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Low vitamin D linked to sudden cardiac death

Sun, 17 Nov 2008 16:06:00 GMT

posted by KeithConnects

Low vitamin D linked to sudden cardiac death

Last Updated: 2008-11-17 12:00:32 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Vitamin D deficiency is associated with heart dysfunction, sudden cardiac death, and death due to heart failure, German researchers report.

An association between vitamin D deficiency and heart trouble is physiologically plausible, the researchers note. For example, vitamin D is known to affect contractility of the heart.

Dr. Stefan Pilz, from the University of Heidelberg, and colleagues assessed vitamin D levels in 3,299 Caucasian patients who were referred for a test used to look for clogged heart arteries called coronary angiography from 1997 to 2000. The subjects were then followed for 7.7 years.

During follow-up, 116 patients died from heart failure and 188 from sudden cardiac death, Pilz and colleagues report.

In analyses taking into factors that might influence the results, they found that severe vitamin D deficiency, compared with optimal vitamin D levels, was associated with nearly a three-fold increased risk of death from heart failure and about a five-fold increased risk of sudden cardiac death.

"These data strongly indicate that the maintenance of an optimal vitamin D status may be a promising approach for the prevention and/or therapy of (heart) diseases, warranting confirmation in interventional trials with vitamin D supplementation," the researchers conclude.

SOURCE: Journal of Clinical Endocrinology and Metabolism October, 2008.

http://www.reutershealth.com/archive/2008/11/17/eline/links/20081117elin030.html

Osteoporosis Meds Linked to Heart Problem

Sun, 27 Oct 2008 16:23:00 GMT

posted by KeithConnects

Osteoporosis Meds Linked to Heart Problem
Bisphosphonates may up rate of serious atrial fibrillation, review finds

By Serena Gordon
HealthDay Reporter

MONDAY, Oct. 27 (HealthDay News) -- The popular bone-building medications known as bisphosphonates may have a rare, but serious, cardiac side effect.

A review of available research concludes that these medications may increase the risk of atrial fibrillation -- an erratic heart rhythm that can lead to blood clots that may cause heart attacks or strokes.

"In addition to possible gastrointestinal side effects, bisphosphonates can have possible cardiac side effects. For serious cases of atrial fibrillation, there was a significant increase in risk -- about 68 percent," said review lead author Dr. Jennifer Miranda, an internal medicine resident at Jackson Memorial Hospital in Miami.

But Miranda noted that the absolute risk of someone experiencing atrial fibrillation while on these medications was actually quite small, probably around 1 percent to 2 percent.

Miranda was expected to present the findings Monday at the American College of Chest Physicians annual meeting, in Philadelphia.

Bisphosphonates are a class of medications that increase bone mineral density. They are commonly prescribed to treat people with osteoporosis and also for people who have suffered hip fractures. Bisphosphonates may also be used to treat Paget's disease of bone.

This class of medications includes alendronate (Fosamax), zoledronic acid (Reclast), ibandronate (Boniva), risedronate (Actonel), and more.

Although effective, these medications can cause serious side effects in some people. Gastrointestinal side effects, such as nausea, stomach pain, constipation and diarrhea can occur. Of more concern are rare side effects, such as osteonecrosis of the jaw, unusual bone fractures, and severe muscle, bone or joint pain.

The U.S. Food and Drug Administration is reviewing the safety of bisphosphonates, but at this time doesn't recommend any changes in clinical practice.

Miranda's review focused on three studies of bisphosphonates that included data on atrial fibrillation as a side effect. Miranda said the authors reviewed 1,646 studies, but only three included information on atrial fibrillation.

All three studies were randomized, placebo-controlled studies published in the New England Journal of Medicine in 2007, and included more than 16,000 patients. The study populations were quite similar and included postmenopausal women between the ages of 69 and 75 who were taking bisphosphonates for osteoporosis.

The overall difference in incidence of atrial fibrillation wasn't statistically significant between those taking bisphosphonates and placebo. However, when the researchers looked just at serious atrial fibrillation, meaning that it was significant enough to require hospitalization or caused death, they found a 68 percent increased risk for those on bisphosphonates.

Miranda said it's not clear why bisphosphonates might increase the risk of atrial fibrillation.

Dr. Arthur Santora, executive director of clinical research at Merck Research Laboratories, said he was surprised that the current analysis only included three studies. Generally, he said, this type of research will include a dozen or more studies. Merck manufactures Fosamax.

Santora said his researchers have also done a meta-analysis to look at atrial fibrillation, but they included 40 studies, and they didn't find an increase in the risk of serious atrial fibrillation.

"Although this is something you want to track, and we do carefully track atrial fibrillation, there doesn't appear to be an increased risk when you look at the 40 studies we included in our meta-analysis," said Santora.

Santora said that if patients have any concerns about potential side effects, they should talk to their physicians about those concerns.

More information

Here's the latest from the U.S. Food and Drug Administration on bisphosphonates and atrial fibrillation.

SOURCES: Jennifer Miranda, M.D., internal medicine resident, Jackson Memorial Hospital, Miami; Arthur Santora, M.D., executive director, clinical research, Merck Research Laboratories, Whitehouse Station, N.J.; Oct. 27, 2008, presentation, American College of Chest Physicians annual meeting, Philadelphia

Last Updated: Oct. 27, 2008

http://www.healthday.com/Article.asp?AID=620659

Loyola Study Finds Catheter Ablation Superior To Medication For Atrial Fibrillation

Wed, 13 Nov 2008 00:00:07 GMT

posted by JohnRB

Treating a common heart rhythm disorder by burning heart tissue with a catheter works dramatically better than drug treatments, a major international study has found. One year after undergoing a treatment called catheter ablation, 75 percent of patients with an irregular heartbeat called atrial fibrillation were free of symptoms. By comparison, only 21 percent of those treated with drugs were symptom-free. Results were so convincing the trial was halted early.

Ablation Technologies in Treatment of Atrial Fibrillation

Fri, 13 Sep 2008 20:43:06 GMT

posted by padraic526

(From “Ablation Technologies Worldwide Market, 2008-2017: Products, Technologies Markets, Companies and Opportunities.” Published 2008 by MedMarket Diligence, LLC. See link.)

Several types of energy-based therapies have a variety of applications to CV disease—the number one killer in most of the world.

When the heart has to work too hard to maintain adequate blood output, it can begin to change shape, with the left ventricle (the heart’s main pumping chamber) often growing larger, less flexible and weaker. Prolonged compensation for these impairments can change both the heart structure and its function. Remodeling of the heart results in errant signals transmitted from the SA node that cause unsynchronized heartbeats. These are treatable with a variety of energy-based therapies including implantable resynchronization devices and surgical ablation therapies. Energy is also being employed in the fight against CV disease as a means to open occluded vessels and revascularize damaged heart muscles.

The chart (“Energy-Based Therapies for Cardiovascular Diseases”) highlights symptoms and energy-based therapies for different cardiovascular diseases.

CV Ablation Therapies

Atrial Fibrillation
Atrial arrhythmias may be focal (arising from only one place in one of the atria) or multifocal (arising from many different places in the atria). Inappropriate sinus tachycardia is a relatively rare and generally harmless condition in which the heart is normal but the heart rate is unusually fast, both at rest and in response to physical activity. Treatment is available, but the cause is unknown.

Premature atrial contractions (PACs) are often referred to as premature supraventricular contractions. PACs are harmless irregular heart rhythms that generally do not need to be treated. They are often due to stress or use of substances such as caffeine and alcohol. They occur when one of the heart’s upper chambers contracts prematurely in the heartbeat cycle. However, in some patients, ablation may be advisable to treat PACs before they can trigger atrial fibrillation.

Paroxysmal atrial tachycardia is a condition originating in the atria, in which the heartbeat increases for several minutes to a number of hours. Treatment may be necessary for short, sudden episodes that begin and end rapidly. Most people with this condition are young with normal hearts. The condition may be exacerbated by the use of even small amounts of caffeine or alcohol. This condition has also been associated with overly high levels of digitalis (a cardiotonic drug) in the bloodstream. Atrial flutter is a specific type of atrial tachycardia in which atria contract regularly, but extremely rapidly. Patients with atrial flutter may have as great a risk of stroke as patients with atrial fibrillation. Treatment such as surgical ablation is often recommended.

Atrial fibrillation (AF) is the result of rapid, disorganized signals in the atria that prompt the ventricles to contract irregularly. When the atria fibrillate (or quiver) instead of beating, blood is not effectively passed through the heart’s chambers and may pool in the atria. A blood clot may form and may travel throughout the body, which could lead to a stroke or heart attack. With AF, electrical signals in the heart’s upper chambers, or atria, cause the heart muscle to flutter wildly, which in turn reduces the efficiency of the ventricles. This allows blood to pool and form clots that can lead to strokes.

There are three main types of AF: paroxysmal (which starts and stops suddenly), persistent (which lasts longer and may require some medical intervention to terminate) and chronic or permanent. Chronic or permanent AF does not respond well to standard treatment.

Postoperative atrial fibrillation is one of the most common complications in cardiac surgery, occurring in 20%–50% of all patients within 2–4 days after heart surgery. Researchers estimate that postoperative atrial fibrillation costs the U.S. health system up to $1.5 billion dollars annually. Postoperative atrial fibrillation requires treatment before the patient is discharged from the hospital.

AF is the most common type of sustained arrhythmia, affecting 2 million people each year in the United States alone with annual incidence of new cases estimated at more than 700,000. It is estimated that AF affects over 4 million people in the developed world.

If left untreated, AF may lead to a variety of medical conditions, including stroke. Approximately 15% of strokes are a direct result of AF, a progressive disease that generally worsens over time. Since the incidence of AF increases as a population ages, the “graying” of world populations will likely lead to a significant increase in the number of cases of chronic AF.

Treatment options include AV nodal ablation with subsequent pacemaker implantation; this has been used successfully for many years in certain patients with chronic AF. Biventricular pacing, an area of significant clinician interest, is sometimes indicated for heart failure (HF) patients. Medical literature suggests benefits of biventricular pacing for such patients versus conventional right-ventricular approaches. However, this is a relatively new field that has not yet been extensively studied. In a study published in the New England Journal of Medicine, researchers found that for older patients at risk of stroke from atrial fibrillation, treatments to control heart rhythm were no better at preventing death than treatments to control heart rate. But other data suggest that for people whose main concern is quality of life, ablation may provide substantial relief. In this treatment, energy is used to burn away specific, tiny areas of tissue, particularly those on veins from the lungs to the heart that trigger arrhythmia.

Doctors have long assumed that the best way to treat atrial fibrillation is to get the heart back to a regular rhythm and maintain it, using electric shock or strong drugs. Restoring normal rhythm, or sinus rhythm, was thought to reduce the risk of strokes and death, make patients feel better and allow them to stop taking blood thinners. If that method does not work, a second approach consisting of simpler, cheaper medications to slow down the heart rate and ease symptoms of palpitations, dizziness and shortness of breath is often employed. Patients treated with this regimen continue to experience abnormal rhythms and continue taking blood thinners to prevent blood clots.

The chart, “Energy-Based Therapies for Atrial Arrhythmias,” shows products by energy modality and primary application being developed and approved for use in the treatment of atrial arrhythmias.

Ablation for atrial arrhythmias

Links:
AtriCure (West Chester, OH; http://www.atricure.com)
ATS Medical (Minneapolis, MN; http://atsmedical.com)
Bard Electrophysiology (Lowell, MA; http://bardep.com)
Biosense Webster (Diamond Bar, CA; http://www.biosensewebster.com)
Biotronik (Berlin, Germany; http://www.biotronik.de)
Boston Scientific (Natick, MA; http://www.bostonscientific.com)
Cardima (Fremont, CA; http://www.cardima.com)
CryoCath Technologies (Montreal, Canada; http://www.cryocath.com)
CryoCor (San Diego, CA; http://www.cryocor.com)
Irvine Biomedical (See St. Jude Medical)
Johnson & Johnson (New Brunswick, NJ; http://jnj.com)
Medtronic (Minneapolis, MN; http://www.medtronic.com)
Spectrasonics (Wayne, PA; http://www.spectrasonics.com)
St. Jude Medical (St. Paul, MN; http://www.sjm.com)
Stereotaxis (St. Louis, MO; http://www.stereotaxis.com)

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Most Patients With Irregular Heartbeat Take Inadequate Blood Thinner Dos

Wed, 28 Aug 2008 16:35:00 GMT

posted by KeithConnects

Most Patients With Irregular Heartbeat Take Inadequate Blood Thinner Dose
Warfarin could cut stroke risk by 67%, but patients and doctors say drug is hard to manage

By Steven Reinberg
HealthDay Reporter

THURSDAY, Aug. 28 (HealthDay News) -- Only 40 percent of patients with atrial fibrillation, a known risk factor for stroke, who did suffer a stroke were taking the anti-clotting drug warfarin, a new study found.

Among those taking warfarin, 75 percent weren't getting the dose needed to prevent a stroke. And an additional 25 percent were taking medications that were less effective at preventing clots or no medication at all, according to the report by Canadian researchers.

"These are missed opportunities for stroke prevention," lead researcher Dr. David J. Gladstone, a stroke neurologist at the University of Toronto, said in a prepared statement. "Sadly, we frequently see patients admitted to a hospital with a devastating stroke who are known to have atrial fibrillation, yet were either not taking warfarin or were taking a dose that is not therapeutic. We consider these to be potentially preventable strokes."

The findings are published online Aug. 29 in the journal Stroke.

Gladstone's team collected data on 2,135 stroke patients listed in the Registry of the Canadian Stroke Network. Among these patients, 597 were diagnosed with atrial fibrillation, an irregular heartbeat, before their stroke. For these patients, 60 percent of the strokes were disabling, and 20 percent were fatal.

Warfarin, by thinning the blood, helps prevent clots from developing and reduces the risk of stroke by about 67 percent in people with atrial fibrillation (AF). Strokes caused by AF can be more severe than other strokes, and studies have shown that warfarin can reduce the severity of strokes in patients with atrial fibrillation, the researchers said.

It's not clear why the rates of warfarin use were so low, the researchers said. "On one hand, we have an extremely effective and cheap medication for stroke prevention -- warfarin -- yet, on the other hand, it remains under-used in people who would benefit most from it," Gladstone said.

The study authors believe that efforts are needed to educate physicians and patients about the benefits of warfarin therapy for those with atrial fibrillation. "This is a public health priority, because atrial fibrillation is one of the most common causes of stroke," Gladstone said. "Many more strokes could be prevented if anti-coagulation therapy were optimized in the population at large."

Dr. Byron Lee, an assistant professor of cardiology at the University of California, San Francisco, thinks part of the problem may owe to the fact that many patients have problems taking warfarin, because it requires blood tests to monitor its effectiveness. Too low a dose is ineffective, while too high a dose can cause internal bleeding. So, patients need to have their warfarin levels measured at least once a month, he said.

"Patients hate taking warfarin, and doctors hate prescribing it," Lee said. "This is mainly because it's a hassle. However, this study confirms that many strokes can be avoided if patients are adequately anti-coagulated. Therefore, both patients and doctors need to do a better job of overcoming the inconvenience of warfarin."

Dr. John Worthington is a stroke physician at Liverpool and Northern Beaches Hospitals at the University of New South Wales in Sydney, Australia, who wrote an accompanying editorial in the journal. He said it's essential for patients with atrial fibrillation to receive warfarin to prevent a stroke.

"Warfarin is usually the best and safest available treatment to prevent stroke in people with atrial fibrillation. Increasing the uptake of warfarin would reduce the risk of death and disability of stroke," he said.

Worthington said patients with AF should ask their doctor why they aren't being prescribed warfarin.

More information

To learn more about atrial fibrillation visit the American Heart Association.

SOURCES: John Worthington, MB, Stroke Physician, Liverpool and Northern Beaches Hospitals, University of New South Wales, Sydney, Australia; Byron Lee, M.D., assistant professor of medicine, University of California, San Francisco; Aug. 28, 2008, online edition, Stroke

Last Updated: Aug. 28, 2008

http://www.healthday.com/Article.asp?AID=618866