Massachusetts General Hospital Installs AXIOM Artis dFC Magnetic Navigation System
System Assists Clinicians in Improving Ease and Accuracy of Catheter Procedures
Massachusetts General Hospital (MGH) is among the first in the country to offer digitally controlled catheter-based procedures, due to the recent installation of the AXIOM Artis dFC Magnetic Navigation System.™ The AXIOM Artis dFC Magnetic Navigation System was developed by Siemens Medical Solutions in conjunction with Stereotaxis, Inc.
The system is capable of helping electrophysiologists improve the ease and accuracy of catheter-based procedures to facilitate interventional medicine, which may translate to better treatments and outcomes for patients.
The system integrates Siemens most advanced digital fluoroscopic imaging system, the AXIOM Artis dFC (Flat Panel Detector System), with Stereotaxis Inc.’s Niobe® Magnetic Navigation System, to direct and digitally control catheter- and guidewire-based devices along complex paths within the heart and coronary vasculature.
“We are committed to offering our patients the best possible care using the most advanced medical technologies,” said Jeremy Ruskin, MD, Director of the Cardiac Arrhythmia Service at MGH. “This is an important step towards the use of computerized controls in cardiac electrophysiology. We plan to jointly explore new cutting-edge applications in electrophysiology with Siemens and Stereotaxis, and this system will potentially allow us to perform invasive electrophysiology with greater precision, safety and efficiency.”
The system uses computer-controlled permanent magnets external to the body for orienting the magnetic tip of specially designed catheters and guidewires. This approach, which allows for 360-degree rotation of the catheter, has the potential to provide greater precision and better movement. This interventional technique allows physicians at MGH to navigate catheters and guidewires to designated target sites in the heart and coronary vasculature.
Because it enables digital control of the catheter devices, the new system may provide an opportunity to increase efficiency, enhance productivity, and help clinicians improve the ease and accuracy of catheter-based procedures. Providing an opportunity to address the concerns associated with manual catheter steering and positioning, the magnets offer the potential to enable more exact movements.
With the flat panel detector technology of the system, image quality is dramatically better. With the combination of better image quality and the potential for more precisely guided catheters, procedures may be completed more quickly and effectively, which may translate to less radiation exposure for the patient. In addition, the system is designed to give clinicians the potential to perform procedures remotely from the control room by using a mouse or joystick.
Britain Faces Epidemic of Heart Rhythm Problem
Britain is facing an epidemic of chronic heart arrhythmia that will worsen as the population ages and stretches healthcare budgets, researchers said.
Atrial fibrillation (AF) is one of the most common heart problems. It occurs when electrical signals that keep the heart pumping are disturbed. The upper chambers of the heart contract in an abnormal way and may increase the risk of stroke.
McMurray of the Western Infirmary in Glasgow, Scotland.
In a report in the journal Heart, McMurray and his colleagues estimated the costs of treating the problem in Britain, where one in 10 people over 65 years old is affected.
By studying hospital admissions, prescription information, outpatient visits and data from family doctors, they calculated the cost of treating patients in 1995 at 244 million pounds ($463 million), or 0.6 percent of the state-funded National Health Service (NHS) budget.
The cost of treating the condition nearly doubled five years later to an estimated 459 million pounds, or nearly one percent of the NHS budget, and is expected to rise further in the future, according to the researchers.
Patients with the condition normally need long-term treatment with blood thinners to reduce the risk of stroke and many require hospital care.
"Consequently, AF is likely to impose a substantial and growing economic burden on health care systems," McMurray added.
Medtronic Begins Study Evaluating Potential for Biventricular Pacing to Inhibit Heart Failure Progression
BLOCK HF Clinical Trial Compares Biventricular Pacing with Right Ventricular Pacing in People with Early to Mid-Stage Heart Failure
Medtronic, Inc., has initiated a major new clinical study designed to determine if biventricular pacing can slow the perilous progression of heart failure in people with mild to moderate heart failure symptoms (NYHA class I, II and III) and the need for a pacemaker. The study, called BLOCK HF, will compare the use of biventricular pacing delivered to both lower chambers of the heart with traditional pacing delivered to the lower right chamber of the heart.
Andrew Merliss, MD, Director of Cardiac Electrophysiology at the BryanLGH Heart Institute in Lincoln, Nebraska, was the first physician worldwide to implant a biventricular pacemaker for this study. It is anticipated that up to 65 investigative institutions in the United States and Canada will participate in the implantation of the Medtronic InSync® III cardiac resynchronization device in up to 1,200 heart failure patients during the course of the study. The research is being conducted under an Investigational Device Exemption from the U.S. Food and Drug Administration.
“Heart failure, which is not uncommon in patients who require pacemakers to treat a slowly beating heart, is a progressive condition that weakens the heart’s ability to pump effectively,” said Dr. Merliss. “We are hopeful that earlier intervention with these new therapies may help to slow or reverse the debilitating effects of congestive heart failure in this population of patients. This trial should help us understand whether biventricular pacing will prove superior to standard pacing methods and whether it can play an effective role in helping these people fight the progression of heart failure during its earlier stages.”
The study’s principal investigator is Anne Curtis, MD, Professor of Medicine and Director of Clinical Electrophysiology at the University of Florida in Gainesville, Florida. “Resynchronization devices with biventricular pacing have rapidly been accepted by the cardiology community because of the immediate and dramatic improvement we have seen in many symptomatic heart failure patients,” said Dr. Curtis. “However, research about cardiac resynchronization therapy so far has excluded patients with mild heart failure who need a pacemaker for traditional pacing indications. BLOCK HF is the first clinical study to assess whether biventricular pacing can slow the progression of heart failure in people with early heart failure symptoms who also need a pacemaker. If positive, this study could point to an unprecedented ability of a therapy to delay the progression of heart failure, one of the world’s leading killers and causes for costly hospitalization.”
Patients in the BLOCK HF trial will have mild to moderate heart failure accompanied by evidence of damage to cells that carry electrical signals from the upper to lower chambers of the heart, blocking the signal on one side of the heart (known as atrioventricular [AV] block). Because the heart’s pumping function is weakened and the heart rate is compromised, the ventricles no longer pump sufficiently to meet the body’s demand for life-sustaining oxygen. Approximately half of all Americans who have pacemakers have AV block, and of these 700,000 pacemaker patients with AV block, up to 25 percent of them may have heart failure.
All patients in the BLOCK HF study will receive an InSync III system initially programmed to traditional right ventricular pacing. They will then be randomized to either continue that therapy or have the device reset to pace both ventricles of the heart. The potential benefits of the therapy will be assessed using a composite endpoint that measures heart failure progression.
“We’ve entered a new era in the treatment of heart failure using device-based therapies, and the potential for extending life for millions of additional people while decreasing hospital costs with biventricular pacing is enormous,” said Steve Mahle, President of Medtronic Cardiac Rhythm Management. “As the global leader in device-based heart failure therapies, one of Medtronic’s highest business priorities is to partner with leading medical centers to research additional benefits of this already proven therapy for more patients. Since 1997, we have supported 20 heart failure clinical studies, including MIRACLE, MIRACLE ICD, SCD-HeFT and CARE-HF. The BLOCK HF study is just one of many new trials to come that will help discover new ways of treating people with heart failure.”
Currently, biventricular pacing systems are approved in the United States and Canada for commercial use in people who have moderate to severe heart failure (NYHA class III and IV) and who have evidence of ventricular dysynchrony. Heart failure is the most costly cardiovascular disease in the United States. The total cost of caring for U.S. heart failure patients is estimated to be up to $40 billion per year.
Medtronic Announces Market Release of Two Left-Heart Delivery Systems Designed to Help Navigate Challenging Heart Anatomies
Attain Prevail™ Steerable and Attain™ Deflectable Catheters Provide Maximal Support for Left-Heart Lead Delivery During Cardiac Resynchronization Therapy Implant Procedures
Medtronic, Inc. announced the market release of two new Attain™ left-heart delivery systems, both designed to facilitate placement of left-heart leads during implantation of CRT devices. The Attain Prevail™ Steerable catheter system and the Attain™ Deflectable catheter system are specifically designed to help physicians navigate challenging heart anatomies during implants.
The Attain family of left-heart leads and delivery systems are used often in the industry, and the two new systems are designed to enhance cannulation of the coronary sinus, which provides access to the left side of the heart, as well as assist with cardiac vein subselection.
The Attain Prevail system is a left-heart lead delivery system that combines steerability, catheter telescoping and vein subselection in a single package. It allows the user to create multiple curve shapes without changing guide catheters, and also permits deep advancement of the guide catheter and guidewire. In addition, its soft, tapered tip design and small size (7 French), helps minimize the chance of venous trauma.
The Attain Deflectable guiding catheter provides physicians with an excellent opportunity for successful coronary sinus cannulation and left-heart lead placement. Implanters are able to vary the catheter curve to match a patient's anatomy and, once cannulation has been achieved, the Attain Deflectable provides a stable workstation for the passing of guidewires, leads and venogram balloon catheters for greater visualization of the cardiac venous anatomy.
“The success of a CRT implant is tied to the ease of the left-heart lead delivery, and these systems are designed to offer the best opportunity for success,” said Steve Mahle, President of Medtronic Cardiac Rhythm Management. “These new delivery tools will help both experienced physicians who do a lot of CRT implants, as well as other physicians who are just beginning to manage their heart failure patients with CRT devices.”
Both new delivery systems allow contrast injection through the lumen to help visualize the anatomy, especially the cardiac veins on the left ventricle. The Attain Prevail can be inserted into straight or other fixed shape catheters to accomplish telescoping techniques, and the Attain Deflectable allows for adjustable curve reach and telescoping with a guidewire and over-the-wire lead.
Attain leads and delivery systems are used with implantable cardiac resynchronization therapy devices such as the InSync® III CRT pacing system and the InSync II Marquis™ system that also includes a defibrillator.
Heart Paradox Found in African Americans
While black heart failure patients tend to fare worse than their white counterparts, researchers have found that, paradoxically, they also have significantly lower rates of a dangerous heart condition. A new study by researchers at the Kaiser Permanente medical system and the University of California at San Francisco (UCSF) found blacks have sharply lower rates of the most common form of the condition, known as atrial fibrillation (AF).
Since AF is linked to more severe heart failure, researchers thought higher rates of the disorder might be seen among blacks, which in turn might help explain why blacks with heart failure tend to have poorer outcomes than whites. Their results, however, showed just the opposite, since the black patients in the study were much less likely to suffer from AF. The finding appears in the Journal of the American College of Cardiology.
“It’s a little surprising,” acknowledges Dr. Alan S. Go, a UCSF Professor of Epidemiology,” especially since we have seen higher risk factors for AF in that group, and then found they had such lower rates — 50 percent lower.”
The researchers combed through information on 1,373 heart failure patients treated at 16 Kaiser hospitals in northern California, including 223 blacks and 1,150 white patients. All of the patients had similar health care insurance coverage and were treated by Kaiser Permanente providers using similar methods, to minimize socioeconomic and treatment differences.
“We found that even after you accounted for those differences, blacks with heart failure had about a 50 percent lower risk of atrial fibrillation. It was a very robust finding; no matter what we adjusted for, it remained consistent,” Go says.
Some specialists say the findings, while intriguing, are part of a complex issue and caution should be used when interpreting them.
“I think AF is very much population-dependent and it's all complicated, too. There are multiple factors that can influence AF,” says Dr. Roosevelt Gilliam, Clinical Director of Cardiac EP at Duke University Medical Center. “You have to ask: how do the populations compare, is the sample size big enough, is 223 enough. Maybe this group got to treatment later than other groups. What about the ones who didn't get to the trial at all?”
The study shows that “we have a lot to learn about this condition,” Gilliam adds. “There may be something. Maybe there is a difference, and once you can understand the ethnic differences maybe you can exploit those differences. Maybe there is some genetics in this, but it's hard to say at this point.”
Women Could be New Target Group for ICD Makers
Although slightly more women than men suffer sudden cardiac arrest each year, the overwhelming majority (about two thirds) of implantable cardioverter defibrillator (ICD) recipients are male. According to Dow Jones-Newswire, Daniel Rosenberg reports that most experts suspect lack of awareness at the roots of this gender discrepancy.
Not only women themselves but also their physicians often downgrade or ignore the risk for cardiac disease. “Men are identified and diagnosed more, so they are more likely to move on to surgery or an ICD,” Dr. Cash Casey from the University of Chicago Hospitals in Illinois told Dow Jones. Myocardial infarction survivor Nancy Loving, now directing the National Coalition for Women with Heart Disease, says women are less likely than men to be referred to a cardiologist. “It's hard to get a referral to a cardiologist until you’re half dead,” she told Dow Jones. Loving wants to investigate further into the lack of medical-device treatment for women and urges the device industry to include more women in their clinical trials and device marketing.
The apparent undertreatment could indeed represent a huge opportunity for ICD makers, with expected market growths of about 25%, analysts say. The Dow Jones article states that Guidant has already seized this opportunity and has taken a leadership role among the device makers, being “very aware of the discrepancies in the rate of ICD implantation between men and women” and calling it “a market opportunity.” Guidant Reaches Out to Women (GROW) was designed to educate women about cardiovascular risk. Simultaneously, the company is educating physicians and salespeople about heart disease in women. The effort seems worthwhile, analysts point out, because getting ICDs implanted in more women could help Guidant and other device makers “keep up their sales pace,” William Blair & Co. analyst Ben Andrew told Dow Jones.
‘Silent’ Heart Arrhythmias More Common than Thought
Episodes of atrial fibrillation, a dangerous heart condition found in 2 million Americans, are more common than experts thought in patients for whom drugs seemed to correct the problem. Drug treatment with warfarin, an anticoagulant, should be continued in these patients who have these so-called ‘silent’ episodes of atrial fibrillation, conclude a team of German researchers who report their finding in the Journal of the American College of Cardiology.
The researchers recommend that doctors continue treatment with warfarin (known under the brand name coumadin) even if patients appear to be free of heart rhythm problems for more than three months. Standard practice is to treat episodes of atrial fibrillation with rhythm-correcting drugs and with anticoagulants — usually warfarin — and to halt the therapy when a patient has not had a repeat occurrence of atrial fibrillation for three months.
In the German study, researchers followed 110 patients with the condition who had implantable pacemakers that recorded their heart rhythms constantly. They found that 38 percent of those who did not report any symptoms of atrial fibrillation (which can include an irregular or rapid heartbeat felt by the patient) actually had a recurrence of atrial fibrillation lasting longer than 48 hours.
This so-called silent fibrillation should be treated, according to the researchers, if the patient has one other risk factor for stroke, such as high blood pressure, diabetes or advanced age.
The new study confirms what several previous studies have also suggested, according to an expert who co-authored an editorial accompanying the study. “This is one of several recent studies suggesting that patients put on anti-arrhythmic drugs who their doctors think are alright have ‘silent’ episodes of atrial fibrillation,” says Dr. Albert L. Waldo, the Walter H. Pritchard Professor of Cardiology and Professor of Medicine at Case Western University in Cleveland. “With silent episodes of atrial fibrillation, the risk of stroke returns,” Waldo adds.
Warfarin is not an easy drug to stay on, he notes, because it interacts with foods and medications such as antibiotics. It’s also difficult to keep the blood level of warfarin steady enough to be constantly effective, Waldo says. However, he and other experts expect a new medication to be approved soon by the U.S. Food and Drug Administration that will do the same job as warfarin but be easier to take.
Meanwhile, even with its downsides, “warfarin is very, very effective,” Waldo says. “It impacts the risk of stroke.” Patients on it must be monitored closely by their doctors, he emphasizes.
Waldo offers this advice for patients: “If they have a history of atrial fibrillation and are at risk for stroke, they need to take an anticoagulant.”
Statin Treatment May Lower Risk of Recurrent Arrhythmia
In patients with atrial fibrillation who undergo successful cardioversion, the treatment with statins, a class of commonly prescribed cholesterol-lowering drugs, reduces the risk of recurrence of arrhythmia, or irregular heart contractions. Whether this is a direct antiarrhythmic effect remains to be seen, according to a study in the American Journal of Cardiology.
Dr. Chung-Wah Siu and colleagues at the University of Hong Kong conducted a study with 62 patients who underwent successful external cardioversion (electric shock to the heart) to treat atrial fibrillation that had persisted for at least three months. Four of the patients had taken an average dose of 20 mg daily oral simvastatin, and six had taken an average dose of 10 mg of atorvastatin, for an average of 32 weeks before cardioversion, for the treatment of high cholesterol.
After two years, atrial fibrillation had recurred in 40 percent of the statin-treated patients and in 84 percent of those who did not receive statins. The authors noted after further analysis, the “use of statins was associated with a significant decrease in the risk of arrhythmia recurrence.”
The benefits of treatment were evident within a few months and persisted during long-term follow-up. The data suggest that statin treatment affected, in part, functional changes in the heart, the researchers report.
While they add that the agents’ mechanism of action is unclear, they speculate that “the beneficial effect of statin therapy in preventing atrial fibrillation may be mediated through its effects on the progression of coronary artery disease.”
Statins may also have direct antiarrhythmic effects by modulating the fatty acid composition and the properties of cell membranes, resulting in alterations in the properties of the transmembrane ion channel, they note.
Pacemakers Most Beneficial to Women and Younger Patients
After insertion of a pacemaker to correct irregular heart rates, women and younger patients do better over the long term than men and folks over 70 years of age, German researchers have found.
Several studies have looked at what predicts survival after pacemaker placement, but in most cases the follow-up period was no longer than six years. Because many patients are still alive 10 years after being given such devices, there is a need to identify factors associated with long-term survival.
As described in the European Heart Journal, Dr. Michael Brunner and colleagues from Universitatsklinik Freiburg studied 6,505 patients who received a pacemaker. The average survival following implantation was about 8.5 years, the researchers note. Nearly 45 percent of patients were alive after 10 years and more than 20 percent survived at least 20 years.
As expected, age at the time of the procedure was an important factor. People younger than 70 years survived an average of over 14 years, more than double the period seen for older patients.
Although women were typically older than men when they were given a pacemaker, women survived longer. The average survival period for women was nearly 10 years, while for men it was less than eight years.
With an observation period of 30 years, “the present study is — to the best of our knowledge — by far the largest analysis of very long-term survival in pacemaker patients,” the authors state.
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