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.