Effects of Cardiac Rehabilitation (CR) on Functional Capacity and Cardiovascular Risk Factors

The design is a single-blinded, single-site pragmatic superiority RCT with 3 parallel arms: comprehensive CR (education and exercise) versus exercise-based CR (no education, as delivered in Brazil) versus wait list control (i.e., no CR). Patient assessments will be undertaken pre-randomization and again at 6 and 12 months later (in accordance with the end of CR). Mortality will be ascertained at 6 months and 1 year post-recruitment.

The main program is 6 months in duration, with 36 1-hour exercise sessions offered at the following frequencies:

1. participants come to CR for 12 sessions, 3x a week (total of 4 weeks of intervention).
2. participants come to CR for 8 sessions, 2x a week (total of 4 weeks of intervention).
3. participants come to CR for 12 sessions, 1x a week (total of 12 weeks of intervention).

Each participant will receive an individualized exercise prescription based on a grade exercise stress test. Participants will be exercising between 50 and 80% of heart rate reserve. In all stages patients will be requested to exercise in their community other days of the week, to accumulate 30 or more minutes of physical activity at a moderate to vigorous-intensity 5 or more days per week, as recommended in the guidelines.

In the comprehensive CR arm, 24 sessions education will be offered, of 30 minutes duration. More specifically, the education component consists of:

• weekly group education sessions, which are strategically mapped based on patients' information needs and sequenced to support the program learning outcomes. Education sessions are delivered by a health educator team. See table 1 for the CR program schedule, including educational topics (e.g.. diet, medication and exercise).
• A comprehensive education workbook to accompany the sessions, containing 20 chapters. The empirically-validated English version has been translated and culturally-adapted to Brazilian-Portuguese. Clinicians and patients have reviewed the material, and a plain language and clear design review was completed in preparation for this trial.

The standard of care for Brazilian adults with CVD does not include access to CR for all patients, given the gross lack of capacity. All participants will have follow-up appointments with their physician as deemed medically appropriate. Consistent with CONSORT guidelines, usual care will be described in detail for each participant (e.g., number of health visits - both inpatient and outpatient, other treatments).

The number of patients approached and date will be recorded, as well as the reasons for inclusion/exclusion. With informed written consent from the patient and CR clearance from the physician, potentially eligible participants will be scheduled to come on-site to complete pre-test assessments. Participants will be asked to complete a sociodemographic questionnaire, to establish the generalizability of the sample, among other surveys. Clinical information will be extracted from participants' charts.

Eligible participants will be randomized to one of the 3 groups. The randomization sequence was generated using the random.org website in random blocks of 4, with a 1:1:1 allocation ratio. To ensure allocation concealment, the local principal investigator has the allocation sequence in a password-protected file, and will only provide randomization information to the student once it is confirmed the participant is eligible. Due to the nature of the intervention, participants and the doctoral student cannot be blind to treatment allocation.

The primary outcome of functional capacity will be assessed again at 6 months. All other post-test assessments will be undertaken 6 months post-randomization. Mortality will be ascertained from hospital charts and family phone call at 6 months and 1-year. With regard to the baseline and 6 months assessments, participants will be invited to come to the study center to:

1. undertake the shuttle walk test as the indicator of functional capacity,
2. undertake assessments of secondary outcomes including a blood draw for lipids, and
3. complete surveys related to tertiary outcomes.

A master's student blinded to random allocation will undertake post-test assessments, outcome ascertainment and data entry. To minimize loss to follow-up, investigators will send mail and telephone reminders for patients to come on-site for these assessments, based on the Dillman method.

Measures Participants will be asked to complete a sociodemographic questionnaire. Clinical characteristics will be extracted from the medical charts, including sex, age, risk factors, cardiac history, cardiac test results, comorbidities and medications. These are based on the Canadian Cardiovascular Society core element and demographic data definitions. CR session attendance will be extracted from program charts at post-test for participants randomized to the CR arms.