Anatomy

Before diving into the different images with all sorts of obscure angles, it's best to try to familiarise yourself with the major arteries and where they are (LAD, LCx and RCA). When I started cath lab I found it helpful to keep the labelled images open on the computer next to me to compare to the real time imaging, and slowly stop relying on the computer to recognise which vessel is which. Get ready to be swept off your feet by the wonders of the heart!

Anatomy of the Heart

This is a great resource to understand how the heart looks in 3D, as you rotate it into different views. Try to correlate the anatomy with 2D imaging below!

Cardiac Anatomy: External view of human heart by HannahNewey on Sketchfab

Left Coronary Arteries

Typically, 5 views are used to visualize the LCA and the 2 main branches:

  • LAD (Left anterior diagonal) Diagonals and Septals
  • LCx (Left circumflex) Obtuse Marginals (OM)

LAD

Supplies anterior portion of LV (critical region) - usually imaged/checked first if possible.

♥ Cranial views elongate the LAD so it is shown running down towards the apex of the heart

  • Diagonals Branch off to the left
  • Septals Branch off to the right
LAD Images

LCx

Supplies left atrium and postero-lateral aspect of LV.

♥ Caudal views show the LCx running down the back of the heart.

The last image is called the 'spider view', which shows the ostium or beginning of the major vessels bifurcating from the LM (left main) - good for visualising proximal stenosis.

  • OM Branch off down
LCX Images

Normal Variants

  • Due to stenosis, smaller vessels may expand to compensate (e.g. septals appearing larger than the LAD)
  • There may be collateral connections between the left and right sides to compensate for stenosis
  • (LCx) If the OM comes off the LM directly, it is called a ramus instead
  • (LM) Some people have a very short LM that bifucrates almost immediately

Right Coronary Arteries

Typically, 3 views are used to visualize the RCA.

Conus

Tiny vessel that supplies blood to the infundibulum (conus) of the RV/right ventricular outflow tract

Acute Marginal

Wraps around front of heart, supplying right ventricle.

PLV and PDA

The RCA is simplier to understand, with fewer projections. You may notice a thicker PLV that is branching far to the left, supplying the LV - indicates right-sided dominance or issue with the left side.

  • PLV (Posterior Left Ventricular) Top
  • PDA (Posterior Descending Artery) Bottom
RCA Image

Cardiac Conduction System

How the heart conducts its own electrical impulses with a specialized network of cells!

Pathway of Electrical Conduction

SA node (right atrium, near the entrance of SVC)
AV node
Bundle of His
Right and left bundle branches
Purkinje fibers

Common Pathology

  • Arrythmia (bradycardia, tachycardia and atrial fibrillation)
  • Heart block (delay or complete block in the conduction of electrical impulses from the atria to the ventricles)