443 Role of electro-anatomical mapping of the right ventricle in evaluation of patients with unexplained cardiac arrest and familial sudden death

Abstract

Cardiac arrest without evident cardiac disease may be caused by uncommon genetic conditions, including primary electrical disease and latent arrhythmogenic right ventricular cardiomyopathy (ARVC). The Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER) was designed to assess the results of systematic assessment of patients with unexplained cardiac arrest (UCA) and their 1st degree relatives. The objective of this study was to assess the role of electro-anatomical mapping of the right ventricle (RV) to aid in the diagnosis of latent ARVC in these patients. After exclusion of structural heart disease and manifest primary electrical disease (normal echo and ECG), patients with UCA and select family members underwent an electro-anatomic map of the RV during SR using a 4 mm Navistar catheter (Biosense-Webster, Diamond Bar, California). The unipolar (filtered at 0.5 to 400 Hz) and bipolar (filtered at 30 to 400 Hz) intracardiac electrograms were sampled at each endocardial site. Areas of abnormal voltage were defined as < 1mV. A total of 18 patients (15 UCA and 3 first degree relatives, age 37 ± 13 years, 61% male) underwent electro-anatomic map of the RV during SR. Three patients had abnormal RV voltage maps; all 3 patients had a history of UCA. Patient 1 is a 57 yo male with additional phenotypic evidence suggestive but not diagnostic of ARVC (T Wave inversion in V2, minor RV abnormality on MRI and borderline SAECG), and is therefore considered likely to have ARVC. Patient 2 was a 55 yo male who had additional phenotypic evidence suggestive but not diagnostic of ARVC. The patient succumbed from electrical strorm and at autopsy was found to have sarcoid cardiomyopathy. Patient 3 is a 71 yo male who developed progressively severe mitral regurgitation secondary to mitral valve prolapse and monomorphic VT originating from below the mitral valve and is felt not to have ARVC. Another patient with a normal RV voltage map had phenotypic evidence suggestive but not diagnostic of ARVC. We found abnormal electro-anatomic maps of the right ventricle in 3/15 patients with UCA. Additional investigations suggested a diagnosis of ARVC in 1/3 patients. Another patient was initially felt to have ARVC but at autopsy was found to have sarcoid cardiomyopathy. The role of electro-anatomical mapping of the RV in evaluation of patients with unexplained cardiac arrest requires further investigation in a large cohort.