Potassium and magnesium are two of the common minerals most needed by body cells, especially muscle cells and cells of the heart that carry electrical impulses. When our body has too little potassium or magnesium we are at risk for abnormal rhythms of the heart (arrhythmias). For most patients, just maintaining a balanced diet will provide enough potassium and magnesium and there will be no need for supplements. Sometimes, however, a blood test may reveal low levels of one or both of these minerals. When this occurs, the doctor will generally recommend a supplement.
Diuretics (water pills) are in common use for high blood pressure (hypertension), excess water (fluid retention) and certain heart conditions (heart failure). Diuretics cause our kidneys to get rid of salt and water and cause our bodies to lose excessive amounts of potassium and magnesium. Vomiting, diarrhea, excess laxative use and drugs such as cortisone and steroids can also cause potassium and magnesium loss.
Diuretics work by forcing the kidneys to produce more urine, thus eliminating more salt and water. Unfortunately, these drugs usually cause the loss of potassium and magnesium as well, an unwanted effect that can be very pronounced at times. To avoid problems related to low potassium and magnesium, your doctor may:
Prescribe diuretics that cause less potassium loss
Prescribe diuretics in lower doses
Supplement your diet with extra potassium and magnesium or encourage use of some salt substitutes
Commonly prescribed diuretics include: (chemical or generic names)
HCTZ* with spirnolactone
HCTZ* with triamterene
HCTZ* with triamterene
HCTZ* with triamterene
HCTZ* with amiloride
[HCTZ* is the abbreviation for HydroChlorThiaZide]
Food sources of Potassium and Magnesium
If your doctor has recommended that you eat a diet rich in potassium or magnesium, consider the following foods:
Rich in potassium
Rich in magnesium
Fruits and their juices
Dates and figs
Fish (flounder, halibut)
Common potassium supplements come in both pill and liquid forms and are generally measured in units of 8, 10, or 20 mEq (mEq stands for the chemical measure milliequivalents. 10mEq of one supplies as much potassium as 10mEq of another so if one brand or type upsets your stomach, ask your physician or pharmacist to recommend another. The chemical symbol for potassium is K or K+ (standing for kalium), so many of the names have the letter K in them.
Common magnesium supplements:
Foods rich in potassium and magnesium are generally components of a balanced, healthful diet, but on occasion these foods must be limited, since too much potassium and magnesium can result in problems with the heart and muscles. In certain individuals with kidney damage or kidney failure, or those on special drugs that cause the body to retain potassium, excess potassium in the diet or by supplementation can be harmful and even life-threatening. If this is the case, your doctor will give you specific guidelines for avoiding potassium build-up.
“Blood thinners” (aspirin and anticoagulants)
Strictly speaking, medications called “blood thinners” do not “thin” the blood, but rather make the formation of a blood clot less likely. Medically, blood clot formation is called “coagulation;” therefore these drugs are referred to as anticoagulant drugs.
You may be surprised to learn that small daily doses of aspirin are recommended by some doctors to prevent blood clotting. Aspirin has been proven to be of benefit in certain situations such as heart attack, severe heart pains (unstable angina) and prevention of stroke. Regular daily use of aspirin as a “blood thinner” should be undertaken only on the advice of your physician, since it can cause excessive bleeding in some people, and in individuals taking other anticoagulants it can increase the risk of bleeding.
The doses of aspirin required for preventing blood clots are generally much lower than those required to relieve pain. Certain arrhythmia patients are sometimes advised by their doctors to take aspirin because of the increased risk of small blood clots forming inside the heart. In other cases, doctors recommend the use of stronger anticoagulants such as warfarin.
Warfarin is the chemical name for a widely prescribed drug that is taken by mouth and used to prevent blood clots from forming in the heart and blood vessels. This medication is commonly used in patients with enlarged heart chambers and sluggish circulations, especially if the heart walls are weakened in areas scarred by heart attack. It is also used in patients with “A. Fib” (atrial fibrillation), since with this abnormal rhythm the walls of the top chambers of the heart (atrium) do not contract and blood clots can form along them as a result of sluggish blood flow.
Patients taking anticoagulants must be carefully monitored to keep the “blood thinning” effect at the proper level. They must be very aware of drugs that can cause an increase or decrease in its “blood thinning” effect. It is important during warfarin use that blood tests be done on a regular basis, as determined by their doctor, to monitor the drug’s effect and thereby maintain the proper dosage. It occasionally takes many blood test (prothrombin time tests) and phone calls to adjust daily dosage before the dose and the effect are at the desired levels.
A quick checklist for patients on warfarin:
Follow the doctor’s instructions exactly regarding dose and follow-up appointments and blood test.
Do not have any surgery, dental work or medical procedures without alerting the doctor that you are taking warfarin.
Contact your doctor at once if you:
Have bleeding from the gums, mouth or nose
Notice blood in urine or stool
Have excessive menstrual flow
Have black or “tarry-appearing” bowel movements which may represent “digested” blood, indicating bleeding into the stomach or intestines
Don’t change your use of any vitamin supplements, alcoholic beverages or special diets, or change medications, without your doctor’s approval (many foods and drugs can alter the effect of warfarin). Antibiotics may increase warfarin’s effect.
Consult your doctor before engaging in any contact or competitive sports, since the risk of injury and bleeding is increased while taking warfarin.
Easy bruising is commonly seen in patients taking warfarin and may occur even when proper dosage is maintained and the drug is doing just what it is supposed to. Easy bruising, however, may be a sign of “too much” warfarin effect, so this should be reported to your doctor promptly if noticed.
Cold remedies and asthma medications. Some of the same medications helpful in controlling stuffy nose, sniffles and wheezing also have fairly important effects on our hearts. These medications can speed up the heart just as adrenaline does and can trigger an abnormal heart rhythm. Some of the common ingredients to watch out for are:
Antihistamines (many different types)
Read the fine print on the label of any over-the-counter medication you’re about to take. Alert your doctor so you can be sure it’s safe for you.
What are you taking?
Medications for the treatment of arrhythmias are carefully chosen by your doctor to be appropriate, effective, free of severe side effects and easy to take. They need to be closely monitored. Their effectiveness and safety varies, depending on the type and dosage of medication and combined use with other drugs. The way you can help the most to assure effective treatment and reduce the occurrence of side effects is to be involved with monitoring the effects of the drug. Stay on the alert for possible reactions!
To increase the effectiveness and reduce the risks of taking medications: Follow your doctor’s instructions exactly. “When in doubt, ask and find out!” This is an excellent rule for questions about medications. Serious unwanted reactions, sometimes requiring hospitalization, can occur when you take too much or too little. Skipping doses may also reduce the benefits.
Take your medication regularly
Never change the dose on your own
Never change the number of times per day you take the medication without your doctor’s knowledge
Know what you’re taking! See if you can answer the following questions about each of your medications. Remember, answering these questions will help assure your good health and reduce the risk of unfortunate and all-too-common mishaps.
What is the brand name and generic (chemical) name?
What is the dose of each pill in milligrams (mg)?
Why are you taking it?
How often should you take it?
Where should you keep it?
What should you do if you forget a dose?
What side effects might you expect?
Are there any special instructions to follow (such as: take with meals or on any empty stomach; don’t drive; don’t take with other medication; don’t drink alcohol)?
Know why you are taking medications. Understanding why will encourage you to follow your doctor’s instructions better!
Keep a written list of your medications at home and in your wallet or purse. A medication card can be extremely helpful. For your convenience, there is a blank medication card at the end. Print it out right now. Fill out and keep it with you at all times. This information will come in handy when you call your doctor with problems, or when another doctor treats you in an emergency. Any doctor treating you needs to know exactly what you are taking in order to avoid reactions with any new medication prescribed.
Tell your doctor about any non-prescription medication before you take it, especially those with “warnings for heart patients” such as cold remedies, inhaled asthma medications and strong or frequently-used laxatives.
Some hints to help you remember to take your medication
Make an easy-to follow schedule (your doctor can help you).
Keep a copy of this schedule handy (where you eat, watch TV or read).
Take your medications at times of other daily activities:
When you brush your teeth
With evening news or at bedtime
Keep your pills in a safe place (away from children or elderly household members).
Find out whether your medication should be taken with meals or on an empty stomach.
Know what your pills look like and check the label when your prescription is refilled (ask your pharmacist if you are in doubt).
Be sure each medication you take should be taken as you are taking it.
Skip your medication just because you are feeling good. (Your good health may depend on taking your medication regularly.)
Try to make up for a missed dose by taking two doses at once unless your doctor so advises.
Put medications in a cold, damp place unless you are told to do so by your physician or pharmacist (most heart drugs do not have to be kept in the refrigerator-dry room temperatures and shield from direct sunlight are generally best).
“Stretch out” your medications because they are costly. Discuss this problem with your physician and obtain help from those close to you. Often, shopping around locally for the lowest price can be rewarding.
Crush or break up your medication unless you’re sure it’s OK (many long-acting or sustained-release forms must be taken intact if they are to work properly.)
Your doctor has probably stressed the importance of taking your medications “as prescribed.” It is crucial that if you have a problem doing this, you discuss it rather than overlook it and hope it doesn’t matter. It might be very important!
What you need to know about side effects
Anytime you take a medication, you anticipate a certain desired effect. Unfortunately, additional “unwanted” effects (so-called side effects) can occur. These are usually minor and harmless, but in some cases they are disturbing and at times even life-threatening. Most side effects are not predictable, because we are all different, with varied allergies, tolerances and body make-ups. Whenever you feel or suspect any type of side effect from your medications, or anything out of the ordinary-call your doctor to discuss it!
When you have a major reaction
If when taking a medication you feel dizzy, confused, faint or lightheaded, have difficulty breathing, wheeze, or develop facial swelling or a rash, take the following steps:
Stop taking the medication.
Contact your doctor immediately.
If your doctor is unavailable, and the side effect persists or gets worse, call for assistance and get to the nearest emergency medical facility.
Give your doctor all the answers to questions like:
What is the exact problem?
When did it begin?
What medication did you take?
How long have you been taking each of your medications?
How long after taking the medication did the problem arise?
What were you doing when it began?
Did you get relief? If so, how?
Have your list of medications for the doctor’s review
Include on the list all non-prescription drugs you take
Check your prescriptions with your pharmacist to be sure no change has been made; ask your pharmacist if your doctor has permitted a generic substitution.
Report any foods or drinks you may have had.
Hospital treatments Cardioversion
Cardioversion means changing the heart’s rhythm back to normal through the use of a brief electrical shock. It is widely used to treat certain persistent abnormal rhythms that do not respond to medications such as atrial fibrillation or atrial flutter. The procedure is done in a laboratory or intensive care facility where the patient’s heart rhythm can be constantly monitored. An intravenous (IV) line is used so that any medications needed can be given promptly.
After the patient is sedated and asleep (so there is no awareness of the brief but uncomfortable electrical shock), a physician places electrode pads or paddles on the chest through which a very brief electrical current is discharged. The electrical impulse “erases” the abnormal rhythm and allows the heart’s normal rhythm to take over if it is strong enough. If the natural pacemaker is weak or not functioning properly, the abnormal rhythm will frequently return. Cardioversions may be repeated if unsuccessful. Following the procedure, the patient’s heart rhythm is monitored as the patient lies comfortably in bed.
Cardioversions are safe procedures and rarely produce complications. Complications that may result include the appearance of a new abnormal heart rhythm and the possibility of blood clots (called emboli) being released from the heart into the circulation when the heart rhythm is constantly monitored by staff during the procedure and additional medications are available if needed.
Defibrillation is a cardioversion in which the underlying rhythm is ventricular fibrillation (VF). In ventricular fibrillation, or ventricular “flutter,” the arrhythmia causes the heart muscle to relax or quiver rather than contract normally. Since VF is always a life-threatening arrhythmia (because it “stops” the heart from pumping blood), defibrillation is always an emergency procedure. It is accomplished as quickly as possible to avoid brain damage or death, which can occur in a matter of minutes as circulation of blood is stopped after the onset of VF.
Ablation is a procedure that damages or destroys an electrical pathway in the heart in an effort to correct an abnormal rhythm. It is generally done at the same time as an electrophysiologic study (EPS).
Technology takes yet another giant step!
Pacemakers today are one of the most common cardiac devices to be implanted. They serve to stimulate the heart muscle electrically and cause it to beat when the rate drops below a preset level. These devices are used for preventing episodes of dizziness, lightheadedness or fainting when it is clear that the symptoms result from an excessively slow heart rate. The two most common reasons for pacemaker implantation are:
A poorly functioning sinus node, which is the natural pacemaker (or “spark plug”) of the heart.
An interruption in the electrical pathways through the middle (junction) of the heart, referred to as “heart block.”
Automatic Implantable Cardioverter Defibrillator. The “AICD” is a battery-powered device implanted in the body designed to detect and treat life-threatening abnormal rhythms of the heart. It is recommended for control of severe arrhythmias which may occur suddenly and that have been poorly or incompletely controlled by medication or surgery.
Pacemaker Cardioverter Defibrillator. The “PCD” has the capability not only of delivering an electrical shock to the heart to correct ventricular fibrillation (VF), it also has the potential for returning the heart to regular rhythm before the problem becomes severe. By keeping the rate near normal (acting as a pacemaker) or promptly correcting irregular rhythms after they begin (such as “cardioaverting” ventricular tachycardia), the PCD prevents the escalation of a serious problem to one that could be catastrophic.
Guidelines for patients with an implanted pacemaker, AICF or PCD:
Always carry identification providing your name, contact person, cardiac condition, primary physician and cardiologist (with emergency phone numbers) and the information about your device (provided by the manufacturer) that lists the name, type and date of implant.
Keep all appointments for follow-up examinations as requested by your physician.
Be sure you understand and follow recommendations about physical exercise. Contact sports are generally not advised.
Avoid contact with, or close proximity to, strong electronic or magnetic equipment that may interfere with your device; for example, magnetic resonance imaging (MRI) scanners used for medical testing, high capacity radio transmitters, airport metal detectors, some anti-theft alarm devices and auto engine parts such as distributor caps and wires, etc.
Avoid holding any electrical appliances close to (directly over) the device.
Whenever troubled or in doubt about symptoms or problems, alert your physician. Also, inquire at your hospital about a support group for you or your family members and friends.
Learn to take your pulse, so that if symptoms appear, you will be able to report on whether your heart rate is fast or slow, regular or irregular.
Additional thoughts for the patient with an implanted device:
Examine the implant site (usually on the abdomen) for signs of infection (warmth, redness, new swelling, tenderness or pain) and alert your doctor promptly if they are present.
Ask whether you are permitted to drive a car (in most states, driving is prohibited after an AICD or PCD is implanted).
Learn whether your unit has a warning sound (usually a beeping sound made when a magnet or electrical device has interfered with the device and reset it either “on” or “off”). Alert your physician immediately if this ever occurs, since it could result in the unit being turned off and failing to provide the necessary protection.
Ask your doctor how to handle any firings (discharges) that you may feel. It may be recommended that you call, or simply keep a diary of the event. In any case, keep a diary of the activity during which the firing occurred, noting especially:
How you felt at the time (whether you felt well, dizzy or lightheaded; had chest pain, sweating, etc.)
Whether your pulse was fast or slow, regular or irregular
Consider learning the basics of cardiopulmonary resuscitation with friends or family members. It can be a good way to openly address the fears that all patients have and help reduce anxiety in a very beneficial way. Ask your doctor or hospital about a local course.