RT Journal Article SR Electronic T1 77 The Pathological Disease Spectrum of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) in Sudden Cardiac Death Emphasising Biventricular Involvement and Challenges in Diagnosis JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP A42 OP A42 DO 10.1136/heartjnl-2015-308066.77 VO 101 IS Suppl 4 A1 Jan Lukas Robertus A1 Mary N Sheppard A1 Alice Burrell YR 2015 UL http://heart.bmj.com/content/101/Suppl_4/A42.1.abstract AB Introduction Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease of the heart muscle characterised by fibrofatty replacement of the myocardium. It is a major cause of sudden death in the young, specifically athletes. ARVC is largely a genetic disease with implications for living family members and cardiological screening. We present the largest detailed pathological study from the UK of arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnosed at post-mortem following sudden death.Methods and results We identified 121 cases of sudden cardiac death due to ARVC in our UK referral sudden death database. Cases were identified using our database compiled from 2873 sudden cardiac death cases received in our specialist national referral centre between 1994 and 2012. This study highlights clinical history, initial pathological opinion, macroscopic and microscopic findings on specialist examination.Individuals were predominantly male (82%) from 8–66 years with highest prevalence at 21–30 years. Cardiac arrest occurred mainly during/immediately after exertion (45%) and at rest (38%).Macroscopic examination showed dilatation of right atrium and ventricle with thinning (44%) and dilatation of left atrium and ventricle (19%). There were pale areas with fat replacement of epicardial muscle in both ventricular walls (70%) and septum (12%). The right ventricular outflow tract (RVOT) was involved in all biventricular cases. Left ventricular hypertrophy showed increased epicardial fat (49%) and right ventricular fatty hypertrophy (15%). 12% were macroscopically normal. Thrombi in the right ventricle occurred in 10% of cases.Histologically fibrofatty replacement with degenerate myocytes was seen in all cases, Biventricular disease predominated (78%). Above the midventricle there was always involvement of the epicardial surface of RVOT. Left ventricular involvement was epicardial and circumferentially with predominant involvement of the posterobasal wall. The biventricular disease cases had left dominance in 21% or right dominance in 17%. Of the 53 opinions by referring pathologists, only 27 were identified as ARVC highlighting the difficulty of diagnosis.Conclusion ARVC ranges from normal appearing hearts to widespread biventricular disease. ARVC has genetic implications and correct pathological diagnosis is vital to ensure that family members at risk are screened to prevent further sudden deaths.