Thank you for your reply. I don't really have an opportunity to try higher elevations before going to Nepal. With my new hip working well I am now starting to test my heart's reaction to more vigorous exercise (at lower elevations where I live). From the readings I've done it would seem I would need longer time than my previous "normal" to acclimatize as I go higher, and monitor my self even more closely for signs of problems. I've always been careful about following the recommended methods for acclimatizing - staying well hydrated, taking Diamox above certain elevations, taking acclimatization days (with hikes where we walk high and sleep low), etc. I would really like to contact a cardiologist who has experience with high altitudes as unfortunately I don't have much faith in my current one.