Archive for the ‘Atrial Fibrillation’ Category
Share Our Mission to Heal
Holy Cross Hospital is seeking studio audience members for A Mission to Heal, a new show all about the heart.
Needed: 75 audience members for each show; Mix of demographics. No children under 18; Community groups are encouraged to have representation in the audience, as well as community leaders.
Where
A studio in Davie, FL. Details will be provided to audience members upon selection.
When
September 30, 2010; Refreshments will be served.
The show is not “live” but it is being recorded “live” so it will be edited and shown at a later date. Audience members should dress comfortably for long periods of sitting. No white blouses, shirts, hats or sweaters.
Please email info@holy-cross.com and put A Mission to Heal in the subject field OR call 954-776-3244 if you are interested in being part of the studio audience.
Please provide your full name, phone number, e-mail address, age range (20s, 30s, 40s, 50+) and race/ethnicity. Someone will be in touch to let you know if you have been selected and provide additional information.
New Tools for Atrial Fibrillation
I have blogged about atrial fibrillation many times as it is a constant feature in the practice of cardiology. An estimated 2.2 million patients in the United States alone have this problem. It has been difficult to prove in some patients and very difficult to follow. The facts are extraordinary.
If you have atrial fibrillation and go out of it by any means, the likelihood is that at one point in time, you will be back in it. If a physician places you on a drug, there is only a 50% chance that it will keep you in normal rhythm. If you have a procedure to terminate it, the range of one year success is variable from 50%-70%. We do not even have a way to figure out what your rhythm or rate control success is on a long term basis.
Until now — Medtronic, a major device company–has released a novel device. A study associated with the device has been published in Circ Arrhythm Electrophysiol. 2010; 3:141-147. This study documents the usefulness of this unique device.
The device records and stores data obtained from the heart without the need for leads into the heart such as a pacemaker would have. It is implanted in a simple procedure under your skin near your heart and is able to sense the electrical activity of your heart without wires into your heart. The procedure takes roughly ten minutes to place the device, and about the same amount of time to remove it. This can be done in an outpatient setting. The device will last up to three years so it provides a long term view of a patient’s atrial fibrillation and whether drug or ablation therapy is working for the patient.
This device also allows the diagnosis of patients who have intermittent symptoms that are virtually impossible to figure out using 24 hour holter monitors. The sensitivity of the device for atrial fibrillation was 96% and it was correct in identifying the problem 85% of the time. This device will also “download” its information wirelessly from a remote location so patients can send reports without going to the doctor’s office and patients can send reports if they sense something that troubles them.
Devices such as this will lead to a new paradigm of treatment for atrial fibrillation, as we can now have long term data which was unable to be obtained previously. This will lead to better treatments and to a better understanding of the disease process. If you cannot study it you can’t make progress, and we now have a tool to help.
A win for a new drug
It’s not often that drug studies are stopped early because of success. Usually they are stopped early because of either a structural problem in the protocol or for reasons of safety. Lately, studies stop because the companies have gone bankrupt.
Apixaban is a drug that we are studying and our study continues in follow-up. A sister study done was stopped because the drug proved significantly more beneficial and it was no longer ethical to proceed.
This drug is one of several in development of a new class of drugs. These compounds are known as factor xa inhibitors. They block the clotting cascade at a different point than Coumadin and are going “head to head” against Coumadin in many studies. One is close to approval in the US and is being presented to the FDA for final approval next month.
The use of these drugs will be felt most in the treatment of atrial fibrillation. As I have blogged about many times, atrial fibrillation is increasing in prevalence as our population grows older and about 10% of people over the age of 80 are affected by it. The big problem with atrial fibrillation is the strokes that occur. If no anticoagulation is given, the risk of stroke is 5% a year. If patients take Coumadin the risk is cut to 1%. It is not perfect. Coumadin however becomes more and more difficult to take as patients get older and comes with many restrictions. These new drugs do not as yet have important drug interactions (I can assure you there will be some) and have no dietary interactions like Coumadin does. The one drawback of the drug is that it must be taken twice a day.
The study reported concerned those patients that can’t or won’t take Coumadin. 5,600 patients received either 5 mg of apixaban or aspirin in varying doses. The study was stopped because, again, aspirin proved not effective in preventing strokes. I should mention that Plavix and the combination of Plavix and aspirin have never been found to be effective either.
So, it will likely be that this drug will be an option for patients who will receive the benefit and sustain fewer side effects than taking Coumadin. This is real progress and this drug is eagerly being awaited by both physicians and patients. It will be a “blockbuster” drug for the company who gets approval first. By the way, a “blockbuster drug” is one that brings in over a billion dollars a year.
The Start of Coronary Angiography
The start of coronary angiography was slow and began in earnest after a mistake was made. The reason was mostly that there wasn’t much to do with the information in the early 1960’s because bypass surgery wasn’t invented.
Dr. Charles Dotter played a seminal role in much of radiology. He is responsible for the concept of angioplasty, which started in the legs and first used ever increasing dilators to open arteries and finally went on to develop balloons for the task. Dr. Dotter was a mentor to Dr. Andreas Gruentzig, who miniaturized the balloons in his kitchen and then used them in the coronary arteries years later. In 1959, Dr. Dotter began experimenting on animals to visualize their coronary arteries by occluding the aorta and injecting contrast nonselectively. It was believed that even a small amount of contrast would kill the animal or a human.
In 1959, Mason Sones, a pediatric cardiologist, while doing an aortic root injection noticed that the catheter accidently entered the right coronary artery and visualized it. The patient sustained ventricular fibrillation and he thumped him on the chest and it stopped (luckily because cardiac defibrillators didn’t exist yet). He went into the animal lab and worked out how to inject coronaries without harming them. During this time, Sven-Ivar Seldinger in 1953 developed the technique that we still use today of entering the peripheral arteries with a small needle and using a wire to gain access to the main circulation and to move the catheters’ around.
Dr. Melvin Judkins developed many of the preformed shapes that the catheters are manufactured in to help enter the coronary arteries during the 1960’s and by the late 1960’s coronary bypass surgery was beginning and patients began to receive cardiac catheterizations for the purpose of defining their coronary anatomy. This process at first used 35mm film and required large amounts of radiation. Now, we use digital imaging and all the data is stored on a computer and the data can be manipulated for analysis by computer. The amount of radiation is significantly less.
Next…the problem now.
Vote for the Blog of the Year
Did Dr. Niederman post a blog in 2009 that you found particularly helpful? Was there a blog that you could not wait to share with someone else? We’d love to receive your feedback.
Please comment on what you think was Dr. Niederman’s best blog in 2009.
High Levels of a Substance Found in Ventricular Myocardium May Lead to Atrial Fibrillation
I have blogged about atrial fibrillation before and now a study arrives, which sheds new light on perhaps a marker of who might develop atrial fibrillation in the future. This study reviewed the data of 5,445 patients followed from 10 to 15 years. The authors used a marker know as BNP.
BNP is a substance found in the ventricular myocardium and since the weight of the left ventricle is so much greater than the right ventricle, it is used as a marker of left ventricular failure. When patients present to the hospital or office with signs of congestive heart failure, such as shortness of breath on exertion or fluid retention one can measure the level of BNP in their blood. The higher the level of BNP the more likely the diagnosis of heart failure is.
This substance is also present in acute coronary syndrome, which is a prelude to myocardial infarctions and is also present in myocardial infarctions. Physicians can measure it and get a sense of how important the attack is based on how high the BNP is. In practice, BNP is measured as NT-proBNP.
Past studies have used the Framingham Heart Study, which I have blogged about in the past and would actually be the subject of a long book. Elevated levels of BNP were found to be predictive but only 68 subjects were found. This study, the Cardiovascular Health Study Circ 2009; 120:1768-1774 utilized 5,445 patients. There were 1,126 cases of atrial fibrillation. Among those with the highest levels of BNP, there was a fourfold increase in the risk of atrial fibrillation compared to the lowest levels.
This study found that BNP was the strongest predictor of atrial fibrillation in comparison to other historic variables such as age, sex, medication use, blood pressure, echocardiographic variables, diabetes and heart failure.
Having a marker that may predict atrial fibrillation would allow us to aggressively treat those patients in an attempt to alter the disease course. I am sure that these studies are in progress or being planned given the expected explosion of these cases as the population continues to age.
The War Against Atrial Fibrillation
The care of patients with atrial fibrillation is complicated by the use of warfarin. Although it has no side effects, it needs to be stopped for procedures, it is hard to manage, and there are significant drug/drug and drug/food interactions. Life-threatening bleeding can occur if the levels are high and stroke can occur if the levels are too low.
Even though warfarin prevents 64% of the strokes in those with atrial fibrillation, it is prescribed to only two-thirds of the appropriate candidates. In real world doctor management in the dosing of warfarin, the correct dose is achieved in only 35% of patients. This causes many to be overdosed or under dosed.
The antithrombins are a class of drug which targets just the thrombin part of the effect that warfarin has on the clotting cascade. They are single-dose drugs, meaning everyone takes the same dose and they do not need to be monitored as they are with warfarin. So, patients do not have to undergo a monthly or more frequent blood test to regulate the dose.
If the drug needs to be stopped, it is gone in 24 hours and the onset of action is rapid, unlike with warfarin, which can take seven to ten days. Patients who are hospitalized often spend several extra days in the hospital as they are started on warfarin because insurance companies do not routinely pay for the transition medication as an outpatient. This adds considerably to the overall cost of health care.
Clearly, if the drug is not inferior to warfarin it would be widely accepted even at an increased cost. What if the drug is superior? That is the case with dabigatran.
The RE-LY study enrolled 18,113 patients in 951 clinical centers in 44 different countries. Two doses of dabigatran were studied 110mg twice a day or 150mg twice a day vs. warfarin. These centers were able to manage the dosing of warfarin better than in general, obtaining adequate levels around 64% of the time. The study found that the 110 mg dose of dabigatran was equal to warfarin in preventing stroke with less bleeding and that the 150mg dose of dabigatran was superior to warfarin in preventing stroke but had the same bleeding effects that warfarin did.
This is a major step forward. The most common side effects were gastrointestinal about 11% at both doses of dabigatran. If approved, everyone involved would benefit by easier management of the ever increasing problem of atrial fibrillation in our aging population. This drug is not yet studied in those patients who take warfarin for valvular heart disease. It is, at this time, just for nonvalvular atrial fibrillation. In Europe, this drug is already being used for the prevention of venous blood clots after knee or hip surgery and is known as Pradaxa. In Canada it is known as Pradax. Hopefully it will soon be available here.
Arrhythmia Nation
The recent European Society of Cardiology meeting in Barcelona, Spain, was the opportunity for the release of several groundbreaking trials. I will report on many of them in detail in the coming weeks.
The first is on a class of drugs that I have worked on for many years and we at the JMHVRI are still working on. They are oral thrombin inhibitors and Dr. Charles Russo is leading the Aristotle study here at the Institute. These drugs are for the anticoagulation therapy of Atrial Fibrillation for which the current standard is warfarin. The first of these drugs known as ximelagatran failed in testing due to liver toxicity. As I have discussed, research is an additive experience and now we have a compound in the same class that is very successful and non-toxic. The drug being tested in Aristotle (apixaban) is in the same class as the drug which I will discuss below and our study remains open for recruitment.
Atrial fibrillation has a prevalence of 0.4%-1% of the general population. The risk increases with age, so that by the time you are 80 you have an 8% chance of having it. Atrial fibrillation is common in patients who have congestive heart failure and it worsens the prognosis of both these illnesses.
There are different types, chronic or persistent, intermittent and secondary. Secondary such as from open heart surgery where roughly >70% of recovering patients will have at least an episode or at times related to another illness such as hyperthyroidism. At times it is chronic and persistent or at times intermittent. All types suffer from the major adverse effect of atrial fibrillation, which is stroke. One in every 6 strokes occurs in patients with atrial fibrillation. When transient ischemic attacks and “silent strokes” are figured in, the rate of stroke exceeds 7% a year. The risk of stroke increases with age and is 23.5% in those over age 80.
It is the most common arrhythmia that cardiologists see and accounts for one-third of the hospitalizations for cardiac rhythm disturbances. It is estimated that more than 2.2 million people in the United States has it and it is increasing. In the past 20 years there has been an increase of more than 60% in the hospitalizations for this condition. The annual cost per patient is said to be around $3,600 or close to a billion dollars.
Anticoagulation with warfarin (Coumadin) is the current treatment for atrial fibrillation with either rate control or conversion back to normal sinus rhythm. Warfarin reduces the rate of stroke significantly but it is associated with increased rates of major bleeding. It is very tedious to regulate and time-consuming for the patients and health care personnel involved. Even a more expensive drug would save tremendous amounts of money.
Up next…the RE-LY study and its groundbreaking conclusions.
Savings Lives One Heart at aTime
Recently, a review article was published in the Journal of the American College of Cardiology. This article reviewed the studies concerning omega-3 polyunsaturated fatty acids, better known as fish oil.
In the United States, physicians generally prescribe statin drugs for the treatment and the prevention of atherosclerotic disease. In Europe it is very common for the treatment protocols to use fish oil pills first and then statins.
The review discussed the varying conditions that were studied. Over 40,000 patients were enrolled in the various trials. These studies involved primary prevention, secondary prevention after sustaining a myocardial infarction heart failure and heart rhythms, such as atrial fibrillation.
Three large trials were done regarding the primary and secondary effects of this compound vs. placebo. Two decades ago the DART (Diet and Reinfarction) showed a 29% reduction in all cause mortality mostly driven by the reduction of cardiovascular mortality. More recently, the GISSI study group randomized over 11,000 patients and found a 15% reduction in the primary endpoint including 21% and 30% reductions in total and CV mortality. This was driven by a 45% reduction in sudden cardiac death.
Additionally, heart rhythms were found to be suppressed by these compounds. These include atrial fibrillation and rhythms which cause sudden cardiac death. Up to a 30% reduction over 12 years was found for atrial fibrillation. We were to participate in a new large trial regarding these compounds which the sponsor cancelled just before inception.
Heart failure is also improved. In a study of patients vigorously treated for heart failure those that took these compounds had an 8-9% reduction in death.
In my next blog I will discuss the various factors you need to know to take these compounds.
New Information on Endoscopic Harvesting Device
Last week an article was published that once again proved the value of research. We often take for truth what seems simpler when the use of a new device or drug appears when they have never been proved to be better or safer. Medical procedures and techniques often seem easier but in general are not proven to be. Drugs and devices are often approved because they are NO WORSE than standard not because they are better.
One of the drivers of medical costs is devices that cost significant amounts of money but add no real benefit. This concept is one of my main focuses of my blogging. I am attempting to provide the public with the information that we as doctors often have, but are very difficult to transmit to patients. I believe that the majority of doctors want to do what’s right by what we call evidenced based medicine but often they don’t know that these studies are in the literature.
One such device is used in endoscopic harvesting of saphenous vein grafts during bypass surgery. Although this device has been in use for several years only now has important information come to light. Briefly, at coronary bypass surgery the surgeon utilizes the greater saphenous vein from the leg as conduits for the graft. This procedure can be done the “classic” way or the “new way.” The classic way is to make a long incision in the leg and remove the vein by hand. The “new” way is to make several small incisions in the leg and with a tool known as an endoscope to remove the vein. It was assumed that this would be better. It is true that the healing of the leg incisions is one of the more trying parts of bypass surgery. Although they always heal it can take some time and the procedure often leaves scars.
Next…why this study may save your life.
About the Institute
Browse by Category
- Acute Coronary Syndrome (14)
- Adult Stem / Cell Treatment (10)
- Angioplasty (4)
- Aortic Aneurysms /Stents / Grafts (13)
- Atherosclerotic Heart Disease (12)
- Atrial Fibrillation (11)
- Cardiac Imaging (4)
- Cardiac Surgery (19)
- Carotid Disease (7)
- Cholesterol (53)
- Chronic Angina (13)
- Clinical trials (3)
- Coronary Artery Disease (34)
- diabetes (15)
- Heart Failure (30)
- High Blood Pressure (22)
- Myocardial Infarction (36)
- Pacemaker / AICDs (9)
- Peripheral Artery Disease (5)