I’ve known people who took 1000 mg/day and had no side effects. Only thing listed in the PDR is possible nausea at large doses.
I used to take 300 mg/day, but then found a brand that is dissolved in vitamin E and vegetable oil making it about 90% bioavailable instead of 30% for the normal powder or capsule form. Now I take 100 mg/day of this fat soluble CoQ-10.
Your cardiologist had better have heard of CoQ-10! She’s probably prescribing statin drugs which deplete your normal level of CoQ-10 along with the LDLs and should be prescribing CoQ-10 right along with the statins! The pharm cos don’t inform the patients of this “drawback” to their drugs, so the patients have to!
Heart cath gives by far the best info, but a new type of echocardiogram is supposedly in the works that can “see” the heart as if it were standing still, which is the biggest problem with using ultrasound.