Heart Rhythm Disorder
Arrhythmia, or heart rhythm disorder, is a general term for an irregular heartbeat. Most arrhythmias are not dangerous, but some may indicate serious underlying heart disease and some can lead to serious problems such as loss of consciousness, stroke and sudden cardiac death. In this episode of Second Opinion, you'll learn about the causes and treatment of arrhythmia, and what to do if someone suddenly collapses next to you. Your early intervention can save lives!
The heart has four chambers. The upper two are the atria (the right and the left atrium) and the lower two chambers are the right and left ventricles. These chambers contract in a regular sequence, or rhythm (the heartbeat); the contractions enable the heart to pump blood to all parts of the body. The normal rhythm of contractions is controlled by the heart's "pacemaker," a group of cells (called the sinoatrial node, SA node, or sinus node) in the right atrium that generate electrical impulses. These impulses travel across the heart's chambers, making them contract. This is the "normal" rhythm, generated at a certain rate, usually 60 to 100 times a minute. When that rate is abnormal or the cadence irregular, the heart may have an arrhythmia, also referred to as dysrhythmia by some experts.
There are several kinds of arrhythmia. A heartbeat can be too fast (technical name: tachycardia ), too slow (technical name: bradycardia), or simply irregular. Arrhythmias can also be classified by where they happen, i.e., there are atrial arrhythmias and ventricular arrhythmias, and there are several kinds of each.
For example, one frequent type of atrial arrhythmia is atrial fibrillation , in which the atria quiver instead of contracting normally. Therefore, the heartbeat does not pump blood through the heart effectively. Untreated atrial fibrillation can lead to heart failure or stroke - but atrial fibrillation may be successfully treated.
Ventricular fibrillation is an especially dangerous form of arrhythmia in which the contractions of the ventricles are rapid, unsynchronized, and uncoordinated, so that the heart pumps very little or no blood. Untreated ventricular fibrillation can cause collapse and sudden death - but again, it may be successfully treated.
For information about defibrillation (treating fibrillation by using electric shocks to restore the heart's correct rhythm) refer to heart rhythm disorder points #2 and #3.
The symptoms of arrhythmia can vary, depending on the type of arrhythmia, but in general they include:
- Feeling like the heart "skipped a beat"
- Throbbing and/or fluttering in the chest
In more serious cases, a person might feel dizzy or faint, have chest pain, and/or shortness of breath.
How often does the average heart beat (expand and contract) each day? About 100,000 times. How much blood does it pump? About 2,000 gallons.
If you live to age 70, your heart will beat more than 2.5 billion times.
Blood flows through the circulatory system, the network of arteries, arterioles (small arteries) and capillaries (tiny blood vessels) that carry blood from the heart, and veins and venules (small veins) that carry blood back to the heart.
- If all these tubes were laid end-to-end, they would stretch for 60,000 miles - enough to circle the earth more than twice!
Arrhythmia is a general term for an irregular heartbeat. A heartbeat can be too fast (technical name: tachycardia), too slow (technical name: bradycardia), or simply irregular.
Most arrhythmias are not dangerous. In fact, about 2.2 million Americans have a type of arrhythmia called atrial fibrillation - and that is only one type of rhythm problem.
Some arrhythmias can lead to serious problems, including heart disease, stroke or sudden cardiac death. But a variety of treatments, including medicines, implantable defibrillators and pacemakers, can regulate the heartbeat and prevent those problems
It takes only a few hours to learn CPR, and when you do, you may save a life! Contact your local chapter of the Red Cross or American Heart Association to find out when and where courses are given.
The American Heart Association has courses that combine CPR and AED (automated external defibrillator) training. They take only about four hours. Contact your local chapter to find out when they're given. You may save a life! Get information about AHA's CPR and AED classes at the American Heart Association web site.
You can join the American Heart Association's program to make AEDs - and people trained to use them - available in your community (in public areas such as sports arenas, office complexes, doctor's offices, shopping malls, gated communities etc.).
Get information about AHA's PAD program at the American Heart Association web site.
Ask Your Doctor
Provided by Nora Goldschlager, M.D.
Director, Coronary Care Unit, San Franciso General Hospital
Professor of Medicine, University of California, San Francisco
This list of questions is a good starting point for discussion with your doctor; however, it is not a comprehensive list.
- Where is my pulse and how do I count it to tell my heart rate?
- How do I know if my heart rate is too slow? How will I feel?
- What are palpitations?
- Which types of palpitations could be dangerous? What should I look out for to tell if my palpitations are dangerous?
- What is an arrhythmia?
- What causes arrhythmia? Can I avoid certain things that could cause it?
- Is family history important in arrhythmias?
- Are arrhythmias the same thing as a heart attack?
- What are some medicines I can treat this with? What are the side effects? Is there any difference between women and men? What about all these other drugs I am taking, are there any interactions?
- What are defibrillators? How do they work? Is getting an implanted cardioverter defibrillator (ICD) open heart surgery? How do I know if I really need an ICD or a pacemaker?
Key Point 1
If someone collapses in your presence, remember the letters A, B, C, D for Airway, Breathing, Circulation, Defibrillation. Your early intervention can save lives!
This formula refers to the emergency steps that should be taken to rescue and revive people who faint because they are having heart (cardiac) or breathing (pulmonary) problems. This is generally known as CPR - cardiopulmonary resuscitation.
First, see if the person is responsive or conscious by gently slapping them. If there is no response, follow the A,B,Cs:
A: make sure the person's airway is open, so the person can breathe. If it is blocked or clogged, remove the blockage.
B: help the person breathe by doing "rescue breathing" (mouth-to-mouth resuscitation).
C: make sure the person's heart is working and blood circulating by doing chest compressions.
The "D" in the formula refers to defibrillation, which means giving a electric shock to the heart to make it start pumping (beating) in the correct rhythm. An automated external defibrillator (AED) is a computerized device - about the size of a laptop computer - that is attached to a person's chest with wires. It then checks the person's heart rhythm, decides if that rhythm is "off," and gives the heart the electric shock (called a defibrillating shock) that should restore the natural, correct rhythm.
AEDs are very accurate and easy to use; learning to use one takes an hour or two at most. Although an AED is easily used by someone who is been trained to use it, it can be used even by an untrained person because it has voice prompts, lights, and text messages that tell you exactly what to do. It literally guides you through each required step, from attaching the wires to the person who has collapsed, to administering the defibrillating shock if needed. The devise automatically defibrillates; the user pushes a button and the machine decides whether a shock is needed and if not the machine does nothing.
Administering the A,B,C,Ds properly takes training. Every local American Heart Association and Red Cross Chapters offer CPR training and there are courses that combine CPR and AED training
The AHA also has programs promoting the placement of AEDs in public areas such as sports arenas, office complexes, airplanes, trains, airports, doctor's offices, shopping malls, gated communities, etc. The more publicly available AEDs - and the more people trained to use them - the more lives that will be saved. You can help make this happen by contacting your local AHA chapter and joining its "PAD" (Public Access Defibrillation) program.
Get information about AHA's PAD program
Key Point 2
Arrhythmia means an irregular heartbeat that sometimes causes sudden collapse. There are several types of arrhythmias each with their own causes and risk factors.
The general causes of arrhythmia mentioned on the program include:
- Coronary artery disease: a history of heart attack, high blood pressure, narrowed heart arteries and other problems can cause arrhythmia
- Drugs: some prescription medicines; over-the-counter diet pills and cold remedies; "street" drugs (illegal or misused) such as cocaine and amphetamine; and the herbal supplement ephedra (ma-huang), can lead to arrhythmia
- Thyroid problems: when your thyroid gland releases too many hormones, your metabolism speeds up, which can cause a fast (tachycardia) or irregular heartbeat (atrial fibrillation); when your thyroid releases too few hormones, your metabolism slows down, which can cause a slower heart rate (bradycardia.)
- Imbalances of body chemicals, especially potassium deficiency, calcium and/or magnesium deficiency, or imbalances in other chemicals such as sodium, adrenalin, oxygen, and bicarbonate.
- Dehydration increases the susceptibility to arrhythmia, as can caffeine.
Other risk factors include:
- Smoking and drinking: caffeine, alcohol and nicotine can lead to a variety of health problems, including damage to the heart and arrhythmia
- Genetics: some people are born with an irregular heartbeat or susceptibility to arrhythmia under certain circumstances or exposures.
- Age: the conduction of electrical impulses through the heart can slow with aging, leading to symptomatic rhythm disturbances. Individuals over the age of 70 have a 25% chance of having an arrhythmia.
- Diabetes: diabetes increases the risk of developing coronary artery disease and hypertension, both of which can lead to an arrhythmia, and the less controlled the diabetes the faster the cardiovascular problems tend to progress
Arrhythmias can be diagnosed through a variety of tests, including:
- Electrocardiogram (EKG or ECG): an EKG machine (attached to the chest with wires) measures and records the heart's electrical impulses and any arrhythmias
- Portable EKG (also known as ambulatory EKG): if an EKG does not give conclusive results, your doctor may give you a portable EKG machine (called a Holter monitor) to wear for a day or more; it records your heart rate and any arrhythmias
- Stress EKG (stress test): an EKG is attached and heart rate readings are taken while you exercise, usually by jogging on a treadmill or riding a stationary bike
- Electrophysiologic study (EPS): in this more invasive test, the doctor inserts a small tube through a blood vessel, running it to the heart, to more closely discover the source of the arrhythmia
You can find detailed information about these and other diagnostic techniques on the American Heart Association's web site.
Key Point 3
Treating an arrhythmia that causes sudden collapse can save lives. Treatments include medications, pacemakers and implantable defibrillators.
Of course the specific treatment recommended depends on the specific type of arrhythmia - and the unique individual who has it. Some people find that simply eliminating caffeine or alcohol from their diet eliminates the symptoms. Others need more aggressive treatments.
Among the medicines typically prescribed are:
- Beta-blockers , calcium entry blockers, and digoxin, that is, drugs that slow down the heart rate and decrease the heart's workload
- Amiodarone, for arrhythmia, and less commonly flecainide, propafenone, procainamide, quinidine, and others
- Aspirin (also useful in preventing blood clots)
- Anticoagulant drugs to prevent blood clots
- Drugs that control high blood pressure, thyroid disease, and drugs that correct the chemical imbalances that can lead to arrhythmia.
Arrhythmias are essentially problems with the heart's electrical system, which controls the frequency and strength of the heartbeat. A number of devices have been developed that monitor the heartbeat, detect arrhythmias, and send tiny electrical charges to the heart to restore the correct, natural rhythm.
The best-known is the pacemaker, which is surgically implanted under the skin, usually below the collarbone. Implantable pacemakers are extremely small - smaller than a matchbook - and have two parts: the generator, which monitors the heart's activity and sends the electrical charges to heart when needed, and the leads (or wires), which are usually put into the right side of the heart, and conduct the electrical charges from the generator to the heart. The pacemaker is usually used to correct bradycardias, that is, heart rhythms that are too slow.
The opposite condition, a heart rhythm that is too fast, is called tachycardia. Tachycardia from the atrium is treated with medications, as are some tachycardias originating in the lower chambers, the ventricles. The dangerous ventricular arrhythmias may need to be corrected with a similar small device called an implantable cardioverter-defibrillator (ICD) . The ICD is usually implanted near the left collarbone. It, too, monitors heart activity and delivers electrical shocks to the heart when needed. But the ICDs shocks are stronger than a pacemaker's because it corrects conditions that need stronger charges, such as ventricular fibrillation. Therefore, using an ICD can be uncomfortable or painful. But that's better than dying, and the conditions ICDs correct can be fatal.
Automated external defibrillators (AEDs) are now used in emergencies to save people who have collapsed because of an arrhythmia. For more information about AED's, see Heart Rhythm Disorder Key Point #1.
Other surgical procedures can also be used to prevent arrhythmia.
On the other hand, the easiest way to prevent arrhythmia, and a variety of other heart problems, is to live in a "heart-healthy" way. That means:
- Get more physical exercise
- Stop smoking
- Stop drinking alcohol heavily
- Keep your blood pressure under control
- Keep your cholesterol under control
- Eat a heart-healthy diet, which includes:
- Fruits and vegetables
- More fish, less meat
- "Good" oils, such as olive oil
- Antioxidants are nutrients and other substances that protect cells in the body from the damage caused by "oxygen free radicals" (molecules that seek to become oxidized, a process that harms body tissues and has been linked to many diseases, including stroke, heart disease, and cancer); antioxidants are found naturally in food but are also available as dietary supplements.
- Important antioxidants include:
- Vitamins A, C, E and beta-carotene (found in carrots)
- Lycopene (found in tomatoes)
- Flavonoids (found in ginkgo biloba, black cherries, blackberries, bilberries and blueberries)
- Quericetin - a specialized flavonoid found in apples, onions, tea and red wine
- Coenzyme Q10 - a vitamin-like substance found in soy, whole grains, mackerel, and chicken
- Folates - foods rich in folic acid, such as:
- Green vegetables
- Strawberries, oranges, raspberries
- Nuts and seeds
And remember, everything you put in your body can have an effect on your heart rhythm. Tell your doctor everything you are taking, nutritional, supplemental, and prescribed.
Conduct an off-site search for Heart Rhythm Disorder information from MedlinePlus. These up-to-date search results are based on search terms specific to Second Opinion Key Points.