Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Low heart rate have so many reasons ,however your heart rate of 55 is not too low especially if the blood pressure is normal as is yours. To know about heart block , we need an ECG that would most of the times tell about any block if present , it may also show about the cause. the treatment mostly need correcting the cause if any , if irreversible a pacemaker is put , ( which I don t think you would need as your rate is very good , and bp normal) for some people 55 may well be normal. however getting and ecg and echo is necessary to rule out some basic causes. I would also like to get thyroid functions test that can also cause low rate. Low HDL does not cause low herat rate. To lower cholesterol weight loss , good diets ie vegeterian diets , and some times if needed some drugs like statin are used if needed. Omega 3 has some role but not very convincing. Hope I have answered your query. Let me know if I can assist you further.