I switched to an Atkins-like lifestyle about a year ago after being told I had be become a type 2 diabetic. I reduced my carbohydrate intake to less than 50 grams per day. I found that my overall heart rhythm improved and noticed a reduction in the number of PVC's.
Not when I tried it - but I guess we all are different. It may actually make your heart rhythm slower and more regular because a stable blood sugar will reduce blood adrenaline.
That said - be sure you get enough potassium, magnesium and calcium, which often may be a problem with those diets. Follow up with your doctor on a regular basis. Maybe you should get an approval from him before you change your diet too? That diet is not for everyone.