Monday, June 5, 2023
HRS 2012 Research Highlights
The Heart Rhythm Society (HRS) 2012 Scientific Sessions took place in Boston, Massachusetts on May 9-12, 2012.
Key presentations at the sessions included:
• Riata ICD lead safety: Attendance was off the charts at the headliner event.
• RAAFT 2: RF catheter ablation with pulmonary vein isolation is more likely to suppress AF recurrences than is standard drug therapy.
• Founders' Lectureship Award: HRS 2012 recipient Dr. Michel Haϊssaguerre.
• FIRM ablation: Patients who have undergone focal impulse and rotor modulation (FIRM) ablation in addition to standard pulmonary vein isolation (PVI) remain AF-free more often than those treated with standard PVI.
• PROTECT-AF: Watchman left atrial appendage closure device reduces the risk for ischemic stroke in patients with AF, entirely without anticoagulation.
• PACES/HRS consensus statement on Wolff-Parkinson-White syndrome: Helps clarify which young people should undergo catheter ablation.
• Posters: New research was highlighted at HRS's Poster Town.
• MagnaSafe Registry: Findings show that MRI with pacemakers and ICDs is safe, with a few minor issues.
• STARTER: "Sweet spot" for echo-guided CRT lead placement explored in trial.
• Douglas P. Zipes Lectureship Award: This year's recipient was Dr. Dan Roden.
• AF ablation: Reaching first-line status.
• AF summit: Tools and technologies for AF ablation.
Riata ICD Lead Failure
A highly promoted late-breaking trial, as well as several abstracts, attempted to define the nature and scope of the problem with the recalled Riata ICD leads
In December 2011, the Riata line of implantable defibrillator leads (St. Jude Medical) was officially recalled because of a high risk for failure. The conductor wires can erode through their silicone insulation and "externalize," sometimes causing electrical abnormalities, lead malfunction, or possibly high-voltage shorts. At HRS 2012, the Riata failure rates and mechanisms took center stage, with groups lining up to report their experiences with the leads, abstract after abstract, as well as a highly promoted late-breaking trial. Pictured is Dr. Raed H. Abdelhadi (Minneapolis Heart Institute, Minneapolis, Minnesota), who reported a failure rate of 1.93% per patient-year for the Riata lead in the Independent Multicenter Riata Study.
"In my mind, cables that externalize, which people have called a cosmetic problem, are a lead failure. It's not how the lead was designed to function," said Dr. Laurence M. Epstein (Brigham and Women's Hospital, Boston, Massachusetts). "One of the concerns I have is that we don't fully understand the mechanism of why these leads are failing, and I think that's really important for us to understand moving ahead."
RAAFT 2
Radiofrequency catheter ablation with pulmonary vein isolation is more likely to suppress AF recurrences than is standard drug therapy
Radiofrequency (RF) catheter ablation with pulmonary vein isolation is not only safe as a first-line treatment for paroxysmal or persistent atrial fibrillation (AF), it's more likely to suppress AF recurrences than is standard antiarrhythmic drug (AAD) therapy. This is what is suggested by a randomized trial with a 2-year follow-up, one of the longest for an AF-ablation trial. A single ablation procedure reduced the risk for AF recurrence by a significant 44% compared with AAD. Of note, in the second (RAAFT 2) trial, which followed all patients with transtelephonic monitoring (TTM), RF ablation's significant advantage over AAD was in reducing bouts of AF that were either symptomatic or asymptomatic.
"So, to be able to claim victory with ablation, you really need to monitor these patients very judiciously," said RAAFT 2 co-principal investigator Dr. Carlos Morillo (Hamilton Health Sciences-McMaster University, Ontario, Canada) when presenting the study at HRS 2012. Ablation also significantly cut the frequency of solely symptomatic AF, he said. "These findings support the indication of radiofrequency pulmonary vein isolation as first-line therapy in patients with paroxysmal atrial fibrillation."
FIRM Ablation
Patients who have undergone focal impulse and rotor modulation (FIRM) ablation in addition to standard pulmonary vein isolation (PVI) remain AF-free more often than those treated with standard PVI
Dr. Sanjiv Narayan (University of California, San Diego VA Medical Center) presented a technique called FIRM ablation, which involves placing commercially available multipole basket catheters into the atria. During AF, the signals are sent to an investigational computer system, which then displays optical images and movies of the activation. Distinct geographic "areas of interest" in either the right or left atrium can be seen in almost all cases of AF. Sometimes the rotors are located in areas typically targeted during PVI, but in many cases they are not. Most remarkably, Dr. Narayan's prior work has shown that when these areas are ablated, AF terminates. Patients who have undergone FIRM ablation in addition to standard PVI remain AF-free more often than those treated with standard PVI.
Dr. Narayan presented new data on the acute termination of AF with FIRM-guided ablation. In a cohort of patients with advanced AF, he showed that rotors or focal impulses could be seen in 98%. Ablation at these focal sites terminated, slowed, or converted AF to flutter in 88% of patients. Almost half converted to sinus rhythm. In one case, ablation for only 1 minute converted the patient to sinus rhythm.
PROTECT-AF
Watchman left atrial appendage (LAA) closure device reduces the risk for ischemic stroke in patients with AF, entirely without anticoagulation
The Watchman LAA closure device cuts the risk for ischemic stroke in patients with AF, entirely without oral anticoagulation, suggests the observational ASA-Plavix (ASAP) Registry. These results add to what had been observed in the Watchman device's main randomized trial, PROTECT-AF, in which patients with the device took warfarin for at least the first 6 weeks. PROTECT-AF found the device noninferior to standard warfarin therapy for protection against stroke, cardiovascular death, or systemic embolism in patients with AF and a CHADS2 score ≥1. Patients getting the Watchman in the ASAP Registry, who took clopidogrel for 6 months and aspirin indefinitely but without ever going on warfarin, still showed only a 1.7% rate of ischemic stroke, compared with 2.2% in the PROTECT-AF Watchman group, 7.3% in historical controls with ASAP-comparable CHADS2 scores taking aspirin alone, and 5.0% in such controls taking aspirin plus clopidogrel.
The findings, said Dr. Vivek Y. Reddy (Mount Sinai School of Medicine, New York, New York) when presenting the analysis, cast doubt on the need for even temporary warfarin in patients implanted with the Watchman device. Most strokes related to thrombus forming at the device would occur in the first 6 months after device implantation, Reddy speculated; so if anything, eliminating the early warfarin might raise the stroke risk, not lower it. Given the low stroke rate seen in the ASAP registry, Reddy said, "It's not clear how important that 45 days of warfarin is. In fact, it's not clear that 6 months of [clopidogrel] helped at all."
PACES/HRS Consensus Statement on Wolff-Parkinson-White Syndrome
Consensus statement helps clarify which young people should undergo catheter ablation
A "first of its kind" consensus statement on the management of asymptomatic patients with Wolff-Parkinson-White (WPW) syndrome should help clarify which young people should undergo catheter ablation. The guidance defines young people as between 8 and 21 years of age. At the crux of the document is the question of just when physicians should intervene -- and when they shouldn't -- in young people found to have the signature electrocardiographic WPW pattern. These are increasingly important questions, given increased emphasis on preparticipation screening for young people seeking to play sports.
The expert consensus statement, a joint effort of the Pediatric and Congenital Electrophysiology Society (PACES) and the HRS, estimates that 1-3 young people per 1000 likely have WPW, although many (around 65%) are asymptomatic.
"While it is a small chance that an asymptomatic young person could end up having a life-threatening heart event, the number is not zero," said lead author on the statement, Dr. Mitchell I. Cohen (Phoenix Children's Hospital, Phoenix, Arizona). "Yet catheter ablation for every child who has ever had a WPW pattern is also not the answer."
Poster Town
New research highlighted
An overwhelming number of posters were presented at Poster Town in the HRS 2012 Exhibit Hall. Poster sessions were available to attendees throughout the conference, as were moderated poster sessions and interactive abstract poster sessions.
Noteworthy topics included placing ECG leads in the right place to avoid false diagnoses; PVC morphology and duration may predict the presence of cardiomyopathy; AF ablation may not yield good results for patients with sleep apnea and metabolic syndrome; LAA isolation is a good thing because patients showed a higher 3-year success rate; and a single case of atrial-esophageal fistula presented following standard cryoballoon ablation.
MagnaSafe Registry
Findings show that MRI with pacemakers and ICDs is safe, with a few minor issues
Interim findings from the MagnaSafe Registry show no important safety issues but some alterations in programming and transient impedance changes during MRI in patients with pacemakers and implantable cardioverter defibrillators (ICDs). No instances of imaging-associated death, device failure, generator or lead replacement, loss of capture, or electrical reset occurred with MRI, which was performed consistently at 1.5 T. Of less apparent significance were the battery-voltage changes seen in 12% of ICDs and the device parameter changes seen in a tenth of pacemaker and a third of ICD patients.
"We can't say whether any of those changes were clinically significant in any way," said Dr. Debra Doud (Scripps Clinic, La Jolla, California). But whether or not there are advantages to such devices, "there still will be a large number of patients with non-MRI-conditional devices who need to undergo an MR scan for one reason or another. And certainly [going ahead with the scan] is much safer than lead extraction and putting in an MR-conditional device for patients who already have a device. The one population of [device] patients we had to exclude was those with ICDs who were pacemaker-dependent," because devices from some manufacturers don't allow ICD functions to be disabled without turning off the pacing functions.
STARTER
"Sweet spot" for echo-guided CRT lead placement explored in trial
Patients are more likely to respond to cardiac resynchronization therapy (CRT), clinically and in terms of reverse remodeling, if speckle-tracking echocardiography guides the placement of their pacing leads. For echo guidance in the trial, called STARTER, leads were positioned at or close to the myocardial site of latest mechanical activation for each patient individually. Those whose lead positions were tailored that way, compared with standardized positioning without echo guidance, benefited with significantly improved ventricular end-systolic volumes and survival without heart failure hospitalization.
"A substantial proportion of patients, about one-third, do not respond to CRT therapy, and we don't know who those people are," said Dr. Samir Saba (University of Pittsburgh, Pittsburgh, Pennsylvania). "Now we are starting to understand better. Once we know where the leads should be appropriately placed, for that specific patient, we achieve better results."
Douglas P. Zipes Lectureship Award: Dr. Dan Roden
The lectureship award named for Douglas P. Zipes recognizes an individual who has contributed to the advancement of cardiac electrophysiology in the area of basic science. This year's award recipient was Dr. Dan M. Roden (Vanderbilt University School of Medicine, Nashville, Tennessee), who presented the lecture "Heart to Heart: Treating Arrhythmias Using Personalized Medicine." The award was presented as part of the Basic/Translational Science Forum on May 9.
AF Ablation: Reaching First-line Status
For the past few years, the evidence base supports the role of catheter ablation in AF patients who have done poorly with medication. But has catheter ablation progressed enough to offer it as a first-line therapy? The North American expert task force guidelines call for trying an antiarrhythmic drug before ablation; the more lenient European guidelines allow us to offer catheter ablation as first-line therapy. Which is the best approach?
An important multicenter study, RAAFT 2, supports the notion that AF ablation (PVI) as a first-line therapy has made the transition to the front line. The trial demonstrated that low-risk symptomatic patients with AF (87% paroxysmal) treated with standard catheter-based PVI had less AF and fewer complications than did those treated with AF drugs. Adverse events occurred in 7.7% of patients who had ablation compared with 19.7% of those treated with medicine.
Although preliminary, this study will have a significant impact. The results of RAAFT 2 add more information to an already complex decision-making process. Until Dr. Narayan's FIRM ablation becomes mainstream, AF ablation remains a daunting challenge. Always important is the doctor-patient relationship, but never more so than in cases when life-threatening therapies are used for non-life-threatening diseases.
AF Summit: Tools and Technologies for AF Ablation
Another conference highlight was a state-of-the-art update concerning the tools and technologies that are available for use in the field of AF ablation. Operators learned about which tools to use and how to use them to achieve maximum success. Topics included the importance of PV isolation and the limitations of current technologies in achieving permanent PV isolation; contact force in lesion creation and the available knowledge about whether newly available force-sensing catheters improve outcomes; and the current and future role of remote navigation technologies in AF ablation.
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Credits and Disclosures
Journalist:
Steve Stiles, theheart.org
Fremont, California
Disclosure: Steve Stiles has disclosed no relevant financial relationships.
Blogger:
John Mandrola, MD
Louisville, Kentucky
Disclosure: John Mandrola has disclosed no relevant financial relationships.
Editor:
Shelley Wood
Managing Editor, heartwire
theheart.org
Kelowna, British Columbia, Canada
Disclosure: Shelley Wood has disclosed no relevant financial relationships.
Contributors:
Steven Rourke
Editorial Programming
theheart.org
Montreal, Quebec, Canada
Disclosure: Steven Rourke has disclosed no relevant financial relationships.
Katherin Vasilopoulos
Montreal, Quebec, Canada
Disclosure: Katherin Vasilopoulos has disclosed no relevant financial relationships.
