I've been suffering from episodes of rapid heart rates in the region of 140 and low rates of as low as 25 for about 6 years, these being measured at home using my BP machine and Fingertip Pulse Oximeter Heart Rate Monitor. The low rates seem to have been getting steadily worse together with episodes of missed beats and pauses in line with the increase in Beta Blockers and more recently Calcium Channel Blockers to the extent that I had to stop taking the Diltiazem recently. I also suffer with lightheadedness, breathlessness and occasionally feel like I am about to blackout and have to grab hold of something. Whilst walking briskly on my treadmill I have noticed my pulse drops from around 100 to low 40 and I suffer lightheadedness and extreme dizziness to the point I have to stop and hang on to the machine in the fear of collapsing. I have read that this could be Sick Sinus Syndrome (SSS) and wonder if anyone has experienced similar. When I mentioned my thoughts with regards to the Beta and Calcium Channel Blockers to my Arrhythmia Nurse during a recent telephone call he said the drugs could not be a cause, yet there seems to be plenty of evidence to suggest a very definitive link to SSS and Beta / Calcium Channel Blockers.