MJ jacks with your heart rate and can cause atrial fibbrilation. In which your atrias (top low pressure pumping chambers of the heart) quiver instead of pumping blood efficiently. Quite a few old hippys I know have the affliction. Not life threatening just makes you feel weird when it first starts. Biggest danger is blood clots forming in the heart because the blood is not being pumped out vigorously. You can get it shocked back into beating right with a procedure called cardio version or similar. If that dont work they put you on blood thinners aka wafferin, coumadin which is actually a rat poison invented back in the 40's. It interrupts what is called the Vitamin K clotting factor. If you get too much it make you bleed out and die as with a rat who eats it. That strategy is usually accompanied by a heart rate limiting drug such as Attenolol and/or Digoxin. There is a last ditch prodcedure called oblation where they go in through the groin and kill the miss firing cells. If they kill too many of the cells then you have to have a pace maker. Hope this helps.

Goober