RE:HEART MONITORING IS A FREE SERVICE covered by OHIP
I can check with my cardiologist later this week (because I have to physcially go to clinic and waste half my day to get my free, OHIP-covered EKG at a hospital), but currently as far as I'm aware, some of the common, portable monitors in Ontario are Holter monitors and Cardiac Loop Event Recorders that you wear for only a few or several days (it has several electrodes you have to stick to yourself). Recently OHIP updated the types of fees the patient has to cover and it may not be as "free" as you think. Plus, you have to return the gizmo at the end of your monitoring phase and there are definitely late fees.
The EKG pen and other CardioComm devices are being designed for ongoing, long-term monitoring (months/years). They are much less intrusive than having a whackadoodle amount of electrodes stuck to your body. You get to keep them as long as you'd like.
Also, the previously descibed devices are only covered by OHIP for diagnostic testing and post-surgical monitoring. Anything deemed not medically necessary isn't covered at all. So "medically necessary" may only be for 72 hours worth of monitoring after you get a new pacemaker. If you are an elite athlete or have any other medical "preference" (rather than "necessity") for detailed monitoring, then it's not covered.