New Advances in Atrial Fibrillation

Atrial fibrillation is a rapid, irregular heart rhythm in the upper chambers of the heart (the atria).  Instead of having a regular, coordinated beat, the atria are rapid and disorganized. When the atria are not beating in a coordinated fashion, the blood in these chambers does not drain effectively into the lower chambers of the heart (the ventricles). When blood is not draining well, it sits in the atria and can form a blood clot. A clot, or a small part of a clot, can break loose, go to the brain and cause a stroke. 

Atrial fibrillation is the most common heart rhythm disturbance with about 5.6 million diagnosed cases in the United States.  If left untreated, atrial fibrillation leads to stroke in 5 out of 100 people per year. Atrial fibrillation is treated with medications such as beta blockers, calcium channel blockers or digoxin to control the rapid heart rate. If doctors want to return a patient to a normal, regular rhythm then antiarrhythmic agents are used, often with cardioversion (shocking the heart back to normal rhythm).  To prevent blood clots and strokes, Coumadin (warfarin) has been prescribed for many decades. Coumadin will decrease the risk for stroke to less than 1 in 100 patients per year. Coumadin however is difficult to take, requiring frequent blood drawing to ensure that the blood is not “too thin” (leading to bleeding) or “too thick” (leading to stroke). In addition, eating green leafy foods will interfere with the level of blood thinning provided by Coumadin (green leafy foods have Vitamin K which reverses the effect of Coumadin). Many common medications interfere with Coumadin’s effect as well. Lastly, there is a significant risk for major bleeding on Coumadin, especially bleeding in the brain.

One recent break through in the management of atrial fibrillation came with the introduction of novel oral anticoagulants (NOACs).  These agents include Dabigatran (Pradaxa), Rivaroxaban (Xarelto) and Apixaban (Eliquis).  The NOACs are easier to take than Coumadin since there are no dietary restrictions. Their blood thinning effect is consistent, so blood drawing to test levels is not needed. In addition, they have been shown to reduce the risk of stroke to a greater degree than Coumadin and they are generally safer with lower risk for major bleeding and bleeding into the brain.  The major down side to the NOACs is that, to date, there is no antidote which can reverse the effect of these medications if a patient comes to the hospital with bleeding (there is an antidote for Coumadin).  Until a reversing agent becomes available, patents with bleeding on a NOAC are supported with blood transfusions, surgery and time (letting the medication wash out of the system).

Another recent innovation in the treatment of atrial fibrillation is catheter ablation. It is felt that atrial fibrillation is caused when tiny electrical wavelets are conducted from the pulmonary veins to the atria (pulmonary veins are vessels that carry oxygenated blood from the lungs to the heart).  Once in the atria, these wavelets perpetuate and cause the rapid chaotic rhythm.  Catheter ablation entails threading an electrical probe from the leg artery into the heart. The catheter is positioned at the inlet of the pulmonary veins into the atria and small areas of the heart tissue are burned, effectively causing a “circuit breaker”, the burned tissue stops the wavelets from reaching the atria. Catheter ablation has been successful in 84% of patients, allowing them to stop many of the medications, including blood thinners, they were taking to control atrial fibrillation.  Catheter ablation is generally recommended for symptomatic atrial fibrillation patients, especially if they have failed one or more antiarrhythmic agents.

Recently an association has been made between atrial fibrillation and obstructive sleep apnea.  Sleep apnea is a condition where patients stop breathing during the sleep cycle.  When they stop breathing the blood oxygen level decreases. When the oxygen level is low, patients are then aroused and gasp for breath. This cycle continues throughout the night. With frequent arousals, patients can’t enter the deepest phase of sleep, so the body does not get its proper rest. When the body can’t rest, it is perpetually aroused, there are excess catecholamines (adrenaline) and that may predispose to atrial fibrillation. When sleep apnea is successfully treated with a CPAP mask (to keep the airway open, stopping the drop in blood oxygen) episodes of atrial fibrillation are reduced.

It is becoming more apparent that atrial fibrillation is a disease related to life style and systemic disease. It has been known for years that atrial fibrillation can occur with binge drinking of alcohol (the so-called “holiday heart syndrome”).  Reducing alcohol intake can reduce episodes of atrial fibrillation. More recently, it has been shown that obesity is related to atrial fibrillation. Obesity can lead to diabetes, hypertension and sleep apnea, all factors in causing atrial fibrillation. Now, for the first time, it has been shown that obese patients who lost 10 per cent of their body weight achieved freedom from atrial fibrillation without the use of any medication or ablation. The more weight that was lost, the greater the freedom from atrial fibrillation.

Atrial fibrillation used to be thought of as a disease. Now we are beginning to see that the atria are a window on overall health and that atrial fibrillation is an exposure to an excess. Medications and procedures for atrial fibrillation can help manage the acute episode, but then the real work begins, as patients then must address life style issues such as alcohol intake and treating obesity and sleep apnea. Despite the new advances in pharmacology and surgery to treat atrial fibrillation, the future cure of atrial fibrillation will more likely come from identifying the life style causes and treating these causes.

The Stethoscope

The stethoscope is a device that doctors can use to listen to the internal sounds of a patient’s body. It was invented in 1816 by Rene Laennec in France and the first American stethoscope was patented in 1882 by William Ford. The basic structure of the stethoscope hasn’t changed much since its original invention. The head of the stethoscope has a diaphragm, which transmits sound when it is applied to a patient’s skin. From the head of the stethoscope there is a plastic tube, which conducts the sound. The doctor listens to the sound through two earpieces.  

Before advanced medical imaging, before modern medications and advances in surgery, the physical examination and the stethoscope were the only ways for doctors to diagnose and follow heart disease. A patient’s pulse was examined and characterized. A doctor would auscultate the heart and analyze each sound, click and heart murmur. Each murmur was further characterized by putting a patient through maneuvers such as squatting, deep breathing, standing and leg raising. This helped determine the cause of the heart murmur. These physical examination techniques are still taught in medical school today.  Since there wasn’t any other way to diagnose a patient and only a few therapeutic options to discuss, the doctor spent quite a lot of time doing the physical examination.

The stethoscope of today is quite similar to the original models. The acoustics have improved, but it remains an analog device. Electronic stethoscopes have been developed which improve the acoustics, and give the ability to amplify, record, and download the heart sounds to a computer.  Most doctors still carry the old analog device, but the newer stethoscopes as well as hand held ultrasound devices (which give both acoustic and visual images of the heart) are being used more and more. Despite the improvements in technology, it has been shown that doctors’ ability to diagnose heart murmurs by physical examination is getting worse over time. Younger doctors and medical students cannot identify murmurs as well as older physicians. There are several reasons for this. Despite the fact that physical examination techniques are still taught and tested in medical school and in training, there is far less emphasis on developing these skills. In addition, in the typical patient encounter, there is much less time to do as extensive an evaluation as in the past. Lastly, with medical imaging such as echocardiography so readily available, there is less reliance on the stethoscope since an ultrasound of the heart can give a better, more accurate diagnosis. In fact, in some medical circles, the physical examination is felt to be a dinosaur and worthless in the diagnosis and treatment of the modern patient.

I still carry and use an analog stethoscope. It is around my neck from the time I leave the house until I return home, often more than 12 hours per day. On days off and on vacation, I feel naked without my stethoscope. My stethoscope requires some maintenance (I clean and disinfect it regularly), but it is always available and ready to use. It is never down due to a power outage or because of a hardware failure. I never have to upgrade its software.   I listen to every patient I see with my stethoscope. I can tell if a patient’s lungs are filling with fluid or if there is a new or changing heart murmur. I can tell if the heart rhythm is regular or not. Most importantly, it brings me close to the patient and gives me a physical connection to them. There is still great value in that.

Exercise as Medicine

Diet and exercise have long been touted as a way to reverse heart disease. Can exercise be as good as medications for heart disease?

Everyone understands medications. A pill is prescribed in a fixed dose and taken at a specified time.  How can exercise be prescribed? How can we “dose” exercise? One way to “dose” exercise is by measuring the intensity of exercise using the metabolic equivalent, or MET, level. The MET is an estimate of the amount of oxygen used by the body during physical activity. One MET is the energy the body uses while sitting quietly at rest. The harder you work, the higher the MET. An activity that burns 3 to 6 METs is considered moderate, while one that burns more than 6 METs is vigorous. Walking is great exercise. For example, walking on level ground at 2.5 mph requires 3 METs, backpacking is 7 METs and climbing hills with a heavy pack uses 9 METs. Tables are available that outline the METs for various activities.

A person who wants to start an exercise program should be given an exercise prescription by their doctor. This prescription should have the frequency of exercise (typically 3-5 times per week), the intensity (usually moderate or 6 METs), the time per session (20-30 minutes), the target heart rate and the type of exercise. The target heart rate can be easily calculated by the formula: (220-age) x 0.85.

What type of exercise is best? The answer is the one you will actually do. If you like an exercise, then you will be more likely to follow through with it. One does not need to spend lots of money on gym memberships to gain the benefit of exercise. Walking is an excellent exercise which is easy to do, requires no extra equipment, is generally safe to do, is easy on the joints and has the lowest drop out rate.

Once a person has their exercise prescription and begins their exercise program, what kind of health benefits can they expect?  A daily regimen of walking reduces the risk for heart attack, stroke, atrial fibrillation, colon cancer, hypertension, diabetes, depression, obesity and Alzheimer’s disease. Walking lowers total cholesterol levels, raises good cholesterol levels (HDL), maintains healthy bones and lowers stress levels. Walking can even help you live longer (one and one half more years for walking daily at 3 METs). More strenuous daily activity can extend your life by three years.

Despite all of the benefits of exercise and government campaigns to promote physical activity, many people remain sedentary. One way to promote and sustain walking behaviors is through walking groups. Walking groups are short walks scheduled weekly or monthly. Walking groups, especially those targeted at older adults, have supportive effects that encourage adherence and positive attitudes toward physical activity, companionship and a shared experience of wellness, providing both physical and psychological health benefits. Walk with a Doc (www.walkwithadoc.org) is a national walking group where local physicians walk side by side with their patients.  The informal setting makes participants comfortable interacting with their doctor, questions or health topics can be discussed while walking and, most importantly, patients witness their physicians practicing what they preach. A Walk with a Doc walking group has been established in the central New Jersey area. The first walk will take place in the Bridgewater Commons Mall on Saturday February 28 2015 at 8:30 AM. The meeting place for the walk is the mall’s food court. For future walks look for information on www.medicor.com.

So to help your heart, start walking today. For the best benefit, take a walk for 30 to 60 minutes each day. Alternatively you can join us at Walk with a Doc. If you really want to challenge yourself, take a hike.