Higher blood pressure from childhood can put black people at risk for congestive heart failure

Starting in early childhood, otherwise healthy blacks show signs of slightly reduced heart muscle strength and slightly higher blood pressure than their white counterparts, potential factors. putting them on a course for the early development of congestive heart failure, researchers report.

The home message for parents and physicians, especially for high-risk cardiovascular populations such as blacks, is that blood pressure should be closely monitored starting in early adolescence, says the corresponding author of the study in Journal of the American Heart Association.

Children with harmful high blood pressure may need early evaluation of heart function and / or medication to lower their blood pressure to protect their future heart health, says Dr. Gaston Kapuku, a person cardiovascular research at the Georgia Institute of Prevention at the College of Medicine. of Georgia at the University of Augusta.

The researchers also found that ejection fraction, a widely used method for assessing the muscle strength of the heart by looking at the amount of blood in the left ventricle, the heart’s main pumping chamber, is pumping -out with each abbreviation is a great way to identify those young people at risk as they move through life.

Instead a study that has long been available, but is less commonly used is called midwall fractional shortening, or MFS, which looks more directly at muscle-to-muscle capacity, giving an earlier view that the heart wall is starting to thicken and weaken in response to pushing against a higher pressure within the aorta, the largest blood vessel in the body, which donates blood full of oxygen to the body.

Kapuku and his colleagues looked at 673 people – about half male and female, half black and half white – who were followed at the Georgia Prevention Institute for more than 30 years as part of the Augusta Heart Study, looking at development cardiovascular risk factors in children with a family history of risk factors such as hypertension and heart attack.

This appears to be the first study intended to examine changes in heart muscle, or myocardium, functioning in a healthy group of individuals over their lifetime.

They found that while ejection fraction was maintained in Black study participants over the 30-year course of the study, MFS was able to record a fraction of a percentage change in cardiac function: Decreased. 54% in MFS in black partners compared to white partners, as both grew from childhood to young adults. They also observed that as the size of the left ventricle increased by 1 gram, or about 0.035 ounces, MFS in Black participants decreased 0.01%. The whole heart weighs 7-15 ounces, and a growing heart is a sign of disease.

Also as pressure within the aorta, through which the ventricle pumps, slowly shrinks over the years, MFS, which indicates muscle strength, slows down.

Small reductions in MFS are associated with an increased risk for congestive heart failure, the researchers write. Kapuku notes that while the small reductions in contractility they have found are not yet clinically significant in these young people, if the transition continues they are likely to be a feature of heart health.

When you look at MFS you can assess the power of your muscle, you know it weakens even though the ejection fraction is normal. “

Dr. Gaston Kapuku, Cardiovascular Researcher, Georgia Institute of Prevention, Georgia College of Medicine, University of Augusta

MFS is a formula that also describes the thickness of the heart wall when it is contracted and relaxed. Kapuku contracts her biceps to show the clear difference that contracting and relaxation makes in muscle size. The heart cavity that fills with blood is much larger when it is relaxed, called a diastole, and the muscle becomes much larger when it is contracting, called a systole.

Kapuku and colleagues say MFS is an easy, sensitive, and inexpensive way to detect small changes in heart muscle strength that sets the stage for a major heart disorder down the road, perhaps especially in young black adults.

Heart disease is the leading cause of death for all Americans, but death rates are higher in blacks than whites and other ethnic groups, and disease develops at a younger age, according to The Heart Foundation. Despite cardiovascular disease being the number one killer, congestive heart failure is the only growing adult cardiovascular disease, Kapuku says, especially as people live longer. longer. Black people have the highest rate of congestive heart failure as a result of aging, rather than from direct damage to heart muscle from a heart attack, Kapuku says.

The study helped show the racial differences, including slightly higher blood pressure and decreasing heart function, already seen at a young age, he says. . Researchers suspect that weight-induced sodium retention, in which a higher percentage of black people retain more sodium, rather than releasing it in their urine, is an important feature. . Higher sodium levels increase fluid volume within blood vessels and blood pressure, including pressure inside the aorta, which the left ventricle must constantly pump, to the canar afterload.

That means that, despite physical fitness, a young Black man’s blood pressure would tend to run higher than the white man’s levels, setting the stage for congestive heart failure earlier than life, Kapuku says.

Like Kapuku biceps that are struggling with increasingly heavier hand weights, the heart will increase muscle mass against this increased weight but, unlike the biceps, the heart does not work better. when it is larger.

“If I hadn’t resisted more, I wouldn’t have increased more heart pressure,” Kapuku says. “We need to reduce blood pressure as soon as possible. Myocardial dysfunction may occur before the currently defined clinical criteria for hypertension.”

That means lowering blood pressure in young black people, perhaps shortly after they enter adolescence, may help maintain heart function.

A better diet will include foods that are low in salt and high in potassium, such as cooked broccoli and spinach, plantains and sweet potatoes, along with regular physical activity, Kapuku says, “but that medical treatment is the ticket to life. “

Organizations such as the American Heart Association say that you can show that you have a “normal” ejection fraction and that they still have heart failure with what is known as a preserved ejection fraction, where the heart muscle is so thick. and so firm it may hold less blood so it seems to be pumping out the normal percentage – 50-70% of the contents of the ventricle – so that the total volume is not enough for to maintain the body.

Early on, as in these study participants, the heart is likely to try to compensate, in order to maintain the ejection fraction, by working harder, which works for a time so as not to that is, Kapuku says.

Controversial heart failure can occur with aging as the cardiac muscle cells, or cardiomyocytes, we are born with begin to die slowly and their previous place will be lost. filled with fibrous tissue, which also begins to circulate remaining cardiomyocytes and eventually weakens the heart’s ability to contract. . Exercise can slow but not stop the process which makes proper filling and pumping increasingly difficult.

The American Academy of Pediatrics and the National Institute of Heart, Lung, and Blood both recommend that children receive annual screening for high blood pressure, starting at age 3, at their annual children’s visits.