Ivabradine for IST

Hi I'm 26 F, supposedly been diagnosed with IST my heart rate at rest is usually above 110 and in standing or walking had reached to 197-198, until now for long ongoing investigation without any other ruled out reason for that. One of the cardiologists I saw is speaking about trying Ivabradine to see if it works ( I can't stand beta blockers because of IDDM and there is close reason to believe that unfortunately treating with verapamil did nothing but creating different degress of AV blocks). Are any of you have any experience with it? I'm not from the US and even not quite positively sure whether its approved by the FDA I know in Europe it is. Also if some of you have, did it work for you? what side effects did you feel? I'm quite afraid because I'm after a few unpleasant hospitalizations in the ICU.

Thank you in advance and take care