In a 67-year-old man post‑atrial fibrillation ablation presenting to the emergency department with a heart rate of 185 bpm and an ECG showing intermittent atrial fibrillation, atrial flutter, and ventricular tachycardia, what is the next step in management?

Management of Post-Ablation Atrial Fibrillation/Flutter with Ventricular Tachycardia and Heart Rate 185 bpm

Immediate synchronized electrical cardioversion is the definitive next step for this hemodynamically unstable patient presenting with intermittent atrial fibrillation, atrial flutter, and ventricular tachycardia at a heart rate of 185 bpm. 1, 2

Immediate Assessment of Hemodynamic Stability

The presence of VT intermixed with AFib/flutter at HR 185 bpm in a 67-year-old post-ablation patient demands immediate assessment for:

• Symptomatic hypotension (systolic BP <90 mmHg with altered mentation or end-organ hypoperfusion) 2
• Acute heart failure decompensation (pulmonary edema, severe dyspnea) 2
• Ongoing myocardial ischemia (chest pain, ST-segment changes) 2

If any of these are present, proceed directly to synchronized cardioversion without delay for pharmacologic therapy. 1, 2

Primary Management: Synchronized Electrical Cardioversion

Synchronized cardioversion should be performed immediately in hemodynamically unstable patients with supraventricular tachycardia or ventricular tachycardia, taking precedence over anticoagulation. 1, 2

Key Technical Points:

• Ensure synchronization mode is activated to avoid delivering shock during the vulnerable period of the cardiac cycle 1
• Start with appropriate energy levels: 100-200 J biphasic for AFib/flutter; 100 J for monomorphic VT 1
• Have defibrillation capability immediately available in case VT degenerates to ventricular fibrillation 1

Anticoagulation Considerations:

• Initiate parenteral anticoagulation (unfractionated heparin or therapeutic LMWH) before cardioversion if feasible, but do not delay emergency electrical conversion. 2
• Continue therapeutic anticoagulation for ≥4 weeks post-cardioversion regardless of baseline stroke risk 2

If Patient is Hemodynamically Stable

Avoid IV Amiodarone as First-Line in This Scenario

IV amiodarone is NOT the preferred initial approach for several critical reasons:

1. Contraindicated in pre-excited arrhythmias: If the intermittent rhythms include any degree of ventricular pre-excitation (which can occur post-ablation with accessory pathway involvement), amiodarone can accelerate ventricular rate and precipitate ventricular fibrillation 1

2. Significant hypotension risk: Amiodarone causes hypotension in a substantial proportion of patients, which may be refractory and fatal 3

3. Proarrhythmic potential: Amiodarone can worsen existing arrhythmias or precipitate new ones, including torsades de pointes, particularly problematic given the mixed rhythm presentation 3

Preferred Pharmacologic Approach for Stable Patients:

For rate control in hemodynamically stable patients with atrial flutter/fibrillation:

• IV beta-blockers (metoprolol 2.5-5 mg IV over 2 minutes, up to 3 doses) or diltiazem (0.25 mg/kg IV over 2 minutes) are first-line agents 1
• These agents achieve rate control in approximately 70% of patients 4

For rhythm control/cardioversion in stable patients:

• IV ibutilide (1 mg over 10 minutes, may repeat once) is the preferred pharmacologic agent for atrial flutter conversion, with ~60% success rate 1, 5
• Requires continuous ECG monitoring during and for ≥4 hours after administration due to torsades de pointes risk (3.6%) 1, 5
• Pretreatment with magnesium increases efficacy and reduces proarrhythmia risk 1

Critical Contraindications and Pitfalls

Absolute Contraindications to AV Nodal Blockers:

Do NOT use beta-blockers, calcium channel blockers, digoxin, adenosine, or amiodarone if there is any evidence of:

• Wolff-Parkinson-White syndrome with pre-excitation (wide QRS complexes during tachycardia) 1, 6
• These drugs can accelerate conduction through the accessory pathway, precipitating ventricular fibrillation 1

In pre-excited AFib/flutter, use IV procainamide (15 mg/kg over 30-60 minutes) instead 1

Post-Ablation Specific Considerations:

• Post-AF ablation patients have ~5% risk of developing atrial tachycardia or non-CTI-dependent flutter 1
• Rate control is often more difficult in post-ablation atrial flutter than in pre-ablation AFib 1
• Many post-ablation arrhythmias occurring within 3 months will not recur and may not require aggressive long-term management 1

Algorithmic Approach

1. Assess hemodynamic stability immediately 2

   • If unstable → Immediate synchronized cardioversion 1, 2
   • If stable → Proceed to step 2

2. Obtain 12-lead ECG to evaluate for pre-excitation 1

   • If wide QRS with delta waves → Use IV procainamide, NOT AV nodal blockers 1
   • If narrow QRS or typical bundle branch block → Proceed to step 3

3. For rate control in stable patients without pre-excitation:

   • First-line: IV metoprolol or diltiazem 1, 7
   • Second-line: Add digoxin if monotherapy insufficient 1
   • Avoid amiodarone unless other agents fail 1

4. For rhythm control in stable patients:

   • Preferred: IV ibutilide with continuous monitoring 1, 5
   • Alternative: Synchronized cardioversion after adequate sedation 1

5. Ensure anticoagulation:

   • Calculate CHA₂DS₂-VASc score 7
   • Initiate DOAC if score ≥2 (males) or ≥3 (females) 7
   • Continue for ≥4 weeks post-cardioversion 2