Background & Aim: Anxiety is a common experience; which is felt as uneasiness, non-specific threat, and activation of autonomic nervous system. The aim of this study was to assess the effect of muscular relaxation on anxiety level of patients underwent cardiac catheterization.

Methods & Materials: In this clinical trial, 118 patients who were expected to have a cardiac catheterization were recruited from an educational hospital at Tehran University of Medical Science. The participants were allocated to two groups, including muscular relaxation group (50 patients), and control group (68 patients). Data were collected using a questionnaire, and a self-report paper for recording anxiety level. Anxiety level was recorded one hour before cardiac catheterization in two groups. Then, the intervention group was asked to listen to the Benson muscle relaxation guide direction tape for 20 minutes through headphone. After using muscle relaxation in the intervention group and immediately before cardiac catheterization, the anxiety level of the respondents was recorded once more. Control group received standard nursing cares. Data were analyzed using χ², Fisher's exact test, Kruscalwallis, Man-Whitney and Wilcoxon statistical tests in the SPSS.

Results: There were no significant difference between two groups in demographic characteristics and anxiety level before the intervention; and one hour before cardiac catheterization. After the intervention, the anxiety level was significantly reduced in the intervention group (P<0.001); while it increased in the control group.

Conclusion: Based on the results of this study, Benson muscle relaxation significantly decreased anxiety level in patients who were expected to go for cardiac catheterization.