What usually causes increased left ventricular wall thickness with age?

Increased left ventricular wall thickness with age is primarily due to increased afterload resulting from the stiffening of blood vessels. As people age, their arteries tend to become less compliant and more rigid, which leads to an increase in resistance that the heart must work against to pump blood. This is referred to as afterload. When afterload is consistently high, the heart responds by thickening its muscular walls to generate the necessary force to overcome this increased resistance, which leads to hypertrophy of the left ventricle.

This phenomenon is a normal adaptive response of the heart to changes in hemodynamic conditions associated with aging. As the walls of the left ventricle become thicker, the heart's ability to effectively pump blood can be compromised over time, which may lead to potential cardiac complications.

Other factors like chronic inflammation, the natural aging process of muscle cells, or increased heart rate do not primarily cause the specific increased wall thickness observed with aging as it pertains to the structural changes in the heart in response to hemodynamic pressures. These factors may play a role in overall cardiac health, but they are not the primary drivers of the hypertrophic changes in the left ventricle associated with aging.