November 22, 2019

At the Johns Hopkins Center for Inherited Heart Diseases, genetic counselors work closely with cardiologists, cardiac electrophysiologists and pediatric cardiologists to identify familial heart diseases and slow their progression through preventive care. Located in Baltimore, Maryland, it is the only center of its kind in the region. 

“One of the big benefits we always talk about in the center is that we don’t necessarily take care of patients, we take care of families,” says Brittney Murray, genetic counseling manager. “We’re never really thinking about the patient in isolation; we’re thinking about them in the context of their family.”

The comprehensive care that the team provides includes education about the diseases, genetic testing, identification and screening of additional family members who may be at risk and medical treatments or suggestions for lifestyle modifications as necessary.

"We focus on all aspects of inherited heart conditions,” says Andreas Barth, center director. This includes patients with inherited arrhythmias in the absence of structural heart disease, such as those with long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia (CPVT), as well as inherited arrhythmias that occur with structural heart disease, like arrhythmogenic right ventricular cardiomyopathy (ARVC).

Another big focus for the center is patients who have dilated cardiomyopathy, dilated familial cardiomyopathy and hypertrophic cardiomyopathy. In addition, the center is connected to the cardiology division’s Lipid Clinic, where genetic counseling has been incorporated for patients being screened for familial hypercholesterolemia. 

Barth himself has expertise in channelopathies — inherited heart diseases caused by defects in the channels that conduct potassium, sodium and calcium ions. When they don’t work properly, it can lead to altered electrical properties of the heart muscle. Without management, patients are at risk for dangerous, life-threatening arrhythmias.

“We teach patients about what conditions are associated with arrhythmias to help them avoid those situations,” says Barth, in addition to prescribing beta blockers, antiarrhythmic drugs or implanting a defibrillator if necessary. “What makes these challenging is the family history is only partly predictive. The family member of a patient who has long QT syndrome or Brugada syndrome is at higher risk and needs to be screened, but if the index patient has a cardiac arrest and we find out the family member has the same condition, it doesn’t mean they necessarily are at risk of sudden cardiac death or will need a defibrillator. It’s very individual and needs to be personalized.”

Overall, the team provides care across various age ranges, Barth says, “so if we see a family with an inherited heart disease, we work closely together with our colleagues in pediatric cardiology.”

Many times, screening will detect the underlying root genetic cause of a condition, adds Murray. “One of the precision preventative medicine aspects of our center is that we’re really able to go throughout the family and identify who else may be at risk presymptomatically and get them in for screening. Often we can save lives or alter the course of disease by early detection in these family members.”

New to the center is cardiologist Olurotimi Mesubi, who joined the faculty in July upon completing an electrophysiology fellowship at Johns Hopkins. Mesubi, whose research is focused on trying to better understand the mechanisms that promote atrial fibrillation, works with Barth managing patients with inherited arrythmias.

With the increased use and availability of genetic testing, more and more patients who carry silent mutations in ion channels are incidentally being identified, says Barth. It isn’t unusual for center physicians to see a patient referred from the Department of Neurology or the Kennedy Krieger Institute who underwent genetic testing for a neurologic condition that identified mutations that predispose them for inherited arrhythmias.

“We see a lot of patients referred who are otherwise completely asymptomatic,” he says. “Often, just with lifestyle measures alone, the outcome is good. However, combining genetic testing with a comprehensive cardiology evaluation allows us to identify patients at highest risk for whom more aggressive treatment can be life-saving.”