High altitude travel with LBBB

Thanks for asking. I’m assuming “LBB” means left bundle branch block (LBBB). Many people with LBBB travel safely, but the key is why the LBBB is present and how the heart functions. High altitude (15,000 ft/4,500 m) has low oxygen and can strain the heart and lungs; risks rise if there’s underlying coronary disease, cardiomyopathy, valve disease, pulmonary hypertension, or reduced ejection fraction. Best approach if the trip is important: get a pre‑travel cardiac review to confirm stability (exam, recent ECG, echo; stress testing only if symptoms/risk). If cleared, use these precautions: ascend gradually (2–3 days acclimatization at 8–10k ft first), go slow the first 48–72 hours, avoid heavy exertion and alcohol/sedatives, stay warm and well hydrated, know altitude sickness signs (headache, nausea, unusual breathlessness at rest, chest pain, confusion) and descend if they appear. Carry regular medicines, a copy of ECG, a pulse oximeter, and have a plan to reach lower altitude quickly. If she develops chest pain, severe shortness of breath, or fainting, treat as an emergency and descend immediately.