June 2004 Diet Foods, Atrial Fibrillation, Pacemakers -EP Lab Digest

CryoCath Announces Exciting Start in Atrial Fibrillation Study With Arctic Circler Balloon Early Results Point to a Breakthrough Solution for AF CryoCath Technologies Inc., a leader in cryotherapy products to treat cardiovascular disease, announced that the first 13 patients in a human feasibility study using the company's proprietary Arctic Circler Balloon catheter to treat atrial fibrillation (AF) has been successfully completed. This trial is being conducted at Homalka Hospital in Prague, under the direction of Dr. Vivek Reddy of Massachusetts General Hospital and Dr. Petr Neuzil of the Czech Republic, and at the Kerkoff Klinik, Germany, under the direction of Dr. H.F. Pitschner. Dr. Vivek Reddy treated the first 10 patients in one week, followed by Dr. Pitschner treating three patients the week after. Dr. Vivek Reddy said, The potential for this technology that Dr. Douglas Packer of the Mayo Clinic and we saw in the animal lab has now been clearly demonstrated in patients. When the balloon is inflated and occludes the vein, complete electrical isolation can be achieved with a single lesion at the ostium. In addition, I am confident that the procedure will be one that will realistically meet the goal of being completed in less than 2.5 hours (skin-to-skin). In fact, I feel we are on the verge of something very important in the treatment of AF, and I think that by this time next year, the whole AF ablation field will be startlingly different because of this CryoCath Balloon technology With 400,000 new cases every year, AF is the most prevalent cardiac arrhythmia, affecting four million patients in the western world. It is one of the leading causes of stroke and short-term hospitalizations. Despite its prevalence, there are no current, practical clinical options to effectively and safely treat AF. As a result, standard treatments for AF are limited to various costly drug regimens that offer only a palliative (non-curative) approach. We could not have asked for better clinical results than what we are seeing in the early going with Arctic Circler Balloon, said Steve Arless, President and CEO of CryoCath. The quality of the lesions, the maneuverability of the catheter, the ease of pulmonary vein ablation, the feedback from the doctors, the acute efficacy, the absence of any acute safety concerns this product has unrivalled potential in the field of cardiac ablation. The Arctic Circler Balloon catheter has been designed to overcome the two principal obstacles in providing a commercially viable ablation solution for treating AF safety limitations and lengthy or complex procedures. With regards to safety, all the clinical results from the prior use of cryoenergy in and around the pulmonary veins suggest that this energy source does not generate serious adverse events such as stenosis, thrombosis, phrenic nerve damage and esophageal perforation four complications that have been consistently reported with alternative heat-based ablation systems. With respect to simplifying the ablation of the pulmonary veins and reducing procedural times, the innovative balloon design allows a large circumferential surface area of the opening of the pulmonary vein to be ablated at one time, thereby reducing the number of lesions required. As well, the balloon’s natural contours allow for simple and effective anatomical placement of the catheter balloon tip in the target region of the opening of the pulmonary vein. In the circumstances where the Arctic Circler Balloon successfully isolated the pulmonary vein ostia, no more than two applications of cryo were required, with the majority requiring only one application. All patients treated were AF-free post-procedure. There were no serious adverse events or stenosis. The trial will treat up to 20 AF patients and is expected to complete enrollment by June 2004. Three-month follow-up data is expected to be available in the Fall of 2004. In addition to the Arctic Circler Balloon, the study’s protocol allows the use of two other catheters, the Arctic Circler Linear and Freezor ® MAX. The trial’s endpoints will be safety (stenosis status at 3, 6 and 12 months) and efficacy (AF free with or without drugs at 6 months). CryoCath intends to use the data from this trial to apply for regulatory approval and commercialization in Europe in the first quarter of 2005, and to have the Arctic Circler Balloon included in the final protocol for its pivotal FDA study for the treatment of AF using a toolbox approach, starting in the first quarter of calendar 2005. Medtronic Announces Implants of the EnRhythm Pacemaker and the EnTrust Defibrillator New Devices Offer MVP Pacing Mode to Automatically Minimize Unnecessary Right Ventricular Pacing Medtronic, Inc. announced clinical implants of a new family of pacemakers and implantable cardioverter-defibrillators (ICDs) the EnRhythm pacemaker and the EnTrust ICD. This family represents Medtronic's next step in the delivery of premium implantable devices that include features such as MVP (Managed Ventricular Pacing), a new pacing mode that is designed to promote natural heart activity by automatically minimizing unnecessary right ventricular pacing. The first implants of EnRhythm occurred in seven centers in the Netherlands, Sweden, Germany, Austria, and Canada. The EnRhythm pacemaker is indicated for patients who have abnormally slow heartbeats (bradycardia), often caused by sinus node dysfunction. It is also indicated for patients who have atrial arrhythmias in addition to bradycardia. The first implants of the EnTrust ICD occurred in seven centers in Austria and Germany. ICDs are indicated for patients who have abnormally fast and potentially life-threatening heartbeats (tachycardia) that can lead to sudden cardiac arrest. The EnTrust ICD offers anti-tachycardia pacing during charging of the capacitor. This means that the device is ready to deliver full power therapy when needed, but not before it attempts to painlessly pace the patient out of the potentially life-threatening rhythm. Recent clinical studies have shown that ATP from Medtronic ICDs can dramatically reduce shocks for terminating ventricular arrhythmias by as much as 77 percent, a significant patient benefit. EnTrust also offers improved diagnostics for clinical efficiency and longevity of approximately seven years, all within a small, 33 cc size. "These products were designed with the patient's safety and comfort in mind," said Steve Mahle, President, Medtronic Cardiac Rhythm Management. In addition to minimizing right ventricular pacing, the new EnRhythm pacemaker has reactive anti-tachycardia pacing, which continually searches for new opportunities to restore a patient's normal sinus rhythm during long atrial tachycardia episodes. It also offers enhanced diagnostic features, especially for patients who may have additional rhythm problems in the upper chambers of the heart (the atria), as well as improved longevity. Both devices are integral parts of the Medtronic Physiologic Pacing Program, a comprehensive initiative focused on providing tailored medical technology solutions to help replicate a patient's normal cardiac function. More than eight million people worldwide have bradycardia, while approximately three million people have hearts that beat too fast. Abnormally rapid heartbeats can deteriorate into a life-threatening condition called ventricular fibrillation, the major cause of sudden cardiac arrest (SCA). In the United States, SCA is the leading cause of death, taking the lives of 450,000 people each year, more than lung cancer, breast cancer, AIDS and stroke combined. ICDs have been proven to be 98 percent effective in treating the rapid rhythms that lead to sudden cardiac arrest. Fish Oil Prevents Deadly Irregular Heartbeats Anti-Arrhythmic Effects May Help Explain Heart-Healthy Benefits of Fish Oil A fish oil infusion may help prevent a potentially deadly quickening of the heart (arrhythmia) in people at risk for sudden cardiac death, a new study shows. Although more studies will be needed to confirm these results, researchers say these early findings may help explain how fish oil, among other diet foods appears to reduce the risk of sudden cardiac death in certain people. Several studies have shown that a diet rich in fatty fish or use of fish oil supplements containing omega-3 fatty acids can reduce the risk of sudden cardiac death. However, until now, researchers have been unable to provide direct evidence of how fish oils may work to prevent the irregular heartbeats, known as arrhythmias, often responsible for triggering sudden cardiac death. In the study, published in The Lancet, researchers examined the effects of fish oil in 10 people at high risk for sudden cardiac death. The patients all had implanted defibrillators (to shock their hearts out of a dangerous arrhythmia if needed) and a history of ventricular tachycardia, or a dangerous quickening of the heartbeat. Researchers injected the patients with an infusion of omega-3 fatty acids and then tried to induce an episode of ventricular tachycardia. At the start of the study, researchers were able to induce this irregular heartbeat in seven out of 10 of the participants. After the fish oil infusion was delivered, researchers were only able to induce the arrhythmia in two of the patients, and the second was only after a more aggressive attempt. In the remaining five, the fish oil appeared to prevent the irregularity. Although researchers say this was a small study designed to look at the safety of using fish oil infusions in protecting against ventricular arrhythmias, the results show that fish oil may have anti-arrhythmic effects. In a commentary that accompanies the study, Christine Albert, MD, of Brigham and Women's Hospital in Boston, says these results are only preliminary. However, combined with previous research, they provide a possible mechanism that explains the selective benefits of fish oil in reducing sudden cardiac death found in other studies. "If these and other trials confirm the anti-arrhythmic properties of these [omega-3 acids], fish oil may become a less toxic and more appetizing alternative to traditional anti-arrhythmic," writes Albert. FDA Approves New CryoCath Clamp-Ablation Device CryoCath Technologies announced that it has received regulatory clearance from the FDA for FrostByte, a clamp-ablation device to be used in the treatment of cardiac arrhythmias. According to the company, the FrostByte/SurgiFrost convertible combination offers surgeons the following clinical advantages: Makes all the necessary lesions to treat cardiac arrhythmias, either endocardially or epicardially (inside surface or outside surface); Accelerates procedural times, a critically important criterion in beating-heart procedures; Provides a high level of safety. "Having had very satisfying results with SurgiFrost, the evolution of this product into an easy-to-use convertible clamp/probe device allows the application of cryoablation in the surgical treatment of cardiac arrhythmia to become increasingly versatile, as this device can be used both endocardially and epicardially," said Dr. Charles Mack, New York Presbyterian Hospital, who performed the preclinical work that led to FrostByte's US clearance and who has been treating patients with the SurgiFrost System since 2003. FrostByte is to be used in tandem with CryoCath's SurgiFrost CryoSurgical Ablation System. The new SurgiFrost probe is positioned within a newly designed, more ergonomic SurgiFrost handle. Its ablation segment docks within the upper jaw of FrostByte a clamp device that secures the contact point between the probe’s 10 cm ablation tip and cardiac tissue. The device's convertibility between probe and clamp allows the surgeon to accelerate lesion formation and provides greater ease of use. In addition, transmurality of the lesion is verified through the use of a temperature gauge in the lower jaw. St. Jude Medical Announces FDA Approval of the Riata i Lead Family St. Jude Medical, Inc. announced U.S. Food and Drug Administration (FDA) approval of the Riata ® i lead family thin and integrated bipolar implantable cardioverter defibrillator (ICD) leads. Excellent helix visibility, handling, ease of implant and a thin ICD lead body distinguish the Riata ® i lead family. The isodiametric body diameter of Riata ® i leads measures 2.2 mm or 2.5 mm (depending on model), and fits an 8 French introducer. These new leads complement the full line of Riata ® true bipolar leads already on the market. "We expect the Riata i lead family will fulfill an important need in the integrated leads market, which currently represents 32% of total ICD lead sales," said Michael J. Coyle, President of St. Jude Medical's Cardiac Rhythm Management business. "This product offering provides our physician customers with additional clinical options to optimize patient care." The new Riata ® i lead family allows physicians even more versatility when managing patients with high defibrillation thresholds (DFTs). The leads are available in six models: dual-coil active fixation (models 1590 and 1591) and single-coil active fixation (model 1592), which affix in the heart using an extendable-retractable helix mechanism; and dual-coil passive fixation (models 1560 and 1561) and single-coil passive fixation (model 1562), which affix in the heart using tines. The decision to use active versus passive fixation depends in part on physician preference and the characteristics of the right ventricle. The Riata ® i leads are multi-lumen silicone leads with St. Jude Medical's exclusive Fast-Pass coating for improved lubricity. The main difference between a single-coil and a dual-coil lead is the path (or "vector") in which the defibrillation energy travels in and around the heart. While no specific vector is right for all patients, many physicians express preferences for a single-coil or a dual-coil ICD lead. The many lead product variations (unipolar versus bipolar, single-coil versus dual-coil, active- versus passive-fixation mechanisms, as well as lengths and other characteristics) create a broad range of products to meet physician requirements. Many physicians develop strong and specific preferences for certain types of leads. Other physicians may prefer a certain type of lead in most cases, but like the option of alternate configurations for special cases. Audicor ® CE Combining ECG with Heart Sounds Analysis Lowers Costs and Improves Outcomes via Earlier Risk Stratification of ACS and CHF A growing number of patients presenting to the Emergency Department with chest pain and/or shortness of breath are diagnostically challenging. The Audicor CE Cardiograph Expansion System works with hospital cardiographs in the first 10 minutes to identify and report S3 and S4 heart sounds evidence-based markers of higher cardiac risk. Audicor also provides a diagnostic ECG algorithm that is up to 84% more sensitive than current systems in the detection of acute MI, particularly in women and in the presence of confounders. Two Audicor sensors attach to the patient via the V3/V4 leads used during a standard 12-lead electrocardiogram. Results are presented in text, waveforms and full-color graphics via the Audicor COR Report (correlated audioelectric cardiography). The system supports ACC/AHA Guidelines and complements ED care pathways for risk stratification. Drug May Help Prevent Irregular Heartbeat A calcium leak inside heart cells triggers a lethal type of irregular heartbeat and a drug that plugs the leak seems to prevent it, say scientists who hope the finding one day will help hundreds of thousands of people. So far the experimental drug has been studied only in mice, but the Columbia University researchers hope to begin human testing next year. Regardless of how that first attempt goes, the discovery is important because it provides a new target to treat irregular heartbeat, as well as the huge problem of congestive heart failure. That's the exciting part about this work, said Dr. David Lathrop, who heads research into irregular heartbeat at the National Institutes of Health. It's definitely a step forward. At issue are ventricular arrhythmias, racing irregular beats of the heart's lower chambers. If it worsens, the heart quits beating and instead quivers, a condition called ventricular fibrillation that can kill within minutes. It claims about 340,000 US lives annually. Heart failure is a major cause of ventricular arrhythmias. It afflicts about 4.6 million Americans and by itself is a relentless killer, but half of patients suffer ventricular arrhythmias, too. Some patients inherit a form of exercise-induced ventricular arrhythmia. In both types, sufferers have a leak in a tiny channel that regulates calcium levels inside their heart cells and that leak triggers the deadly irregular heartbeat, discovered Dr. Andrew Marks, Director of Columbia's Center for Molecular Cardiology. The experimental drug, code-named JTV519, can literally plug the leak and prevent the irregular heartbeat, he reports in the journal Science. Marks' laboratory bred mice to have the same leaky defect and gave half the drug. Stressing them with exercise pushed all of the untreated mice into ventricular arrhythmias, and 89 percent died. However, none of the mice given the drug could be stressed into the irregular heartbeat. There has to be some event at the molecular level that triggers the arrhythmia. We think we've discovered what that event is, and how to prevent it, Marks said. The leak seems to worsen heart failure, too, so plugging it holds the promise to treat the overarching disease. In additional animal studies not yet published, Marks has found that fixing the leak improves overall heart function. Today's heart-failure medications typically treat the symptoms, but not the deadly disease's underlying cause, Marks explained. Many patients eventually need an implanted heart pump or a heart transplant difficult and expensive options. Nor are there good drugs to prevent ventricular arrhythmias. Implanted defibrillators can shock the heart back into rhythm, if doctors realize someone's at risk in time to do the surgery. Doctors have long known that calcium causes heart muscles to contract. The question was exactly how. Small calcium channels on the surface of heart cells play some role; indeed, calcium channel blockers are an old type of heart drug that limit the amount of calcium entering cells that way. They have been real big disappointments, sometimes causing serious side effects, Marks said. In contrast, Marks discovered a far bigger calcium channel that works inside heart cells one he calls the key to controlling heart contractions. Inside that ryanodine-receptor channel is a protein called calstabin2. Between heartbeats, it is supposed to keep the channel closed so calcium can't leak out. However, in heart failure and the inherited ventricular-arrhythmia syndrome, the calstabin2 doesn't do its job well enough. The resulting calcium leak worsens an already weakened heart and destabilizes the heart cell's electrical activity so an arrhythmia can form. The experimental new drug works by enhancing the natural protein's ability to close the channel an entirely new approach of fixing a broken calcium channel instead of blocking it. Biophan Showcasing Latest Technology and Research Results at Heart Rhythm 2004 Conference Biophan Technologies, Inc. an innovator, developer and marketer of MRI-related and other advanced biomedical technology, announced that it will exhibit at the NASPE – Heart Rhythm Society’s Heart Rhythm 2004 Conference, which will take place May 19–22, 2004 at The Moscone Center in San Francisco, California. According to the Society, over 6,000 healthcare professionals have registered to attend the conference to learn more about the newest advances in heart rhythm management. At the conference, the company’s exhibit will include information regarding a recent study at the University of Rochester confirming the danger to pacemaker patients caused by both excessive tissue heating and interference with proper pacemaker functionality. To date, several million people who have pacemakers have been denied the benefit of magnetic resonance imaging (MRI) diagnostics due to the risk of injury or death. Medtronic recently announced that more than half of pacemaker recipients are denied MRI due to safety problems, and stated that pacemakers offering MRI safety will be the new gold standard. At last year’s conference, Biophan provided research results showing the effectiveness of an RF filter technology, based on a patented solution developed at Johns Hopkins University, and licensed exclusively to Biophan for implantable devices. The RF filter was prototyped and tested in an MRI machine and shown to reduce the negative effects of device heating to within the FDA guidelines of less than 2 degrees Centigrade. The recently conducted study results show an off-the-shelf pacemaker experienced lead heating significantly in excess of FDA guidelines, when tested in heart tissue in an MRI machine. Michael Weiner, Biophan’s CEO, stated, Our strategy has always been to improve the utility of MRI diagnostics by making all biomedical devices safe and image compatible for use with MRI. By providing both conclusive proof of the danger of pacemaker device heating and induced voltages that can cause rapid heart beats, and a viable solution that can be affordably deployed into future devices, there is no longer any need for pacemaker patients to be denied MRI. With the evidence of the problem now demonstrated, and a solution at hand, it is only a matter of time before pacemakers will be made safe and compatible with this ever growing and important MRI diagnostic capability, Weiner explained. Additionally, with our nanomagnetic particle thin film coating, we can also minimize the effects of image artifacts, so that pacemakers and pacemaker leads, once made safe, can also be imaged under MRI. Our technology also allows the pacemaker lead, and the stylet used to introduce it, to be visible under MRI to aid in installations using MRI versus x-ray and fluoroscopy. This can benefit not only the pacemaker patient, but the physician implanting the pacemaker. Today cardiologists and electrophysiologists who implant pacemakers have to wear heavy lead aprons to avoid exposure to ionizing radiation. Many are reported to suffer back problems as a result. With an MRI safe pacemaker that is also image compatible, future pacemakers (and defibrillators) can be implanted without the need for the use of the lead aprons. The benefits accrue to the patient, the physician, and the device manufacturers.