also affect the heart's structure, they do not specifically lead to eccentric remodeling in the same way that volume overload does. Dilated cardiomyopathy typically involves global dilation and impaired contraction without the specific aspect of hypertrophy as seen in eccentric LVH. Myocardial infarction usually leads to concentric hypertrophy as a compensatory mechanism to maintain cardiac output after damage to a segment of the heart muscle.

Thus, the primary mechanism resulting in eccentric LVH is indeed due to the adaptation of the myocardium to sustained volume overload.