Heart Rhythm 2007: Coverage

ICD Reliability Shows Significant Improvement: Study Tests Devices from Three Manufacturers for Longevity, Performance Implanted cardioverter defibrillators (ICDs) manufactured in recent years are more reliable, last longer and rarely fail due to electronic defects, according to a new study (PO3-38: Improvement in the Reliability and Longevity of Implantable Cardioverter Defibrillators) presented at Heart Rhythm 2007, the Heart Rhythm Society s 28th Annual Scientific Sessions. Analysis of clinical ICD data for three major device manufacturers Medtronic, Guidant and St. Jude Medical found continuous improvement in longevity and reliability for ICDs implanted in 2004-2006 compared to those implanted from 2001-2003. There has been a lot of concern recently about ICD performance, but this study should reassure physicians and patients that these devices have improved dramatically in recent years and are now safer than ever, said Robert Hauser, MD, lead author and a cardiologist at the Minneapolis Heart Institute. The study examined dates of implant and replacement, reason for replacement and cause of failure for more than 1,200 ICDs from nine centers in North America. Normally functioning ICDs that were electively replaced because of a recall advisory were not included in the study. The study findings included: Average longevity (implant time) increased 26% for dual-chamber devices implanted in 2004-2006 compared to those implanted earlier. Average longevity for single-chamber devices in 2004-2006 was almost 6 years, a 36% improvement over 2001-2003. Only nine ICDs experienced unexpected failures in 2004-2006, compared with 35 in 2001-2003. Four devices delivered inappropriate shocks or contributed to other major adverse events in 2004-2006, compared to 10 such device-related events in 2001-2003. iPods Interfere with Pacemaker Function: High School Senior Leads University Study iPods caused pacemakers to malfunction in 50 percent of patients, according to a new study (AB16-1: Pacemaker Interference with iPod MP3 Players) presented by a 17-year-old high school student at Heart Rhythm 2007. When held two inches from the patients chests for five to 10 seconds, iPods interfered with telemetry equipment monitoring the heart, caused implantable pacemakers to misread the heart s pacing, and, in one case, caused the device to stop functioning. For people depending on these pacing devices, iPod interference can lead physicians to misdiagnose the actual heart function, said Jay Thaker, lead author and a high school senior at Okemos High School in Okemos, Michigan. Our findings are disconcerting because although the typical pacemaker patient may not be an iPod user, they are often in close contact with grandchildren or other young people who are avid users. The study tested iPods on 83 patients at the Thoracic and Cardiovascular Institute at Michigan State University with dual-chamber and single-chamber pacemakers. Telemetry interference was found in 29 percent of patients, oversensing (pacemakers misreading the heart s function) in 20 percent, and pacemaker inhibition (pacemaker stopped functioning) in one patient. In some cases, interference was detected even when iPods were held as far as 18 inches from the chest. After reading news stories about studies involving cell phones and pacemakers, Thaker approached Krit Jongnarangsin, MD, at the University of Michigan about doing a similar study using iPods. At first I was surprised when Jay contacted me with the idea. He seemed genuinely interested in doing the research and had a real curiosity about the subject, said Dr. Jongnarangsin, senior author and an assistant professor in the Division of Cardiovascular Medicine at the University of Michigan. I felt comfortable with Jay doing the research. Besides Jay, this study was performed by physicians including an electrophysiologist and fellows in electrophysiology at Michigan State University. Thaker, whose father is an electrophysiologist and mother is also a physician, has not yet decided where to attend college next year, but is leaning toward Michigan State. He plans to go on to medical school. Heavy Drinking Greatly Increases Risk of AF: Study Finds Drinking Less Can Significantly Lower Risks People who drink excessive amounts of alcohol were almost three times (2.8) more likely than moderate drinkers and non-drinkers to suffer from atrial fibrillation (AF), according to a new study (PO2-103: The Role of Moderate Alcohol Intake in First-detected Atrial Fibrillation: The Imperial College New AF Study) presented at Heart Rhythm 2007. Moderate drinkers did not face significantly greater risks of AF, the nation s most common irregular heart rhythm that increases the risk for heart disease and stroke. The study found that even a small reduction of alcohol consumption could lead to significant declines in AF incidence. The good news for people who are already drinking more than they should is that by making small changes in their drinking patterns, they may be able to significantly reduce their chances of developing this troublesome arrhythmia, said Joe Martins, MD, lead author and a cardiologist at the Imperial College in London. The study recorded the weekly alcohol consumption over 26 months of 203 patients with first-detected AF and 781 patients without AF at the Rapid Access Arrhythmia Clinic at London s Charing Cross Hospital. Moderate alcohol consumption was equal (48 percent) in both patients with and without AF. Excessive consumption was considerably higher in patients with AF compared to patients without AF (27 percent versus 17 percent, respectively). The study defined excess drinking as the amount above the recommended weekly allowance of 21 units for men and 14 units for women. Two units are roughly equal to a pint of beer. Compared to non-drinkers, excessive drinkers increased their risk of AF by two percent for each additional unit per week they consumed. Because alcohol excess was prevalent in almost one in five (19%) patients assessed, targeting this behavior could potentially lead to a substantial reduction in the population burden of AF, concluded Dr. Martins. First Case of Speech-Induced Atrial Fibrillation Presented: Talking was On-Off Switch The world s first known case of speech-induced atrial fibrillation (AF) was reported on at Heart Rhythm 2007 (Session entitled Ablation of a Case of Speech-Induced Atrial Fibrillation). The patient, a 68-year-old female librarian from Kentucky, was successfully treated by repeating the word Mississippi, enabling physicians to locate and ablate the AF. The patient entered the hospital complaining of palpitations and severe fatigue, symptoms that seemed to worsen during family gatherings, work meetings, emotional church sermons and while talking on the phone. Physicians noticed minor AF when the patient spoke one or two words, and several minutes of AF when she used longer sentences. When she first came in we could see she was having runs of AF, but soon we noticed the AF would only present itself when she started talking, said Peter Gallagher, MD, lead author and director of the electrophysiology laboratory at Central Baptist Hospital in Lexington, Kentucky. Talking acted like an on-off switch for her AF. When medication proved ineffective, physicians performed catheter ablation. Nine months after the patient received the ablation, she has not had any reoccurrence of AF. This is not only the first reported case of speech-initiated AF, but this case also represents the first non-cardiac trigger of AF successfully mapped and ablated, said Dr. Gallagher. Tasers Pose Potential Risks for Pacemaker Patients: Weapons May Cause Arrhythmias in Patients with Cardiac Devices Tasers may cause significant arrhythmias in patients with pacemakers, according to a new study (PO4-88: Taser-Induced Rapid Ventricular Myocardial Capture Demonstrated by Pacemaker Electrograms) released at Heart Rhythm 2007. The study was the first human case to demonstrate how voltage in the weapon may be captured by the heart and speed up heart rates in pacemaker patients. Under certain circumstances, Tasers could result in potentially dangerous arrhythmias in patients with these cardiac devices, said Leslie Saxon, MD, lead author and chief of the division of cardiovascular medicine at the University of Southern California. The study involved a 53-year-old Los Angeles man with a dual-chamber pacemaker who had received a Taser shot consisting of two barbs delivered simultaneously. The pacemaker recorded two high ventricular rate episodes at the exact time of the Taser application. The pacemaker returned to normal function following the Taser shots. Dr. Saxon said the study raises the question of whether devices such as Tasers cause the cardiac capture. National ICD Registry Provides Physicians and Hospitals with Quality Improvement Data: First Year s Data Includes More Than 100,000 Patient Cases The National Implantable Cardioverter Defibrillator (ICD) Registry, the nation s first comprehensive database of detailed information about patients receiving these lifesaving medical devices, has released its first set of data reports to more than 1,450 hospitals participating in the program. The ICD Registry collected in-hospital data ranging from assuring the right patient received the right device to device performance issues for more than 100,000 patients in its first year. These detailed data reports will give physicians new insight on their performance relative to their peers and will help advance the quality of care given to patients, said Stephen Hammill, MD, FHRS, chair of the ICD Registry Steering Committee and past president of the Heart Rhythm Society. Having access to this type of data is invaluable, said Laurent Lewkowiez, MD, director of clinical cardiac electrophysiology at the University of Colorado Hospital and Heart Rhythm Society member. By analyzing patient characteristics and device trends over time, we can determine if changes need to be made to our medical protocols to ensure the best patient care possible. All hospitals that implant these medical devices for primary prevention of sudden cardiac arrest in Medicare beneficiaries are required to routinely submit data to this registry as a condition of government payment. Every hospital can voluntarily submit additional data on all of their patients receiving ICDs to receive benchmark scores. We are extremely pleased that in response to the Heart Rhythm Society s promotion to include all ICD procedures in this registry, an overwhelming majority of hospitals have voluntarily submitted data on all patients receiving ICD implants, added Hammill. I am confident that physicians will thoroughly review their data reports and benchmark scores to learn from their colleagues around the country and make positive changes to attain best practices. The data set will also provide critical information to both government and private entities. For example, the Centers for Medicare and Medicaid Services (CMS) will be able to utilize this data to confirm that lifesaving medical technologies are benefiting Medicare patients in the real world. Health insurance companies will have the opportunity to use the aggregated data to better understand how this technology is used by a variety of physicians and hospitals. Medical device manufacturers will have the opportunity to enhance post-market surveillance efforts for new and existing technologies. Physician associations, such as the Heart Rhythm Society, will publish the research findings in peer-reviewed journals and continuously evaluate the data to determine the effectiveness of existing clinical guidelines. The findings from the ICD Registry will have a direct impact on the use of this medical technology in current and future patients, noted Hammill. The creation of the National ICD Registry began in September 2004 with the convening of the National ICD Registry Working Group, an interdisciplinary committee led by the Heart Rhythm Society and consisting of 17 organizations including: physician associations; health insurance providers; government officials; medical device manufacturers and registry experts. This workgroup addressed the lack of information available for determining if ICDs benefited Medicare patients, a patient population that is both older and in some cases less healthy than patients receiving ICDs in the clinical trials. The working group also determined the best approach to develop and implement the registry to collect this information without overburdening hospital participants. As a result, the ICD Registry, a partnership of the Heart Rhythm Society and the American College of Cardiology Foundation, was created. In October 2005, CMS announced the ICD Registry as the official national repository of ICD information. HRS Unveils Guidelines on Catheter and Surgical Ablation for Atrial Fibrillation Some of the world s most prominent heart organizations released the first international clinical consensus statement on using catheter and surgical ablation techniques to treat AF at Heart Rhythm 2007. The Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation aims to improve patient care by providing physicians with a state-of-the-art review of catheter and surgical ablation for AF, the most common heart rhythm disorder and a rapidly growing health problem for more than three million Americans. Studies have found that only one quarter of patients with AF receive appropriate care. These guidelines are a major step toward helping physicians provide better, safer and more consistent care for heart patients worldwide, said Hugh Calkins, MD, chair of the Heart Rhythm Society s scientific and clinical guidelines committee and director of the arrhythmia service and electrophysiology laboratory at The Johns Hopkins Hospital. Convened by HRS, a Task Force of international heart rhythm specialists representing the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the European Cardiac Arrhythmia Society (ECAS), the Society of Thoracic Surgeons (STS) and HRS has developed guidelines to provide a foundation of current knowledge for medical personnel involved with catheter and surgical ablation of AF. The statement addresses the indications, techniques, training, and follow-up for patients undergoing these procedures. We felt it was important to develop these guidelines so that patients in every corner of the world can receive the highest quality of care available, said Josep Brugada, MD, PhD, president-elect of EHRA and chief of cardiology at the Hospital Clinic, University of Barcelona, Spain. According to the Expert Consensus Statement, ablation for AF should be considered in AF patients whose symptoms are severe enough to interfere with their quality of life and have failed or been intolerant to treatment with at least one antiarrhythmic medication. Ablation of AF is more difficult, associated with greater risks, and requires more careful follow-up than other ablation procedures. This landmark Expert Consensus Statement was created in an effort to improve global patient care by providing a foundation of current knowledge for those involved with catheter and surgical ablation of AF.