Photo:The 4D Flow MRI measures blood flow through the heart over time.
Treatments focus on genetic testing to help stem problems before they occur.
As far back as 2000, the University of Miami Health System’s Cardiovascular Genetics Clinic began seeing patients with rare heart conditions that doctors knew had a genetic link. As research broadened the understanding of the genetic disorders, the family members of those patients became an important part of the clinic’s practice.
Today, entire families come in for genetic testing for certain conditions, says Dr. Robert Myerburg, a cardiac electrophysiologist, professor of medicine and physiology and the American Heart Association chair in cardiovascular research at the University of Miami Miller School of Medicine. Myerburg runs the Cardiovascular Genetics Clinic. He mostly works with patients who have conditions that affect the heart muscle, known as inherited cardiomyopathies. “Let’s say you have somebody who is 25 years old and has had a cardiac arrest due to an inherited cardiomyopathy or channelopathy. Most of them would end up getting an implantable defibrillator The genetics for that individual is not terribly important because you already have the diagnosis and have already instituted the therapy,” Myerburg says. “The important point is for the family members.” Patients whose genes indicate an inherited heart condition might opt for close monitoring or additional tests before participating in strenuous exercise, or they might start medication or have a defibrillator implanted.
UHealth and Miller School of Medicine chief of cardiovascular medicine Dr. Jeffrey Goldberger is also working to reduce cardiovascular risks for patients. Like Myerburg, he is a cardiac electrophysiologist, but his focus is on the mechanisms that lead to stroke among patients with atrial fibrillation (AFib). Current methods of predicting whether AFib patients are at risk for stroke are only a little bit more accurate than chance. Yet, patients who seem to be at higher risk for stroke are usually put on blood thinners, which can lead to major bleeding. Those at lower risk are usually not given blood thinners.
Before he joined UM three years ago, Goldberger approached a colleague at Northwestern University to try to find a better way to measure the risk of stroke in AFib patients. His colleague had developed a method that used a standard cardiac MRI with special software and analysis to measure blood flow. They used the technique, called 4D Flow MRI, to measure blood flow through the heart over time. It’s an important predictor of stroke risk for AFib patients.
This technique is still in the development phase. Goldberger and his colleagues aren’t certain which speeds of blood flow indicate that a patient should be on blood thinners, but he is certain the current way of assessing stroke risk needs work. “Most of our approaches are mediocre,” he says, “and we can improve them a great deal.”
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