Supraventricular tachycardia
| Classification according to ICD-10 | |
|---|---|
| I45.6 | Pre-excitation syndrome
|
| I47.1 | Paroxysmal SV tachycardia
|
| I47.9 | Paroxysmal tachycardia
|
| ICD-10 online (WHO version 2019) | |
Supraventricular tachycardia (abbreviation SV tachycardia or SVT ) is a medical term and describes a whole group of different cardiac arrhythmias . What they have in common is an inappropriately fast pulse of more than 100 beats per minute and the origin of the arrhythmia above the ventricles (see structure of the heart ).
Forms and nomenclature
The assignment of individual arrhythmias to the SVT is handled inconsistently. Depending on the place of origin and the structures involved in the excitation conduction system , u. a. between
- Sinus node reentry tachycardias,
- Inadequate sinus tachycardia ,
- focal atrial tachycardias,
- atrial macro reentry tachycardias,
- junctional ectopic tachycardias ,
- AV nodal reentry tachycardias and
- AV reentry tachycardias with accessory pathway
distinguished. Most sinus tachycardia and tachycardia associated with atrial flutter and atrial fibrillation are also referred to as SVT. The historical names Bouveret syndrome or paroxysmal tachycardia of the Bouveret-Hoffmann type for atrial tachycardias with an abrupt beginning and end are no longer common .
As paroxysmal tachycardia are designated by sudden onset and equally sudden end. The term Reentry (from English. : Reentry) describes in connection with tachycardias an unusual " circulating excitation " in the heart.
Symptoms
The acceleration of the pulse caused by the tachycardia is immediately noticed by most patients as "heart pounding" or "racing heart ". In the case of atrial fibrillation, the pulse is irregular and often palpable with varying strength; in the other forms, it is regular. However, the tachycardia can go unnoticed for hours and even days. Shortness of breath ( dyspnea ) or tightness in the chest ( angina pectoris ) can also occur if the tachycardia leads to heart failure or insufficient blood flow to the heart muscle. At high pulse rates, dizziness and even loss of consciousness ( syncope ) are common. After the tachycardia has ended, many patients experience a noticeable need to urinate .
diagnosis
Although tachycardia can already be diagnosed by measuring the pulse as part of the physical examination , a distinction between ventricular and supraventricular tachycardia or a more precise differentiation of SVT is only possible with the help of the 12-channel electrocardiogram . There, SV tachycardia usually has narrow QRS complexes (see ECG nomenclature ) that are similar to those of normal sinus rhythm. However , if there is also bundle branch block with widened QRS complexes, SV tachycardia cannot initially be distinguished from ventricular tachycardia. In this case, a precise shape analysis of the QRS complexes often helps, whereby the following criteria speak for a ventricular tachycardia:
- QRS width> 140 milliseconds (ms) for right bundle branch block or> 160 ms for left bundle branch block
- RS interval> 100 ms in a chest wall lead
- Negative QRS complex in all chest wall leads (negative concordance)
- Ventricular fusion beats or AV dissociation.
Adenosine can be administered for the differential diagnosis of supraventricular tachycardias . This causes an AV block III ° lasting a few seconds . As a result, only atrial actions are visible in the ECG, which provide further information. AV nodal reentry tachycardia (AVNRT) can be ended in this way and thus saved as a diagnosis.
therapy
Sinus tachycardias generally do not require any special therapy. However, an attempt is made to identify a possibly underlying cause and, if necessary, to treat it. With the exception of the rare Inappropriate Sinus Tachycardia. Therapy is usually necessary for patients with IST. The basics of the treatment of atrial fibrillation and atrial flutter are set out in the article Atrial Fibrillation.
The majority of patients with the other mentioned SV tachycardias either do not need any or only temporary drug therapy in the event of an attack . Thereby u. a. Adenosine, amiodarone , flecainide or propafenone are used, occasionally beta blockers or verapamil . In the case of frequent and disturbing seizures, prophylaxis with a beta blocker or another antiarrhythmic drug can be tried, the success of which cannot, however, be foreseen.
Only with unsatisfactory effect of drugs or unacceptable side effects one is invasive therapy either in the context of a heart catheter treatment or in the form of heart surgery considered. However, a minority of patients can be treated with catheter ablation so sustainably and with low risk that this is preferable to drug therapy.
prevention
SV tachycardias can be triggered by influences of the autonomic nervous system . Affected patients should therefore avoid excitement and stressful situations as much as possible. The consumption of alcohol , nicotine and caffeine should also be restricted, at least on a trial basis, as they can trigger tachycardias.
Tachycardias can also occur in connection with the consumption of amphetamine , heroin and cocaine as well as cannabis (active ingredient cannabinol ).
literature
- S2k guideline tachycardia cardiac arrhythmias in children and adolescents of the German Society for Pediatric Cardiology (DGPK). In: AWMF online (as of 2013)
