Coronary angiography is an invasive imaging technique that directly visualizes the anatomical structure of the coronary arteries and is considered the gold standard for diagnosing significant coronary artery disease. In the post-coronary angiography period, alleviating pain and enhancing patient comfort are important goals of clinical care. Reiki is an energy-based complementary therapy aimed at supporting the body's natural healing processes and promoting relaxation. Among non-pharmacological interventions, Reiki-a practice rooted in Traditional Chinese Medicine and meaning universal life energy-is a safe, cost-effective, and easily applicable method. Studies have shown that Reiki is effective in reducing pain, anxiety, fear, and stress, as well as in improving comfort and holistic well-being. This study was designed to examine the effects of Reiki therapy administered after coronary angiography on patients' levels of pain and comfort.

This study is a randomized, single-blind, placebo-controlled trial designed to evaluate the effect of Reiki therapy on pain and comfort levels in patients undergoing coronary angiography. Participants are randomly assigned to one of three groups: Reiki intervention, sham Reiki, or control group.

The Reiki intervention is administered by a trained practitioner for approximately 21-30 minutes following the procedure, focusing on standard energy points. The sham Reiki group receives a similar procedure without therapeutic intent, while the control group receives standard care only.

Pain levels are assessed using the Visual Analog Scale (VAS), and comfort levels are measured using the General Comfort Scale Short Form. Measurements are conducted at baseline and at specified intervals following the intervention.

The study aims to provide evidence regarding the effectiveness of Reiki as a complementary, non-pharmacological intervention in post-procedural nursing care.

Inclusion Criteria:

• Adults aged 18-80 years.
• Undergoing coronary angiography for the first time.
• No additional interventions (e.g., stent placement) performed during angiography.
• Coronary angiography performed via femoral artery.
• Elective (non-emergency) coronary angiography.
• No prior experience with Reiki, Therapeutic Touch, or other energy therapies.
• Able to understand and speak Turkish.
• Open to communication and able to participate in face-to-face interviews.

Exclusion Criteria:

• Development of acute complications during or after coronary angiography (e.g., myocardial infarction, severe arrhythmia, embolism, bleeding at the intervention site, hematoma).
• Any diagnosed psychiatric disorder.
• History of chronic pain or regular use of analgesics.
• Previous experience with Reiki or similar complementary therapies.
• Requirement for sedative or opioid analgesic use during the study period.

Participants are blinded to their group allocation. Reiki and sham Reiki sessions are delivered in identical settings (duration, environment, body position, and practitioner interaction) to maintain blinding. Practitioners, who also serve as data collectors, are aware of the intervention type due to the nature of the technique. Statistical analysis will be performed by an independent researcher blinded to group allocation.