An automatic tachycardia is a

cardiac arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the Cardiac cycle, heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per mi ...

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. Most automatic tachycardias are supraventricular tachycardias (SVT). It is important to recognise an automatic tachycardia because the treatment will be different to that for a reentrant tachycardia. The most useful clue will be the presence of 'warm up' and 'cool down'. This means that whereas a reentrant tachycardia will both begin and end abruptly as cardiac conduction utilises then ceases to utilise the accessory pathway, an automatic tachycardia will rise and fall gradually in rate as the automatic focus increases and decreases its automatic rate of electrical discharge.Lister B et al. Paediatric BASIC: Basic Assessment and Support in Paediatric Intensive Care. Department of Anaesthesia and Intensive Care of The Chinese University of Hong Kong, Hong Kong 2016.

Types

The different types are the following: *

Sinus tachycardia Sinus tachycardia is an elevated sinus rhythm characterized by an increase in the rate of electrical impulses arising from the sinoatrial node. In adults, sinus tachycardia is defined as a heart rate greater than 100 beats per minute (bpm). Th ...

may be considered an automatic tachycardia, since the

sinoatrial node The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approxi ...

(SAN) is discharging at an abnormally fast rate. * Atrial ectopic tachycardia, in which the focus or foci are in the atria of the heart, is an automatic tachycardia. * Atrial fibrillation may be considered an automatic tachycardia. *

Junctional ectopic tachycardia Junctional ectopic tachycardia (JET) is a rare syndrome of the heart that manifests in patients recovering from heart surgery. It is characterized by cardiac arrhythmia, or irregular beating of the heart, caused by abnormal conduction from or th ...

, in which the focus is in the

atrioventricular node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

(AVN), and * Accelerated idioventricular rhythm, involving a ventricular focus, are also examples. Idioventricular tachycardia is notable because it is the only automatic tachycardia which is not an SVT.

Treatment

Treatment depends on the origin of the automatic tachycardia, however the mainstay of treatment is either antidysrhythmic medication or cardiac pacing. Specifically overdrive pacing may be used for all forms of automatic tachycardia; a pacemaker assumes control of the heart rhythm in overdrive pacing. In some cases

ablation Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for a ...

of the ectopic focus may be necessary.

References

{{Circulatory system pathology Cardiac arrhythmia

Types

Treatment

See also

References