as per title Comparative Efficacy of Aerobic Interval Training versus Moderate-Intensity Continuous Training on heart rate Recovery, Myocardial Workload, Functional Capacity and Health-Related Quality of Life in Post-CABG Patients Undergoing Phase II Cardiac Rehabilitation: A Randomized Controlled Trial. give me primary and secondary outcome measures,dependent and independent variables
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aerobic interval training continuous training CABG cardiac rehabilitation
Based on the study title provided, here is a complete breakdown of the primary and secondary outcome measures, and the independent and dependent variables:
Study Variables & Outcome Measures
Independent Variable (Intervention/Cause)
This is what is being manipulated by the researcher:
| Independent Variable | Groups |
|---|---|
| Type of exercise training | Group 1: Aerobic Interval Training (AIT) |
| Group 2: Moderate-Intensity Continuous Training (MICT) | |
| (Both delivered within Phase II Cardiac Rehabilitation post-CABG) |
Dependent Variables (Outcome/Effect)
These are what the researcher measures in response to the intervention. They map directly to the four constructs in the title:
| Dependent Variable | Measurement Tool/Method |
|---|---|
| Heart Rate Recovery (HRR) | Difference in HR at peak exercise minus HR at 1–2 minutes post-exercise (from exercise stress test / CPX test) |
| Myocardial Workload | Rate Pressure Product (RPP) = Heart Rate × Systolic Blood Pressure (measured at rest and peak exercise) |
| Functional Capacity | Peak VO₂ or MET level via cardiopulmonary exercise test (CPET); or 6-Minute Walk Test (6MWT) distance |
| Health-Related Quality of Life (HRQoL) | Validated questionnaire — typically SF-36, MacNew Heart Disease HRQoL, or EQ-5D |
Primary Outcome Measures
The primary outcomes are the main constructs the study is powered to detect a difference in. Given the title's structure and standard practice in Phase II cardiac rehab RCTs, the primary outcomes are most likely:
- Functional Capacity — Peak VO₂ or 6MWT (most commonly the primary endpoint in cardiac rehab RCTs, as it reflects the core rehabilitation goal)
- Heart Rate Recovery — A key autonomic/cardiovascular safety and efficacy marker post-CABG
In practice, researchers often designate one primary outcome to power the sample size calculation. Based on similar published trials (e.g., Shafiee et al., Clin Hemorheol Microcirc 2023, PMID 36683497), peak VO₂ / functional capacity is the most commonly powered primary endpoint in CABG rehab RCTs.
Secondary Outcome Measures
The secondary outcomes support the primary and provide a broader clinical picture:
- Heart Rate Recovery (if not primary) — autonomic nervous system recovery index
- Myocardial Workload / Rate Pressure Product (RPP) — reflects cardiac oxygen demand; important post-CABG safety parameter
- Health-Related Quality of Life (HRQoL) — patient-reported outcome capturing physical, psychological, and social dimensions
- Resting HR, resting SBP/DBP — often reported as tertiary/secondary measures
- Exercise tolerance (workload in watts, exercise duration) — supplementary functional data
Summary Table
| Category | Variable |
|---|---|
| Independent | Type of training (AIT vs. MICT) |
| Primary Dependent | Functional Capacity (Peak VO₂ / 6MWT); Heart Rate Recovery |
| Secondary Dependent | Myocardial Workload (RPP); HRQoL score |
| Controlled variables | Phase II CR setting, post-CABG patient population, session duration/frequency, time post-surgery |
Supporting Evidence
Two directly relevant RCTs and reviews from PubMed confirm this outcome structure:
- Shafiee et al. (2023) — MICT vs. HIIT in CABG patients used VO₂max and cardiac function as primary endpoints (PMID 36683497)
- Chichagi et al. (2024) — Systematic review confirms functional capacity and HRQoL as the dominant outcomes in this population (PMID 39839564)
- Hong & Liu (2025) meta-analysis confirms cardiopulmonary function and QoL as standard endpoints in post-PCI/CABG interval training trials (PMID 40671125)
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