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Johns Hopkins

Johns Hopkins Pediatric

Creative Approaches for Patients with Congenital Heart Disease and Electrical Heart Complications

Konstantinos Aronis, an electrophysiologist at Johns Hopkins, dedicates part of his time to caring for a one-of-its kind population: adults with congenital heart disease who also have an electrical heart problem.A transparent 3D heart model

Konstantinos Aronis used this 3D heart model to plan a surgery for a unique patient.

“The uniqueness of the patients in this group is the fact that they have complex and unique anatomy,” says Aronis, director of the Adult Congenital Heart Disease Complex Ablation Program. “Part of it is how they were born, and then the cardiac surgery interventions that they’ve required along their medical journey. There is no one-solution-fits-all approach.”

Konstantinos Aronis, in a formal portrait, wearing a plaid suit jacket, white button down shirt and brown tie

 “The key element in the care of these patients, because of the complexity, is the multidisciplinary approach.” — Konstantinos Aronis

With advances in medical care, these patients — who previously would have died young — are living longer and requiring creative treatment. Aronis and his colleagues at Johns Hopkins are particularly well suited to help them. A native of Greece, Aronis completed cardiology and electrophysiology fellowships at Johns Hopkins, plus a research fellowship in computational electrophysiology at the Johns Hopkins Whiting School of Engineering, and he joined the medical faculty in 2023.

Aronis meets once each month with other electrophysiologists, and cardiac surgeons and imaging specialists, to discuss patients with complex conditions and to decide on the best management plan. Two recent cases showcase the collaborative nature of their approach.

In one, a woman in her 40s needed a pacemaker for conduction system pacing to restore a normal heartbeat. Typically, cardiologists treat this condition through the skin, by inserting pacemaker leads into the center of the heart. But this patient was born with her ventricles (lower heart chambers) flipped. A childhood surgery that kept her alive also reversed the atria — the upper heart chambers.

“Because of the ventricles being flipped, the target was on the opposite side, so we had to drill across her heart and land on the piece of the heart with the right orientation,” Aronis says. “That was a challenge.”

Aronis turned to Stacy Fisher, associate director of the Adult Congenital Heart Disease Center at Johns Hopkins, for help using CT images to create a 3D printed model of the patient’s heart that Aronis could use to map out the procedure. The day before the insertion, he spent time in his office devising a strategy, which cut the estimated procedure time from six hours to about three.

In the second case, Aronis and Johns Hopkins cardiac surgeon Danielle Gottlieb Sen performed what may be the first intraoperative ablation for atrial tachycardia (rapid heartbeat).

“This was a scenario where the patient had a tachycardia from the atrium that was right next to a nerve that controls breathing,” Aronis says.

Aronis couldn’t cauterize the area the typical way, by going through the chest, because it would damage the nerve. The patient was scheduled for cardiac surgery to replace an artificial valve, so the team mapped the electrical abnormalities in real time during the surgery, and Aronis performed the ablation in the operating suite.

Both patients are doing well.

Aronis and colleagues now plan to launch an adult congenital disease arrhythmia-specific research group, making use of patient registries to contact patients who would be appropriate for new research studies and tracking patient outcomes.

“The key element in the care of these patients, because of the complexity, is the multidisciplinary approach,” Aronis says. “Everybody claims they do personalized medicine, but this is where it really applies.”

Clinical Trial

A personalized approach continues in the clinical trial Optima, which is for patients with persistent atrial fibrillation — a common but difficult to treat rapid heart rhythm. Johns Hopkins biomedical engineer Natalia Trayanova uses participants’ cardiac MRI scans to build personalized computer models of the heart so she can do a deep dive into what areas might be triggering a fast heartbeat and simulate ablating those regions to see if it helps. Then, patients are randomized to receive either traditional ablation or traditional ablation plus cauterizing of extra areas identified by Trayanova’s eagle eye.

“These are spots that are outside of the regions that we would typically target,” says David Spragg, an electrophysiologist at Johns Hopkins and the study’s principal investigator. “We’re hoping to find more intelligent ways to ablate this very common arrhythmia and eliminate the need for repeat procedures.”

For more information or to refer a patient, send an email to For information on other clinical trials, visit

To refer a patient, call 443-997-0270.


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