If Clozaril is known for that issue, you might consider asking for an annual EKG. I know that Geodon is known for it, so I had frequent (though every other year) EKGs, but they never showed that issue. I also have a tachycardia diagnosis, but my betablocker does a great job at keeping my heart rate just right. I don't have a health issue that would require Metformin. Definitely consult with your doctor that could see the big picture on this. Perhaps you need some med adjustment? Or are you anxious lately? Anxiety does all kinds of things to me, physically. I also have Mitral Valve Prolapse. Mine is not a big deal, but I have read it can cause symptoms like you describe.