A study presented at Thursday’s Late-Breaking Clinical Trials session found that the use of ganglionic plexus (GP) ablation in thoracoscopic surgery for patients with advanced atrial fibrillation (AF) does not improve heart rhythm outcomes and is associated with significantly more adverse events than pulmonary vein isolation (PVI) alone.
“Routine GP ablation offers no clinical benefit and should not be performed in this patient population,” concluded Joris R. de Groot, MD, PhD, assistant professor of cardiology at the Academic Medical Center, University of Amsterdam, who presented the randomized AFACT study.
The AFACT trial was one of six trials presented at the Thursday session.
For the AFACT study, Dr. de Groot and his colleagues randomized 240 advanced AF patients to receive GP ablation in addition to PVI alone. The significant adverse events they found associated with GP ablation included major bleeding, clinically relevant sinus-node dysfunction, necessity for sternotomy and pacemaker implantation, and four deaths.
The VANISH trial, presented by John L. Sapp, MD, FHRS, is a randomized trial comparing the use of VT ablation with escalation of AAD therapy for patients with an ICD and ischemic cardiomyopathy who developed VT despite the AAD therapy.
The study randomized 259 patients to receive either catheter ablation with baseline AADs or escalated AAD therapy with amiodarone. The primary endpoint was a composite of death, ICD shock, or three or more VT episodes within 24 hours.
The primary outcome occurred in 59.1 percent of patients in the ablation group and 68.5 percent of those in the escalated AAD therapy group. Two patients in the ablation group had cardiac perforations, and three had major bleeding. Among patients in the drug escalation group, there were two deaths from pulmonary toxicity and one from hepatic dysfunction.
“In patients with ischemic cardiomyopathy and an ICD who had ventricular tachycardia despite antiarrhythmic drug therapy, there was a significantly lower rate of the composite primary outcome of death, ventricular tachycardia storm, or appropriate ICD shock among patients undergoing catheter ablation than among those receiving an escalation in antiarrhythmic drug therapy,” said Dr. Sapp, professor of cardiology at Dalhousie University in Halifax, Nova Scotia.
He concluded that catheter ablation was superior to escalated AAD therapy for reducing the final endpoints of death, appropriate shock, and VT storm, mostly driven by reductions in recurrent ventricular arrhythmias.
Gery F. Tomassoni, MD, FHRS, director of electrophysiology at Central Baptist Hospital in Lexington, Ky., presented a study that assessed the safety and efficacy of multipoint pacing (MPP) in heart-failure patients who were implanted with a CRT defibrillator capable of delivering either quadripolar biventricular pacing or MPP.
The CRT defibrillator was implanted in 455 patients, and the patients were randomized to either quadripolar biventricular pacing or MPP at three months after implantation. The study’s primary safety endpoint was freedom from system-related complications at nine months. The primary efficacy endpoint was non-inferiority of the proportion of non-responders in the MPP treated patient group vs. the biventricular pacing patients.
Study results met both primary endpoints. However, MPP provided significantly higher clinical response rates of 93 percent at nine months and converted all of the non-responders to responders among patients who had MMP programmed with wide cathode spacing equal to or greater than 30 mm and the shortest intraventricular timing delay of 5 ms, Dr. Tomassoni said.
“When MPP was programmed with cathode spacing equal to or greater than 30 mm and 5 ms LV delay, the CRT response was greatest,” he said.
The RESPOND-CRT trial, a prospective, double-blind, multicenter, non-inferiority randomized trial presented by Josep Brugada, MD, PhD, head of the pediatric arrhythmias unit at Barcelona Children’s Hospital in Spain, examined the clinical response to CRT therapy using a SonR hemodynamic sensor vs. echocardiographic-guided optimization.
Following CRT, more than 1,000 patients from three continents were randomized 2:1 to SonR-driven repetitive, automatic programming vs. echo-guided pacemaker optimization. The primary efficacy endpoint was the rate of clinical responders at 12 months. Clinical responders were defined as a composite of patients who were alive without heart-failure-related events and with improvements in the New York Heart Association class or quality of life.
Among patients treated using the SonR leads, more than 91 percent were free from acute complications, and more than 94 percent were free of chronic complications. Patients with a history of AF had the highest response rates.
“Cardiac resynchronization therapy with the SonR optimization technology was as effective as echo-guided optimization with a response rate of 75 percent, thus meeting the primary efficacy endpoint. Patients with a history of atrial fibrillation had an absolute 22 percent increase in response,” Dr. Brugada said.
Same Day Discharge
Ranjit Suri, MD, President of Heart Rhythm Associates of New York and Director of the cardiac electrophysiology laboratory at Mount Sinai St. Luke’s Hospital in New York, presented a randomized, controlled trial of same-day discharge from a hospital after elective ICD procedures compared with overnight observation in the hospital.
Six hundred patients were prospectively enrolled in the trial at 30 U.S. sites. After implantation of a single- or dual-chamber ICD, the patients were monitored for three to four hours then given a chest x-ray. Stable patients were randomized to either same-day discharge or overnight observation.
The primary outcome of the study was procedure-related complications within 30 days of implantation. Secondary outcomes included quality of life and direct medical costs. Direct medical costs were estimated. Quality of life was assessed using the EuroQoL EQ-5D questionnaire before discharge and at a postoperative visit.
Dr. Suri and colleagues found an overall complication rate of 3.2 percent in the same-day discharge patients and 1.5 percent in the patients kept overnight for observation. There were no significant differences in per-patient direct costs or quality of life.
The researchers concluded that in patients who receive ICD for primary prevention, same-day discharge is safe and comparable in outcomes without affecting quality of life.
Drivers of VF
Michel Haïssaguerre, MD, Professor of cardiology at the University Victor-Segalen Bordeaux 2 and head of the Department of Cardiac Arrhythmias at the University Hospital of Bordeaux in Pessac, France, presented the session’s final study.
It was the first study to define the characteristics of drivers maintaining ventricular fibrillation in humans. It included 72 patients with drug-resistant VF from 12 medical centers. Patients received unipolar epicardial VF electrocardiograms for 155 spontaneous or induced VF episodes during the initial 18 to 20 seconds after the episodes to characterize VF frequency distribution, wave propagation, and phase maps. Endocardial cycle length mapping was performed simultaneously.
The study showed that VF was driven by a limited number of wave fronts spanning large surface areas emanating centrifugally from focal breakthroughs and re-entrant activity. The VF cycle length was shortest at re-entry sites compared with remote sites, confirming their driver role.
The drivers’ type and behavior varied with the patient’s underlying heart disease, ranging from a discrete driver region responsible for the entire fibrillatory activity to reentries meandering diffusely in both ventricles. Patients with ventricular scarring had more sustained reentries than those without scarring.
“VF mapping can help identify individual drivers of the disease,” Dr. Haïssaguerre said. It represents “direct panoramic epicardial visualization of the human VF spectrum in vivo, opening a new window into the drivers maintaining ventricle fibrillation.”