The clinical syndrome characterized by ventricular arrhythmias, collapsing episodes, sudden cardiac death and, sometimes, heart failure in the Boxer was previously referred to as Boxer Cardiomyopathy. More recent studied have demonstrated striking similarities, including the inheritance, to a human disease called Arrhythmogenic Right Venticular Cardiomyopathy (ARVC). The familial nature as well as the devastating outcome of the disease has lead to significant interest in developing screening methods for asymptomatic dogs prior to use for breeding. Screening is to develop a blood test are underway. However, although these screening methods will detect affected dogs, it appears that not all dogs that are affected will ever develop clinical signs. Unfortunately, these dogs may be removed from showing or breeding programs because of their abnormal status. The objective of this study is to evaluate asymptomatic and syncopal Boxers for findings that may relate to the development and presence of symptoms, including ventricular premature couple number, grade of arrhythmia, left and right ventricular size and function, BNP, Troponin I and family history.