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Left Posterior Fascicular Block
A left posterior fascicular block (LPFB), also known as left posterior hemiblock (LPH), is a condition where the left posterior fascicle, which travels to the inferior and posterior portion of the left ventricle, does not conduct the electrical impulses from the atrioventricular node. The wave-front instead moves more quickly through the left anterior fascicle and right bundle branch, leading to a right axis deviation seen on the ECG. Definition The American Heart Association has defined a LPFB as: * Frontal plane axis between 90° and 180° in adults * rS pattern in leads I and aVL * qR pattern in leads III and aVF * QRS duration less than 120 ms The broad nature of the posterior bundle as well as its dual blood supply makes isolated LPFB rare. See also * Left bundle branch block * Left anterior fascicular block Left anterior fascicular block (LAFB) is an abnormal condition of the left ventricle of the heart, related to, but distinguished from, left bundle branch block (LBBB) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left Posterior Fascicle
The bundle branches, or Tawara branches, are offshoots of the bundle of His in the heart's Ventricle (heart), ventricle. They play an integral role in the electrical conduction system of the heart by transmitting cardiac action potentials from the bundle of His to the Purkinje fibers. Structure There are two branches of the bundle of His: the left bundle branch and the right bundle branch, both of which are located along the interventricular septum. The left bundle branch further divides into the left anterior fascicle and the left posterior fascicle. These structures lead to a network of thin filaments known as Purkinje fibers. They play an integral role in the electrical conduction system of the heart by transmitting cardiac action potentials to the Purkinje fibers. Clinical significance When a bundle branch or their fascicles becomes injured (by underlying heart disease, myocardial infarction, or cardiac surgery), it may cease to conduct electrical impulses appropriately, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Conduction System Of The Heart
The cardiac conduction system (CCS) (also called the electrical conduction system of the heart) transmits the signals generated by the sinoatrial node – the heart's pacemaker, to cause the heart muscle to contract, and pump blood through the body's circulatory system. The pacemaking signal travels through the right atrium to the atrioventricular node, along the bundle of His, and through the bundle branches to Purkinje fibers in the walls of the ventricles. The Purkinje fibers transmit the signals more rapidly to stimulate contraction of the ventricles. The conduction system consists of specialized heart muscle cells, situated within the myocardium. There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular heart rhythms including rhythms that are too fast or too slow. Structure Electrical signals arising in the SA node (located in the right atrium) stimulate the atr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrioventricular Node
The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, and conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm).Full Size Picture triangle of-Koch.jpg Retrieved on 2008-12-22 Structure Location The AV node lies at the lower back section of the |
Left Anterior Fascicle
The bundle branches, or Tawara branches, are offshoots of the bundle of His in the heart's ventricle. They play an integral role in the electrical conduction system of the heart by transmitting cardiac action potentials from the bundle of His to the Purkinje fibers. Structure There are two branches of the bundle of His: the left bundle branch and the right bundle branch, both of which are located along the interventricular septum. The left bundle branch further divides into the left anterior fascicle and the left posterior fascicle. These structures lead to a network of thin filaments known as Purkinje fibers. They play an integral role in the electrical conduction system of the heart by transmitting cardiac action potentials to the Purkinje fibers. Clinical significance When a bundle branch or their fascicles becomes injured (by underlying heart disease, myocardial infarction, or cardiac surgery), it may cease to conduct electrical impulses appropriately, resulting in alte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Heart Association
The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and deaths caused by cardiovascular disease and stroke. Originally formed in New York City in 1924, it is currently headquartered in Dallas, Texas. The American Heart Association is a national voluntary health agency. They are known for publishinguidelineson cardiovascular disease and prevention, standards on basic life support, advanced cardiac life support (ACLS), and pediatric advanced life support (PALS), and in 2014 issued its first guidelines for preventing strokes in women. They are known also for operating a number of highly visible public service campaigns starting in the 1970s, and also operate a number of fundraising events. In 1994, the ''Chronicle of Philanthropy'', an industry publication, released a study that showed the American H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left Bundle Branch Block
Left bundle branch block (LBBB) is a conduction abnormality in the heart that can be seen on an electrocardiogram (ECG). In this condition, activation of the left ventricle of the heart is delayed, which causes the left ventricle to contract later than the right ventricle. Causes Among the causes of LBBB are: * Aortic stenosis * Dilated cardiomyopathy * Acute myocardial infarction * Extensive coronary artery disease * Primary disease of the cardiac electrical conduction system * Long standing hypertension leading to aortic root dilatation and subsequent aortic regurgitation * Lyme disease Mechanisms Slow or absent conduction through the left bundle branch means that it takes longer than normal for the left ventricle to fully depolarise. This can be due to a damaged bundle branch that is completely unable to conduct, but may represent intact conduction that is slower than normal. LBBB may be fixed, present at all times, but may be intermittent for example occurring only durin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left Anterior Fascicular Block
Left anterior fascicular block (LAFB) is an abnormal condition of the left ventricle of the heart, related to, but distinguished from, left bundle branch block (LBBB). It is caused by only the left anterior fascicle – one half of the left bundle branch being defective. It is manifested on the ECG by left axis deviation. It is much more common than left posterior fascicular block. Mechanism Normal activation of the left ventricle (LV) proceeds down the left bundle branch, which consist of three fascicles, the left anterior fascicle, the left posterior fascicle, and the septal fascicle. The posterior fascicle supplies the posterior and inferoposterior walls of the LV, the anterior fascicle supplies the upper and anterior parts of the LV and the septal fascicle supplies the septal wall with innervation. LAFB — which is also known as left anterior hemiblock (LAHB) — occurs when a cardiac impulse spreads first through the left posterior fascicle, causing a delay in activation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
