Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is predominantly an inherited cardiomyopathy with typical histopathological characteristics of fibro-fatty infiltration mainly involving the right ventricular (RV) inflow tract, RV outflow tract, and RV apex in the majority of patients. The above pathologic evolution frequently brings patients with ARVD/C to medical attention owing to the manifestation of syncope, sudden cardiac death (SCD), ventricular arrhythmogenesis, or heart failure. To prevent future or recurrent SCD, an implantable cardiac defibrillator (ICD) is highly desirable in patients with ARVD/C who had experienced unexplained syncope, hemodynamically intolerable ventricular tachycardia (VT), ventricular fibrillation, and/or aborted SCD. Notably, the management of frequent ventricular tachyarrhythmias in ARVD/C is challenging, and the use of antiarrhythmic drugs could be unsatisfactory or limited by the unfavorable side effects. Therefore, radiofrequency catheter ablation (RFCA) has been implemented to treat the drug-refractory VT in ARVD/C for decades. However, the initial understanding of the link between fibro-fatty pathogenesis and ventricular arrhythmogenesis in ARVD/C is scarce, the efficacy and prognosis of endocardial RFCA alone were limited and disappointing. The electrophysiologists had broken through this frontier after better illustration of epicardial substrates and broadly application of epicardial approaches in ARVD/C. In recent works of literature, the application of epicardial ablation also successfully results in higher procedural success and decreases VT recurrences in patients with ARVD/C who are refractory to the endocardial approach during long-term follow-up. In this article, we review the important evolution on the delineation of arrhythmogenic substrates, ablation strategies, and ablation outcome of VT in patients with ARVD/C.

BACKGROUND AND OBJECTIVES: The differences between electromagnetic-based mapping (EM) and impedance-based mapping (IM) in 3D anatomical reconstruction have not been fully clarified. We aimed to investigate the anatomical accuracy between EM (MediGuide™) and IM (EnSite Velocity™) systems. METHODS: We investigated 15 consecutive patients (10 males, mean age 58±9 years) who underwent pulmonary veins (PVs) isolation for paroxysmal atrial fibrillation (PAF). Contrast-enhanced computed tomography (CT) image of the left atrium (LA) was acquired before ablation and the 3D geometry of the LA was constructed using EM during ablation procedure. We measured the 4 PV angles between the main trunk of each PV and the posterior LA after field scaling. Additionally, the posterior LA surface area was measured. The variables were compared to those of CT-based geometry. A control group of 40 patients who underwent conventional PVs isolation using IM were also evaluated. RESULTS: The actual and relative changes of EM and CT-based geometry in all PV angles and posterior LA were significantly smaller compared to those of IM and CT-based geometry. Intraclass correlation coefficient (ICC) between EM and CT-based geometry were 0.871 (right superior pulmonary vein [RSPV]), 0.887 (right inferior pulmonary vein [RIPV]), 0.853 (left superior pulmonary vein [LSPV]), 0.911 (left inferior pulmonary vein [LIPV]), and 0.833 (posterior LA). On the other hand, ICC between IM and CT-based geometry were 0.548 (RSPV), 0.639 (RIPV), 0.691 (LSPV), 0.706 (LIPV), and 0.568 (posterior LA). CONCLUSIONS Image integration with EM enables high accurate visualization of cardiac anatomy compared to IM in PAF ablation.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is predominantly an inherited cardiomyopathy with typical histopathological characteristics of fibro-fatty infiltration mainly involving the right ventricular (RV) inflow tract, RV outflow tract, and RV apex in the majority of patients. The above pathologic evolution frequently brings patients with ARVD/C to medical attention owing to the manifestation of syncope, sudden cardiac death (SCD), ventricular arrhythmogenesis, or heart failure. To prevent future or recurrent SCD, an implantable cardiac defibrillator (ICD) is highly desirable in patients with ARVD/C who had experienced unexplained syncope, hemodynamically intolerable ventricular tachycardia (VT), ventricular fibrillation, and/or aborted SCD. Notably, the management of frequent ventricular tachyarrhythmias in ARVD/C is challenging, and the use of antiarrhythmic drugs could be unsatisfactory or limited by the unfavorable side effects. Therefore, radiofrequency catheter ablation (RFCA) has been implemented to treat the drug-refractory VT in ARVD/C for decades. However, the initial understanding of the link between fibro-fatty pathogenesis and ventricular arrhythmogenesis in ARVD/C is scarce, the efficacy and prognosis of endocardial RFCA alone were limited and disappointing. The electrophysiologists had broken through this frontier after better illustration of epicardial substrates and broadly application of epicardial approaches in ARVD/C. In recent works of literature, the application of epicardial ablation also successfully results in higher procedural success and decreases VT recurrences in patients with ARVD/C who are refractory to the endocardial approach during long-term follow-up. In this article, we review the important evolution on the delineation of arrhythmogenic substrates, ablation strategies, and ablation outcome of VT in patients with ARVD/C.
Anti-Arrhythmia Agents ; Arrhythmogenic Right Ventricular Dysplasia ; Cardiomyopathies ; Catheter Ablation ; Catheters ; Death, Sudden, Cardiac ; Defibrillators ; Epicardial Mapping ; Follow-Up Studies ; Heart Failure ; Humans ; Prognosis ; Recurrence ; Syncope ; Tachycardia ; Tachycardia, Ventricular ; Ventricular Fibrillation

BACKGROUND AND OBJECTIVES: The differences between electromagnetic-based mapping (EM) and impedance-based mapping (IM) in 3D anatomical reconstruction have not been fully clarified. We aimed to investigate the anatomical accuracy between EM (MediGuide™) and IM (EnSite Velocity™) systems. METHODS: We investigated 15 consecutive patients (10 males, mean age 58±9 years) who underwent pulmonary veins (PVs) isolation for paroxysmal atrial fibrillation (PAF). Contrast-enhanced computed tomography (CT) image of the left atrium (LA) was acquired before ablation and the 3D geometry of the LA was constructed using EM during ablation procedure. We measured the 4 PV angles between the main trunk of each PV and the posterior LA after field scaling. Additionally, the posterior LA surface area was measured. The variables were compared to those of CT-based geometry. A control group of 40 patients who underwent conventional PVs isolation using IM were also evaluated. RESULTS: The actual and relative changes of EM and CT-based geometry in all PV angles and posterior LA were significantly smaller compared to those of IM and CT-based geometry. Intraclass correlation coefficient (ICC) between EM and CT-based geometry were 0.871 (right superior pulmonary vein [RSPV]), 0.887 (right inferior pulmonary vein [RIPV]), 0.853 (left superior pulmonary vein [LSPV]), 0.911 (left inferior pulmonary vein [LIPV]), and 0.833 (posterior LA). On the other hand, ICC between IM and CT-based geometry were 0.548 (RSPV), 0.639 (RIPV), 0.691 (LSPV), 0.706 (LIPV), and 0.568 (posterior LA). CONCLUSIONS: Image integration with EM enables high accurate visualization of cardiac anatomy compared to IM in PAF ablation.
Atrial Fibrillation ; Atrial Flutter ; Catheters ; Fluoroscopy ; Hand ; Heart Atria ; Humans ; Magnets ; Male ; Pulmonary Veins