New Exercise Program After Anterior STEMI With Reduced Ejection Fraction
Alan, 70, is three months post anterior STEMI treated with PCI and a drug-eluting stent to the LAD. Echocardiography shows an ejection fraction of 30%, and he is NYHA class II. Medications are metoprolol succinate 100 mg, sacubitril/valsartan, eplerenone, atorvastatin, aspirin, and ticagrelor. Resting heart rate is 58 bpm and blood pressure is 108/68. His 6-minute walk distance is 380 m; he stops for dyspnea at a heart rate of 96 and SpO2 of 96%. He has no ICD and wants to begin exercising at home. He asks for "a heart-rate zone I can follow."
1. Calculate a heart-rate range using the heart-rate reserve method at 40–60%, and explain why you would not rely on it for this patient.
Read the worked answer
Predicted maximum: 220 − 70 = 150 bpm. Heart-rate reserve = 150 − 58 = 92.
- 40%: 58 + 0.40(92) ≈ 95 bpm
- 60%: 58 + 0.60(92) ≈ 113 bpm
So the calculated range is roughly 95–113 bpm. It should not be the primary guide because he is on a full-dose beta blocker, which blunts chronotropic response, and because heart failure itself can produce chronotropic incompetence. A heart rate of 96 already accompanied dyspnea at the end of a 6-minute walk, well below the calculated 60% value. Using 113 as a ceiling could push him past his actual tolerable intensity.
Use RPE 11–13, the talk test, workload, and symptom response as the primary intensity anchors, with heart rate as a secondary check. Recheck his resting and exercise heart rate over the first two weeks and adjust.
2. Write the initial aerobic and resistance prescription (FITT) for the first four weeks.
Read the worked answer
Aerobic: 3–4 days/week, 20–30 minutes per session, at RPE 11–13 or 40–50% of VO2 reserve, using walking or a stationary bike. Warm up 5–10 minutes and cool down 5–10 minutes. Interval format may be better tolerated: 2–3 minutes of work alternating with 1–2 minutes of easy recovery.
Resistance: 1–2 days/week, 1–2 sets of 10–15 repetitions at a low-to-moderate load (RPE 12–13), emphasizing large muscle groups, avoiding heavy isometric work and Valsalva. Do not perform resistance training on the same day as the longest aerobic session initially.
Flexibility: gentle range-of-motion work after sessions.
Progression: add 5 minutes to the aerobic session every 1–2 weeks if he remains asymptomatic, rather than increasing intensity first. Keep sessions at home short and frequent; a 20-minute walk he completes is better than a 40-minute walk he abandons.
3. What would make you stop a session and refer back to cardiology?
Read the worked answer
Stop the session and refer for any of the following:
- Chest pain, pressure, or anginal equivalent.
- Dyspnea disproportionate to the workload (RPE dyspnea ≥15) or dyspnea that does not resolve with rest.
- Dizziness, lightheadedness, or a fall in systolic blood pressure with increasing workload.
- Palpitations or a new irregular rhythm, or heart rate that fails to rise appropriately.
- SpO2 falling below 90% or symptomatic desaturation.
- A weight gain of 2–3 lb in a day or 5 lb in a week, or increasing edema, suggesting decompensation.
Refer urgently for syncope, sustained palpitations, or resting dyspnea. Document each event with the workload, heart rate, blood pressure, symptoms, and what resolved them, and communicate it to the cardiology team rather than adjusting medications yourself.