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Wandering Pacemaker
Wandering atrial pacemaker (WAP) is an atrial rhythm where the pacemaking activity of the heart originates from different locations within the atria. This is different from normal pacemaking activity, where the sinoatrial node (SA node) is responsible for each heartbeat and keeps a steady rate and rhythm. Causes of wandering atrial pacemaker are unclear, but there may be factors leading to its development. It is often seen in the young, the old, and in athletes, and rarely causes symptoms or requires treatment. Diagnosis of wandering atrial pacemaker is made by an ECG. Pathophysiology The SA node is considered the primary pacemaker of the heart. In wandering atrial pacemaker, there are other locations within the atria besides the SA node that are responsible for each heartbeat. This is unusual because the SA node, AV node, bundle of His, bundle branches, and Purkinje fibers are the structures that have pacemaking capability. The atrial and ventricular muscle tissue do not hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiology
Cardiology () is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a sub-specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery. Specializations All cardiologists in the branch of medicine study the disorders of the heart, but the study of adult and child heart disorders each require different training pathways. Therefore, an adult cardiologist (often simply called "cardiologist") is inadequately trained to take care of children, and pediatric cardiologists are not trained to treat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier Science Direct
ScienceDirect is a searchable web-based bibliographic database, which provides access to full texts of scientific and medical publications of the Dutch publisher Elsevier as well of several small academic publishers. It hosts over 18 million publications from more than 4,000 academic journals and 30,000 e-books. The access to the full-text requires subscription, while the bibliographic metadata are free to read. ScienceDirect was launched by Elsevier in March 1997. Usage The journals are grouped into four main sections: *''Physical Sciences and Engineering'' *''Life Sciences'' *''Health Sciences'' *''Social Sciences and Humanities''. Article abstracts are freely available, and access to their full texts (in PDF and, for newer publications, also HTML) generally requires a subscription or pay-per-view purchase unless the content is freely available in open access. Papers published under several open access licenses are available on ScienceDirect without cost. Access to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PR Interval
In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200 ms in duration. The PR interval is sometimes termed the PQ interval. Interpretation Variations in the PQ interval can be associated with certain medical conditions: * Duration ** A long PR interval (of over 200 ms) indicates a slowing of conduction between the atria and ventricles, usually due to slow conduction through the atrioventricular node (AV node). This is known as first degree heart block. Prolongation can be associated with fibrosis of the AV node, high vagal tone, medications that slow the AV node such as beta-blockers, hypokalemia, acute rheumatic fever, or carditis associated with Lyme disease. ** A short PR interval (of less than 120ms) may be associated with a Pre-excitation synd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinus Rhythm
A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. It is necessary, but not sufficient, for normal electrical activity within the heart. On the electrocardiogram (ECG), a sinus rhythm is characterised by the presence of P waves that are normal in morphology. The term normal sinus rhythm (NSR) is sometimes used to denote a specific type of sinus rhythm where all other measurements on the ECG also fall within designated normal limits, giving rise to the characteristic appearance of the ECG when the electrical conduction system of the heart is functioning normally; however, other sinus rhythms can be entirely normal in particular patient groups and clinical contexts, so the term is sometimes considered a misnomer and its use is sometimes discouraged. Other types of sinus rhythm that can be normal include sinus tachycardia, sinus bradycardia, and sinus arrhythmia. Sinus rhythms may be present together with various othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P Wave (electrocardiography)
In cardiology, the P wave on an Electrocardiography, electrocardiogram (ECG) represents atrial depolarization, which results in atrial contraction, or systole#Atrial systole, atrial systole. Physiology The P wave is a summation wave generated by the depolarization front as it transits the atria. Normally the right atrium depolarizes slightly earlier than left atrium since the depolarization wave originates in the sinoatrial node, in the high right atrium and then travels to and through the left atrium. The depolarization front is carried through the atria along semi-specialized conduction pathways including Bachmann's bundle resulting in uniform shaped waves. Depolarization originating elsewhere in the atria (atrial ectopics) result in P waves with a different morphology from normal. Pathology Peaked P waves (> 0.25 mV) suggest right atrial enlargement, cor pulmonale, (''P pulmonale'' rhythm), but have a low predictive value (~20%). A P wave with increased amplitude can in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Rhythm
''Heart Rhythm'' is a peer-reviewed medical journal published by Elsevier that covers the study and management of cardiac arrhythmia. It is the official journal of the Heart Rhythm Society, the Cardiac Electrophysiology Society, and thPediatric & Congenital Electrophysiology Society Its major focus is research and therapy of heart rhythm disorders, including mechanisms and electrophysiology, clinical and experimental, genetics, ablation, devices, drugs, and surgery. Other sections include contemporary reviews, unique case reports, viewpoints, Hands On, images, creative concepts, and editorial commentaries. New sections in 2024 include Iconic Figures and Top Stories. History The first issue of ''Heart Rhythm'' was published in May 2004 with Douglas Zipes, MD, FHRS, as the founding editor in chief. The Editor-in-Chief from 2014-2023 was Peng-Sheng Chen, MD, FHRS. The Editor-in-Chief since January 2024 is Sami Viskin, MD. The companion journals to ''Heart Rhythm'' are '' HeartRh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Family Physician
''American Family Physician'' (''AFP'') is the editorially independent, peer-reviewed and evidence-based medical journal published by the American Academy of Family Physicians. Published continuously since 1950, each issue delivers concise, easy-to-read clinical review articles for physicians and other health care professionals. The journal is published monthly in print, online, and app formats. It is mailed to an audience of more than 180,000 family medicine and other primary care physicians and health care professionals and viewed online by more than 2.5 million unique visitors monthly. The predecessor to ''American Family Physician'' was the journal ''GP'', an acronym for "General Practitioner". ''GP'' was first published in 1950 by the American Academy of General Practice, which was the predecessor organization to the American Academy of Family Physicians. See also *'' JAMA'' *''The New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrial Fibrillation
Atrial fibrillation (AF, AFib or A-fib) is an Heart arrhythmia, abnormal heart rhythm (arrhythmia) characterized by fibrillation, rapid and irregular beating of the Atrium (heart), atrial chambers of the heart. It often begins as short periods of abnormal cardiac cycle, beating, which become longer or continuous over time. It may also start as other forms of arrhythmia such as atrial flutter that then transform into AF. Episodes can be asymptomatic. Symptomatic episodes may involve heart palpitations, syncope (medicine), fainting, Presyncope, lightheadedness, Unconsciousness, loss of consciousness, or shortness of breath. Atrial fibrillation is associated with an increased risk of heart failure, dementia, and stroke. It is a type of supraventricular tachycardia. Atrial fibrillation frequently results from bursts of tachycardia that originate in muscle bundles extending from the Atrium (heart), atrium to the pulmonary veins. Pulmonary vein isolation by catheter ablation, trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digoxin Toxicity
Digoxin toxicity, also known as digoxin poisoning, is a type of poisoning that occurs in people who take too much of the medication digoxin or eat plants such as foxglove that contain a similar substance. Symptoms are typically vague. They may include vomiting, loss of appetite, confusion, blurred vision, changes in color perception, and decreased energy. Potential complications include an irregular heartbeat, which can be either too fast or too slow. Toxicity may occur over a short period of time following an overdose or gradually during long-term treatment. Risk factors include low potassium, low magnesium, and high calcium. Digoxin is a medication used for heart failure or atrial fibrillation. An electrocardiogram is a routine part of diagnosis. Blood levels are only useful more than six hours following the last dose. Activated charcoal may be used if it can be given within two hours of the person taking the medication. Atropine may be used if the heart rate is slow wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinus Node Dysfunction
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart rates. Signs and symptoms Often sinus node dysfunction produces no symptoms, especially early in the disease course. Signs and symptoms usually appear in more advanced disease and more than 50% of patients will present with syncope or transient near-fainting spells as well as bradycardias that are accompanied by rapid heart rhythms, referred to as tachycardia-bradycardia syndrome Other presenting signs or symptoms can include confusion, fatigue, palpitations, chest pain, shortness of breath, headache, and nausea. Patients can also present with symptoms of congestive heart failure, stroke or transient ischemic attacks due to the abnormal rhythm. Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibers and serves as a major pathway that connects the brain to various organs, including the heart, lungs, and digestive tract. As a key part of the parasympathetic nervous system, the vagus nerve helps regulate essential involuntary functions like heart rate, breathing, and digestion. By controlling these processes, the vagus nerve contributes to the body's "rest and digest" response, helping to calm the body after stress, lower heart rate, improve digestion, and maintain homeostasis. The vagus nerve consists of two branches: the right and left vagus nerves. In the neck, the right vagus nerve contains approximately 105,000 fibers, while the left vagus nerve has about 87,000 fibers, according to one source. However, other sources report sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
