Updated cardiac care guidelines for people living with Duchenne, as well as carriers.
Duchenne is a muscle disease, so why do clinicians and researchers care so much about the heart? Because the heart is a muscle too! Heart health is critical and the updated Care Considerations include tools for lifelong cardiac evaluation and management for people living with Duchenne, as well as recommendations for carriers that will help keep their hearts healthy, too.
At diagnosis, the cardiologist should collect family history and do an initial screen of the heart. An EKG will give the cardiologist an evaluation of the rate (how fast) and rhythm (how regularly the heart beats) of the heart. If there is any concern about heart rate or rhythm, or if the cardiologist just wants to get a screen of heart rate and rhythm over a longer period of time, a 24 hour Holter monitor will be ordered.
An echocardiogram or cardiac MRI will get images of the heart, showing the structure and function of the heart. The cardiac MRI is able to give a more exact image of the heart and, with contrast (given through an IV during the MRI), is able to show if there is any fibrosis (scar tissue) in the heart muscle. The echocardiogram ("echo") is a sonogram of the heart that can show the structure and function of the heart. Images from the echo are not as precise as images from a cardiac MRI, and an echo cannot show fibrosis in the heart muscle. An echo is an appropriate imaging tool for patients that are not able to tolerate a cardiac MRI.
Hearts should be checked in this way at least once every year, starting at diagnosis, (more often if abnormalities are found). If there is any evidence of dysfunction or fibrosis, cardiac medication should be started. Medication should also be started by age 10, even if everything is normal – it is hoped that this will help to protect the heart and keep it beating effectively and efficiently for a very long time.
ACE inhibitors are medications that end in "pril" (lisinopril, captopril, enalapril, etc.). These medications help the blood vessels coming from the heart to open up, so that the heart doesn't have to pump as hard to distribute the blood throughout the body. Decreasing the "squeeze" of the heart decreases the pressure that the heart needs to use to squeeze the blood out (thus decreasing the blood pressure). ACE inhibitors usually have no side effects, especially if they are started at low doses and are increased slowly. Occasionally, patients will develop a cough from ACE inhibitors. If this happens, they can be changed to angiotensin receptor blockers (ARBs). ARBs (losartan) have basically the same action as ACE inhibitors, but do not cause cough. ACE inhibitors are usually started before ARBS because they have been used a great deal in pediatric patients and have been found to have very little risk. It is important to regularly check blood pressures so that they do not get too low.
Beta-blockers are medications that end in "lol" (metoprolol, carvedilol, etc). These medications slow the heart rate down. When the heart beats slower, it is able to fill and pump more effectively. Beta-blockers can make patients feel a little sleepy when they first start taking them. This sleepiness is usually less if beta-blockers are started at a low dose and the dose is increased slowly. It is helpful, when increasing doses, to do it over the weekend – if the new doses is started on Friday, by Monday, any tiredness caused by the increased dose is usually gone. It is important to regularly check the heart rate, so that it does not get too slow.
Eplerenone and spironolactone are in a class of medications called aldosterone antagonists. These medications are used to help lower blood pressure by decreasing the volume of blood in the body that the heart needs to pump and circulate. Early studies have shown that eplerenone or spironolactone, when taken in combination with ACE inhibitors or ARBs, may delay the development of fibrosis in the heart muscle. It is hoped that delaying fibrosis, we will also delay the onset of heart dysfunction. In studies, treatment in younger patients seemed to lead to a longer delay in the development of fibrosis. As with ACE inhibitors, it is important to regularly check blood pressures, so that they do not become too low.
Female carriers are at risk for the development of cardiomyopathy. Carriers are encouraged to have their hearts checked by EKG and cardiac MRI every 3-5 years, if findings are normal (they should be checked more often if abnormalities are found). We will know much more about how to care for carrier hearts when the data from the Nationwide Carrier Study is analyzed, sometime this spring.
Your cardiac journey can help tell the story of heart health in Duchenne and increase the understanding of experts in the field. That's why we are asking you to update your Heart Module in the DuchenneConnect Registry. Log into your DuchenneConnect account, go to your profile page, and click on the Heart Module link. Either complete the survey for the first time, or select "Retake this survey" if you are updating your information.
Your heart is important to you, and to everyone around you. PPMD will continue to do everything we can to push cardiac research and care, for people living with Duchenne and for carriers. We believe that discoveries in cardiac muscle may lead to the advancement of skeletal muscle care and research, and that discoveries in female carriers may in turn lead to the advancement of care and research in people living with Duchenne.
So in honor of your heart, from all of us working diligently to keep your hearts healthy, Happy Heart Month!