I am having high blood pressure and cholesterol with arrythmia. What diet exercise and regular check up advised ?

I m on BP meds for many years,(cardizem 240 mg cap one daily) and also on cholesterol meds(combined cholesterol level-170) and have been diagnosed via an echocardiagram with an enlarged upper atria.. I have had an arrythmia all of my lfe, described as an extra beat . My primary care MD wanted to check out the arrythmia so he referred me to the cardio MD. Have been trying to lose weight on the Atkins Diet . Its difficult for me to exercise in the dead of winter , but when the weather is more cooperative, will start a walking regimen. I am 67 years old and other than overweight , am in good health. Non smoker, no signs of diabetes. Am not a sugar addict and use artificial sweetners where possible. Am I doing the right thing? My cardio MD didn t seem concerned and has set another appointment for six months. Should I be concerned?I weigh about 317 and am six feet tall.