How One Center Keeps Pace at Electrophysiology’s Frontiers

When Oussama Wazni, MD, takes over as head of Cleveland Clinic’s Section of Cardiac Electrophysiology and Pacing in September 2017, he’ll be leading a vibrant, internationally recognized team committed to advancing the standard of care for patients with abnormal heart rhythms and related complications.

“I’m excited to continue our leading-edge clinical work and build on our research efforts,” says Dr. Wazni, who has been a member of the section since 2006, most recently directing its outpatient clinic. “We have the capability to study a clinical problem from the bench to the preclinical lab and then ultimately in patients.”

Translation in practice

That translational approach is well-represented by work done within the section’s Atrial Fibrillation Center, a multidisciplinary specialty treatment group devoted to addressing both paroxysmal and persistent atrial fibrillation (AFib) using new mapping technology, lead removal when devices go awry and new approaches to stroke prevention.

“It’s an exciting time for ablation,” says Atrial Fibrillation Center Director Walid Saliba, MD. “We are acquiring new tools to make our work easier, safer and more efficient. For the first time we are using sophisticated mapping to help us understand what goes on during AFib. There’s a long way to go, but we hope that improved understanding can yield better ablation success rates.”

Management of ventricular tachycardia (VT) is another area of expertise — one in which a major initiative has been mapping and ablation in patients with severe forms of VT who are often turned away by other centers. “At Cleveland Clinic, because of our close collaboration with heart failure colleagues and cardiac surgeons, we’re able to tackle the most complex cases of VT, with encouraging outcomes,” Dr. Wazni says.

A multidisciplinary take on stroke prevention

In the realm of stroke prevention, Cleveland Clinic’s Atrial Fibrillation Stroke Prevention Center has helped pioneer the use of implanted devices designed to close the left atrial appendage (LAA) to prevent clot migration in patients with nonvalvular AFib who are at high risk for bleeding. In addition to electrophysiologists, the center is staffed by interventional cardiologists, imaging cardiologists, neurovascular medicine specialists and gastroenterologists with expertise in the bleeding complications of anticoagulants.

“The whole concept of the center — and of closing the LAA for stroke prevention — is new,” Dr. Saliba notes.

The center is currently participating in a head-to-head trial of two LAA closure devices — the FDA-approved WATCHMAN™ (photo at top shows a WATCHMAN implantation procedure at Cleveland Clinic) and the investigational AMPLATZER™ Amulet™. “These devices work similarly but have different designs, and their implantation is different,” Dr. Wazni notes. “We’re hopeful that both will perform well.”

Mapping and intervening when AFib persists

Another major research effort centers on elucidating the mechanisms behind persistent AFib. “We know a lot about paroxysmal AFib, but uncertainty remains around persistent AFib,” Dr. Wazni explains. “We’ve put intense effort into understanding persistent AFib, as it continues to be a clinical problem without a very good solution.”

Last year, Cleveland Clinic researchers published a study demonstrating the importance of performing catheter ablation as soon as possible following diagnosis of persistent AFib (Circ Arrhythm Electrophysiol. 2016 Jan 13 [Epub ahead of print]). And in a separate study published earlier this year (J Cardiovasc Electrophysiol. 2017;28:483-488), they found that the use of contact force sensing in persistent AFib ablation is associated with shorter procedure times and fewer arrhythmia recurrences.

Cleveland Clinic electrophysiologists are also among a select few to work with several different manufacturers to employ the latest multielectrode 3-D mapping technology for both clinical use and research into AFib and VT. “We map AFib with the goal of understanding where it’s coming from,” Dr. Wazni observes. “Several different systems will likely yield the answer, but we don’t yet know which ones.”

And in the area of paroxysmal AFib, Cleveland Clinic’s team has developed expertise in “redo” ablations for patients who continue to experience AFib despite a prior ablation, as reflected in a study presented at the Heart Rhythm Society’s 2017 scientific sessions. In these cases, the redo is typically needed because the pulmonary veins weren’t completely ablated, arrhythmias other than AFib are at play, or the patient may have post-ablation atrial flutter, which requires further mapping to localize and eliminate, Dr. Saliba explains.

Taking lead management beyond extraction

While many U.S. centers place cardiac implantable electronic devices (CIEDs) to treat arrhythmias, Cleveland Clinic is one of far fewer with expertise in removal of the devices’ leads in the event of infection, recall or malfunction. But this focus on leads extends beyond simple extraction, according to Bruce Wilkoff, MD, Director of Cardiac Pacing and Tachyarrhythmia Devices.

“We tend to talk about ‘lead management,’ or how to plan for lifelong therapy with pacemakers and defibrillators with leads,” he says. “We continue to work on reducing the need for lead extraction while improving the safety of doing so if it’s necessary.”

In one such effort, Cleveland Clinic is serving as lead center in a randomized, prospective, international study of nearly 7,000 CIED recipients to learn whether the TYRX™ antibiotic-releasing absorbable envelope for CIEDs reduces the risk of infection during the year following implantation. The study is nearly fully enrolled and will continue for another year, says Dr. Wilkoff, who chairs its steering committee.

Data diving to promote extraction safety

Another focus involves the use of a novel compliant endovascular balloon device during transvenous lead extraction in the unlikely event of a tear in the superior vena cava. While such tears happen in less than 2 percent of procedures, the case fatality rate due to rapid bleeding is roughly 50 percent. Approved by the FDA in February 2016, the Bridge™ Occlusion Balloon temporarily occludes the torn vessel to give a surgeon sufficient time to repair the damage.

Dr. Wilkoff and colleagues searched the FDA’s Manufacturer and User Facility Device Experience (MAUDE) database for superior vena cava tears related to lead extraction procedures during the final six months of 2016. The sample was small — 35 tears in all — but the results were striking: 100 percent of patients (9/9) were discharged alive when the balloon was used, compared with 50 percent (13/26) when it wasn’t.

Those data were presented at the Heart Rhythm Society’s 2017 scientific sessions and published in Heart Rhythm (2017 May 13 [Epub ahead of print]). “This device is just beginning to be used on a regular basis,” says Dr. Wilkoff. “We’re working to establish best practices for its safe use.”

Balancing future and present

While Cleveland Clinic cardiologists are also involved in several trials of leadless pacemakers, those devices are currently limited to single-chamber right ventricular pacing, whereas many patients require dual- or triple-chamber pacing. “Leads are going to be around for a long time to come,” Dr. Wilkoff remarks.

Indeed, he is co-chairing a panel working on a consensus document on lead management, which will be published as an upcoming Heart Rhythm Society guideline.

These endeavors and others (see this post on the launch of a CRT optimization clinic) contribute to Dr. Wazni’s vision for the Section of Cardiac Electrophysiology and Pacing under his leadership. “We’ll continue to aspire toward impactful research that both informs the field and directly improves patient care.”