<prompt> Myocardial re-infarction inhibitorBeta blockersNitratesCalcium channel blockersPotassium channel openers  <response>: Beta-blockers when given in MI, prevent arrhythmias and also reinfarction.Hence they. increase the morbidity and decrease the moality . patient when discharged is put on beta blockers. REF: KD Tripathi 8th ed. 