Key result
Acute high altitude exposure in patients with prior myocardial infarction was accompanied by higher sympathetic activity (LF/HF ratio) compared with normal volunteers, alongside diminished parasympathetic tone during post-stress recovery.
Why the study?
Does acute high altitude exposure alter autonomic and hemodynamic responses to mental stress in patients with prior myocardial infarction compared to healthy volunteers?
Observational (n=26)
No
Does acute high altitude exposure alter autonomic and hemodynamic responses to mental stress in patients with prior myocardial infarction compared to healthy volunteers?
Patients with prior myocardial infarction exhibit impaired autonomic adaptation and sustained sympathetic activation during acute high-altitude exposure, potentially increasing their risk for arrhythmias.
Answers are grounded in this paper and cite their sources.
May warrant caution during high-altitude exposure post-MI; leaves open prospective validation of arrhythmia risk.
BACKGROUND: High sympathetic tone creates a significant risk for ventricular arrhythmias and sudden death, which can especially affect patients after a myocardial infarction (MI) when exercising in a hypoxic environment. METHODS AND RESULTS: The 16 patients after MI and 10 normal volunteers (NV) underwent a 1-day trip from low altitude (540 m, Bern) to high altitude (3,564 m Jungfraujoch, Swiss Alps). Autonomic function under resting and mental stress conditions at low and high altitude was assessed. MI patients demonstrated a significantly lower stroke volume (P<0.05) at rest compared with the NV at low as well as high altitude. High altitude exposure was accompanied by higher low-frequency/high-frequency values in the MI patients compared with NV (P<0.01). Following mental stress, MI patients failed to show the normal return to resting values at high altitude, suggesting sustained sympathetic and diminished parasympathetic activation during post-stress recovery. CONCLUSIONS: Although all MI patients were either on beta-blockers or AII inhibitors, they showed higher sympathetic activity during exposure to high altitude compared with NV. In addition, the respective parasympathetic tone was reduced, especially during recovery. This puts patients after MI at an increased risk for cardiac arrhythmias and they should be advised of this if going to high altitudes.
No takes yet. Share an insight, caveat, or question.
Messerli‐Bürgy et al. (2009) conducted an observational in Myocardial Infarction (n=26). Acute high altitude exposure (3,564 m) vs. Normal volunteers and low altitude (540 m) was evaluated on Low-frequency/high-frequency (LF/HF) ratio during high altitude exposure (p=<0.01). Acute high altitude exposure in patients with prior myocardial infarction was accompanied by higher sympathetic activity (LF/HF ratio) compared with normal volunteers, alongside diminished parasympathetic tone during post-stress recovery.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: