|
Premature Heart Beat
A premature heart beat or extrasystole is a heart rhythm disorder corresponding to a premature contraction of one of the chambers of the heart. Premature heart beats come in two different types: premature atrial contractions and premature ventricular contractions. Often they cause no symptoms but may present with fluttering in the chest or a skipped beat. They typically have no long-term complications. They most often happen naturally but may be associated with caffeine, nicotine, or stress. Usually no treatment is needed. They are the most common arrhythmia. Physiopathology The normal heart contraction comes from a cyclic membrane depolarization (reversal of the electrical polarity of the cell membrane) of a group of cells located on the upper part of the right atrium, the sinoatrial node. This depolarization spreads to the whole heart and causes muscle cells to contract. It is followed by a "refractory period", a short time when the cells are no longer stimulable. The heart ... [...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] |
ExtraSystole
A premature heart beat or extrasystole is a heart rhythm disorder corresponding to a premature contraction of one of the chambers of the heart. Premature heart beats come in two different types: premature atrial contractions and premature ventricular contractions. Often they cause no symptoms but may present with fluttering in the chest or a skipped beat. They typically have no long-term complications. They most often happen naturally but may be associated with caffeine, nicotine, or stress. Usually no treatment is needed. They are the most common arrhythmia. Physiopathology The normal heart contraction comes from a cyclic membrane depolarization (reversal of the electrical polarity of the cell membrane) of a group of cells located on the upper part of the right atrium, the sinoatrial node. This depolarization spreads to the whole heart and causes muscle cells to contract. It is followed by a "refractory period", a short time when the cells are no longer stimulable. The heart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Ventricular Contraction
A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger. The electrical events of the heart detected by the electrocardiogram (ECG) allow a PVC to be easily distinguished from a normal heart beat. However, very frequent PVCs can be symptomatic of an underlying heart condition (such as arrhythmogenic right ventricular cardiomyopathy). Furthermore, very frequent (over 20% of all heartbeats) PVCs are considered a risk factor for arrhythmia-induced cardiomyopathy, in which the heart muscle becomes less effective and symptoms of heart failure may develop. Ultrasound of the heart is therefore recommended in people with frequent PVCs. If PVCs are frequent or troublesome, medication (beta blockers or certain calcium channel blockers) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Atrial Contraction
Premature atrial contraction (PAC), also known as atrial premature complexes (APC) or atrial premature beats (APB), are a common arrhythmia characterized by premature heartbeats originating in the atria. While the sinoatrial node typically regulates the heartbeat during normal sinus rhythm, PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat, in contrast to escape beats, in which the normal sinoatrial node fails, leaving a non-nodal pacemaker to initiate a late beat. The exact cause of PACs is unclear; while several predisposing conditions exist, single isolated PACs commonly occur in healthy young and elderly people. Elderly people that get PACs usually don't need any further attention besides follow-ups due to unclear evidence. PACs are often completely asymptomatic and may be noted only with Holter monitoring, but occasionally they can be perceived as a skipped beat or a jolt in the chest. In mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holter Monitor
In medicine, a Holter monitor (often simply Holter) is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring (the monitoring of the electrical activity of the cardiovascular system) for at least 24 hours. The Holter's most common use is for monitoring ECG heart activity (electrocardiography or ECG). Its extended recording period is sometimes useful for observing occasional cardiac arrhythmias which would be difficult to identify in a shorter period. For patients having more transient symptoms, a cardiac event monitor which can be worn for a month or more can be used. When used to study the heart, much like standard electrocardiography, the Holter monitor records electrical signals from the heart via a series of electrodes attached to the chest. Electrodes are placed over bones to minimize artifacts from muscular activity. The number and position of electrodes varies by model, but most Holter monitors employ between three and eight. These e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Doppler Imaging
Laser Doppler imaging (LDI) is an imaging method that uses a laser beam to image live tissue. When the laser light reaches the tissue, the moving blood cells generate Doppler components in the reflected ( backscattered) light. The light that comes back is detected using a photodiode that converts it into an electrical signal. Then the signal is processed to calculate a signal that is proportional to the tissue perfusion in the imaged area. When the process is completed, the signal is processed to generate an image that shows the perfusion on a screen. The laser Doppler effect was first used to measure microcirculation by Stern M.D. in 1975. It is used widely in medicine, some representative research work about it are these: Use in ophthalmology The eye offers a unique opportunity for the non-invasive exploration of cardiovascular diseases. LDI by digital holography can measure blood flow in the retina and choroid. In particular, the choroid is a highly vascularized tissue supply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrocardiography
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including: * Cardiac rhythmicity, Cardiac rhythm disturbances, such as atrial fibrillation and ventricular tachycardia; * Inadequate coronary artery blood flow, such as myocardial ischemia and myocardial infarction; * and electrolyte disturbances, such as hypokalemia. Traditionally, "ECG" usually means a 12-lead ECG taken while lying down as discussed below. However, other devices can record the electrical activity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse
In medicine, the pulse refers to the rhythmic pulsations (expansion and contraction) of an artery in response to the cardiac cycle (heartbeat). The pulse may be felt ( palpated) in any place that allows an artery to be compressed near the surface of the body close to the skin, such as at the neck ( carotid artery), wrist (radial artery or ulnar artery), at the groin (femoral artery), behind the knee ( popliteal artery), near the ankle joint ( posterior tibial artery), and on foot (dorsalis pedis artery). The pulse is most commonly measured at the wrist or neck for adults and at the brachial artery (inner upper arm between the shoulder and elbow) for infants and very young children. A sphygmograph is an instrument for measuring the pulse. Physiology Claudius Galen was perhaps the first physiologist to describe the pulse. The pulse is an expedient tactile method of determination of systolic blood pressure to a trained observer. Diastolic blood pressure is non-palpable and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palpitations
Palpitations occur when a person becomes aware of their heartbeat. The heartbeat may feel hard, fast, or uneven in their chest. Symptoms include a very fast or irregular heartbeat. Palpitations are a sensory symptom. They are often described as a skipped beat, a rapid flutter, or a pounding in the chest or neck. Palpitations are not always the result of a physical problem with the heart and can be linked to anxiety. However, they may signal a arrhythmia, fast or irregular heartbeat. Palpitations can be brief or long-lasting. They can be intermittent or continuous. Other symptoms can include dizziness, shortness of breath, sweating, headaches, and chest pain. There are a variety of causes of palpitations not limited to the following: Palpitation may be associated with coronary artery disease, coronary heart disease, perimenopause, hyperthyroidism, adult heart muscle diseases like hypertrophic cardiomyopathy, congenital heart diseases like atrial septal defects, diseases causing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Heart Beat Revealed By Laser Doppler Holography Of The Eye Fundus , a horror short story by American writer Edgar Allan Poe, published in 1844.
*
*
{{disambig ...
Premature may refer to: * ''Premature'' (2014 film), an American comedy film * ''Premature'' (2019 film), an American romantic drama film * ''PREMature'', a 2015 British television drama miniseries See also * Premature aging, of an organism * Premature birth, a preterm baby birth * Premature ejaculation, a condition in which a man ejaculates earlier than he or his partner would like him to * Adult premature aging syndrome, a disease with the appearance of premature aging * Premature Burial Premature burial, also known as live burial, burial alive, or vivisepulture, means to be buried while still alive. Animals or humans may be buried alive accidentally on the mistaken assumption that they are dead, or intentionally as a form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Ventricular Contractions
A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger. The electrical events of the heart detected by the electrocardiogram (ECG) allow a PVC to be easily distinguished from a normal heart beat. However, very frequent PVCs can be symptomatic of an underlying heart condition (such as arrhythmogenic right ventricular cardiomyopathy). Furthermore, very frequent (over 20% of all heartbeats) PVCs are considered a risk factor for arrhythmia-induced cardiomyopathy, in which the heart muscle becomes less effective and symptoms of heart failure may develop. Ultrasound of the heart is therefore recommended in people with frequent PVCs. If PVCs are frequent or troublesome, medication (beta blockers or certain calcium channel blockers) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinoatrial Node
The sinoatrial node (also known as the sinuatrial node, SA node, sinus node or Keith–Flack node) is an ellipse, oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of Cell (biology), cells known as pacemaker cells. The sinus node is approximately 15 millimetre, mm long, 3 mm wide, and 1 mm thick, located directly below and to the side of the superior vena cava. These cells produce an Action potential, electrical impulse known as a cardiac action potential that travels through the electrical conduction system of the heart, causing it to muscle contraction, contract. In a healthy heart, the SA node continuously produces action potentials, setting the rhythm of the heart (sinus rhythm), and so is known as the heart's cardiac pacemaker, natural pacemaker. The rate of action potentials produced (and therefore the heart rate) is influenced by the nerves that supply it. Structure The sinoatrial node is an Ellipse, oval-shaped structure that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
