(redirected from extrasystoles)
Also found in: Dictionary, Thesaurus, Medical.


Premature beat of the heart.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the most common form of arrhythmia. The condition is characterized by irregular heart contractions (extra-systoles) caused by impulses from an additional focus of excitation arising in the myocardium. Since the heart muscle remains unexcitable for some time after every contraction, the next normal impulse usually cannot cause a systole. As a result, a longer than normal contraction, that is, a compensatory pause, occurs. An extrasystole is generally felt as a temporary sinking sensation, or an “interruption in the heart.” Atrial extrasystoles arise in the atria, and ventricular extrasystoles in the ventricles. Extrasystoles may be single or multiple, and they may occur chaotically or with a certain rhythm, for example, after every normal contraction (bigeminal). Sometimes several extrasystoles occur in succession.

Extrasystoles can occur in healthy persons, and, in most cases, occasional infrequent extrasystoles have little clinical significance. Atrial extrasystoles, however, may result from myocardial disease, for example, mitral insufficiency or cardiosclerosis. Frequent atrial extrasystoles in these diseases are an early sign of auricular fibrillation, especially when they occur in rapid succession. Ventricular extrasystoles may result from myocardial disease or neurological, mental, and other disorders. Successive ventricular extrasystoles originating from different places may precede a severe form of arrhythmia called ventricular fibrillation.

Electrocardiography plays an important part in diagnosing ex-trasystoles. Treatment is determined by cause. The administration of antiarrhythmic agents, for example, propranolol and potassium preparations, is sometimes required.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Detection of Potentially Eligible Extrasystoles. Corrected RR interval time series were automatically analyzed: RR intervals reduced by more than 20% compared with the preceding RR interval identified a potentially eligible extrasystole (the 20% limit ensures an altered preload at the subsequent postectopic beat [8]).
KEY WORDS: Anxiety, Burnout, Critical Care, Extrasystoles, Nursing.
Figure 9 shows the response evoked by the application of an early extrasystole in the papillary muscle of diabetic rats.
This increase in [Ca.sup.2+] transients leads to an increase in sarcoplasmic reticulum (SR) [Ca.sup.2+] load which is responsible for the generation of delayed after depolarizations (DADs), which, if sufficiently large, may achieve threshold and generate spontaneous action potentials, leading to extrasystoles and ventricular arrhythmias.
The most common dysrhythmias that occur during digoxin toxicity are AV block and extrasystoles, although any type of dysrhythmia may occur.
Perioperative factors, such as atrial extrasystoles, change in autonomic tone, electrolyte shifts, inadequate myocardial protection, b blocker withdrawal, or the response to cardiopulmonary bypass, can trigger AF in these at-risk patients14.
Ventricular cardiac rhythm impairments were identified in 5 (23.8 [+ or -] 9.5%) patients and manifested as extrasystoles, bigeminy and trigeminy.
Unsupervised classification of ventricular extrasystoles using bounded clustering algorithms and morphology matching.
Those reactions are accompanied by various symptoms, typical for the developed picture of a HIV-infection: problem with the breathing, rhinorrhea, obstruction of respiratory tracts, extrasystoles, gastro-intestinal disturbances leading to loose stool and diarrhea.Many patients develop urticarial rush.
The most commonly observed complications during anesthesia included desaturation (SpO2<95%) in 320 patients (80%), arrhythmia (bradicardia, tachycardia, ventricular extrasystoles) in 289 (72%) patients, hypercarbia in 108 (27%) patients, bronchospasm in 88 (22%) patients.
* Severe sympathetic discharge is often seen during dental procedures, presenting with hypertension, tachycardia and ventricular extrasystoles. t Cleaning of the potentially soiled airway is essential before emergence from anaesthesia and awake extubation.