Abstract 17536: Cardiac Macrophage is Required to Avoid Atrioventricular Block After Right Heart Pressure Overload

Right heart dysfunction is of current interest in managing severe heart failure and pulmonary hypertension, and cardiomyocyte-immune cell interactions play an important role after myocardial infarction. However, the contributions of cardiac immune cells to right heart function is not well understood. We assessed the hypothesis that immune cells contribute to stress responses to right heart stress. We analyzed a right heart pressure overload model in mice using pulmonary artery banding (PAB) to develop right heart hypertrophy and fibrosis without lung injury. All wild-type mice with PAB could survive for at least several months. After PAB, macrophages, CD4 T cells, CD8 T cells, and B cells were increased in the heart. To analyze the function of these cells, PAB was performed in macrophage-depleted, CD4, CD8 T cell, or B cell knockout mice. Only macrophage-depleted mice showed a complete atrioventricular block (CAVB) and sudden death two hours after PAB. Gap junction protein Cx40 was significantly reduced i...