IRCT201411097225N2 IRCT 2014-12-15 Investigator The effect of rhythmic breathing on Acute Coronary Syndrome The effect of rhythmic breathing on chest pain and cardiorespiratory parameters Acute Coronary Syndrome patients admitted at CCU 2014-05-22 anticipated 112 Complete https://irct.ir/trial/7662 interventional Randomization: Randomized, Blinding: Not blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment. N/A Condition 1: Acute Coronary Syndrome. Condition 2: Acute Coronary Syndrome. Condition 3: Acute Coronary Syndrome. Condition 4: Acute Coronary Syndrome. Condition 5: Acute Coronary Syndrome. Condition 6: Acute Coronary Syndrome. Condition 7: Acute Coronary Syndrome. Intervention 1: The intervention group will do the rhythmic breathing for twenty minutes every five minutes once and it will take a minute and during their breathing will focus only on entering and leaving air. In this way that the patient will be supine state with eyes closed and with counting numbers 1, 2 and 3 will enter air through the nose into the lungs, then by counting 1, 2 and 3 will keep the air in their lungs and finally, by counting 1, 2 and 3 will out the air through the mouth. Intervention 2: In control group, the intervention will not take place except routine treatments.