Regional Perfusion of the LV
The ventricle is divided into segments for regional wall assessment. Segmentation schemes reflect coronary perfusion territories result in segments with comparable myocardial mass, and allow standardized communication within echocardiography and with other imaging modalities. Currently there are 17 segments used in regional wall assessment and out of the scope for FoCUS interrogation since multiple chamber views are needed. However they are mentioned here for illustration purposes
As a reminder, the objectives of FoCUS here is to do semiquantification of ranges of function (e.g., the left ventricle is hyperkinetic, normokinetic, hypokinetic, or severely hypokinetic).
1A. Coronary perfusion model: 3D overview
The right coronary artery (RCA) originates from the right aspect of the aortic bulb. The RCA gives of the Right Marginal Artery (RMA) which supplies the entire right ventricle. The RCA gives off the Posterior Descending Artery (PDA).
The left main coronary artery branches into the left anterior descending artery (LAD) and the left circumflex coronary artery (Cx). The LAD gives off the Diagonal (D1) branches which supply the anterior and anterolateral walls of the left ventricle. The Cx give off the obtuse marginal arteries (M1) which supply the lateral wall of the left ventricle
3D model showing major coronary arteries. Images created with the use of Z-anatomy.
1B. Coronary perfusion territories
The LV is divided into base mid and apex while on the parasternal short axis view. The following images represent our current model of perfusion.
Coronary perfusion territories. On the right, the cuts obtained depending on the level of the short axis; base, mid or apex. We will concern ourselves with the midventricular walls for a focused cardiac assessment. Notice that the anterolateral (AL) papillary muscle is perfused by two vessels while the posteromedial (PM) is only perfused by one in this model. RCA is the right coronary artery, the LAD is the Left anterior descending artery and the Circ or Cx is the Circumflex artery.
2. Segmentation model
The LV is divided into base, mid and apex while on the parasternal short axis view. Regional wall can thus occur at each of the segments walls.