Arrhythmia Associates LLP

Our Process - Treatment - Medical Therapy

Medical Therapy

Role for Antiarrhythmic Drugs

The initial treatment for many rhythm disorders sometimes includes antiarrhythmic drug therapy. These drugs can slow the conduction of rapid heart rhythms and/or convert them to a normal sinus rhythm. Other drugs help the heart maintain regular rhythm. Drugs, however, do not cure heart rhythm disorders. Rather, antiarrhythmic drugs only suppress them, and they are not effective in all patients. They also require that a patient maintain a very strict schedule of follow-up care with his or her physician as some of these medications can have serious medical side effects. Blood tests are needed for those on long-term therapy to monitor the functioning of other organ system which may be affected by the drugs.

Amiodarone

Special consideration is required in the discussion of Amiodarone. Amiodarone is an antiarrhythmic drug with unique electrical properties. There are advantages and disadvantages to this particular medicine. Amiodarone is widely regarded as one of the most effective antiarrhythmic drugs for the treatment of a variety of arrhythmias. The disadvantage to using Amiodarone is that it can potentially affect other organ systems including the skin, liver, lung, and thyroid systems. Clinically, we will use the lowest possible dose to minimize medical side effects but laboratory tests will be scheduled to monitor for any problems. Generally, we will schedule pulmonary (lung) function tests yearly. Liver and thyroid tests are generally performed twice a year.

If any changes to these tests are identified, the Amiodarone dose may be adjusted or the medicine may need to be discontinued. Amiodarone can also interact with some common medications. Warfarin (Coumadin) levels, for example, may need to be adjusted in the setting of Amiodarone therapy.

Anticoagulation

Some heart rhythms predispose patient to formation of blood clots in the heart. Blood thinning medications (anti-coagulation) are sometimes used in conjunction with other treatments to decrease the stroke risk in some patients. One of the most potent blood thinning medications is warfarin (Coumadin). No other oral medication is demonstrated to be as effective as Coumadin for the prevention of blood clots. Coumadin blood tests must be carefully monitored by a blood test called a "protime." That laboratory test is now standardized or "normalized" across all clinical laboratories and is called the "International Normalized Ratio" or INR. The standardization allows our patients to have their lab test performed anywhere in the world and allows your doctors to adjust your Coumadin dose appropriately.

Generally, the INR is maintained between 2 to 3. This means that the time for blood to coagulate in this test is 2-3x longer than normal and this has been proven to be the most effective level for most patients. If the INR level is greater than 4-5, this is sometimes associated with spontaneous bleeding. Rarely, your doctors may seek a slightly higher level for your INR if this is clinically indicated. An INR less than 2 has been shown to be ineffective in the prevention of blood clots. Therefore, Coumadin is optimally effective in a very narrow therapeutic range.

Blood tests are frequently performed to maintain your INR in the appropriate range. Coumadin levels can be affected by a variety of foods as well as other medications. In general, dark leafy green vegetables such as spinach, kale, and collard greens contain an ingredient called vitamin K, which counteracts Coumadin and can make the INR level too low. Other medications such as some antibiotics can inhibit the metabolism of Coumadin and can make the INR too high. Careful monitoring of Coumadin can be performed through our office or may be performed by your other doctors.

Below is a list of some foods that will make the INR too low. The more vitamin K in that food, the more that it affects your Coumadin level.

Foods with very high vitamin K content (>200 mcg)	Foods with high vitamin K content (100-200 mcg)	Foods with medium vitamin K content (50-100 mcg)	Foods with low vitamin K content (<50 mcg)

Brussel sprouts Chick peas Collard greens Coriander Endive Kale Liver Parsley Red leaf lettuce Spinach Swiss chard Black/green teas Turnip greens Watercress	Basil Broccoli Butterhead lettuce Canola oil Chives Coleslaw Cucumbers (with peel) Green onions Mustard greens Soybean oil	Apples (green) Asparagus Cabbage Cauliflower Mayonnaise Nuts (pistachios) Summer squash	Apples (red) Avocados Beans Breads/grains Carrots Celery Cereal Coffee Corn Cucumbers (without the peel) Dairy products Eggs Fruits Iceberg lettuce Meats/Fish/Poultry Pastas Peanuts Peas Potatoes Rice Tomatoes