Branches from the left main arteryMain vessels carrying blood from the heart; the arteries have minimal elasticity and contain approximately 20% of the blood supply. Major Vessels 1. Six Second ECG Guidebook (2012), T Barill, p. 15, 190 and wraps the left ventricleThe left ventricle ejects blood into the aortic arch to the body. Within the arch, the coronary arteries branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian artery). The chambers... travelling between the left ventricle and the left atriaRight and left atria (1/3 volume and muscle mass of the ventricles) pump blood to the ventricles. Chambers and Layers of the Heart 1. Six Second ECG Guidebook (2012), T Barill, p. 190 along the epicardial surface of the heart.
Coronary ArteriesThe coronary arteries provide blood to the heart tissues, carrying blood first across the epicardium, then the myocardium and finally terminating in the endocardium. The epicardium forms the outer layer of the heart. The myocardium forms the middle layer and...
In order to beat over 100,000 times daily, the heart muscle requires a substantial blood and oxygen supply. The coronary arteries distribute the oxygen and nutrients necessary to provide energy to meet the workload demands of the heart. Even at rest, the cardiac cells extract 75% of the oxygen from the coronary arteries to meet energy demands. Essentially, the heart is entirely dependant on increased coronary artery blood flowThe purpose of the cardiac cycle is to effectively pump blood. The purpose of the cardiac cycle is to effectively pump blood. The right heart delivers deoxygenated blood to the lungs. Here oxygen is picked up and carbon dioxide is... to meet any increases in cardiac workload.
About 4-5% of the body’s blood volume is contained by the heart’s arteries and veinsBlood vessels that carry blood to the heart.. This is a large volume considering that the heart comprises less than 1% of an adult’s body mass. The heart’s blood supply is provided mostly as the heart relaxes and dilates during diastoleThe phase of relaxation during the cardiac cycle; occurs for the atria and the ventricles; blood enters the heart’s chambers and the coronary arteries during diastole; note that diastole is as important as systole – the negative pressure created by.... This is unique – most organs receive pulsations of new oxygen-rich blood during cardiac systoleA contraction phase of the cardiac cycle; systole takes about 1/3 of the time of the cardiac cycle (2/3 of the time is taken by diastole). A complete cardiac cycle occurs with each audible ‘lub-dub’ that is heard with a... (contractile phase of the heart).
The quantity of blood circulating through the coronary arteries is directly related to the coronary perfusion pressure, the difference between aortic diastolic pressure and central venous pressure (right atrial pressure). During events with increased central venous pressure and lower aortic diastolic pressure (i.e. right ventricular infarctionThe necrosis of tissue; acute myocardial infarction involves the acute death of myocardial cells. 1. Six Second ECG Guidebook (2012), T Barill, p. 198) coronary perfusion often suffers.
The right coronary arteryBranches from the aorta near the aortic valve and serves the right ventricle, the AV node (90% of the time), and part of the posterior aspect of the left ventricle. In order to beat over 100,000 times daily, the heart... (RCA), sprouts off of the aortaBegins with the aortic valve, the largest main vessel that carries oxygenated blood from the ventricles to the body. Major Vessels 1. Six Second ECG Guidebook (2012), T Barill, p. 15, 190 superior to the aortic valve, primarily serving the right ventricleThe right ventricle ejects blood through the main branches of the left and right pulmonary arteries to the lungs. The chambers of the heart are the main drivers within an intricate pathway, delivering blood to the lungs for gas exchange... and the right atria. In about 50% of the population, the RCA branches early on to form the conus artery to further serve the right side of the heart. The RCA serves the right ventricle, the right atrium, the SA nodeThe SA node, usually the dominant pacemaker, is located in the right atrium at the opening of the superior vena cava. The SA (sinoatrial) node is a clump of hundreds of specialized cardiac cells that have the ability to self-initiate... (50-60% of people) and the AV nodeIs located in the inferior aspect of the right atria; functions to slow the conduction speed to allow for atrial conduction prior to ventricular conduction (atrial kick); also serves as a pacemaker if the SA node fails to fire. The... (90% of people). Note that the AV node and the bundle of HisPart of the AV junction, the bundle of His conducts the impulse through the fibrous plate that separates the atria and the ventricle; the bundle of His is also a pacemaker, firing at 40-60/minute. The bundle of His serves as... are often served by both the RCA and the circumflex artery.
The left main begins at the left border of the aorta opposite the entrance to the RCA. The left main soon splits into 2 arteries: 1) the circumflex wraps around the surface of the left heart; and 2) the left anterior descending artery travels down the anterior surface of the left ventricle. The circumflex also serves the SA node (40-50% of people) and the AV node (10% of people).
The coronary veins exit into the right atrium via the coronary sinusThe common venous outlet into the right atria that drains the heart’s venous system from the coronary arteries. Six Second ECG Guidebook (2012), T Barill, p. 194. A one-way valve covers the coronary sinus, called the Thebesian valve (now this is definitely trivia).
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 14-15, 194