Study identifies possible link between orthostatic hypotension and atrial fibrillation

Published on November 21, 2013 at 12:22 AM · No Comments

Johns Hopkins-led study suggests physicians check for heart rhythm disturbance in those with orthostatic hypotension

Results of a Johns Hopkins-led study have identified a possible link between a history of sudden drops in blood pressure and the most common form of irregular heartbeat.

The study suggests that a bout of orthostatic hypotension — a steep blood pressure drop that occurs when a person stands up after a period of lying down — appears to be associated with an overall 40 percent increase in the risk of developing atrial fibrillation over the following two decades.

While a simple, inexpensive doctor’s office test can check for orthostatic hypotension, the researchers caution that the condition itself does not generally need treatment, nor have they demonstrated that it is a cause of atrial fibrillation.

They further note that because atrial fibrillation is often present without causing noticeable symptoms, some people may already have the rhythm disturbance before an episode of orthostatic hypotension, though they tried to exclude those subjects from the study.

But the researchers say their findings do suggest the need for further study and that clinicians who diagnose orthostatic hypotension in their patients need to be more vigilant than they otherwise might be in watching out for atrial fibrillation. The arrhythmia is an underdiagnosed condition that increases the risk of stroke fivefold, as well as risks of heart failure and dementia. People with atrial fibrillation are often treated with blood thinners to reduce the risk of stroke, and with other medications that regulate the rate and rhythm of the heartbeat. The findings were published last week in the journal PLOS ONE.

“We hope our research will sensitize physicians to a possible link between orthostatic hypotension and atrial fibrillation, and that they will go the extra step to see if something more serious is going on when patients experience rapid blood pressure fluctuations,” says study leader Sunil K. Agarwal, M.D., M.P.H., Ph.D., a fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine. “We want this on their radar screens.”

For the study, the researchers followed 12,071 African-American and white men and women ages 45 to 64 years who were enrolled in the Atherosclerosis Risks in Communities (ARIC) study. From 1987 to 1989, each subject had a baseline visit during which information on socioeconomic indicators, medical history, family history, cardiovascular disease risk factors, serum chemistries, electrocardiograms (ECGs), medication use and anthropometrics was collected. Three follow-up visits were conducted, as well as annual telephone interviews and active surveillance of hospitalizations and death.

Five percent of the subjects (603 of them) were diagnosed with a rapid drop in blood pressure when going from lying down to standing up. The authors defined orthostatic hypotension as a 20 mmHg or greater drop in systolic blood pressure or a dip of at least 10 mmHg in diastolic pressure. Those who had a history or symptoms of atrial fibrillation at baseline were excluded from the study.

During an average follow-up of 18.1 years, 1,438 (11.9 percent) of the study participants developed atrial fibrillation. Those with orthostatic hypotension, after accounting for factors such as race, age, gender and other common risk factors for the arrhythmia, were 40 percent more likely than those without orthostatic hypotension to develop an irregular heartbeat. Atrial fibrillation was identified by 12-lead ECGs recorded during three follow-up visits at three-year intervals through 1998, and by hospitalizations and/or death certificates through 2010.

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