Hi, I had a heart attack 4 months ago, had a stent put in, and started the usual meds. I did well on a stress test and started cardio rehab. Had no flutters or pain while exercising, until Cardiologist started me on Metoprolol. He had me stop this drug 3 days ago and I still have these flutters and chest tightness (mostly while exercising). How long does this drug stay in your system after stopping usage ?( I only took half of 25mg tab daily for 4 wks. I have a slow heart-rate at rest, always have)