In this blog-post, I’d like to report on the first random study of patients with Atrial fabulation, A-Fib, and sleep apnea, comparing the health outcome of those who use a C-PAP, a “Continuous Positive Airway Pressure” device, to the outcome those who do not. The original study was published in May, 2021 (read it here) in the American Journal of Respiratory and Critical Care Medicine. The American Journal, Pulmonary Advisor published a more-popular version here.

As a background, if you are over 65 and overweight, there is a 25% chance or so that your heart rate will begin to surge semi-randomly, and that it will flutter. This is Atrial fabulation, A-Fib. It tends to get worse and tends to lead to heart attacks and strokes. People with A-fib tend to be treated with drugs, aspirin, warfarin, beta blockers, and anti arrhythmics. They also tend to be prescribed a C-PAP because overweight, older folks tend to snore and wake up a lot during the night (several times per hour: apnea).

A C-PAP definitely stops the snoring and the Apnea, and the assumption was that it would help your heart as well, if only by giving you a better night’s sleep. As it turns out, the C-PAP seems to decrease heart health — significantly.

For this study, adult patients between 18 and 75 years old diagnosed with paroxysmal A-Fib (that’s occasional AF) were screened for moderate to severe sleep apnea. Those who agreed to participate were randomly assigned to either a treatment of C-PAP plus usual care (drugs mostly) or just usual care for the next 5 months. Of the 109 who enrolled in the study, 55 got the C-PAP plus usual care, 54 got usual care alone. The outcome was that there were 9 serious, adverse heart events (strokes and heart attacks); 7 were in the C-PAP group.

The CPAP pressure was, on average, 6.8 cm H₂O; mean time of use was 4.4±1.9 hours per night. The C-PAPs did their jobs on the apnea too, reducing residual apnea-hypopnea to 2.3±1.9 events per hour for those in the C-PAP group.

There was a non-statistically significant reduction is AF among the C-PAP group. They reduced their time in AF by 0.6 percentage points compared to the control group  (95% CI, -2.55 to 1.30; P =.52). That not a statistically significant difference, and is most likely random.

There was a statistically significant decrease in heart health, though. A total of 7 serious adverse events occurred in the C-PAP group and only 2 in the control group. A total of 9 is a relatively small number of events, but there is a strong statistical difference between 7 and 2.

The authors conclude: “CPAP treatment does not seem to reduce or prevent paroxysmal AF.” They should also have concluded that it reduced heart health with a statistical confidence of ~82%: (1-2(36+10)/512) =82%. See more on this type of statistics.

A possible explanation of why a C-PAP would would make heart health worse is an outcome of the this recent sleep study (link here). It appears that the C-PAP helps restore breathing, but by doing so, it interferes with a mechanism the body uses to deal with A-fib. It seems that, for people with A-Fib, their bodies use breathing stoppages to get their heart back into rhythm. For these people, many of their breathing stoppage are not obstructive, but a bio-pathway to raise the CO2 level in the blood and thus regulate heart rate. The use of a C-PAP prevents this restorative mechanism and this seem to be the reason it is destructive to the heart-health of patients with A-fib. On the other hand, a C-PAP does improve the sleep those patients whose apnea is obstructive. It seems to me that sleep studies should do a better job distinguishing the two causes of apnea. C-PAPs seem counter-indicated for patients with A-fib.

Robert Buxbaum, March 30, 2022. I was diagnosed with apnea and A-Fib some years ago. The sleep doctor prescribed a C-PAP and was adamant that I had to use it to keep my heart healthy. There were no random studies backing him up or contradicting him until now.