Not directly. But maintaining an ideal body weight is good for the overall health of the heart.
Does losing weight (20 lbs+) help decrease the chances of arrythmias?
I am aware of the continuing debate about the safety of the Atkins (and related high-protein) diets. Certainly, I would never suggest that one eat in such a way in the long term. However, two respected internists, one a long time friend of mine, and one a relative, and my family doctor, have all opined that they think an overall reduction in carbohydrate intake is an excellent way to control weight. Relatives and friends who have used the diet in the short term show weight loss, decreased blood sugar levels, decreased triglycerides, and reduced bad cholesterol. After reaching their weight reduction goals, they have been able to add return complex to their diets at alevel that allows them to maintain their desired weight, blood work results, and eat a balanced diet.
Let's face it: the Atkins credo of butter-soaked steak with hollandaise is not the way to go in the long term. But it does point out that high consumption of complex carbohydrates is significantly responsible for the fattening of America.
A lot of cardiologists and nutritionists I know are skeptical about the long term efficacy and safety of that diet.
I agree that processed foods high in carbohydrates do contribute to obesity. However, I do not think the solution would be to substitute a diet that is high in meat, even in the short term.
Regarding your weight loss, I might consult "Dr. Atkins New Diet Revolution". Atkins is a cardiologist, and claims great results for heart patients.
Rhythmol can be used even for arrhythmia that are not life-threatening. It would be reasonable to repeat the stress test on the Rhythmol to see if it is working. I would do this first, before recommending a specific exercise regimen.