What is the initial management for a patient presenting with supraventricular tachycardia (SVT) on electrocardiogram (EKG)?

Initial Management of Supraventricular Tachycardia (SVT) on EKG

The initial management for a patient with SVT on EKG should begin with vagal maneuvers, followed by adenosine if vagal maneuvers fail, and synchronized cardioversion for hemodynamically unstable patients. 1, 2

Assessment of Hemodynamic Stability

• First, assess the patient's hemodynamic stability - check for hypotension, altered mental status, chest pain, heart failure, or shock 2, 3
• For hemodynamically unstable patients, proceed directly to synchronized cardioversion 1, 2

Management Algorithm for Hemodynamically Stable Patients

Step 1: Vagal Maneuvers

• Perform vagal maneuvers with the patient in the supine position 1, 2
• The modified Valsalva maneuver (MVM) is the most effective vagal maneuver with the highest success rate 4
• Proper Valsalva technique: have patient bear down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg pressure) 1
• Carotid sinus massage can be performed after confirming absence of carotid bruits by auscultation, applying steady pressure over right or left carotid sinus for 5-10 seconds 1, 2
• Cold stimulus (ice-cold wet towel to face) can also be effective 1
• Switching between different vagal maneuver techniques can increase overall success rate to approximately 27.7% 1, 2

Step 2: Pharmacological Management

• If vagal maneuvers fail, administer adenosine IV (Class I recommendation) 1, 2
• Adenosine is effective in 90-95% of patients with brief side effects lasting <1 minute in about 30% of patients 1
• Be prepared for potential atrial or ventricular premature complexes immediately after conversion that may induce further episodes of SVT 1
• Have electrical cardioversion equipment available as adenosine may precipitate atrial fibrillation that could conduct rapidly to ventricles 1

Step 3: Additional Pharmacological Options

• If adenosine fails, consider calcium channel blockers (diltiazem or verapamil) or beta-blockers (Class IIa recommendation) 2, 3
• Calcium channel blockers are more effective than beta-blockers for acute conversion 2

Step 4: Synchronized Cardioversion

• If pharmacological therapy is ineffective or contraindicated in hemodynamically stable patients, proceed to synchronized cardioversion 1, 2

Special Considerations

Pre-excited AF (Wolff-Parkinson-White Syndrome)

• For patients with pre-excited AF who are hemodynamically unstable, perform synchronized cardioversion immediately 1, 2
• For hemodynamically stable patients with pre-excited AF, administer ibutilide or IV procainamide 1, 2
• AVOID AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation as they may accelerate ventricular rate and lead to ventricular fibrillation 2, 5

Important Pitfalls to Avoid

• Never apply pressure to the eyeball as this practice is dangerous and has been abandoned 1, 2
• Always obtain a 12-lead ECG to distinguish SVT from ventricular tachycardia before treatment 2, 6
• Ensure proper ECG diagnosis to distinguish between different types of SVT (AVNRT, AVRT, atrial tachycardia) 2, 3
• Avoid calcium channel blockers and beta-blockers in patients with suspected pre-excited AF, ventricular tachycardia, or systolic heart failure 2