Management of Supraventricular Tachycardia (SVT)

Mechanisms of Spontaneous Resolution

Vagal maneuvers can effectively terminate SVT by increasing parasympathetic tone, which slows conduction through the AV node, potentially breaking the reentry circuit 2, 3
The American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) guidelines recommend vagal maneuvers as first-line intervention for acute termination of SVT 2, 3

Valsalva maneuver: Patient raises intrathoracic pressure by bearing down against a closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) 2, 3
Carotid sinus massage: After confirming absence of carotid bruit, steady pressure is applied over the right or left carotid sinus for 5-10 seconds 2, 4
Cold stimulus: Applying an ice-cold, wet towel to the face can trigger the diving reflex and terminate SVT 2, 5
Studies show Valsalva maneuvers are more successful than carotid sinus massage, with an overall success rate of 27.7% when both techniques are attempted sequentially 2, 3

For hemodynamically stable patients who don't respond to vagal maneuvers, adenosine is recommended as the next step with 90-95% effectiveness 2
Intravenous diltiazem or verapamil are effective in 64-98% of hemodynamically stable patients 6
Beta blockers can be used but have limited evidence for acute termination 6
For hemodynamically unstable patients, synchronized cardioversion is recommended 2, 3

Oral medications (beta blockers, diltiazem, or verapamil) are useful for ongoing management in patients who do not have ventricular pre-excitation during sinus rhythm 6, 7
"Pill-in-the-pocket" approach with oral beta blockers, diltiazem, or verapamil may be reasonable for patients with infrequent, well-tolerated episodes 7

Patients with pre-excitation syndromes (e.g., Wolff-Parkinson-White) require special consideration as certain medications can accelerate conduction through accessory pathways 5, 4
Recurrent SVT may indicate underlying structural heart disease or other cardiac conditions that require further evaluation 8
In patients with adult congenital heart disease, SVT management should be undertaken in collaboration with specialized cardiologists 8