IRCT20190611043864N1 IRCT 2020-12-30 Karaj University of Medical Sciences Low-dose ketamine effectiveness in acute coronary syndrome : Low-dose ketamine effectiveness in acute coronary syndrome with opioid unresponsive or hemodynamically unstable patients 2020-09-14 anticipated 140 Complete https://irct.ir/trial/50114 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Samples are readily available in the study (recruitment) and are divided into two groups of intervention and control based on random allocation (random block). Block Randomization method using the site (https://www.sealedenvelope.com/simple) has been used to assign samples to the intervention and control groups. 35 blocks of 4 with a specific code are prepared and used, Blinding description: The method of blinding is that the five-digit serial numbers produced in the process of random allocation are placed in sealed envelopes and assigned by an independent person from the research team and by telephone to each of the eligible individuals. 3 Acute Coronary Syndrome. Intervention 1: Intervention group: A group of patients receiving low-dose ketamine as part of treatment (0.1-0.3 mg / kg). Intervention 2: Control group: A group of patients who do not receive low-dose ketamine as part of treatment (0.1-0.3 mg / kg). Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is I have to consult with my teachers.