Author: Dr. David Thorpe, President of Pass My Physical
Heart murmurs a relatively common in our society. According to the American Heart Association a heart murmur exists in 40 to 45% of children and 10 percent of adults. Murmurs can come and go throughout a person’s lifetime, and most are innocent. Also, since murmurs don’t often cause noticeable symptoms, you could have a murmur and not even know it.
It is when murmurs become more severe or are a result of a pathology or problem within the heart, in particular in the heart valves, then it becomes more of a problem. How are these harmful murmurs identified? Typically they are identified when a medical provider, including the DOT medical examiner, who hear them when they listen to your heart.
The harmful heart murmurs can disqualify the driver based on their location, if they produce symptoms, and if they are treated. Often times they lead to delays in certification as the DOT medical examiner must send a driver to a specialist to properly diagnose the murmur and decide if it needs treatment.
What causes a heart murmur?
Heart murmurs usually result from an abnormal blood flow through a heart valve. There are four heart valves in the heart, each one located either between a blood vessel and one of the hearts chambers (aortic and pulmonic) or between the different chambers of the heart (tricuspid or bicuspid). In adults (truck drivers) these murmurs can be caused by a variety of things. Sometimes they have been present for many years and are innocent. Other times they are a result of a malformed valve or damage or aging in a valve. Their presence is identified when the medical provider listens to your heart with a stethoscope and hears the tell tail “whoosh” noise. From there they can identify what valve is involved based on the position on the chest that they are listening to your heart. The severity of the murmur is typically determined by how loud the “whoosh sound” is.
Murmurs are caused by two specific processes, either stenosis or regurgitation. Stenosis is the narrowing of a valve which causes the valve to not open properly. The flaps of the valve may thicken, stiffen or fuse together. As a result the valve cannot fully open. The heart then has to work harder to pump blood through the valve, and the body may suffer from a reduced supply of oxygen from less blood flow.
Regurgitation is when a valve doesn’t close properly and there is back flow of blood when the heart pumps to push blood to specific parts of the body. This is typically caused when there has been damage to the valve for example after when someone has had a heart attack.
Even though we mentioned that many murmurs do not have any symptoms, when they become more severe there are some symptoms that a person can develop. These symptoms include:
- Shortness of breath or difficulty catching ones breath.
- Weakness or dizziness.
- Discomfort in the chest.
- Swelling in the ankles, feet or abdomen (stomach area).
Symptoms that are innocent are typically left along, Those that are a problem can be treated medically or surgically. When surgically treated, the valve is often times replaced with an artificial valve. These having this type of treatment is typically very successful but may have its own requirements for DOT certification for a truck driver.
Which types of murmurs are of concern, and how do DOT medical examiners decide when you need to consult a specialist?
DOT medical examiners will listen to how loud and what part of the heart beat the murmur occurs. Anything that is moderately loud and occurs when the heart is resting is of notable concern. As a result the medical examiner will look for information either from a treating provider (if the murmur is being treated) or from a specialist (if it was not diagnosed before).
Murmurs where no evaluation is required are classified as class I or II murmurs. They are very quiet, the driver has no symptoms and are usually benign. The medical examiner will however require a specialist evaluation in a number of cases, especially when very loud, and are accompanied with symptoms of heart disease.
Drivers that have require surgery will be required to have a waiting period following that surgery ( 3 months) and medical clearance from the surgeon. They often times will be taking blood thinners that have separate and specific requirements (such as providing testing results). Regardless of the treatment, the maximum certification period will be 1 year in most cases based on the treatment and its success. There are some however that are shorter then 1 year.
What is a driver to do?
If you know that you have a murmur already (it’s been diagnosed) made sure you have visited the cardiologist relatively close to when your medical certification exam is required. Have the cardiologist provide a clearance letter stipulating the type of murmur (innocent or harmful), type of treatment if any (medical or surgical), and if it is stable meaning not getting any worse. If a driver where to do this, then the likelihood of any delay in certification would be very minimal.