What is the preoperative protocol for managing supraventricular tachycardia (SVT) in a surgical patient?

Preoperative Management Protocol for Supraventricular Tachycardia

In patients with SVT scheduled for non-cardiac surgery, correct aggravating factors (respiratory failure, electrolyte imbalances) first, then use vagal maneuvers or adenosine for acute episodes, and consider prophylactic beta-blockers, calcium channel blockers, or amiodarone for recurrent SVT in the perioperative setting. 1

Immediate Preoperative Assessment

Identify and Correct Reversible Causes

• Check and correct hypoxia, hypokalemia, and hypomagnesemia before proceeding with surgery 1
• Evaluate for respiratory failure or metabolic derangements that may trigger arrhythmias 1
• Review all medications for potential proarrhythmic effects 1

Determine SVT Type and Risk Stratification

• Obtain 12-lead ECG to identify pre-excitation patterns (Wolff-Parkinson-White syndrome) 1
• Patients with pre-excited atrial fibrillation and accessory pathways require special consideration—avoid AV nodal blocking agents (digoxin, calcium channel blockers) as they can accelerate ventricular conduction and cause hemodynamic collapse 1
• In rare cases with WPW syndrome and pre-excited AF, consider preoperative catheter ablation if surgery timing permits 1

Acute SVT Management in Preoperative Period

For Hemodynamically Stable Patients

• First-line: Vagal maneuvers (modified Valsalva maneuver has 43% success rate) 2, 1
• Second-line: Adenosine 6-12 mg IV (90-95% effective for orthodromic AVRT and AVNRT) 1, 2
• Third-line: IV diltiazem or verapamil (64-98% success rates) if no pre-excitation present 1, 3
• Alternative: IV beta-blockers for rate control 1

For Hemodynamically Unstable Patients

• Immediate synchronized electrical cardioversion is required if vagal maneuvers or adenosine fail or are not feasible 1
• Have defibrillation equipment immediately available, as adenosine may precipitate atrial fibrillation with rapid ventricular response 1

Prophylactic Management for Recurrent SVT

Medication Selection Based on Cardiac Status

• For patients without structural heart disease: Beta-blockers, calcium channel blockers (verapamil, diltiazem), or amiodarone are recommended for prophylaxis 1
• For patients with heart failure: Amiodarone is preferred as first-line since digoxin is frequently ineffective in high adrenergic states like surgery 1
• Flecainide or propafenone may be used in patients without structural heart disease or ischemic heart disease 1, 4

Special Considerations for Specific Populations

Ebstein Anomaly Patients:

• Preoperative catheter ablation or intraoperative surgical ablation of accessory pathways is reasonable (Class IIa recommendation) when undergoing surgical repair 1
• Failure to address accessory pathways can lead to recurrent arrhythmias and perioperative instability 1
• Preoperative electrophysiological evaluation is often warranted 1

Adult Congenital Heart Disease:

• Coordinate arrhythmia management with the surgical team 1
• Consider preoperative EP study with planned intraoperative ablation 1

Critical Perioperative Pitfalls to Avoid

Medication Errors

• Never use calcium channel blockers (verapamil, diltiazem) for wide-QRS-complex tachycardia of unknown origin, especially with myocardial dysfunction—presume ventricular tachycardia until proven otherwise 1
• Avoid digoxin and calcium channel blockers in pre-excited atrial fibrillation as they can cause cardiovascular collapse 1
• Beta-blockers, diltiazem, and verapamil carry risk of enhancing accessory pathway conduction if AVRT converts to AF 1

Anticoagulation Management

• For patients with chronic atrial fibrillation on oral anticoagulants, discontinue several days before surgery 1
• Consider bridging anticoagulation with low-molecular-weight or unfractionated heparin based on thromboembolic risk 1
• Warfarin can be reversed emergently with parenteral vitamin K or fresh frozen plasma if needed 1

Timing Considerations

• Beta-blockers accelerate conversion of atrial fibrillation to sinus rhythm in the ICU after non-cardiac surgery 1
• Most patients with sustained VT experience 80% of proarrhythmic events within 14 days of antiarrhythmic therapy initiation 4
• For patients requiring flecainide, hospital initiation with rhythm monitoring is mandatory due to proarrhythmic risk 4

Device Management

• Patients with ICDs who have preoperative tachytherapy inactivation require continuous cardiac monitoring with external defibrillation immediately available 1
• Ensure systems are in place to reactivate ICD tachytherapies before discontinuing monitoring 1