A 73-year-old woman with aortic valve disease was referred to Duke Medicine for aortic valve surgery. She had a nonfunctional bicuspid aortic valve, a relatively common congenital abnormality, and an enlarged aortic root. The patient’s case was complicated by congestive heart failure and high blood pressure.
Postoperatively, the patient experienced atrial fibrillation, which occurs in 30% to 40% of patients undergoing cardiac surgery, and bleeding. The patient was prescribed medications to slow her heart rate (approximately 120-130 beats/minute) and restore normal sinus rhythm. However, these medications also slowed down her normal rhythm, and the combined presence of abnormally fast and slow rhythms caused tachycardia–bradycardia syndrome.
Occasionally, her heart would completely stop beating due to sinus node dysfunction, and, at one point, she went into cardiac arrest.
Due to her tachycardia–bradycardia syndrome and recurrent, dangerously slow heart rhythms, the patient required a pacemaker (approximately 5% of patients require one following aortic valve surgery).
Question: Because this patient only needs pacing infrequently (< 1% of the time) and traditional pacemaker surgery has risks, is there an alternative option for this patient?
Answer: Yes, her medical team chose a leadless pacing system currently undergoing clinical trials at Duke.
Jonathan Piccini, MD, a heart-rhythm specialist and associate professor of medicine at Duke Medicine, identified the patient as a good candidate for the Micra leadless pacemaker (Medtronic, Minneapolis, MN), given her infrequent but definite need for pacing.
The Micra Transcatheter Pacing System doesn’t use leads, also called wires, to deliver pacing therapy. Rather, the device is attached to the heart with small tines and delivers electrical impulses that pace the heart via an electrode on the device.
“We approached the patient about the clinical trial because of her difficult postoperative course and her higher risk for complications with a traditional pacemaker,” Piccini explains. Implanting a traditional dual-chamber pacemaker is more invasive than a leadless pacing system because it requires minor surgery to create a pacemaker pocket and the insertion of 2 leads into a blood vessel that goes to the heart.
A leadless pacing device is confined to a single chamber; the generator and pacing apparatus are combined into one piece of hardware placed in the right ventricle. Eligible patients should have an indication for single-chamber ventricular pacing (and not dual chamber pacing), because the device only paces the right ventricle.
Other advantages exist as well. “With a traditional pacemaker, the risk of infection is 1% to 2%, often because patients develop a hematoma around the pacemaker and pocket,” adds Piccini. “The leadless system has a significantly lower risk because there is no pocket to become infected and it has less hardware.” In addition, bleeding is less common.
Although a traditional pacemaker takes up to 1.5 hours to implant, the system that the Duke team chose for this patient requires only 30 to 45 minutes. From a cosmetic standpoint, no incision is made—thus, no scar—and the patient has no outward signs of having the device. Both types of pacemakers work for up to approximately 10 years.
Piccini says that he implanted the leadless pacemaker into the patient in December 2014. “The procedure went very smoothly. She didn’t have any complications or difficulties with the device. She is doing great, ” he explains, and “she is asymptomatic, has no limitations, and is very active.”
Duke frequently participates in or designs clinical trials that provide patients access to new technologies. Duke’s electrophysiology program emphasizes innovation, research, and world-class clinical care and teaching that center on patient needs, adds Piccini.