What information should be included in a referral letter for a patient undergoing reablation, including their medical history, current medication regimen, and potential risks and benefits of the procedure?

Referral Letter for Reablation: Essential Components

Your referral letter should comprehensively document the clinical indication for reablation, prior ablation details, current arrhythmia burden, medication history with response/intolerance, anticoagulation status, and procedural risks specific to repeat intervention.

Patient Identification and Clinical Indication

• Clearly state the specific arrhythmia requiring reablation (e.g., recurrent symptomatic atrial fibrillation, atrial flutter, AVNRT, accessory pathway-mediated tachycardia, or ventricular tachycardia) 1
• Document symptom severity and impact on quality of life, including frequency of episodes, hemodynamic tolerance, and functional limitations 1
• Specify the Class I indication criteria met: drug resistance, drug intolerance, or patient preference to avoid long-term pharmacotherapy 1

Prior Ablation History

• Date(s) of previous ablation procedure(s) with specific location and technique used (radiofrequency vs. cryoablation) 1
• Initial success rate and time to recurrence after the index procedure 1
• Complications from prior ablation, if any, including valve damage, pericardial tamponade, AV block, pulmonary/systemic emboli, or nerve injury 1
• Mapping findings from previous procedure if available, particularly for ventricular tachycardia cases where multiple VT morphologies may exist 1

Current Arrhythmia Burden and Monitoring Data

• Recent ECG or rhythm monitoring documentation showing recurrent arrhythmia with specific morphology and rate 1
• Frequency and duration of episodes based on patient symptoms, device interrogation (if pacemaker/ICD present), or ambulatory monitoring 1
• For atrial fibrillation patients: CHA₂DS₂-VASc score to guide anticoagulation decisions perioperatively 1

Medication History

Antiarrhythmic Drug Trials

• List all antiarrhythmic medications tried with specific doses, duration of therapy, and reason for discontinuation (inefficacy vs. intolerance) 1
• Document specific adverse effects that led to drug intolerance (e.g., bradycardia, QT prolongation, thyroid dysfunction with amiodarone, pulmonary toxicity) 1

Current Anticoagulation Regimen

• Specify the anticoagulant agent and dose: warfarin with target INR 2.0-3.0, or direct oral anticoagulant (DOAC) with specific agent and dosing 1, 2
• Recent INR values if on warfarin (within 7 days of referral) 2
• Renal function (creatinine clearance) as this affects DOAC dosing and perioperative management 1
• Duration of anticoagulation therapy and any history of thromboembolic events or bleeding complications 1, 2

Other Relevant Medications

• Antiplatelet agents (aspirin, clopidogrel, ticagrelor) with indication and whether they can be safely discontinued 3
• Rate control medications (beta-blockers, calcium channel blockers, digoxin) with current doses 1
• Medications that interact with warfarin if applicable, including NSAIDs, antibiotics, or herbal supplements 2

Cardiac Structure and Function

• Left ventricular ejection fraction from recent echocardiography (within 6 months) 1
• Presence of structural heart disease: ischemic cardiomyopathy, prior myocardial infarction, valvular disease, or congenital abnormalities 1
• Left atrial size for atrial fibrillation/flutter cases, as this impacts success rates 1
• Presence of intracardiac thrombus on recent imaging, which would contraindicate immediate ablation 1

Risk Stratification for Reablation

Procedural Risks (Higher in Reablation)

• Overall complication rate from initial ablation: 2.1% for accessory pathways, 3% for ventricular tachycardia 1
• Mortality risk: 0.2% for accessory pathway ablation, with rare late deaths reported 1
• Specific risks for repeat procedures: increased scar tissue may complicate mapping, higher risk of perforation/tamponade, potential for AV block requiring permanent pacing 1

Bleeding Risk Assessment

• History of prior bleeding events (gastrointestinal, intracranial, or other major bleeding) 2, 4
• Risk factors for bleeding: age ≥65 years, hypertension, cerebrovascular disease, anemia, malignancy, renal insufficiency 2
• Concomitant medications increasing bleeding risk: NSAIDs, antiplatelet agents, or other anticoagulants 2, 3

Thromboembolic Risk

• CHA₂DS₂-VASc score for AF patients: score ≥2 in men or ≥3 in women indicates need for continued anticoagulation 1
• History of stroke, TIA, or systemic embolism which increases perioperative thrombotic risk 1, 2
• Presence of mechanical heart valve which requires specific anticoagulation management 1, 2

Perioperative Anticoagulation Plan

For Patients on Warfarin

• Temporary cessation without bridging is recommended for most patients (excluding recent stroke/TIA or mechanical valve) 1
• Bridging with low-molecular-weight heparin should NOT be administered except for mechanical valve or recent stroke/TIA 1
• Target INR <1.5 for procedure, with warfarin held 5 days prior 2

For Patients on DOACs

• Timing of interruption guided by specific agent, renal function, and bleeding risk of the procedure 1
• Preference for uninterrupted or interrupted DOAC over warfarin with bridging when feasible 1
• Resume anticoagulation when hemostasis is secure, typically within 24 hours post-procedure 1

Aspirin Management

• For patients on chronic anticoagulation with coronary disease: adding aspirin increases cardiovascular events (hazard ratio 1.53) and major bleeding (hazard ratio 3.35) compared to anticoagulation alone 3
• Aspirin should be discontinued perioperatively unless there is a compelling recent coronary indication 3

Laboratory and Imaging Requirements

• Complete blood count with platelet count >80,000 cells/mm³ 1
• Coagulation studies: PT/INR, aPTT 1, 2
• Comprehensive metabolic panel including serum creatinine (should be <2.5 mg/dL) 1
• Thyroid function tests if on amiodarone or considering its use 1
• Recent transesophageal echocardiogram (within 48 hours) if AF/flutter present to exclude left atrial thrombus 1

Expected Outcomes and Success Rates

Arrhythmia-Specific Success Rates

• Accessory pathways: 91% for left free-wall, 87% for septal, 82% for right free-wall locations 1
• Ventricular tachycardia: 71% overall success, but only 54% in ischemic heart disease; may be palliative rather than curative in structural heart disease 1
• AVNRT and typical atrial flutter: high success rates with first ablation, but reablation success may be lower due to scar tissue 1

Realistic Expectations

• For VT with extensive structural heart disease: catheter ablation may not eliminate need for ICD or antiarrhythmic therapy 1
• Multiple VT morphologies: single ablation may only address one circuit 1

Patient Preferences and Contraindications

• Patient's informed preference for ablation over continued medical therapy 1
• Absolute contraindications: active infection, inability to tolerate anticoagulation, pregnancy 1
• Relative contraindications: severe renal impairment, active malignancy with limited life expectancy, severe hepatic impairment 1

Contact Information and Urgency

• Your contact information for procedural questions or urgent clinical changes
• Urgency level: routine vs. expedited (e.g., for VT with ICD receiving multiple shocks despite reprogramming) 1
• Patient's availability for procedure scheduling and follow-up