arrhythmia

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arrhythmia

(ārĭth`mēə), disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heartheart,
muscular organ that pumps blood to all parts of the body. The rhythmic beating of the heart is a ceaseless activity, lasting from before birth to the end of life. Anatomy and Function

The human heart is a pear-shaped structure about the size of a fist.
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 disorders; however, they are usually of no medical significance except in the presence of additional symptoms. The heart's rhythm is controlled by an electrical impulse that is generated from a clump of tissue on the right atrium called the sinoatrial node, often referred to as the heart's natural pacemaker. It travels to a second clump of tissue called the atrioventricular node and then to the ventricles.

Bradycardia, or slow heartbeat, is often present in athletes. It may, however, indicate conduction problems, especially in older people. In one type of bradycardia, called sinoatrial or atrioventricular block, or heart block, rhythm can be maintained by implanted electrodes that act as artificial pacemakerspacemaker, artificial,
device used to stimulate a rhythmic heartbeat by means of electrical impulses. Implanted in the body when the heart's own electrical conduction system (natural pacemaker) does not function normally, the battery-powered device emits impulses that trigger
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.

Tachycardia, or heartbeat faster than 100 beats per minute in the adult, can be precipitated by drugs, caffeine, anemia, shock, and emotional upset. It may also be a sign of overactivity of the thyroid glandthyroid gland,
endocrine gland, situated in the neck, that secretes hormones necessary for growth and proper metabolism. It consists of two lobes connected by a narrow segment called the isthmus. The lobes lie on either side of the trachea, the isthmus in front of it.
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 or underlying disease. Flutters, and the even faster fibrillations, are rapid, uncoordinated contractions of the atrial or ventricular muscles that usually accompany heart disorders. Atrial fibrillation may be idiopathic, the result of rheumatic mitral valve disease (see rheumatic feverrheumatic fever
, systemic inflammatory disease, extremely variable in its manifestation, severity, duration, and aftereffects. It is frequently followed by serious heart disease, especially when there are repeated attacks. Rheumatic fever usually affects children.
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) in young people or hypertensive heart disease (see hypertensionhypertension
or high blood pressure,
elevated blood pressure resulting from an increase in the amount of blood pumped by the heart or from increased resistance to the flow of blood through the small arterial blood vessels (arterioles).
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) and arteriosclerotic heart diseases (see arteriosclerosisarteriosclerosis
, general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are frequently accompanied by accumulations inside the vessel walls of lipids, e.g.
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) in older people. It may result in a rapid pulse rate and may be associated with thrombus formation in the atria and a risk of embolization to the brain (strokestroke,
destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called apoplexy.
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) or other organs. Atrial fibrillation is often treated with digitalisdigitalis
, any of several chemically similar drugs used primarily to increase the force and rate of heart contractions, especially in damaged heart muscle. The effects of the drug were known as early as 1500 B.C.
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 and other drugs that regulate heart rhythm or heart rate. It may also be treated by catheter ablation, in which an electrode produces heat to destroy cells causing the arrhythmia. Ventricular fibrillation is a sign of the terminal stage of heart failure and is usually fatal unless defibrillation is achieved by immediate direct-current defibrillation. Some tachycardias can be managed by the implantation in the upper chest of small defibrillatorsdefibrillator,
device that delivers an electrical shock to the heart in order to stop certain forms of rapid heart rhythm disturbances (arrhythmias). The shock changes a fibrillation to an organized rhythm or changes a very rapid and ineffective cardiac rhythm to a slower, more
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 that sense dangerous fibrillations and administer an electric shock to the heart to restore normal rhythm.

Arrhythmia

 

disruption of the normal rhythm of the heart. Arrhythmia is manifested as an increase in frequency (tachycardia) or a slowing (bradycardia) of the heart contractions, in the appearance of premature or additional contractions (extrasystole), in heart palpitations (paroxysmal tachycardia), and in complete irregularity of the intervals between individual contractions (fibrillation). Arrhythmia may appear, among other causes, as a result of heart disease (myocarditis, cardiosclerosis); it may be functional or be caused by disturbance of the nervous regulation of the heart—for example, when the interconnection between the auricles and ventricles is interrupted (heart block). So-called respiratory or juvenile arrhythmia (acceleration of heartbeat upon inspiration) is a physiological phenomenon in children and adolescents. Some arrhythmias cause disturbance of blood circulation, unpleasant feelings of “irregularity of heart action,” dizziness, and the like. Other arrhythmias are not felt by patients. Treatment is directed toward removing the basic disease and restoring the normal heart rhythm.

arrhythmia

[ā′rith·mē·ə]
(medicine)
Absence of rhythm, especially of heart beat or respiration. Also spelled arhythmia.
References in periodicals archive ?
Conclusion: Most common cause of ventricular arrhythmias was coronary artery disease followed by ischemic and dilated cardiomyopathies.
Compared with patients not on allopurinol, those taking it for more than 2 years had a significant 28% reduced rate of arrhythmias; those on it for 6 months to 2 years had a significant 24% reduction in incident arrhythmias; and those on it for 1-180 days had no significant change in their arrhythmia incidence.
The objective of the study was to determine the frequency, time and outcome of ventricular arrhythmias in patients with NSTEMI during their hospital stay.
The ablation procedures were performed in eleven arrhythmia patients including atrial fibrillation patients in Prague at Homolka Hospital, led by electrophysiologist Vivek Reddy, MD, director of arrhythmia services at The Mount Sinai Hospital and the Mount Sinai Health System, and Petr Neuzil, MD, director of Cardiology, Homolka Hospital.
In this context, Minami et al had previously reported that a similar screening methodology, on which ours was modelled, recorded arrhythmias in approximately 10% of subjects with a prior history versus 1.
Keywords: Ambulatory ECG recording Arrhythmias Holter monitoring QT interval INTRODUCTION
Utilizing a genetically modified mouse model they were able to manipulate the sensor and completely prevented calcium-triggered arrhythmias.
Combined with the new PENTARAYA Nav Catheter, you can reduce the number of required catheter maneuvers to quickly diagnose any arrhythmia.
The predisposing factors for atrial arrhythmias following the Fontan procedure are extensive sutures performed on the right atrium resulting in healed non-conductive scar tissue, damage to the sinus node or the artery in previously performed hemi-Fontan procedures, injury to the crista terminalis, extensive right atrial incisions performed in intracardiac repair operations, and multi-step operations (5-7).
Nine patients (17%) in the antiarrhythmics group and 23 (40%) in the control group developed clinically significant atrial arrhythmias or couldn't tolerate the medications, said Dr.
The new money will be invested in services to assess, treat and support patients with arrhythmias and to pay for pacemakers and implantable cardiac defibrillators (ICDs).