Endoscopic technique: All the patients included in the protocol (intervention group and control group) will be studied by upper endoscopy with Magniview™ scopes and EPK-i7010 processor (OE system™). The endoscopy images will be seen on a 27inch, flat panel, high definition LCD monitor (Radiance™ ultra SC-WU27-G1520 model). The endoscopies will be performed by three endoscopist trained on this new technology (all of them with more than 10 procedures).