❤️‍🩹 Cardiovascular System Lesson

LAD, LCx, RCA — the coronary arteries

The heart is a muscle that needs its own blood supply. These three coronary arteries supply the heart itself — and blockages here are the cause of most heart attacks.

LAD

Ant. LV

LCx

Lateral LV

RCA

Right heart

📖 Full Breakdown

Three coronary arteries and the territory each one feeds

Coronary arteries arise from the aortic root, just above the aortic valve — the very first branches off the aorta.

LAD

Left Anterior Descending

Supplies the anterior left ventricle and the interventricular septum. Nicknamed the "widow maker" because an LAD occlusion causes a massive anterior MI with especially high mortality — it feeds the largest territory of any single coronary artery.

LCx

Left Circumflex

Branches off the left coronary artery alongside the LAD, supplying the lateral and posterior walls of the left ventricle.

RCA

Right Coronary Artery

Supplies the right heart, and in most people also supplies the SA node and AV node — which is why RCA occlusion often causes an inferior MI along with conduction problems (bradycardia, heart block).

🩺 Clinical / Exam Application

A patient having an inferior-wall MI on ECG also develops a slow heart rate and a new heart block. This combination makes sense once you know the RCA supplies both the inferior LV wall AND, in most people, the SA and AV nodes — a single blocked artery can cause a muscle injury and an electrical conduction problem simultaneously. Recognizing which artery supplies which territory lets you anticipate complications before they show up on the monitor.

⚠️ Exam Alert

The LAD is the single highest-yield artery name on any exam because of its "widow maker" association with high-mortality anterior MIs — expect it to be tested by name recognition alone.

🚧 Common Trap

Don't assume every MI affects the electrical conduction system the same way. LAD occlusions primarily damage contractile muscle (anterior wall), while RCA occlusions are more likely to also disrupt the SA/AV nodes since the RCA usually supplies them — the location of the blockage predicts the type of complication.

✅ Quick Check

A patient has an anterior MI. Which coronary artery is most likely occluded, and what makes that artery's territory clinically significant?

📝 Exam Prep

Common Exam Questions

❓ Why is LAD occlusion called the "widow maker"?

✅ The LAD supplies the anterior left ventricle and interventricular septum — a large and critical territory. Occlusion causes a massive anterior MI with especially high mortality, giving it the nickname.

❓ Why can RCA occlusion cause both an inferior MI and a heart block?

✅ The RCA typically supplies both the inferior wall of the left ventricle AND the SA/AV nodes in most people, so a blockage there can damage muscle tissue and disrupt the heart's electrical conduction system at the same time.