The Small Cardiac Vein is a small vein on the right side of the heart. It helps drain low-oxygen blood from heart muscle (myocardium) into the heart’s venous system. It is most often discussed as part of the coronary venous anatomy that leads into the coronary sinus. Clinicians reference it during cardiac imaging, electrophysiology, and some heart procedures that involve the coronary sinus region.

The Middle Cardiac Vein is a vein on the surface of the heart that drains blood from the heart muscle itself. It runs in a groove on the back of the heart and typically empties into the coronary sinus, a larger collecting vein. Clinicians most often reference it when describing cardiac venous anatomy, cardiac imaging findings, or catheter-based heart rhythm and device procedures.

The Great Cardiac Vein is one of the main veins that drains blood from the heart muscle. It runs along the front of the heart and typically empties into the coronary sinus, a large venous channel on the back of the heart. It is commonly referenced during heart imaging, electrophysiology procedures, and some types of cardiac surgery.

The Coronary Sinus is a large vein on the back (posterior) side of the heart. It collects most of the “used” blood from the heart muscle (myocardium). It normally drains into the right atrium, one of the heart’s upper chambers. Clinicians often refer to it during electrophysiology procedures, device implantation, imaging, and some types of heart surgery.

PDA most often means **patent ductus arteriosus**, a congenital (present at birth) heart connection that stays open. It is a blood vessel between the **aorta** and the **pulmonary artery** that is normal before birth but usually closes after delivery. When it remains open, it can change blood flow through the heart and lungs. PDA is commonly discussed in **newborn and pediatric cardiology**, and sometimes in adult congenital heart disease care.

The Posterior Descending Artery is a coronary artery branch that runs on the back (posterior) surface of the heart. It typically travels in a groove between the lower heart chambers and supplies blood to the inferior (bottom) part of the heart muscle. Clinicians often refer to it when describing coronary anatomy, coronary “dominance,” and heart attack patterns. It is commonly discussed in coronary imaging and when planning procedures to restore blood flow.

RCA most commonly means the **right coronary artery** in cardiovascular medicine. It is one of the main **coronary arteries** that supplies oxygen-rich blood to the heart muscle. Clinicians refer to the RCA in heart attack evaluation, coronary artery disease assessment, and cardiac procedures. RCA can also appear in imaging reports, cath lab notes, and operative summaries.

The Right Coronary Artery is one of the main blood vessels that supplies oxygen-rich blood to the heart muscle. It arises from the aorta near the aortic valve and runs along the right side of the heart in a groove called the atrioventricular (AV) groove. Clinicians commonly reference it when evaluating chest pain, heart attack patterns on ECG, and coronary artery disease.

LCx is an abbreviation for the **left circumflex coronary artery**. It is one of the main arteries that supplies oxygen-rich blood to the heart muscle. LCx is most commonly used in cardiology notes, imaging reports, and catheterization (“cath”) lab discussions. It helps clinicians describe **where** a coronary blockage, spasm, or other finding is located.

The Left Circumflex Artery is one of the main arteries that supplies blood to the heart muscle. It usually branches from the left main coronary artery and travels in a groove around the left side of the heart. Clinicians commonly discuss it when evaluating chest pain, heart attacks, and coronary artery disease. It is also referenced in heart imaging, cardiac catheterization, and bypass surgery planning.

LAD most often means the **left anterior descending coronary artery**, one of the main arteries that supplies blood to the heart muscle. It runs on the front surface of the heart and gives off branches that nourish the left ventricle. Clinicians commonly mention LAD in discussions of **coronary artery disease**, heart attacks, stents, and bypass surgery. In some contexts, LAD can also mean **left axis deviation** on an ECG, but this article focuses primarily on the coronary artery meaning.

The Left Anterior Descending Artery is a major coronary artery that supplies blood to the front wall of the heart. It runs along the front groove of the heart toward the tip (apex). Clinicians refer to it often when evaluating chest pain, heart attacks, and coronary artery disease. It is also a key target in stenting procedures and bypass surgery.

The Left Main Coronary Artery is the main blood vessel that supplies oxygen-rich blood to a large portion of the left side of the heart. It arises from the aorta and typically divides into the left anterior descending (LAD) and left circumflex (LCx) arteries. Clinicians refer to it frequently in heart attack evaluation, coronary artery disease workups, and planning of stents or bypass surgery. Because it feeds major branches, disease in this vessel can carry important clinical implications.

Coronary Arteries are the blood vessels that supply oxygen-rich blood to the heart muscle. They run on the surface of the heart and branch into smaller vessels that feed the myocardium. They are commonly discussed when evaluating chest pain, shortness of breath, and heart attack risk. They are also central in cardiology imaging and procedures that restore blood flow to the heart.

Purkinje Fibers are specialized heart cells that rapidly carry electrical signals through the ventricles. They help the lower chambers contract in a coordinated way to pump blood effectively. Clinicians commonly discuss them when interpreting ECG findings or evaluating certain rhythm problems. They are part of the heart’s normal electrical “wiring,” not a device or medication.

The Left Bundle Branch is a key part of the heart’s electrical wiring system. It carries electrical signals from the center of the heart to the left ventricle. Clinicians often discuss it when interpreting an electrocardiogram (ECG/EKG) or evaluating conduction problems. It is also referenced in some pacing approaches that aim to restore coordinated heart contraction.

The Right Bundle Branch is a specialized electrical pathway inside the heart. It carries impulses from the atrioventricular (AV) node area to the right ventricle. It is most commonly discussed when interpreting an electrocardiogram (ECG/EKG) or evaluating a conduction problem such as bundle branch block.

His Bundle is a short segment of specialized heart tissue that carries electrical signals from the upper heart chambers to the lower chambers. It sits in the central part of the heart’s electrical “wiring,” near the atrioventricular (AV) node and the heart’s fibrous skeleton. Clinicians refer to His Bundle when interpreting rhythm problems and when planning certain electrophysiology procedures. It is also a target for a pacing approach called His Bundle pacing in selected patients who need a pacemaker.

The Bundle of His is a small pathway of specialized heart muscle cells that carries electrical signals from the upper to the lower chambers of the heart. It sits in the heart’s central “wiring” system between the atria and the ventricles. Clinicians reference it when explaining heart rhythm problems such as heart block or bundle branch block. It is also a target for certain pacing strategies designed to support a more natural pattern of ventricular activation.

The AV Node is a small cluster of specialized heart cells that helps control how electrical signals travel from the atria to the ventricles. It acts like a timing and filtering station between the upper and lower chambers of the heart. Clinicians talk about the AV Node when evaluating heart rhythm problems, slow heart rates, and certain types of rapid heartbeats. It is commonly referenced when interpreting an ECG, diagnosing heart block, or planning rhythm treatments.