Right bundle branch is a group of pathways for rhythmetic electrical impulses to pass to energize the rightside ventricle to contract and no impulse puts cells in relaxation mode. Incomplete (partial) block could cause irregular (skipped) heartbeats, etc. and it may or may not be of any medical significance.
A myocardiac infarction (MI) and acute ST elevation (EKG segment printout) indicates heart cell damage due to a heart attack in the anterior region of the heart. An EKG is not a very reliable source to determine heart cell damage...requires an echo to support that finding and clinical evidence.
High blood pressure is usually due to heardening and occlusion of system vessels. Untreated it can overwork the heart and eventually cause a failure of the heart to adequately supply blood/oxygen to the system, a heart attack, stroke, etc.