This randomised controlled trial will be conducted to evaluate the effect of breathing exercise on anxiety, pain and vital signs in patients undergoing coronary angiography before angiography.

Hypotheses of the study; H11: The anxiety level of the patients who underwent breathing exercise is lower than the patients in the control group.

H12: The pain level of the patients who underwent breathing exercise is lower than the control group H13: The vital signs of the patients who underwent breathing exercises are within normal limits compared to the control group.

In the study, there will be an intervention group in which breathing exercise will be applied and a control group in which no intervention will be applied.

Data will be collected with the pre-test data collection form half an hour before the angiography procedure in patients in the intervention and control groups. Patients in the intervention group will be given breathing exercises, while patients in the control group will not be subjected to any intervention. After the angioplasty procedure, data will be collected from the intervention and control groups with post-test data collection forms.

In determining the groups; simple randomisation method will be used in order to form the sample in a way to ensure equal number and random distribution of the two groups. Randomisation will be done by using the website (https://www.randomizer.org). In line with the randomisation list; patients who meet the inclusion criteria will be included in the intervention and control groups. Inclusion in the intervention and control groups will be made by the researchers in line with the randomisation list. In order for the responsible researcher to apply breathing exercises; he/she has a breathing techniques coaching certificate. In the research; triple breathing technique (full yogic breathing) and square breathing technique will be used. Patients will be informed about the research and their written and verbal consent will be obtained. Data will be collected with the pre-test data collection form half an hour before the angiography procedure in patients in the intervention and control groups. Patients in the intervention group will be given breathing exercises, while patients in the control group will not be subjected to any intervention. The breathing exercise will be performed as a single session and will last approximately 15-20 minutes. After the angioplasty procedure, data will be collected from the intervention and control groups with post-test data collection forms.

Inclusion Criteria:

• Patients undergoing coronary angiography for the first time
• Over 18 years of age
• No respiratory distress
• No problems with communication
• Volunteering to be included in the study.

Exclusion Criteria:

• Taking any medication to suppress anxiety symptoms
• Patients undergoing emergency coronary angiography and/or patients complaining of chest pain
• Patients on antihypertensive treatment before the procedure due to hypertension
• Patients who underwent emergency intervention during coronary angiography, surgical procedure and intensive care unit for follow-up were excluded from the study.

The post-test measurements will be collected by a nurse working in the angiography ward who is not connected with the study.