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Minimaze Procedure
The mini-maze procedures are cardiac surgery procedures intended to cure atrial fibrillation (AF), a common disturbance of heart rhythm. They are procedures derived from the original maze procedure developed by James Cox, MD. The origin of the mini-maze procedures: The Cox maze procedure James Cox, MD, and associates developed the "maze" or "Cox maze" procedure, an "open-heart" cardiac surgery procedure intended to eliminate atrial fibrillation, and performed the first one in 1987. "Maze" refers to the series of incisions arranged in a maze-like pattern in the atria. The intention was to eliminate AF by using incisional scars to block abnormal electrical circuits (atrial macroreentry) that AF requires. This required an extensive series of endocardial (from the inside of the heart) incisions through both atria, a median sternotomy (vertical incision through the breastbone) and cardiopulmonary bypass (heart-lung machine; extracorporeal circulation). A series of improvements we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiofrequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies that humans can hear (though these are not electromagnetic) and the lower limit of infrared frequencies, and also encompasses the microwave range. These are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves, so they are used in radio technology, among other uses. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conductors can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrinsic Cardiac Nervous System
The Intrinsic cardiac nervous system (ICNS), also known as the heart's "little brain," is a complex network of neurons and Ganglion, ganglia embedded within the Cardiac muscle, heart tissue that regulates cardiac function independently of the central nervous system. It modulates heart rate, Cardiac conduction system, conduction, and cardiac contractility in response to local and External stimulus, external stimuli. Anatomy The ICNS consists of clusters of neurons, or ganglia, primarily located in the atrial and Ventricle (heart), ventricular walls, with higher concentrations in the Sinoatrial node, sinoatrial (SA) and Atrioventricular node, atrioventricular (AV) nodes. These ganglia contain: * Afferent neurons: Detect mechanical and chemical changes in the heart. * Efferent neurons: Modulate cardiac muscle activity. * Interneurons: Facilitate communication within the ICNS. * The system is organized into Ganglionated plexi, ganglionated plexuses, interconnected by nerve fibers, for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Nervous System
The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates viscera, internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its Myocardial contractility, force of contraction, digestion, respiratory rate, pupillary dilation, pupillary response, Micturition, urination, and Animal sexual behaviour, sexual arousal. The fight-or-flight response, also known as the acute stress response, is set into action by the autonomic nervous system. The autonomic nervous system is regulated by integrated reflexes through the brainstem to the spinal cord and organ (anatomy), organs. Autonomic functions include control of respiration, heart rate, cardiac regulation (the cardiac control center), vasomotor activity (the vasomotor center), and certain reflex, reflex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catheter Ablation
Catheter ablation is a procedure that uses radio-frequency energy or other sources to terminate or modify a faulty electrical pathway from sections of the heart of those who are prone to developing cardiac arrhythmias such as atrial fibrillation, atrial flutter and Wolff-Parkinson-White syndrome. If not controlled, such arrhythmias increase the risk of ventricular fibrillation and sudden cardiac arrest. The ablation procedure can be classified by energy source: radiofrequency ablation and cryoablation. Medical uses Catheter ablation may be recommended for a recurrent or persistent arrhythmia resulting in symptoms or other dysfunction. Atrial fibrillation frequently results from bursts of tachycardia that originate in muscle bundles extending from the atrium to the pulmonary veins. Pulmonary vein isolation by transcatheter ablation can restore sinus rhythm. Effectiveness Catheter ablation of most arrhythmias has a high success rate. Success rates for Wolff–Parkinson� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-intensity Focused Ultrasound
High-intensity focused ultrasound (HIFU), or MR-guided focused ultrasound surgery (MR-guided focused ultrasound ablation), is an incisionless therapeutic technique that uses non-ionizing ultrasonic waves to heat or ablate tissue. HIFU can be used to increase the flow of blood or lymph or to destroy tissue, such as tumors, via thermal and mechanical mechanisms. Given the prevalence and relatively low cost of ultrasound generation mechanisms, the premise of HIFU is that it is expected to be a non-invasive and low-cost therapy that can at least outperform care in the operating room. The technology is different from that used in ultrasonic imaging, though lower frequencies and continuous, rather than pulsed, waves are used to achieve the necessary thermal doses. However, pulsed waves may also be used if mechanical rather than thermal damage is desired. Acoustic lenses are often used to achieve the necessary intensity at the target tissue without damaging the surrounding tissue. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganglionated Plexi
Ganglionated plexi (GP, also called Ganlionic plexi) comprise the intrinsic cardiac autonomic nervous system composed of autonomic ganglia of the heart atrium and ventricles. Cholinergic neurons throughout the GPs project to all areas of the heart, The GP are embedded in the epicardial fat pads, consisting of only a few neurons or as many as 400 neurons. Post ganglionic neurons from the vagal nerve pathways are components of the Ligament of Marshall, forming part of the "intrinsic" heart nervous system. Vagus nerve stimulation has been shown to inhibit the activity of the GP, possibly through nerves that express Nav1.8 (a sodium channel subtype that is necessary for action potentials in these nerves), but combining GP ablation with pulonary vein isolation may be a superior option. GP are spatially close to the pulmonary veins, so pulmonary vein isolation necessarily affects the GP. GP has been shown to be a contributor to atrial fibrillation (AFib), such that ablation of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Nervous System
The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates viscera, internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its Myocardial contractility, force of contraction, digestion, respiratory rate, pupillary dilation, pupillary response, Micturition, urination, and Animal sexual behaviour, sexual arousal. The fight-or-flight response, also known as the acute stress response, is set into action by the autonomic nervous system. The autonomic nervous system is regulated by integrated reflexes through the brainstem to the spinal cord and organ (anatomy), organs. Autonomic functions include control of respiration, heart rate, cardiac regulation (the cardiac control center), vasomotor activity (the vasomotor center), and certain reflex, reflex ... [...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] |
Pericardium
The pericardium (: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium). It encloses the pericardial cavity, which contains pericardial fluid, and defines the middle mediastinum. It separates the heart from interference of other structures, protects it against infection and blunt trauma, and lubricates the heart's movements. The English name originates from the Ancient Greek prefix ''peri-'' (περί) 'around' and the suffix ''-cardion'' (κάρδιον) 'heart'. Anatomy The pericardium is a tough fibroelastic sac which covers the heart from all sides except at the cardiac root (where the great vessels join the heart) and the bottom (where only the serous pericardium exists to cover the upper surface of the central tendon of diaphragm). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly. Signs and symptoms of stroke may include an hemiplegia, inability to move or feel on one side of the body, receptive aphasia, problems understanding or expressive aphasia, speaking, dizziness, or homonymous hemianopsia, loss of vision to one side. Signs and symptoms often appear soon after the stroke has occurred. If symptoms last less than 24 hours, the stroke is a transient ischemic attack (TIA), also called a mini-stroke. subarachnoid hemorrhage, Hemorrhagic stroke may also be associated with a thunderclap headache, severe headache. The symptoms of stroke can be permanent. Long-term complications may include pneumonia and Urinary incontinence, loss of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryosurgery
Cryosurgery (with ''cryo'' from the Ancient Greek ) is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation. Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions. History In 1841, English physician James Arnott described therapeutic applications of extremely cold temperatures, namely a mixture of crushed ice and salt applied locally (to skin or mucous membrane). He theorized his technique was capable of "arresting the accompanying inflammation, and perhaps destroying the vitality of the cancer cell." His works were the first to hypothesize that extreme cold could be used to selectively damage or destroy harmful tissue. Uses Warts, moles, skin tags, solar keratoses, molluscum, Morton's neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
