Deficient Sleep Heightens Atrial Fibrillation Risk

Several studies have shown that patients with sleep apnea are more likely than others to develop atrial fibrillation (AF), but recent information indicates that any type of disrupted sleep may indicate an elevated risk.

Investigators from the University of California, San Francisco examined data from almost 14 million patients and found that people with insomnia — regardless of whether the condition manifested itself as trouble falling asleep, early rising or poor sleep quality throughout the night – were more likely than sound sleepers to eventually be diagnosed with AF.

The investigators separately analyzed three sources of patient data. The first was the Health eHeart Study, an Internet-based cross-sectional study of more than 4,600 people. The second was the Cardiovascular Health Study, and 11-year longitudinal study of 5,700 patients (including 1,600 patients who developed AF). The third was the California Healthcare Cost and Utilization Project, a hospital-based database with five years of data on almost 14 million patients.

After adjusting for age, sex, race, diabetes, high blood pressure, heart failure, and smoking, the investigators found that insomnia-plagued patients from all three cohorts were between 26% and 29% more likely than other patients to develop AF.

“The idea that these three studies gave us consistent results was exciting,” said lead study author Matt Christensen, currently a fourth-year medical student at the University of Michigan in Ann Arbor.

The same investigators then reviewed a subset of the Cardiovascular Health Study to analyze the effect of sleep disruptions during particular phases of sleep on subsequent AF risk. (In all cases, the sleep disruption stemmed from something other than sleep apnea.) Records showed how long it typically took patients to fall asleep, how long they typically slept and how much time they typically spend in various sleep phases.

Using 10 years of data from 1,131 people (average age: 77 years), the research team found that the lower the ratio of REM sleep to non-REM sleep, the higher the risk of incident AF.

The analysis did not uncover a particular mechanism that linked sleep quality to AF, but the study authors said that the particular importance of REM sleep might provide a clue.

“By examining the actual characteristics of sleep, such as how much REM sleep you get, it points us toward a more plausible mechanism. There could be something particular about how sleep impacts the autonomic nervous system,” said Christensen, who noted that autonomic nervous system plays a major role in controlling heart rate and blood pressure.

Prior research shows that poor sleep increases the risk of developing a wide range of health problems, including high blood pressure, obesity and heart disease. The new study, however, provides yet another reason for people to get a good night sleep.

“Ultimately, even without a clear understanding of the responsible mechanisms, we believe these findings suggest that strategies to enhance sleep quality, such as incorporating known techniques to improve sleep hygiene, may help prevent this important arrhythmia,” said senior author of both abstracts Gregory Marcus, MD, MAS, a cardiologist at the University of California, San Francisco.

The findings were presented last month at the American Heart Association's Scientific Sessions.

Related Coverage:

Genetic Explanation for Some Unexplained Cardiac Deaths

Tissue Plasminogen Activators Safe for Patients Who Wake Up with Stroke Symptoms

Fixing 'Gaps' in Warfarin Treatment for Veterans with Atrial Fibrillation