My first blog!

Heart + Coronary Artery Anatomy

The heart is slightly larger than a clenched fist and located in the chest (duhhh!). It consists of endocardium (endothelium), myocardium (muscle) and epicardium (mesothelium). There are two atria, two ventricles, separated by a fibrous skeleton, which keeps the valves patent, provides attachments for parts of the valves and the myocardium and electrically isolates the ventricles from the atria to facilitate proper contraction. It has four surfaces, sternocostal, diaphragmatic and right and left pulmonary surfaces. There are four valves (aortic, pulmonary, tricuspid and mitral) of which, the mitral and tricuspid are anchored by papillary muscles and chordae tendineae to prevent backflow into the atria. The upper border of the heart corresponds to a line connecting the inferior border of the second left costal cartilage to the superior border of the right third costal cartilage. The right border is a line connecting the third right costal cartilage to the sixth right costal cartilage. The inferior border is a line connecting the inferior of the right border to a point in the fifth intercostal space close the left MCL. The left border connects the inferior and superior. The apex should be in the fifth intercostal space MCL.

The heart is supplied by the coronary arteries, which can be varied in position and supply, thay are the first branch of the aorta and consist of left and right coronary arteries, which take separate routes around the pulmonary trunk. The right coronary artery originates at the right aortic sinus and passes right of the pulmonary trunk, giving a branch to the sino-atrial node (60% of the time). It than travles in the coronary groove, giving the right marginal branch to supply the right border of the heart. It then continues to the posterior aspect of the heart giving a branch to the AV node. In the majority (67%) the right will give the posterior interventricular branch making it the dominant artery. In conclusion, the RCA supplies the right atrium, most of right ventricle, part of the left ventricle, part of the IV septum, and the SA and AV nodes. The left coronary artery arises from the left aortic sinus, passing left of the pulmonary trunk and into the coronary groove. In 40% of people it will supply the SA node, while it also divides into the left descending and circumflex branches, with the former dividing again into the anterior Iv and lateral diagonal branches, while the circumflex gives a left marginal branch, and in one third of people will continue to form the posterior IV, making it the dominant artery. The LCE therefore, supplies the left atrium, most of the left ventricle, part of the right ventricle most of the IVS and occasionally the SA node. Hearts are 67% right dominant, 15% left dominant and 18% co-dominant.

Hope you are confused, because I most certainly am. Pictures help, this all came from Moore and Dalley which did a great job.

Angiography

This is done by inserting dye into the coronary arteries via a catheter inserted in femoral or brachial arteries. Radio-opaque dye is injected and radiographs are taken to determine the paths and any blockage or stenotic areas of the vessels. Pretty simple?

For video: http://ccal.stanford.edu/case/case16/movie16_3.html