Heart Rhythm Disorders/Arrhythmias FAQs

Defibrillator Implantation and Electromagnetic Interference

Question: My 36-year-old brother’s heart stopped while he was at work last week. A defibrillator was used to restart his heart, and he was then flown to the hospital. He was diagnosed with an enlarged heart, and the doctors said it does not pump hard enough. (It is only pumping 25 percent, instead of 60–65.) They do not know what caused his condition, but they implanted a defibrillator/pacemaker. He is a welder, and they said he could never weld again. Exactly what is the reason for this? Couldn't he wear some sort of protective clothing and continue to do this job?

Answer: Although gas welding does not pose a danger to someone with an implantable cardioverter defibrillator (ICD) or pacemaker, electric welding does — because the generator creates an electromagnetic interference (EMI) field. This field has a signal content that mimics a serious heart rhythm disorder known as ventricular fibrillation. Proximity to this electrical field could trigger unnecessary shocks from the ICD. Generally, one must be a minimum of 10 feet from the generator to avoid the EMI field, which may require a long tether — the longer the better. It is not impossible for a patient with an ICD to continue to weld, if appropriate precautions are taken. There are commercial services equipped to survey workplace environments for EMI fields that might interfere with implantable medical devices such as pacemakers and ICDs. This information can be used to develop a strategy for safe operation with an implantable device. These matters should be discussed with the cardiac electrophysiologist who implanted the device, who is aware of your brother’s specific clinical circumstances.

Maximum Heart Rate

uestion: I am 57 years old, and I train on a treadmill. When running, my heart rate goes up to 160, as my maximum heart rate (MAX HR) is supposed to be 163 (calculated as follows: 220 minus my age). I feel fine, and could keep going, but I am concerned about the numbers. My doctor says I am in good shape and that I should just ignore the numbers. What is your opinion? Am I taking risks?

Answer: I'm inspired by a 57-year-old who trains on the treadmill to a heart rate of 160. While you give me no information regarding the rest of your cardiovascular risk profile and the frequency of your workouts, that description alone provides me with some reassurance that you are on the right track. Regarding your concern about your measured heart rate, I agree with your doctor. The rule of thumb that the maximum heart rate should be 220 minus age may be a widely used approximation, but is considered out of date by some. This arbitrary number should not cause you concern in and of itself, or deter you from your physical activity.

New Treatments for Atrial Fibrillation

Question: I have atrial fibrillation. Is this considered a disease? What new treatments are available for this condition?

Answer: Atrial fibrillation describes an arrhythmia, or abnormal heart rhythm. Several conditions — including valvular heart disease, high levels of thyroid hormone, and certain forms of heart failure (weakened heart muscle) — can cause it. Some people have no apparent cause — a condition called “lone” atrial fibrillation. Atrial fibrillation can also accompany aging, and this is one of the reasons why the prevalence of this form of abnormal heartbeat is on the rise. In atrial fibrillation, the upper chambers of the heart (the atria) wiggle ineffectively without pumping properly, and with chaotic rather than orderly contraction. This situation causes several troublesome problems. Often, but not always, people with atrial fibrillation experience a rapid, irregular heartbeat that can be annoying or even frightening, and can also cause low blood pressure, low heart output, and faintness or fatigue. In patients with underlying arterial blockages in the heart — a condition known as coronary artery disease — the rapid heart action can cause chest pressure known as angina pectoris. If left unchecked, prolonged rapid heart beating can weaken the heart muscle, and produce heart failure.

The lack of proper contraction of the atria causes stagnation or pooling of the blood in these chambers, which can lead to blood clot formation. These blood clots can then travel through the arteries, lodging in branches that supply blood to various organs — most dramatically, the brain. Atrial fibrillation is an all too common cause of strokes, but is to a great extent preventable. This is why all patients with atrial fibrillation should undergo an evaluation of their risk of taking anticoagulants (commonly known as “blood thinners”) versus their stroke risk. Doctors use simple scoring systems to help guide the decision of whether to recommend the use of anticoagulants. Proper use of anticoagulants such as warfarin (Coumadin), or newer agents such as dabigatran (Pradaxa), unquestionably can lower the risk of stroke in patients with atrial fibrillation, but at the cost of a risk of bleeding. A low risk of bleeding in a patient with atrial fibrillation usually warrants anticoagulant treatment, though warfarin has many drug interactions and requires frequent laboratory tests to monitor the dose. New anticoagulant medications that are simpler to use than warfarin, that seem at least as effective in preventing stroke in patients with atrial fibrillation, and that perhaps cause less bleeding, now are becoming available. Long-term experience with these medications is not yet available, however, and they cost more than warfarin.

The management of atrial fibrillation is a large and controversial topic that requires individual consultation with an experienced cardiologist or arrhythmia specialist (a cardiologist trained in electrophysiology). The first step is to seek and treat underlying triggers, including high levels of thyroid hormone, heart failure, heart valve disease, and alcohol or drug use. Under some circumstances, patients and their cardiologists may choose to control the heart rate with medication (and usually anticoagulants) rather than with an attempt to restore normal rhythm. In symptomatic patients, restoring and maintaining a normal rhythm may be preferable. Medications (antiarrhythmics) are usually the first approach to achieve this goal. An invasive treatment known as “ablation” is an option for individuals who tolerate atrial fibrillation poorly and who do not achieve adequate control with medication. The procedure involves passing wires into the heart through the veins in the legs and isolating the source of the abnormal rhythm. In very experienced hands, it is a quite effective and fairly safe procedure, but it does not always provide permanent protection from recurrence of the arrhythmia, and it has some risks.

As you can appreciate from the complexity of this response, atrial fibrillation is a challenging condition. It requires in most cases a long-term partnership between the patient and his or her physician, and a lot of choices, some of which are difficult. Fortunately, many management options are available today, and new treatments and strategies on the horizon continue to improve our ability to deal with this condition and to reduce its complications.

Managing Atrial Fibrillation (AF)

Question: I have been diagnosed with atrial fibrillation (AF). My cardiologist put me on 81 mg aspirin, 100 mg metoprolol, 20 mg potassium, and 20 mg torsemide, and told me that I didn't have to come back to see him for 3 months. Does this mean that I live with the AF and check in every 3 months? Does it go away? Should I get a second opinion?

Answer: Today, there are many options for the management of AF — including controlling the rate of the heart beat and taking blood thinners, attempting to restore and maintain normal rhythm with electrical treatment and/or medication, and performing invasive procedures to “ablate” the source of the disordered heart rhythm. The choice between these options, which each have their place in the therapy of this complex condition, depends on each particular medical situation and should involve the patient’s input. Not all options are appropriate for all individuals with AF. The doctor and patient should discuss the pros and cons of the various management options.

An anticoagulant such as warfarin (Coumadin) usually provides better protection than aspirin alone against complications such as stroke. As your doctor has given you a strong diuretic medication (torsemide), your case may be more complicated than some. I suspect that your doctor feels that you have good reasons not to take warfarin (such as a history of, or high risk of, bleeding or falls). It is important that you feel that all possible treatment options have been discussed with you. A second opinion, or further conversation with your present doctor, is in order if you feel that your options have not been sufficiently explained.

Bunny Ears on an EKG

Question: What are bunny ears on an EKG?

Answer: I’m not sure what is behind your question, but the straightforward answer would be that an electrocardiogram main complex (called the QRS by doctors) can resemble “bunny ears” (called an RSR' pattern by doctors), recorded in a particular position to the right of the sternum (called lead V1) in a condition known as “right bundle branch block.” This condition can be a normal variant or a sign of disease. A history, physical examination, sometimes combined with an echocardiogram can sort out whether this finding needs follow-up. In cardiology, we generally need to speak to and examine the patient, not just peer at wavy lines on the electrocardiogram to sort matters out!

Sudden Heart Beat Increase

Question: I have been experiencing sudden increases in my heartbeats. It happens about every 2 or 4 months; my heart beats very fast for about 15 seconds. I am 43 years old, in generally good health, and I have not had any pain. Should I have this symptom checked out?

Answer: What you describe is a very common symptom, and not necessarily a sign of a major heart problem. If you feel lightheaded or lose consciousness during these spells, however, such symptoms require expeditious evaluation. One approach to finding out what is behind these symptoms involves a complete history and physical examination, and often, the use of a device known as an “event monitor” that can transmit a record of the heartbeat (electrocardiogram) by telephone, allowing the cardiologist to make a precise diagnosis if there is an abnormal rhythm. The management strategy depends on the results of the clinical evaluation and capturing any abnormal heart beat on the event monitor.

Undiagnosed Heart Palpitations 

Question: I have been through every test imaginable because of my constant complaining about palpitations (EP study, stress test, Holter test, etc.). The only findings on the Holters tests were 10 premature ventricular complexes (PVCs) and 20 premature atrial contractions (PACs) and a short salvo. I am a 48-year-old female with no other health problems, but I have had this condition since my late 20s. I feel my heart skipping and fluttering and the cardiologists I have seen tell me not to worry, because I have a normal heart and I am just tuned in to this because I focus on it. I usually feel it doing some sort of funky rhythm during the day. Is this normal? Do other people experience it? One cardiologist told me that everyone gets irregular heartbeats throughout the day, and most people usually shrug them off; he says he gets them too. Am I unncessarily worrying about nothing?

Answer: If you have normal heart pumping function, have not had a fainting spell due to an abnormal heartbeat, and have no rhythm problem that lasts for more than a few beats, your symptoms are probably more of a nuisance than a threat. You might try avoiding caffeine or other stimulants as a first step in managing your symptoms. If you smoke, you should stop. Your doctor can review any medications that you take to see if they might predispose you to arrhythmia, and can see if the salts in your blood — such as potassium or magnesium — need adjusting in a way that might decrease your extra heartbeats. I would certainly try these simple measures before taking any medicines. You mention that the heartbeat recording showed a “salvo,” but this term could refer to several specific rhythm problems. If your symptoms persist and cause you continued concern, a consultation with an arrhythmia specialist can help you with management schemes and provide an assessment of your personal risk of a serious complication based on a complete examination.

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