Development of the Interview Guide: The first phase involves developing a semi-structured interview guide, ensuring that it comprehensively captures the factors influencing outpatient CR participation among CVD patients. The development of the interview guide will involve four steps:

Step 1: Literature Review and Item Generation: A comprehensive literature search is conducted using PubMed, CINAHL, and GOOGLE Scholar to identify previous studies that discuss the factors associated with the utilization of CR. Search terms included: "cardiovascular diseases," "cardiac rehabilitation in India," and "barriers and facilitators of cardiac rehabilitation." Findings from four prior studies were reviewed to generate relevant interview items. These items were categorized into key themes such as awareness, accessibility, psychological barriers, economic constraints, and support systems. 

Step 2: Translation and Validation: The interview guide will be developed in English and Gujarati by professional linguistic experts, with expertise in both the language. A back-translation process will be conducted to ensure linguistic and conceptual equivalence. Additionally, a panel of subject matter experts in cardiology, rehabilitation, and qualitative research will validate the guide for accuracy and comprehensiveness.

Step 3: Cognitive Interviews (Think-Aloud Method): To assess the clarity and relevance of the interview guide, cognitive interviews will be conducted with representatives involved in CR, including healthcare professionals and CVD patients. The think-aloud method will be used, where participants will read questions aloud and verbalize their thoughts, helping researchers evaluate how questions are interpreted. These interviews will be audio-recorded, transcribed, and analyzed for potential refinements. 

Step 4: Pilot Study: A pilot study will be conducted with 5-7 participants who share similar characteristics with the study population. This process helps the researcher identify any flaws, limitations, or weaknesses in the interview design, allowing for necessary revisions before the actual study is conducted. Additionally, the pilot test aids researchers in refining their research questions, a topic that will be explored in the following section. Following the pilot study, necessary modifications will be made, and the final version of the interview guide will be prepared for implementation. 

Interview of CVD Patients: This study adopts a phenomenological approach to explore the lived experiences of CVD patients in participating in CR. Phenomenology is ideal for uncovering deep, personal insights into the subjective experiences, beliefs, and attitudes that influence CR participation, enabling a holistic understanding of barriers and facilitators. The steps are detailed below:

Recruitment of Participants: With the necessary approvals from the hospital, participants for the study will be selected through purposive sampling to ensure a diverse representation across various factors, including age, gender, socioeconomic status, cultural background, and the extent of their participation in CR programs. To facilitate recruitment, potential participants will be identified and approached only after prior consultation with their treating physicians. The study population will consist of adult patients diagnosed with CVD, specifically those aged between 30 and 60 years, who have been referred to outpatient CR programs in hospitals and rehabilitation centers across the Surat region. Recruitment efforts will take place within both inpatient and outpatient cardiac care departments. Eligible participants will be identified with the active involvement of cardiologists, physiotherapists, and rehabilitation staff, who will assist in screening and selecting individuals who meet the study’s inclusion criteria.

Obtaining Informed Consent: Each potential participant will be provided with a Participant Information Sheet in English and Gujarati, detailing the study’s objectives, procedures, risks, and benefits. Written informed consent will be obtained before participation, ensuring patients understand their rights, including the option to withdraw at any time without consequences. Anonymity and confidentiality will be maintained, with each participant assigned a unique identification number to protect their identity. 

Conducting Semi-Structured Interviews: Face-to-face, in-depth interviews will be conducted in a quiet and comfortable setting (e.g., hospital consultation rooms or rehabilitation centers). The interviews will be conducted in Gujarati or English, depending on the participant’s preference, and audio-recorded with consent. A semi-structured interview guide, developed in Phase 1, will be used to collect the data. 

Ensuring Thematic Saturation: Data collection will continue until thematic saturation is achieved, meaning no new themes or insights emerge. Based on existing qualitative research, saturation typically occurs between 20-30 interviews, though this will be assessed continuously.