Why are electrophysiological studies (EPS) done for arrhythmogenic right ventricular dysplasia (ARVD)?

Electrophysiological Studies in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Electrophysiological studies (EPS) in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) are primarily performed for risk stratification, differential diagnosis, and to guide therapeutic decisions, particularly in asymptomatic patients or those with syncope of unclear etiology.

Primary Indications for EPS in ARVD/C

Risk Stratification

• EPS can help identify patients at high risk for sudden cardiac death who may benefit from ICD implantation
• According to the 2017 AHA/ACC/HRS guidelines, EPS may be considered for risk stratification in asymptomatic patients with clinical evidence of ARVD/C (Class IIb, Level of Evidence B-NR) 1
• The filtered QRS duration on signal-averaged ECG is highly predictive of VT inducibility during EPS in ARVD/C patients (sensitivity 91%, specificity 90%) 2

Differential Diagnosis

• EPS may be considered for differentiating ARVD/C from benign right ventricular outflow tract (RVOT) tachycardia or cardiac sarcoidosis (Class IIb, Level of Evidence B-NR) 1
• This distinction is crucial as management strategies and prognosis differ significantly between these conditions

Guiding Therapy

• EPS can guide catheter ablation procedures for ventricular tachycardia in ARVD/C patients
• Induction of VT/VF is often attempted before catheter ablation to guide the procedure and determine success after ablation 1
• EPS can help determine the mechanism of wide complex tachycardias in ARVD/C patients

When to Consider EPS in ARVD/C Patients

EPS should be considered in the following scenarios:

1. Patients with syncope: When bradyarrhythmias or tachyarrhythmias are suspected based on symptoms or non-invasive assessment, especially in patients with structural heart disease (Class I, Level of Evidence C) 1

2. Asymptomatic patients: For risk stratification in asymptomatic patients with clinical evidence of ARVD/C (Class IIb, Level of Evidence B-NR) 1

3. Diagnostic uncertainty: When differentiating between ARVD/C and benign RVOT tachycardia or sarcoidosis (Class IIb, Level of Evidence B) 1

4. Before catheter ablation: To guide VT ablation procedures and assess their efficacy 1, 3

Limitations of EPS in ARVD/C

• EPS is not recommended for risk stratification in patients who already meet criteria for ICD implantation (Class III: No Benefit, Level of Evidence B-R) 1
• The progressive nature of ARVD/C suggests that catheter ablation guided by EPS would not be a long-term curative procedure 4
• EPS results alone should not be the sole determinant for ICD placement decisions, as several authors have concluded that patients meeting Task Force criteria for ARVD/C are at high risk for sudden cardiac death regardless of EPS results 4

Complementary Diagnostic Approaches

EPS should be considered as part of a comprehensive evaluation that includes:

• Cardiac MRI (Class I, Level of Evidence B-NR for suspected ARVD/C with VA or ECG abnormalities) 1
• Signal-averaged ECG (Class IIa, Level of Evidence B-NR) 1
• 12-lead ECG and echocardiography 1, 5
• Genetic testing and counseling (Class IIa, Level of Evidence B-NR) 1

Conclusion

EPS serves as a valuable tool in the management of ARVD/C, particularly for risk stratification in asymptomatic patients and differential diagnosis from other conditions with similar presentations. However, its role should be considered within the context of a comprehensive evaluation that includes other diagnostic modalities and clinical factors.