The supraventricular tachycardia statpearls
The supraventricular tachycardia statpearls Supraventricular tachycardia (SVT) is a broad term encompassing rapid heart rhythms originating above the ventricles, primarily within the atria or the atrioventricular (AV) node. This condition is characterized by episodes of abnormally fast heartbeats, typically exceeding 100 beats per minute, often reaching 150-250 bpm. These episodes can be sudden in onset and termination, leading to symptoms such as palpitations, dizziness, shortness of breath, or chest discomfort. Although SVT is generally not life-threatening in healthy individuals, recurrent episodes can impair quality of life and may require medical intervention.
The pathophysiology of SVT involves abnormal electrical circuits within the heart. Most cases are due to reentrant pathways, where electrical impulses loop back upon themselves, causing rapid activation of the atria or AV node. Some SVTs are due to increased automaticity of atrial tissue or accessory pathways, such as in Wolff-Parkinson-White syndrome. The common types include atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and atrial tachycardia. Each has distinct electrophysiological mechanisms but presents similarly with rapid, regular rhythms.
Diagnosis of SVT relies heavily on electrocardiogram (ECG) findings. During an episode, the ECG typically shows narrow QRS complexes and a rapid, regular rhythm. In AVNRT, P waves are often hidden within the QRS complex or appear as pseudo R’ waves in V1. AVRT may show delta waves during sinus rhythm due to accessory pathways. The challenge lies in capturing the arrhythmia on ECG, which sometimes requires ambulatory monitoring or electrophysiology studies for definitive diagnosis. Differentiating SVT from other tachyarrhythmias like atrial fibrillation or ventricular tachycardia is critical, as management strategies differ significantly.
Management of SVT involves acute treatment to terminate ongoing episodes and long-term strategies to prevent recurrence. For acute episodes, vagal maneuvers such as the Valsalva maneuver or carotid sinus massage are first-line, as they increase vagal tone and often restore normal rhythm. Pharmacologic agents like adenosine are highly effective due to their ability to transiently block AV nodal conduction, terminating reentrant circuits. In some cases, intravenous calcium channel blockers or beta-blockers are used if adenosine is contraindicated or ineffective.
For recurrent SVT, options include medication and catheter ablation. Antiarrhythmic drugs such as flecainide, propafenone, or beta-blockers can reduce episodes but may have side effects. Catheter ablation, targeting the reentrant pathway or accessory pathway, has emerged as a definitive treatment with high success rates and low complication risks. Lifestyle modifications and management of underlying conditions, such as electrolyte imbalances or thyroid disorders, are also important.
In summary, supraventricular tachycardia is a common arrhythmia with distinct electrophysiological mechanisms and characteristic clinical features. Advances in diagnostic techniques and minimally invasive treatments have greatly improved patient outcomes, making effective management accessible and safe.
