From the Guidelines
SVT aberrancy should be managed with vagal maneuvers and adenosine as first-line treatments, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Definition and Mechanism
SVT aberrancy refers to supraventricular tachycardia with abnormal ventricular conduction, causing the ECG to show wide QRS complexes that can be mistaken for ventricular tachycardia. This occurs when rapid atrial impulses reach the ventricles while part of the conduction system is still refractory, forcing the electrical signal to travel through alternative pathways. The most common form is rate-related bundle branch block, typically right bundle branch block.
Diagnosis
To differentiate SVT with aberrancy from ventricular tachycardia, look for characteristic features like:
- RS complexes in precordial leads
- Absence of AV dissociation
- Specific QRS morphology patterns
Management
Management includes:
- Vagal maneuvers
- Adenosine (6mg IV push, followed by 12mg if needed) as first-line treatments, which can both terminate the arrhythmia and help establish the diagnosis
- If these fail, calcium channel blockers like verapamil (5-10mg IV) or beta-blockers like metoprolol (5mg IV) may be used, as recommended by the European Heart Rhythm Association (EHRA) and ESC Council on Hypertension 1
- Electrical cardioversion is reserved for hemodynamically unstable patients
Importance of Accurate Diagnosis
Understanding SVT aberrancy is crucial because misdiagnosis as ventricular tachycardia could lead to unnecessary and potentially harmful treatments. Accurate diagnosis and management can improve patient outcomes and reduce morbidity and mortality.
From the Research
Svt Aberrancy
- Svt aberrancy refers to an abnormality in the conduction of electrical impulses in the heart, leading to supraventricular tachycardia (SVT) 2, 3, 4, 5, 6
- SVT is a condition characterized by an abnormally fast heart rate, typically exceeding 100 beats per minute 2, 3, 4, 5, 6
Treatment Options
- Hemodynamically unstable patients with SVT should be treated with electrical cardioversion 2
- For stable patients, acute termination of tachycardia can be achieved by vagal maneuvers or medical therapy 2, 3, 4, 5, 6
- Vagal maneuvers, such as the Valsalva maneuver, carotid massage, and ice to the face, can increase vagal stimulation and terminate SVT episodes 2, 3, 4, 5, 6
Efficacy of Vagal Maneuvers
- The Valsalva maneuver has a success rate of 19.4% in terminating SVT 4, 5
- Carotid sinus massage has a success rate of 10.5% in terminating SVT 4, 5
- A modified Valsalva maneuver has been shown to have a higher success rate of 43% in terminating SVT 3, 6