The anterior interventricular branch of left coronary artery, (also left anterior descending artery (LAD), or anterior descending branch) is a branch of the left coronary artery. Occlusion of this artery is often called the widow-maker infarction.
Video Anterior interventricular branch of left coronary artery
Structure
It passes at first behind the pulmonary artery and then comes forward between that vessel and the left atrium to reach the anterior interventricular sulcus, along which it descends to the notch of cardiac apex.
Although rare, multiple anomalous courses of the LAD have been described. These include the origin of the artery from the right aortic sinus.
In 78% of cases, it reaches the apex of the heart.
Branches
The LAD gives off two types of branches: septals and diagonals.
- Septals originate from the LAD at 90 degrees to the surface of the heart, perforating and supplying the anterior 2/3rds of the interventricular septum.
- Diagonals run along the surface of the heart and supply the lateral wall of the left ventricle and the anterolateral papillary muscle.
Maps Anterior interventricular branch of left coronary artery
Function
The artery supplies the anterolateral myocardium, apex, and interventricular septum. The LAD typically supplies 45-55% of the left ventricle (LV) and is therefore considered the most critical vessel in terms of myocardial blood supply.
Widow maker
The widow maker is an alternate name for the anterior interventricular branch of the left coronary artery. The name widow maker may also apply to the left coronary artery or severe occlusions to that artery.
This term is used because the left main coronary and/or the left anterior descending supply blood to large areas of the heart. This means that if these arteries are abruptly and completely occluded it will cause a massive heart attack that will likely lead to sudden death. The blockage that kills is made up of platelets streaming to the site of a ruptured cholesterol plaque. Even a small amount of plaque in this area can (for a variety of poorly understood reasons) rupture and cause death; bypassing chronic blockages or trying to open them up with angioplasty does not prevent heart attack but it can restore blood flow in case of a sudden blockage or heart attack and if performed within a rapid time period can minimize the damage done. An example of the devastating results of a complete occlusion of the LAD artery was the sudden death of former NBC News Washington Bureau Chief Tim Russert.
From the minute a widow maker heart attack hits, survival time ranges from minutes to several hours. Rapidly progressing symptoms should signal the need for immediate attention. Symptoms of initial onset may include nausea, shortness of breath, pain in the head, jaw, arms or chest, numbness in fingers, often of a novel but imprecise sensation which builds with irregular heart beat. Early symptoms may be mistaken for food poisoning, flu or general malaise until they intensify. A widow maker cannot kill instantly but induces cardiac arrest which may do so within 10 to 20 minutes of no circulation. A victim with no pulse or breath is still alive, living off oxygen stored in the blood and may be able to be rescued if treatment is begun promptly within this window.
Additional images
References
This article incorporates text in the public domain from page 547 of the 20th edition of Gray's Anatomy (1918)
External links
- Anatomy photo:20:09-0102 at the SUNY Downstate Medical Center - "Heart: The Left Coronary Artery and its Branches"
- Anatomy figure: 20:03-08 at Human Anatomy Online, SUNY Downstate Medical Center - "Anterior view of the heart."
Source of the article : Wikipedia
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