Cardiologist gave me bisoprolol 1.25mg for post orthostatic tachycardia syndrome even though i have mild asthma and resting hr sometimes 52. this ok?

Make sure doc knows: Those could be problems . Many people w asthma could tolerate a low dose of beta-blockers but might need to consider other options. Limited choices however w resting heart rate slow. One possibility might be Clonidine (though it might slow hr too). This blocks some of the sympathetic outflow in your nervous system (the trigger for your postural tachycardia).