Sir there are studies to provide reasonable amount of data, that testosterone can cause various arrhythmia, in your case ectopic beats (most benign arrhythmia) , US Fda also has started putting working about heart risk on testosterone supplements. So if alternative means are available you should try them, however I may assure than an ectopic beats is not dangerous and you shouldn t be anxious about the same. Apart from it many a times, carrier oil may be something you are allergic, do see the content. Something the anxiety associated with the shots may make you feel your hear pumping harder making you feel your heart beats. This may just wean in some weeks. Having explained different ways the ectopic may be produced, as a responsible doctor I will suggest you to a out the testosterone replacement if not hypoandrogenic