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Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. [2] This is in contrast to the other group of fast heart rhythms – ventricular tachycardia , which start within the lower chambers of the heart . [ 2 ]
Paroxysmal supraventricular tachycardia (PSVT) is a type of supraventricular tachycardia, named for its intermittent episodes of abrupt onset and termination. [3] [6] Often people have no symptoms. [1] Otherwise symptoms may include palpitations, feeling lightheaded, sweating, shortness of breath, and chest pain. [2] The cause is not known. [3]
A supraventricular extrasystole (SVES) is an extrasystole or premature electrical impulse in the heart, generated above the level of the ventricle. This can be either a premature atrial contraction or a premature impulse from the atrioventricular node .
Arrhythmia may be classified by rate (tachycardia, bradycardia), mechanism (automaticity, re-entry, triggered) or duration (isolated premature beats; couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds). [citation needed] Arrhythmias are also classified by site of origin: [citation needed]
An automatic tachycardia is a cardiac arrhythmia which involves an area of the heart generating an abnormally fast rhythm, sometimes also called enhanced automaticity.These tachycardias, or fast heart rhythms, differ from reentrant tachycardias (AVRT and AVNRT) in which there is an abnormal electrical pathway which gives rise to the pathology.
Bigeminy is contrasted with couplets, which are paired abnormal beats. Groups of three abnormal beats are called triplets and are considered a brief run of non-sustained ventricular tachycardia (NSVT), and if the grouping lasts for more than 30 seconds, it is ventricular tachycardia (VT).
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.
The cause of this condition is not accurately known, though it is probably of nervous origin and can be aggravated by physical wear and tear. The symptoms are sometimes very alarming but it is not considered in itself dangerous. [citation needed] It has an increased risk of developing in WPW syndrome and LGL syndrome. [4]