AF Symposium 2015

Dr. John Camm

Silent Undiagnosed A-Fib More Dangerous Than Symptomatic A-Fib

by Steve S. Ryan, PhD

Background: Back in 2004, Dr. John Camm of St. George’s Hospital in London, England was one of the first to identify the importance of “silent” or asymptomatic A-Fib. (See the first summary under Boston AF Symposium, January 16-17, 2004.)

In his 2015 presentation, Dr. Camm pointed out that silent (asymptomatic) A-Fib can have similar long-term effects as A-Fib with symptoms. Silent A-Fib may progress and get worse just like symptomatic A-Fib. Increased fibrosis may develop, the atrium may become stretched and dilated, the frequency and duration of the unnoticed A-Fib attacks may increase over time (electrical remodeling).

But what’s worse is that the risk of an A-Fib stroke may increase with the result that a patient is hospitalized or dies from an A-Fib stroke without knowing they had A-Fib. If someone with A-Fib has symptoms such as heart palpitations, shortness of breath, chest pains, tiredness, swelling of legs and a decline in mental ability due to reduced blood flow, etc., they and their doctors can usually determine that they have A-Fib. They can take precautions like taking anticoagulants to prevent an A-Fib stroke. But all too often people with silent A-Fib have a stroke and only then find out they have A-Fib.

Improved Device Monitors for A-Fib

Doctors today have a wealth of new A-Fib monitoring devices to detect A-Fib, such as the Medtronic Reveal DX which is inserted just under the skin and can monitor the heart for over a year, or the Zio Patch which you wear like a Band Aid for 1-2 weeks, or phone apps like the AliveCor Heart monitor for SmartPhones. But how can we get heart monitors to the people who need them the most—people with silent A-Fib? (I believe that everyone when they turn 50 or 60 years old should be given not only an EKG, but also some form of a long-term monitor to detect silent A-Fib. [In the US this could be a part of Obamacare.] That would save a lot of lives and permanent disabilities from A-Fib strokes. An EKG only works if one has A-Fib in the doctor’s office. But people with intermittent A-Fib often need a more long-term monitor to detect their A-Fib.)

Dr. Camm described studies such as REVEAL-AF and CHARISMA which are using monitoring devices to identify A-Fib as soon as possible in patients who are vulnerable to it.

In the new clinical study called ARTESiA, devices to detect A-Fib will be used to compare patients taking apixaban versus aspirin in reducing the risk of ischemic stroke and systemic embolism.

A-Fib May Not be the Only Factor in Ischemic Stroke

Dr. Camm made a thought-provoking statement about A-Fib and stroke. We know that people who get A-Fib are at a greater risk of having an ischemic stroke. But “there is not a clear relationship between the timing of the A-Fib and stroke.” Someone may develop A-Fib and have a stroke within a year, while others may go much longer without having a stroke or throwing a clot. Right now we can’t predict when someone in A-Fib will develop a clot and have a stroke. This suggests that “A-Fib itself may not be the only factor that is relevant, and that other underlying cardiovascular problems contribute to that ischemic stroke.”

Stroke Risk Low After an Ablation

What about the risk of silent A-Fib after a successful catheter ablation? (See also 2006 BAFS: Dr. Hans Kottkamp, The Frequency and Significance of Asymptomatic A-Fib After Catheter Ablation.)

Dr. Camm pointed out that a large number of studies have indicated that following ablation, “ischemic stroke rates are very low.” (See also my article: Catheter Ablation Reduces Stroke Risk even for Higher Risk Patients.)

Editor’s Comments:

Is “Silent A-Fib” Really Silent?
Some people question whether “silent” A-Fib is really silent from a clinical aspect. Even though someone isn’t experiencing the feeling that their heart is trying to jump out of their chest, in A-Fib one loses 15%-30% of normal blood flow to the brain and other organs which certainly has an effect. Even though people get used to it or their body adjusts or they write off the symptoms of tiredness, dizziness, mental slowness, etc. as old age, almost everyone in A-Fib is clinically affected and changed by A-Fib to some extent.

Silent A-Fib After an Ablation Less of a Danger
If you’ve had symptomatic A-Fib and been “cured” by a catheter ablation, it’s highly unlikely you wouldn’t notice if you went back into A-Fib. People with symptomatic A-Fib are usually very attuned to their heart and watchful. (One way to tell when someone has A-Fib is to watch them slyly check their pulse when no one is looking. I was particularly obsessive and used to wear a Polar Heart Rate monitor 24/7. Even after 17 years of being A-Fib free, I still check my pulse every night with a Pulse Oximeter.)

And EPs today are much more aware of silent A-Fib and its dangers. Plus they now have an awesome array of A-Fib monitoring devices. It’s highly unlikely that today’s EPs wouldn’t catch significant bouts of silent A-Fib, though they aren’t infallible. (When I had my yearly heart check-up, it included a stress test. Then my EP had me wear a Holter monitor for a day. [No A-Fib!] Several years ago he had me wear a Zio patch monitor for two weeks. [Again, no A-Fib!]) This is the kind of watchful observation most EPs employ on patients who have had catheter ablations.)

We Must Do Something About Silent A-Fib
Silent A-Fib is a serious public health problem. Up to 30%-50% of people with A-Fib aren’t aware they suffer from A-Fib and that their heart health is deteriorating.¹ As a society we must develop the political will to identify everyone with silent A-Fib long before they die or are permanently disabled from an A-Fib stroke! And with the amazing new varieties of device monitors on the market, it should be easy to identify people with silent A-Fib.

I call upon the Heart Rhythm Society and the American Heart Association/American Stroke Association to develop protocols for identifying silent A-Fib. And heart doctors should not only be encouraged but required to use these protocols on everyone over a certain age. Think of the lives and permanent disabilities that would be saved by inexpensive, easily administered monitoring for silent A-Fib. 

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Last updated: Monday, January 25, 2016

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