This study was designed as a randomized controlled experimental type in order to determine the effect of slow breathing exercise applied after the procedure on heart rate, blood pressure and quality of life in patients who underwent Primary Percutaneous Coronary Intervention (PCI) I after the diagnosis of ST Elevation Myocardial Infarction (STEMI).

Patients who underwent primary PCI due to STEMI in a Training and Research Hospital in Istanbul will constitute the study population. A sample will be formed with a total of 80 patients, 40 experimental and 40 control groups, selected by computer assisted simple randomization method among volunteer patients who underwent primary PCI and met the inclusion criteria.

In this study, slow breathing exercise training will be given to the experimental group by the coordinator. In their home followmup after discharge, they will be asked to do slow breathing exercises for 10 minutes twice a day for eight weeks.

Data will be collected using the "Patient Information Form", "MacNew Heart Disease Health Related Quality of Life Scale", "VAS Breath Therapy Satisfaction Evaluation Form", "Self-Monitoring Form" and "Patient Follow up Form". Patients will be seen again during the outpatient clinic examination in the fourth and eighth weeks and the effectiveness of slow breathing exercises will be evaluated with data collection forms.

Cardiovascular Diseases (CVD) is still the leading cause of death in the world and in our country, despite significant advances in its diagnosis and treatment. Acute Coronary Syndromes (ACS), which are among the CVD's, occur with the deterioration of the integrity of the atherosclerotic plaque in the coronary vessels. The deadliest form of ACS is ST Elevation Myocardial Infarction (STEMI).

Primary Percutaneous Coronary Intervention (PCI) is recommended primarily in the treatment of acute myocardial infarction. In these patients, changes in vital signs resulting from diagnosis and treatment and a permanent effect on quality of life can be observed.

Slow breathing exercise is a behavioral technique in which a low breathing rate is applied. Breathing exercises reduce heart rate, blood pressure, reduce anxiety and pain while shown to improve symptoms and improve quality of life in patients with chronic obstructive pulmonary disease and asthma. This technique provides conscious deep and slow breathing and effective breathing, as well as improving conscious control over relaxation and increasing awareness.

This study was designed as a randomized controlled experimental type in order to determine the effect of slow breathing exercise applied after the procedure on heart rate, blood pressure and quality of life in patients who underwent PCI after the diagnosis of STEMI. Study data will be collected between 23 October 2023- 30 April 2024 Patients who underwent primary PCI due to STEMI in a Training and Research Hospital in Istanbul will constitute the study population. A sample will be formed with a total of 80 patients, 40 experimental and 40 control groups, selected by computer assisted simple randomization method among volunteer patients who underwent primary PCI and met the inclusion criteria.

In the study, slow breathing exercise training will be given to the experimental group by the coordinator. In their home followmup after discharge, they will be asked to do slow breathing exercises for 10 minutes twice a day for eight weeks. It will be ensured that video calls and breathing exercises are performed together in the form of conference calls.. "Slow Breathing Exercise Training Booklet" and "Slow Breathing Exercise Short Film Video" will be used in the trainings. A calibrated portable digital upper arm sphygmomanometer will be used for heart rate and blood pressure measurement. Groups will be asked to record their own pulse and blood pressure measurements at home.

Data will be collected using the "Patient Information Form", "Mac New Heart Disease Health Related Quality of Life Scale", "VAS Breath Therapy Satisfaction Evaluation Form", "Self-Monitoring Form" and "Patient Follow up Form". Patients will be seen again during the outpatient clinic examination in the fourth and eighth weeks and the effectiveness of slow breathing exercises will be evaluated with data collection forms.

SPSS (IBM Corp., Armonk, NY, USA) program will be used in the analysis of the findings. Before analysis, the normality of the data will be evaluated with the Shapiro-Wilk test. Comparisons between the two groups will be made with descriptive statistics (frequency, percentage, etc.) in the analysis, as well as the Independent Sample t-test (in data with normal distribution) and Mann-Whitney U test (in data that does not show normal distribution) in quantitative data. In comparisons of more than two groups, One-Way Analysis of Variance (One-way ANOVA) or its non-parametric equivalent Kruskal-Wallis test will be used. Paired Samples t-Test or its non-parametric equivalent Wilcoxon test will be used to test the difference in quantitative repeated measurements. Qualitative comparisons between groups will be made with the Chi-Square test. Results, significance in the 95% confidence interval will be evaluated under p<0.05.

Inclusion Criteria:

• Young adult patients between the ages of 18-65,
• Patients who have not received fibrinolytic therapy before or simultaneously with Percutaneous Coronary Intervention (PCI) procedure,
• Patients who have passed 24 hours after the PCI procedure,
• Patients with a pulse > 60/min (whether or not beta blockers are used after PCI),
• Patients without rhythm problems,
• Patients with hypertension (systolic blood pressure 140-179 mmHg, diastolic blood pressure 90-109 mmHg), (whether or not they use antihypertensive and beta blocker drugs),
• Patients without a diagnosis of mental or psychiatric disease,
• Patients who have the materials to watch the breathing exercise video,
• Patients who can receive reminder messages and make video calls (with devices such as a smartphone, computer, tablet, etc.),
• Patients with a portable blood pressure monitor suitable for pulse and blood pressure measurement during home monitoring (the necessary equipment will be provided within the scope of the TUBITAK project),
• Patients without hearing or visual impairment,
• Patients who can read and write
• Patients who can communicate,
• Patients without language problems,
• Patients who volunteer and indicate this verbally and in writing

Exclusion Criteria:

• Patients with elective/appointed appointments for whom PCI is planned in advance,
• Patients whose PCI procedure failed,
• Patients who underwent only thrombus aspiration and balloon angioplasty during the PCI procedure,
• Patients who have previously undergone PCI and at least one year has not passed since,
• Patients who do not comply with planned interventions,
• Patients who do not volunteer to participate in the study,
• Patients with physical limitations and respiratory distress who cannot do breathing exercises,
• Patients with rhythm problems,
• Patients with diseases that can increase heart rate (anemia, hyperthyroidism, hyperthermia, infection),
• Patients who are morbidly obese (Body Mass Index > 40 kg/m2),
• Patients with hearing impairment,
• Patients with mental disabilities or perception problems,
• Patients who have previously received breathing therapy training will not be included in the study.

The IPD sharing will be decided after the data collection has been started. It is planned to share the study protocol.