Pitié-Salpêtrière Hospital, France
Title: First histologic demonstration of Atrial Dysplasia in two ARVD patients
Biography: Guy Hugues Fontaine
Since the reproduction of the disease-in-the-dish by the group of San Diego (Kim Nature 2013), the original term of ARVD is now back in Force (Fontaine Editorial AJC 2014). ARVD has been discovered by its disorder in ventricular abnormal activation leading to premature reactivation of myocardium called an extrasystole producing a basic bump in the chest. In a most severe form several consecutive bumps are observed poorly tolerated by women when they are frequent. In the worst situation this abnormal fast cardiac activity may result in sudden unexpected death. The disease is the result of a genetic anomaly mostly affecting the RV in which the myocardium is occupied bat fat and fibrosis. In addition, presence of lymphocytes is the marker of poor prognosis. In anecdotal cases it was observed that patients later confirmed as typical ARVD had atrial arrhythmias as the first presentation of the disease suggesting that the disease can start by the atrium before the ventricle and that atrium was also involved. This concept has been recently confirmed and published. However, I am the first to study the histology of the atrium in two patients with known ARVD who died suddenly in whom I performed myself the extraction of the heart immediately after death and in whom samples were taken from both ventricles and atria giving perfect gross pathology before immersion in formalin.
Special histologic staining was performed to clearly identify fibrosis. In the first patient only severe interstitial fibrosis was observed all over right and left ventricle. In the second patient a less severe interstitial fibrosis was observed but was associated to replacement fibrosis with some lymphocytes suggesting superimposed myocarditis.
The systematic study of the right ventricle of 82 individuals who died of non-cardiac cause in a general hospital showed that 3.7% had the histologic pattern of RVD and not ARVD since those individuals had non arrhythmias. Therefore, these cases represent the quiescent form of ARVD. It is therefore possible to consider that the same situation exists in the general population as far as atrial dysplasia is concerned. This situation may lead to atrial fibrillation spontaneously because of the anatomic creation of an anatomic substrate or it could a more stable form which become arrhythmogenic in case of superimposed myocarditis (Bonny CRP 2001).