Cardiac Rehabilitation: The 4 Phases of Recovery

Cardiac Rehabilitation is a structured, multidisciplinary intervention designed to optimize physical, psychological, and social functioning after a cardiac event (e.g., Myocardial Infarction, CABG, Angioplasty). It is not just "exercise"; it involves education, risk factor modification, and psychosocial support. This guide breaks down the 4 Phases of recovery and the critical safety parameters.

1. Understanding Intensity: What are METs?

Cardiac rehab uses Metabolic Equivalents (METs) to prescribe intensity. One MET is the energy cost of sitting quietly.

• 1 MET: Resting.
• 2-3 METs: Washing dishes, walking 2 mph (light).
• 3-6 METs: Walking 4 mph, vacuuming (moderate).
• >6 METs: Jogging, carrying heavy loads (vigorous).

The "Talk Test":
If a patient can sing, the intensity is too low. If they can talk comfortably, it's Moderate (Safe Zone). If they cannot speak a full sentence, it's too high.

2. The 4 Phases of Cardiac Rehab

Phase	Setting	Timeframe	Goal
Phase I (Inpatient)	Hospital / ICU	Day 1 to Discharge (3-7 days)	Mobilization, self-care (ADLs), education, prevent DVT/Pneumonia.
Phase II (Outpatient Immediate)	Hospital Gym (Monitored)	Discharge to 12 weeks	ECG-monitored aerobic exercise, symptom management, risk factor modification.
Phase III (Intermediate)	Community Center / Gym	3 - 6 months	Supervised (but not continuous ECG) exercise, building endurance and strength.
Phase IV (Maintenance)	Home / Gym	Lifelong	Independent maintenance of healthy lifestyle.

3. Phase I: Inpatient (The "Acute" Phase)

Starts once the patient is medically stable (no angina, stable BP/HR).

• Intensity: Very Low (1 - 3 METs). HR < 120 bpm (or Rest + 20).
• Activities: Bed mobility, sitting up, ankle pumps, walking to bathroom, corridor ambulation.
• Safety: Sternal Precautions (for Open Heart Surgery).

⚠️ Sternal Precautions (Post-CABG/Valve Replacement):
To prevent dehiscence of the sternum (breastbone):
1. Do NOT lift > 5-10 lbs.
2. Do NOT push/pull with arms (no pushing off chair to stand).
3. Do NOT reach behind back or overhead bilaterally.
4. Hug a pillow ("Heart Pillow") when coughing.

4. Phase II: Outpatient (The "Conditioning" Phase)

The most critical phase for physiological change. Patients attend sessions 3x/week.

• Monitoring: Continuous telemetry (ECG) to detect arrhythmias during exertion.
• Exercise (FITT):
  • F: 3-5 days/week.
  • I: 40-80% of Heart Rate Reserve (Karvonen). Borg RPE 11-13 ("Somewhat Hard").
  • T: 20-60 minutes.
  • T: Aerobic (Treadmill, Cycle) + Light Resistance (later stages).
• Education: Diet, smoking cessation, stress management.

[Image of patient on treadmill with ECG monitoring]

5. Phase III & IV: Maintenance

Transitioning from "Patient" to "Active Adult."

• Phase III: Supervision is available, but patients self-monitor pulse. ECG is not continuous. Focus on higher level weights and endurance (5-8 METs).
• Phase IV: Unsupervised. The patient joins a local gym or walking club.

6. Safety: When to STOP Exercise

🛑 TERMINATE SESSION IF:
• Systolic BP drops > 10 mmHg with exercise.
• Systolic BP > 250 mmHg or Diastolic > 115 mmHg.
• Angina (Chest pain) or severe Dyspnea.
• ST-segment depression (> 1mm) or elevation on ECG.
• Severe Dizziness/Ataxia.

7. Revision Notes for Students

Phase I: Inpatient. Low level (1-3 METs). Focus: ADLs + Safety.
Phase II: Outpatient Monitored. ECG used. Focus: Aerobic conditioning.
Phase III: Community Supervised. No continuous ECG. Focus: Independence.
Sternal Precautions: No pushing/pulling/lifting >10lbs for 6-8 weeks.
Borg Scale: Target RPE 11-13 (6-20 scale) or 3-4 (0-10 scale).
Karvonen Formula: Target HR = [(Max HR - Rest HR) × %Intensity] + Rest HR.

8. FAQs

Q1. When can a post-MI patient start Phase II?

Typically 2-6 weeks after hospital discharge, depending on stability and local protocols. A symptom-limited stress test is often done first.

Q2. Can patients with Heart Failure do rehab?

Yes! While traditional CR was for ischemia, tailored programs for Heart Failure (HF) are now standard. Intensity is lower, intervals are often used, and rest breaks are frequent.

Q3. Why use the Borg Scale instead of just Heart Rate?

Because many cardiac patients are on Beta-Blockers, which blunt the heart rate response (prevent HR from rising). HR might be low even if they are working hard. RPE (Rate of Perceived Exertion) is more reliable.

9. 10 Practice MCQs

Q1. Phase I of cardiac rehabilitation takes place in:

Answer: A) It begins as soon as the patient is medically stable in the hospital.

Q2. Sternal precautions typically include avoiding lifting more than:

Answer: B) Approximately the weight of a gallon of milk.

Q3. Continuous ECG monitoring is a hallmark feature of which phase?

Answer: B) Phase II is the outpatient monitored phase to ensure safety during higher intensity exercise.

Q4. 1 MET (Metabolic Equivalent) represents:

Answer: C) Approx 3.5 ml O2/kg/min.

Q5. Which is an absolute indication to STOP exercise?

Answer: C) A drop in BP during exercise indicates pump failure (the heart can't keep up).

Q6. The target Borg RPE (6-20 scale) for most cardiac patients is:

Answer: B) This corresponds roughly to 60-70% of Max HR.

Q7. Why is the Borg scale preferred over Heart Rate for patients on Beta-Blockers?

Answer: B) The heart rate will not rise linearly with effort, masking the true intensity.

Q8. Phase III rehab is typically characterized by:

Answer: C) Intermediate phase where patients are more independent but staff are present.

Q9. The "Karvonen Formula" uses which variable to calculate target HR?

Answer: C) This method accounts for individual fitness levels (resting HR).

Q10. Which activity is generally contraindicated during Sternal Precautions?

Answer: B) This places significant shear force on the healing sternum.

References

• AACVPR. (2020). Guidelines for Cardiac Rehabilitation and Secondary Prevention Programs (6th ed.). Human Kinetics.
• ACSM. (2021). ACSM's Guidelines for Exercise Testing and Prescription (11th ed.). Wolters Kluwer.
• Frownfelter, D., & Dean, E. (2012). Cardiovascular and Pulmonary Physical Therapy. Mosby.