What is the recommended pre-procedural workup for a patient with atrial flutter being admitted for an ablation procedure?

Pre-Procedural Workup for Atrial Flutter Ablation

All patients with atrial flutter scheduled for ablation require anticoagulation for at least 3 weeks prior to the procedure and imaging to exclude left atrial thrombus, following the same protocols as atrial fibrillation. 1

Anticoagulation Management

• Initiate oral anticoagulation at least 3 weeks before catheter ablation in patients at elevated thromboembolic risk to prevent peri-procedural ischemic stroke and thromboembolism 1
• Continue uninterrupted oral anticoagulation through the ablation procedure—do not hold anticoagulation 1
• Prefer DOACs over warfarin when eligible, as they reduce bleeding risk while maintaining stroke prevention 1
• The stroke risk in atrial flutter averages 3% annually, similar to atrial fibrillation, making anticoagulation essential 1, 2

Cardiac Imaging for Thrombus Exclusion

ECG-gated cardiac CT with IV contrast is the preferred imaging modality for pre-procedural planning, as it provides anatomic mapping data while screening for thrombus with high negative predictive value 1

CT Heart Function and Morphology With IV Contrast

• Provides comprehensive assessment of left atrium, left atrial appendage, and pulmonary venous anatomy 1
• Specificity and negative predictive value of 88% and 100% respectively for thrombus detection compared to TEE 1
• Adding a delayed phase imaging increases specificity to 100% 1
• Allows selective use of TEE only when CT is positive, with no difference in periprocedural stroke rates (0.2% vs 0.2%, p>0.99) 1
• Identifies cardiovascular anatomic variants in 18.7% of cases that may affect procedural planning 1
• Assesses left atrial size, which predicts arrhythmia recurrence (HR 1.011/mL, 95% CI 1.003-1.020, p=0.002) 1

Alternative: CTA Chest With IV Contrast

• Non-ECG-gated CTA provides adequate anatomic assessment with significantly lower radiation dose (p<0.0001) compared to gated studies 1
• No significant difference in visual quality, catheter ablation parameters, or AF recurrence rates compared to ECG-gated protocols 1

Transesophageal Echocardiography

• Reserve TEE for cases where CT is positive for thrombus or contraindicated 1
• Not routinely necessary when high-quality cardiac CT with delayed imaging is available 1

Baseline Laboratory and Cardiac Assessment

Essential Pre-Procedural Testing

• Transthoracic echocardiogram to assess:

  • Left ventricular ejection fraction (LVEF <50% suggests possible tachycardia-induced cardiomyopathy) 3
  • Left atrial size (increased volume predicts recurrence) 1
  • Structural heart disease presence 4
  • Valvular abnormalities 1

• 12-lead ECG to document:

  • Baseline rhythm and conduction intervals
  • Presence of pre-excitation (contraindication to AV nodal blockers) 1
  • QT interval (important for post-procedural antiarrhythmic selection) 2

• Basic metabolic panel including renal function (affects anticoagulation dosing and dofetilide eligibility) 5

• Complete blood count and coagulation studies (baseline for anticoagulation monitoring) 1

Risk Stratification for Post-Ablation Atrial Fibrillation

Document the following high-risk features, as 50-82% of patients develop atrial fibrillation after flutter ablation during long-term follow-up: 1, 6

• History of prior atrial fibrillation (strongest predictor of post-ablation AF) 1, 7, 4
• Number of prior cardioversions 7
• Number of failed antiarrhythmic drugs 4
• Depressed left ventricular function 1
• Structural heart disease or ischemic heart disease 1, 4
• Increased left atrial size 1
• Presence of heart failure symptoms (NYHA class) 3

Medication Review and Optimization

Rate Control Medications

• Continue beta blockers, diltiazem, or verapamil for rate control if already prescribed 1, 5
• Higher doses or combination therapy often needed for adequate rate control in flutter compared to fibrillation 1
• Avoid AV nodal blockers if pre-excitation is present on ECG (risk of ventricular fibrillation) 1, 2

Antiarrhythmic Drugs

• Document current antiarrhythmic use and response 7, 4
• Consider continuing amiodarone, dofetilide, or sotalol through the procedure if already prescribed 1, 5

Cardioprotective Medications

• ACE inhibitors/ARBs and diuretics may reduce post-ablation atrial fibrillation risk and should be continued if prescribed for other indications 7

Common Pitfalls to Avoid

• Failing to anticoagulate for full 3 weeks pre-procedure increases stroke risk 1
• Holding anticoagulation peri-procedurally is contraindicated—continue uninterrupted 1
• Using only unenhanced CT cannot adequately assess for thrombus or integrate with electroanatomic mapping 1
• Assuming successful flutter ablation eliminates need for ongoing anticoagulation—continue based on CHA₂DS₂-VASc score, not ablation success 1
• Not screening for tachycardia-induced cardiomyopathy in patients with reduced LVEF, as 55% may have complete resolution after ablation 3
• Inadequate counseling about post-ablation atrial fibrillation risk, which occurs in 50% of patients during long-term follow-up 6