Oussama Wazni, MD, Electrophysiologist at Cleveland Clinic, talks about a drug that brings cholesterol levels to such a low point they are able to prevent some heart diseases.
Could you explain what AFib is and what is happening in the heart and cardiovascular system as a result of AFib?
WAZNI: Atrial fibrillation is the most common sustained arrhythmia. An arrhythmia means that the heart is not beating at a regular rhythm or rate. When a patient has atrial fibrillation, the atrium, which is the upper chamber of the heart, is not beating. When not in atrial fibrillation, the usual heart rate in the atrium is about 60 to 100, 120 depending on activity. When in atrial fibrillation, the rate in the atrium is about 400 to 600 beats per minute. But the good news is, there is something called the AV node that blocks most of those beats from getting down to the main chamber which pumps blood, called the ventricle. The patient will end up with a heart rate, depending on age and medications that are used, between 60 to 120, 130 beats per minute. The problem with that is the patient has a higher heart rate and it’s irregular. The biggest issue though is that in the atrium, because it’s really not pumping, it’s just quivering, blood can stagnate and cause a clot which can cause a stroke. Regardless of the stroke or in addition to the risk of having a stroke, the patients don’t feel well when they have atrial fibrillation because they lose what we call an atrial kick or the contribution of the efficiency of the heart from the atrium because the atrium isn’t doing much work. So, patients end up with palpitations due to the fast heart rate, shortness of breath on exertion or with doing activity, and decreased endurance and fatigue.
What are the standard treatments for AFib?
WAZNI: The most important aspect of managing atrial fibrillation is stroke prevention. Not everybody who has atrial fibrillation is at higher risk for stroke, but there are other risk factors that must be taken into account when managing a patient. We go by something called the CHADS-VASc score. Congestive heart failure, hypertension, age, diabetes, previous history of stroke and vascular disease, and gender. Female gender carries a higher risk. In those patients that have a higher risk of stroke, they should be placed on a blood thinner. But that does not address the symptoms that the patients have. If a patient is symptomatic with atrial fibrillation, then we must slow down the heart rate. Usually, we use medications such as beta blockers or calcium channel blockers. But even after controlling the heart rate, many patients continue to have symptoms. In those patients, we must get them back into a normal rhythm and maintain normal rhythm. The way we do that is a cardio-version, or a shock, to reset the heart. That doesn’t mean they won’t go back into atrial fibrillation. That’s why atrial fibrillation is a recurrent problem. To maintain them in normal range, we use either another class of medications called anti-arrhythmic drugs that suppresses the AFib and maintains sinus rhythm, or another option is to do an atrial fibrillation ablation procedure where we go into the left atrium and ablate the areas where atrial fibrillation comes from.
Could you describe the new catheter?
WAZNI: What we’ve been researching here at the clinic and been very interested in is if we intervene early, or try to ablate atrial fibrillation early instead of trying medications first, would the outcomes be better in the long run? The fact is that if we suppress the AFib, we’re able to maintain sinus rhythm and that begets more sinus rhythm. Because we know from previous experience that the longer a patient has atrial fibrillation, the more difficult it is to manage. It can progress through what we call persistent chronic or even permanent atrial fibrillation. The earlier studies had indicated to us that that’s a better strategy and we should intervene early. Then we thought, what is the catheter that could help us achieve this with the lowest risk possible and the most efficient way of doing it? That’s where we go into the cryoballoon. The cryoballoon has been on the market for many years now, but we elected to use it in this study. We took patients who have early AFib and randomized them. They had never been on antiarrhythmic drugs, so these were what we call antiarrhythmic drug naive patients. We randomized them to an ablation with the cryoballoon vs. a drug to suppress atrial fibrillation and followed them for up to one year. The results were amazing at close to 75% who had the ablation, maintained sinus rhythm and felt so much better. That’s what led to the new FDA announcement that, for the first time, we have a catheter, the cryoballoon, that is indicated for first-line ablation. When we say first-line ablation, that means you can ablate before you try medication. Up until that point, there was no catheter indicated for first-line ablation. All catheters were indicated for once a medication failed. Because of the Stop AF First study and other studies, we now have a catheter that can be used before a patient fails medicine type.
What does this mean for patients now?
WAZNI: This is very important for patients and doctors. From the Stop AF First study and others, we showed that medications are successful 50% of the time. This means that now the patients can get relief and get treated sooner than later instead of having to try one medication and then another. But by then, it may be too late. So now, once a patient is early on in the disease process and they’re having symptoms, we can offer them an ablation sooner than later and they won’t have to deal with the medications and their side effects and also the risk of progression of atrial fibrillation.
How does the cryoablation procedure compare to drug therapy for controlling AFib?
WAZNI: If we intervene early in the disease process, cryoablation is successful at keeping people in normal rhythm at 1 year in almost 75% of the cases. And, the good news is that it is very safe. There was only one complication in the drug arm that was handled very well and did not cause any long-term problems for the patient. Now, the medications success rate is only 45%, but we didn’t even talk about the possible side effects from the medications. These medications are very strong, antiarrhythmic drugs, somebody has to be an electrophysiologist to prescribe them because they can cause a lot of issues for the patients. Some issues include very slow heart rate, some other issues with headaches, and even some of them can cause deadly arrhythmias themselves. For example, there’s a medication called Dofetilide that we start in the hospital. We have to monitor the patients very closely because it can cause sudden cardiac arrest if people are not very careful.
And finally, is there anything you’d like to add for our viewers?
WAZNI: The thing that I want to remind everybody is that, although now we have ways to intervene early and ablate AFib and hopefully maintain normal rhythm, our listeners and our patients should also take care of themselves, meaning they have to do some risk factor modification if they have those risk factors. That’s going to be the foundation of their management. If they’re overweight, I encourage them to lose weight. If they have sleep apnea, I encourage them to get that treated. Diabetes and hypertension must be very well-managed. Then, they will get the full benefit from early ablation.
Interview conducted by Ivanhoe Broadcast News.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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