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Fibrillation
Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regard to the heart. Cardiology There are two major classes of cardiac fibrillation: atrial fibrillation and ventricular fibrillation. * Atrial fibrillation is an irregular and uncoordinated contraction of the cardiac muscle of atria. It can be a chronic condition, usually treated with anticoagulation and sometimes with conversion to normal sinus rhythm. In this condition the normal electrical pulses coming from the sinoatrial node are overwhelmed by disorganized electrical impulses usually originating in the roots of the pulmonary veins, leading to irregular conduction of impulses to the ventricles which generate the heartbeat. * Ventricular fibrillation is an irregular and uncoordinated contraction of the cardiac muscle of ventricles. It is a common cause of cardiac arrest and is usually fatal if not reversed by defibrillation. Fibrillation may sometimes b ... [...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] |
Ventricular Fibrillation
Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the Ventricle (heart), ventricles of the heart Fibrillation, quiver. It is due to disorganized electrical conduction system of the heart, electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and no pulse. This is followed by sudden cardiac death in the absence of treatment. Ventricular fibrillation is initially found in about 10% of people with cardiac arrest. Ventricular fibrillation can occur due to coronary heart disease, valvular heart disease, cardiomyopathy, Brugada syndrome, long QT syndrome, electric shock, or intracranial hemorrhage. Diagnosis is by an electrocardiogram (ECG) showing irregular unformed QRS complexes without any clear P wave (electrocardiography), P waves. An important differential diagnosis is torsades de pointes. Treatment is with cardiopulmonary resuscitation (CPR) and defibrillation. Defibrillation#Change to a biphasic waveform, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defibrillation
Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). Defibrillation delivers a dose of electric current (often called a ''counter-shock'') to the heart. Although not fully understood, this process depolarizes a large amount of the heart muscle, ending the arrhythmia. Subsequently, the body's natural pacemaker in the sinoatrial node of the heart is able to re-establish normal sinus rhythm. A heart which is in asystole (flatline) cannot be restarted by defibrillation; it would be treated only by cardiopulmonary resuscitation (CPR) and medication, and then by cardioversion or defibrillation if it converts into a shockable rhythm. A device that administers defibrillation is called a defibrillator. In contrast to defibrillation, synchronized electrical cardioversion is an electrical shock delivered in synchrony to the cardiac cycle. Although the person may still ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Arrest
Cardiac arrest (also known as sudden cardiac arrest [SCA]) is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the brain and other organs is decreased. When the brain does not receive enough blood, this can cause a person to lose consciousness and brain cells can start to die due to lack of oxygen. Coma and persistent vegetative state may result from cardiac arrest. Cardiac arrest is also identified by a lack of Pulse, central pulses and respiratory arrest, abnormal or absent breathing. Cardiac arrest and resultant hemodynamic collapse often occur due to arrhythmias (irregular heart rhythms). Ventricular fibrillation and ventricular tachycardia are most commonly recorded. However, as many incidents of cardiac arrest occur out-of-hospital or when a person is not having their cardiac activity monitored, it is difficult to identify the specific mechanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Arrhythmia
Arrhythmias, also known as cardiac arrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be lightheadedness, passing out, shortness of breath, chest pain, or decreased level of consciousness. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in sudden death. Arrhythmias are often categorized into four groups: extra beats, supraventricular tachycardias, ventricular arrhythmias and bradyarrhythmias. Extra beats incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardioversion
Cardioversion is a medical procedure by which an abnormally fast heart rate (tachycardia) or other cardiac arrhythmia is converted to a normal rhythm using electricity or drugs. Synchronized electrical cardioversion uses a therapeutic dose of electric current to the heart at a specific moment in the cardiac cycle, restoring the activity of the electrical conduction system of the heart. ( Defibrillation uses a therapeutic dose of electric current to the heart at a random moment in the cardiac cycle, and is the most effective resuscitation measure for cardiac arrest associated with ventricular fibrillation and pulseless ventricular tachycardia.) Pharmacologic cardioversion, also called chemical cardioversion, uses antiarrhythmia medication instead of an electrical shock. Electrical To perform synchronized electrical cardioversion, two electrode pads are used (or, alternatively, the traditional hand-held "paddles"), each comprising a metallic plate which is faced with a saline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Veins
The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation. Structure There are four main pulmonary veins, two from each lung – an inferior and a superior main vein, emerging from each hilum. The main pulmonary veins receive blood from three or four feeding veins in each lung, and drain into the left atrium. The peripheral feeding veins do not follow the bronchial tree. They run between the pulmonary segments from which they drain the blood. At the root of the lung, the right superior pulmonary vein lies in front of and a little below the pulmonary artery; the inferior is situated at the lowest part of the lung hilum. Behind the pulmonary artery is the bronchus. The right main pulmonary veins (contains oxygenated blood) pass behind the right atrium a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the thorax, chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right Atrium (heart), atria and lower left and right Ventricle (heart), ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent cardiac regurgitation, backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrium (heart)
The atrium (; : atria) is one of the two Heart#Chambers, upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the Ventricle (heart), heart ventricles through the atrioventricular valve, atrioventricular mitral valve, mitral and tricuspid valve, tricuspid heart valves. There are two atria in the human heart – the left atrium receives blood from the pulmonary circulation, and the right atrium receives blood from the venae cavae of the systemic circulation. During the cardiac cycle, the atria receive blood while relaxed in diastole, then contract in systole to move blood to the ventricles. Each atrium is roughly cube-shaped except for an ear-shaped projection called an atrial appendage, previously known as an auricle. All animals with a closed circulatory system have at least one atrium. The atrium was formerly called the 'auricle'. That term is still used to describe this chamber in some other animals, such as the ''Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In computer science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction. Clinical uses EMG testing has a varie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
