I ran out of my ivabradine. my heart was beating so hard. can i replace it by taking bb? i used to take them before. cant reach my ep till thursday.

Sort of, but no: Ivabradine is a truly novel medicine; it works in a way no other medicine available does. (for that matter, it's not avail in the us... Where did you get it? I have a few patients who'd love to know). Anyway, a beta blocker will have some effect on rhythm, but if so, via a totally different mechanism and potentially with some side effects. I'd call the office.