From the Guidelines
SVT is generally not dangerous for most people, though it can be concerning and uncomfortable, and in rare cases, it can lead to complications in people with underlying heart conditions or if episodes are very frequent or prolonged. SVT is a rapid heart rhythm originating above the ventricles that typically causes heart rates of 150-250 beats per minute 1. While most episodes resolve on their own or with simple maneuvers like the Valsalva maneuver (bearing down as if having a bowel movement), persistent SVT may require medical intervention. For immediate treatment, doctors might administer adenosine (6-12mg IV push) or other medications like beta-blockers or calcium channel blockers 1.
Key Points to Consider
- The incidence of SVT is 1–3 cases per 1000 persons, with a prevalence of 0.2% in the general population, and this prevalence increases with age 1.
- Common symptoms of SVT include palpitations, chest discomfort, fatigue, light-headedness, shortness of breath, anxiety, dizziness, dyspnoea, and, uncommonly, syncope 1.
- Untreated SVT can result in heart failure (HF), pulmonary oedema, and/or myocardial ischaemia secondary to an increased heart rate, and in adults with congenital heart diseases (ACHD) SVT increased the risk of HF, stroke, and sudden cardiac death 1.
- For definitive treatment, catheter ablation offers a high success rate (90-95%) with low complication risk 1.
Recommendations for Management
- Vagal maneuvers are recommended for acute treatment in patients with SVT, and adenosine is beneficial for acute treatment in patients with orthodromic AVRT 1.
- Synchronized cardioversion should be performed for acute treatment in hemodynamically unstable patients with SVT when vagal maneuvers or adenosine are ineffective or not feasible 1.
- The most important consideration in managing SVT is to prioritize the patient's hemodynamic stability and to promptly restore sinus rhythm in patients who are hemodynamically unstable.
From the Research
SVT Danger Level
- SVT is generally considered a benign condition, but it can cause significant patient discomfort and distress 2, 3.
- Untreated PSVT is associated with adverse outcomes, including high symptom burden and tachycardia-mediated cardiomyopathy 2.
- Patients may rarely develop tachycardia-mediated cardiomyopathy (1%) due to PSVT 2.
- SVT can cause symptoms such as palpitations, chest discomfort, dyspnea, fatigue, lightheadedness, and altered consciousness 3, 4.
Risk Factors
- Approximately 50% of patients with PSVT are aged 45 to 64 years and 67.5% are female 2.
- Patients with underlying heart conditions or other health issues may be at higher risk for complications from SVT 3, 4.
- Special populations, such as pediatric patients, pregnant women, and heart transplant patients, may require modified management of SVT 5.
Management and Treatment
- Vagal maneuvers, such as the modified Valsalva maneuver, and intravenous adenosine are commonly used as first-line therapies for acute management of SVT 2, 3, 5.
- Catheter ablation is a highly effective and recommended therapy for preventing recurrence of PSVT 2, 3, 4.
- Pharmacotherapy, including beta blockers and calcium channel blockers, may be used for acute and long-term management of SVT 2, 3, 4, 5.