How do ACE inhibitors primarily work to lower blood pressure?

ACE inhibitors primarily work by preventing the formation of angiotensin II, a hormone that causes blood vessels to constrict. By inhibiting the angiotensin-converting enzyme (ACE), these medications decrease the production of angiotensin II, leading to the relaxation and widening of blood vessels. This process reduces vascular resistance, which lowers blood pressure. Additionally, by reducing levels of angiotensin II, ACE inhibitors help decrease the secretion of aldosterone, a hormone that can lead to sodium and water retention, further supporting their role in lowering blood pressure.

The other options do not accurately describe the main mechanism of action for ACE inhibitors. Increasing heart rate typically raises blood pressure rather than lowers it. Blocking calcium channels is the mechanism of calcium channel blockers, not ACE inhibitors. Promoting vascular occlusion would imply a constricting action on blood vessels, which is contrary to the purpose of ACE inhibitors.