With the number of AF-attributed deaths increasing in recent years, optimizing management of the condition stands to have a significant impact on a patient and societal level.
Welcome to this special CardioView presentation. Atrial fibrillation (AF) represents one of the most common, yet overlooked, forms of cardiovascular disease. With the number of AF-attributed deaths increasing in recent years, optimizing management of the condition stands to have a significant impact on a patient and societal level. In this edition of CardioView, two experts provide an overview of AF and take a deep dive into the current state of its management, including risk factors, patient presentation, the role of implantable cardiac monitors (ICMs) and best strategies based on actionable data.
The guests for this special presentation of CardioView are:
Deepak L. Bhatt, M.D., M.P.H.,
Executive Director of Interventional Cardiovascular Programs,
Brigham and Women’s Hospital, Boston, Massachusetts
Solomon Sager, M.D., Director of the Electrophysiology Division and Managing Director of the Chicago Cardiology Institute, Chicago, Illinois
Risk Factors for AF
Deepak Bhatt, M.D., M.P.H.: AF is the most common arrhythmia in the United States and worldwide, with a prevalence that is growing. Why is the prevalence growing? Because of a number of trends.
First is the aging of the population. In the U.S. and globally there are many older people and prevalence increases markedly in both men and women as people get older. When patients enter their 70s, 80s and 90s, the incidence of AF is much higher than at younger ages. So this is a real issue in terms of a growing burden of AF.
Beyond the aging population, several other factors appear to be contributing to AF. It wasn’t fully appreciated until relatively recently that obesity contributes to AF and it appears that weight loss can decrease AF burden.
Obesity is a risk factor for cardiovascular disease, whether it’s ischemic heart disease or heart failure. That’s well known, but it turns out that it is also a risk factor for developing AF. In people who have AF, obesity can also increase disease burden. Even in patients who have had an AF ablation, it appears that weight loss decreases the risk of recurrence.
Regardless of the stage of AF — at risk for it, has it, has had an ablation for it — it appears that weight loss decreases risks of recurrent AF, de novo AF, and AF after procedure. For patients who are overweight, particularly (those) who are obese, if they’re asking what can they do to decrease AF risk, weight loss is definitely on that list.
Another risk factor that’s relatively new is alcohol intake. A number of studies now point to the fact that even a single drink a day increases the risk of AF. This is true of people who have AF and it also appears to be true of people who are just at risk for AF but don’t have it yet.
In terms of things patients can do to decrease AF risk, they can cut down or eliminate alcohol intake. That’s not always a popular answer, but that’s what the data show. We know that binge drinking can precipitate the occurrence of AF; that’s been known by physicians for years. There’s no question that acute alcohol intake, especially large amounts, can trigger AF, but what’s novel and true is that more modest chronic intake can do it as well. Studies show that even a single drink can increase the risk of developing AF.
Interestingly, we’ve thought coffee or caffeine intake is a trigger for AF, but the trials are more ambiguous about whether that’s true. I’ve certainly met patients who are convinced that AF has been triggered by caffeine intake, but that’s not been as clearly established by rigorous clinical trial data.
It can get tricky because if someone is drinking a lot of caffeine, it might mean they’re also staying up all night, under a lot of stress and not eating right. So there are other bad things going on that could also serve as triggers for AF. It gets tricky figuring out what an actual trigger for AF is. I’m not saying that an individual patient’s caffeine, stress and lack of sleep might not be part of it. I’m sure it is, but in terms of very rigorous data, we can say with certainty that alcohol is a trigger for AF.
Challenges in AF Treatment
Bhatt: Although AF is very common, there are a lot of challenges to it as well. There’s been a lot of controversy through the years.
For example, is rate control sufficient or do we also need to control the rhythm to restore normal sinus rhythm? Intuitively, it makes a lot of sense to restore normal sinus rhythm, but older trials suggested no benefit to a rhythm control strategy versus rate control alone.
Obviously, you need to control the (person’s) rate if (it) is very quick. You want to get their heart rate down with beta-blockers, calcium channel blockers or those sorts of medicines, but should you also restore a normal sinus rhythm? Then should that be done with anti-arrhythmic medications, like amiodarone and dronedarone, or should that be done with procedures? Or should it be done with medicines, and if people fail medicines, then procedures?
The general feeling is that if people are healthy, not having heart failure and (are) asymptomatic, rate control is probably sufficient, but if they’re very symptomatic with their AF it’s important to see if the rate is controlled with exercise. Even if it is controlled at rest, it may not be well controlled with exercise, especially in younger more active people.
Assuming that the rate is well controlled, if they’re still symptomatic, that is a reason to do more with drugs, procedures or potentially with both. In part it depends on underlying comorbidities, patient preference and so forth. Obviously, AF ablation is an invasive procedure. There can be complications, but the procedure has (become) safer, especially in experienced hands.
In patients with heart failure as well, there appears to be a benefit of ablation. Even some meta-analyses suggest there might be lower mortality in patients, especially patients with heart failure with reduced ejection fraction who have AF, (if they) undergo ablation. It’s a bit controversial, but there are meta-analyses that support that.
In a young person, what about them? There are a lot of challenges. On the one hand, they’re probably going to tolerate things pretty well if they have rate control without rhythm control. On the other hand, the longer people are in AF, the harder it is to get out of it. So we’re in a theoretical appeal to try to restore normal sinus rhythm early before the left atrium remodels, dilates, and becomes fibrotic. There’s some work looking at things like MRI (magnetic resonance imaging) to see if left atrial fibrosis can help guide exactly what our therapy should be.
There are a lot of challenges in knowing exactly what to do with AF in different patients. Randomized clinical trials and guidelines are useful in that decision-making, and ongoing research such as the imaging research might end up being really useful in terms of tailoring therapy to different types of patients with AF.
for AF Diagnosis
Solomon Sager, M.D.: We use ICMs quite frequently in patients who have undergone full workups and still don’t have a diagnosis but (have) symptoms such as syncope, palpitations or dizziness.
There’s two different ways that we can reach the diagnosis. First, the patients have a button that they can push, which will have the ICM store data from a certain period of time from before and after … they clicked that button. The amount of time before and afterward is proprietary to each company’s device.
The second way is that the devices are automatically set to look for low and/or high heart rates based on algorithms in each device, even if a patient doesn’t have the clicker by their side to click when they have symptoms. If something abnormal happened, the device will automatically store that data and then will communicate it via the programmer at the patient’s bedside to the cloud. Most practices and hospitals are checking that data on a daily basis to allow for ongoing communication within 24 hours of symptom onset.
AF’s Comorbidity Burden
Bhatt: The predominant risk we worry about is stroke. (In other words) systemic embolism, primarily left atrial appendage thrombus going to the brain causing stroke, but it can go elsewhere as well. For example, it can have emboli to the coronary arteries, causing a myocardial infarction. It’s an unusual cause of myocardial infarction, but 1% to 3% of myocardial infarctions and acute coronary syndromes are due to emboli from the left atrial appendage from AF.
Other places that systemic emboli can lodge in are the kidneys and the feet, causing acute peripheral limb ischemia or kidney failure. Those are much less common than stroke, but systemic embolism is also on the list of bad things that AF can cause. But by far, numbers 1, 2 and 3 are thromboembolic stroke.
Other complications include heart failure, and AF can contribute to heart failure. It can prompt episodes of heart failure, including in patients with heart failure with preserved ejection fraction but also in those with reduced ejection fraction. Sometimes it can be the sole cause for heart failure, not just worsening heart failure that otherwise exists, but promoting or causing that heart failure. In particular, if the rate of AF is very high, that can cause a tachycardia-induced cardiomyopathy, and controlling the rate might be sufficient to reverse that if the AF is detected early enough.
In any work-up for heart failure, you always want to see if AF is a cause and screen for things like thyroid disease, which can lead to heart failure and atrial arrhythmias. So it’s important to remember that. In terms of negative outcomes in AF, stroke is at the top of the list, but you always want to (remember) that it can cause or promote heart failure.
Among the arrhythmias, AF creates the greatest burden. It’s a burden in terms of the patient’s morbidity and mortality, in terms of stroke and heart failure risk. Beyond the patients, it’s also a burden to the health care system. It’s a major cause of health care costs. AF is a growing burden for reasons I cited previously, in terms of an aging population and other risk factors that are increasing the prevalence of AF.
This is AF that we’re detecting clinically because it’s jumping up and getting our attention. It doesn’t even capture AF that’s silent. That’s a big issue because for a nontrivial proportion of strokes, often the first presentation of AF is with a stroke, sometimes a very disabling stroke. Strokes in the context of AF can be quite disabling.
There’s the burden of AF-induced stroke, the disability it causes to patients and downstream health care costs. Sometimes the strokes can be fatal, not just disabling. A lot of burden is placed on patients who have AF, including the ones who have silent AF but then go on to have complications such as stroke, which is an enormous burden on the health care system.
Advantages of Early
Sager: What we talk about a lot is the timing of when we want to implant ICMs. This is an ongoing topic of conversation.
In the current health care paradigm, there’s an ongoing dialogue between doctors and insurance companies about what needs to be done before we can recommend an ICM for patients. Depending on the insurance plan, there are different policies and different guidelines for all the diagnoses.
There’s a lot of great data that would suggest that the earlier you get an ICM into patients, the better it is for them. It can avoid many unnecessary health care costs including unnecessary monitoring and procedures that may be preempted by just getting to the ICM right away.
Moreover, the longer the period of time that you … monitor … patients’ beat-by-beat analysis, the more likely you are to find a diagnosis and potentially discover data that can lead to improved clinical care. There are multiple ongoing studies determining when the optimal timing is for using ICMs.
I can tell you from my own practice that for AF management, the earlier you get an ICM in the more likely you are and the sooner you are to get data that is actionable for patient care.
ICM Benefits in Clinical Decision-Making
Sager: AF is the new paradigm for ICMs. We used to use them only for syncope or for cryptogenic stroke or for undiagnosed symptoms. However, as the usage of ICMs and the technology has improved, we’ve started to use it much more for the management of AF.
The data that we collect over a period of time can help us determine what the best course of treatment is for our patients and to individualize the care for each patient. (An ICM is) a powerful tool and patients have to do minimal activity in order to generate the data. The monitor for the device just sits by their bed and overnight the communicator by the bed sends the data to a web-based portal from which we the doctors and our technicians can gather information every morning to help us guide clinical decision-making.
When we’re managing patients with heart rhythm disorders, the more data we can collect, the better it is for patient care. ICMs allow us to collect data on a beat-by-beat basis for up to three to four years. They are inserted very easily under the skin. It takes about 60 to 120 seconds and can be done in the office. The data that we collect can guide a variety of different clinical decision-making scenarios.
It helps us guide medical management for patients with AF. It helps guide what kind of ablations we may want to perform based on whether the AF is paroxysmal, persistent or even permanent. It helps us decide whether or not patients have enough AF that would warrant anticoagulation and it helps guide decisions regarding anti-arrhythmic therapy. Sometimes patients have palpitations and we’re not sure if they have AF, and the ICM can help us to diagnose AF in those patients.