From the Guidelines
Supraventricular tachycardia (SVT) is primarily caused by abnormal electrical pathways or focal areas in the heart above the ventricles, with the most common mechanisms being re-entry, abnormal automaticity, and triggered activity, as noted in the 2020 European Heart Journal guidelines 1. The causes of SVT can be multifactorial, including:
- Abnormal electrical pathways, such as accessory pathways in Wolff-Parkinson-White syndrome
- AV nodal reentry tachycardia (AVNRT)
- Atrial tachycardia
- Triggers like caffeine, alcohol, stress, fatigue, and stimulant medications
- Medical conditions, including hyperthyroidism, heart failure, chronic lung disease, and electrolyte imbalances
- Genetic predisposition
- Structural heart abnormalities, such as congenital heart defects or valve problems
- Certain medications affecting heart rhythm
- Age, with some forms of SVT being more common in younger adults while others develop later in life, as reported in the 2020 European Heart Journal guidelines 1. Understanding these causes is crucial for guiding appropriate treatment, which may include vagal maneuvers, medications like adenosine or beta-blockers, and in some cases, catheter ablation to eliminate the abnormal electrical pathway, as recommended in the 2020 European Heart Journal guidelines 1. The mechanisms underlying SVT, including re-entry, abnormal automaticity, and triggered activity, are well-described in the 2003 Journal of the American College of Cardiology guidelines 1 and the 2003 Circulation guidelines 1, but the most recent and highest quality study, the 2020 European Heart Journal guidelines 1, provides the most up-to-date information on the causes and treatment of SVT.
From the Research
Causes of Supraventricular Tachycardia (SVT)
- SVT is caused by reentry phenomena or automaticity at or above the atrioventricular node 2
- The condition involves atrial or atrioventricular node tissue from the His bundle or above 3
- SVT encompasses subclasses of tachycardias such as atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reciprocating tachycardia (AVRT), atrial tachycardia, and atrial flutter 4
Mechanisms of SVT
- Reentry phenomena: a self-sustaining loop of electrical activity that can cause rapid heart rhythms 2
- Automaticity: abnormal electrical activity that can cause rapid heart rhythms 2
- AVNRT, AVRT, and atrial tachycardia are common types of SVT, each with distinct mechanisms and clinical manifestations 3, 2, 4
Clinical Manifestations of SVT
- Symptoms may include palpitations, chest pressure or discomfort, dyspnea, fatigue, lightheadedness, or altered consciousness 3, 2, 5
- Patients may rarely develop tachycardia-mediated cardiomyopathy due to SVT 5
- SVT can cause significant patient discomfort and distress, and is a common cause of hospital admissions 6