From the Guidelines
Supraventricular Tachycardia (SVT) is a type of abnormal heart rhythm, or arrhythmia, characterized by a rapid heart rate originating from above the ventricles, with atrial and/or ventricular rates exceeding 100 beats per minute at rest.
Definition and Characteristics
- SVT encompasses various tachyarrhythmias that involve atrial and/or atrioventricular nodal tissues for initiation and sustenance, as noted in the European Heart Journal 1.
- It is an umbrella term that includes conditions such as inappropriate sinus tachycardia, atrial tachycardia (including focal and multifocal), macroreentrant atrial tachycardia, junctional tachycardia, atrioventricular nodal reentrant tachycardia (AVNRT), and various forms of accessory pathway-mediated reentrant tachycardias, as defined by the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society 1.
- SVTs typically start and stop abruptly and are rarely life-threatening, but they can lead to complications such as heart failure, pulmonary edema, and myocardial ischemia if left untreated, as highlighted in the European Heart Journal 1.
Symptoms and Presentation
- Common symptoms of SVT include palpitations, chest discomfort, fatigue, lightheadedness, shortness of breath, anxiety, dizziness, dyspnea, and occasionally syncope, as reported in the European Heart Journal 1 and Circulation 1.
- The pattern of symptoms, including the number of episodes, duration, frequency, mode of onset, and possible triggers, is crucial for clinical decision-making, as emphasized in the guidelines for the management of patients with supraventricular arrhythmias 1.
Epidemiology
- The incidence of SVT is approximately 1–3 cases per 1000 persons, with a prevalence of 0.2% in the general population, increasing with age and being more common in women, as stated in the European Heart Journal 1.
From the Research
Definition of Supraventricular Tachycardia (SVT)
Supraventricular Tachycardia (SVT) is a general term used to describe a variety of fast heart rhythms originating in any part of the conduction system above the ventricles 2. It encompasses subclasses of tachycardias such as:
- Atrioventricular nodal reentrant tachycardia (AVNRT)
- Atrioventricular reciprocating tachycardia (AVRT)
- Atrial tachycardia
- Atrial flutter
Characteristics of SVT
SVT can affect all age groups and is a source of significant morbidity, often encountered in otherwise healthy individuals without structural heart disease 3. The most common SVTs include atrioventricular nodal re-entrant tachycardia, atrioventricular re-entrant tachycardia, and atrial tachycardia 4. SVT is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above 5.
Mechanisms and Classification
The mechanisms of most forms of SVT have been elucidated, and pharmacologic and invasive therapies have evolved simultaneously 6. Knowledge of the mechanism of each SVT is important in determining management at the bedside and in the electrophysiology laboratory 6. The term SVT encompasses a heterogeneous group of arrhythmias with different electrophysiologic characteristics 6.
Symptoms and Diagnosis
Presenting symptoms of SVT may include altered consciousness, chest pressure or discomfort, dyspnea, fatigue, lightheadedness, or palpitations 5. Diagnostic evaluation may be performed in the outpatient setting and includes a comprehensive history and physical examination, electrocardiography, and laboratory workup 5. Extended cardiac monitoring with a Holter monitor or event recorder may be needed to confirm the diagnosis 5.
Treatment Options
Treatment options for SVT include vagal maneuvers, pharmacologic therapy, and catheter-based radiofrequency ablation 2, 3, 4, 5, 6. Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal SVT 5.