| RARS | Refractory Anemia with Ringed Sideroblast = AISA |
|---|---|
| AERPAP | antegrade effective refractory period accessory pathway |
| ARMS | adverse reaction monitoring system; amplification refractory mutation system |
| AVNFRP | atrioventricular node functional refractory period |
| AVRP | atrioventricular refractory period |