Belittled

HI! I work with a doctor who constantly is riding my case about something. Regardless how ridiculous the complaint may seem he is always criticizing my work. If I am in charge, he constantly puts me down, telling me that I am not demanding enough toward the other nurses, and I should be directing them as what to do next, not taking an assignment myself. He consistantly is doing things to "irk" me, even when he knows it's wrong. For example....he once gave a patient 3 sublingual nitro at one time, even with me standing there telling him not to. He argues with me in front of patients, and once even argued with me about whether or not a patient was having an AMI vs gallbladder symptoms. It was obvious on the EKG, that I had done that it was an inferior MI, but he insisted that I never should have done an EKG, because the patient was having epigastric pain, not an AMI......the patient ended up coding. None of the other docs have a problem with me or my judgement, it's just him...in fact, the other docs trust me to the point where they allow me to tell them what I want to do for the patient. So why does this particular doctor constantly belittle me in front of my peers and patients? How do I handle this?