AFib and Sleep Apnea slide show.
This presentation discusses the connection between Sleep Apnea and AFib.
Learn about the autonomic nervous system and it's relationship to both Sleep Apnea and AFib.
Learn how important it is to diagnose and treat sleep apnea if you have AFib.
The amazing connection between Sleep Apnea and AFib is the Autonomic Nervous System ANS.
The ANS includes large parts of the brain and spinal cord. It has nerve connections to all internal organs and blood vessels and continuously regulates all the functions of our bodies that seem to us to be automatic.
The biggest effects of the ANS are Sympathetic and Parasympathetic. The balance between the stimulating effects of the Sympathetic Response and the restful slowing effects of the Parasympathetic Response enable our bodies to be prepared either to fight or rest.
When the Sympathetic Response of the ANS becomes activated when it not needed, damage is done to the body. Many chronic diseases have their roots in this Sympathetic Imbalance.
This includes damage to the heart which can lead to AFib, but this is not how the ANS is felt to relate Sleep Apnea and AFib.
The ANS also has nerve connections to specific and individual parts of many internal organs, including the heart. Abnormal ANS stimulation in particular parts of the heart can cause abnormal function of those parts. Often this leads to abnormal "extra heart beats". This can be the source of many types of abnormal heart rhythms.
The ANS is significantly effected by Sleep Apnea. During breathing obstruction the SNA (sympathetic nerve activity) increases with increased heart rate. When breathing resumes the SNA is suddenly reduced and the Parasympathetic heart rate slowing effects become dominant leading to severe slowing of the heart rate. (This never requires a pacemaker to be implanted.) This increased SNA also leads to hypertension and elevated lung pressures.
But how does all of this relate to AFib?
AFib occurs in many circumstances, not just Sleep Anea, but in most patients with AFib the Autonomic Nervous System ANS is part of the problem.
Most patients with AFib have some damage to there heart that comes with aging or having dealt with chronic heart conditions. Other patients are younger and healthy but have a genetic predisposition to AFib. Lifestyle problems such as obesity, inactivity, and alcohol can damage the heart. Aggravating factors such as surgical stress, high thyroid, and sleep apnea are also frequent. But what specifically triggers an episode of AFib to begin?
Two conditions must be present for AFib to start. First there is some damage to the atrial muscle, usually fibrosis between muscle cells that interferes with the electrical connections between muscle cells. This is the SUBSTRATE.
Next, abnormal rapid electrical firings TRIGGERS occur . These come from the pulmonary veins. When the TRIGGER and SUBSTRATE combine AFib results.
How is the Autonomic Nervous System ANS involved?
There are Autonomic nerves that go directly to region of the Pulmonary Veins (veins that drain blood from the lungs to the Left Atrium of the heart).
Stimulating these nerves causes abnormal rapid electrical firing in the veins that TRIGGERs AFib.
Apnea in dogs has been shown to cause firing of these SAME Autonomic Nerve conections and cause AFib.
This suggests that apnea in people can have the same result.
In fact it turns out that AFib is particularly common in patient with sleep apnea. In this study 27% of patients with the central form of sleep apnea had AFib compared to 3% of patients without sleep apnea.
Many studies have looked at the patients with both sleep apnea and AFib.
On average 50% of patients have sleep apnea and in 15% it is severe.
In patients with sleep apnea the risk of developing AFib is increased 4 times.
It is very unlikely that these two conditions would have such common occurrence by chance.
Many patients with AFib find it difficult to believe that they have sleep apnea because the symptoms of sleep apnea are not always obvious.
Patients also wonder how sleep apnea could cause AFib when they are not asleep.
The explanation as to why AFib can occur later when the patient is not sleeping is called REMODELING. This means that persistent changes in heart occur as a result of the abnormal Autonomic Stimulation and resulting AFib.
The good news is that treatment such as CPAP can eliminate the abnormal Autonomic Stimulation and reverse the Remodeling!
The best evidence that treatment of sleep apnea is important in patients who also have AFib come from studying patients after a cardioversion or an ablation.
The risk of having recurrence of AFib after a cardioversion or an ablation is much higher if sleep apnea is present and is lower if sleep apnea is treated.
Ablation for AFib is a procedure that seperates the TRIGGERS in the pulmonary veins from the SUBSTRATE in the left atrium.
This procedure works well but the results are not as good if sleep apnea is present and not treated!
The Cryoballoon is an effective and well tolerated way to accomplish pulmonary vein isolation for ablation of AFib. Experience with the Cryoballoon has increased, the Cryoballoon has been improved with a second generation device, and some studies comparing it to RF ablation have shown the Cryoballoon works better.
Please contact me if you have more question about Sleep Apnea and AFib, AFib treatment, or Cryoballoon.
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