Thyroid problems linked to irregular heart rhythm

November 28, 2012

People with an overactive thyroid gland (hyperthyroidism) carry a greater risk of developing irregular heart rhythm (known as atrial fibrillation) than those with normal thyroid function, finds a study published on BMJ today.

As such, the researchers suggest there should be an increased focus on atrial fibrillation in patients with raised thyroid function.

occurs when the thyroid gland makes too much (), causing many of the body's functions to speed up. About 1 in 100 women and 1 in 1,000 men develop hyperthyroidism at some stage of their life and it can happen at any age.

It is well known that overt hyperthyroidism is associated with atrial fibrillation, but it's still not clear whether milder (subclinical) hyperthyroidism has a similar effect. Data on the risk of atrial fibrillation in patients with an underactive thyroid (hypothyroidism) is also limited.

So a team of researchers in Denmark set out to examine the risk of atrial fibrillation in relation to the whole spectrum of in a large group of patients.

Using nationwide registries, they identified 586,460 patients who had consulted a general practitioner in Copenhagen from 2000 to 2010 and had a thyroid function blood test. This measures the amount of thyroid-stimulating hormone (TSH) circulating in the blood. In people with hyperthyroidism the level of TSH will usually be low, whereas in people with hypothyroidism the level of TSH will usually be high.

During an average five and a half years follow-up, 17,154 (3%) of patients had a diagnosis of a first atrial fibrillation, 53% of whom were women.

Compared to patients with normal thyroid function, the risk of atrial fibrillation increased with decreasing levels of thyroid-stimulating hormone. For example, patients with subclinical hyperthyroidism had a 30% increased risk of atrial fibrillation, while patients with high-normal had a 12% increased risk.

In contrast, hypothyroidism was associated with a lower risk of atrial fibrillation.

The authors stress that, although atrial fibrillation was closely associated with thyroid activity, they cannot prove a direct cause-and-effect relationship. However, they say their study is "the first to assess the association between the whole spectrum of thyroid disease and the subsequent risk of atrial fibrillation in a population of primary care patients."

They conclude: "These results support long term screening for in patients with thyroid disease."

Explore further: Thyroid condition linked to heart problems: study

Related Stories

Thyroid condition linked to heart problems: study

April 25, 2012
(HealthDay) -- New evidence suggests that a type of overactive thyroid condition appears to boost the risk of heart problems, especially atrial fibrillation (a form of irregular heartbeat) and premature death.

Elderly may be more likely to die if they have subclinical hyperthyroidism

June 6, 2011
A common hormone abnormality in older adults -- a mild form of overactive thyroid called subclinical hyperthyroidism -- is linked to a much higher risk of dying, a new study finds. The results will be presented Sunday at ...

Rheumatoid arthritis linked to irregular heart rhythm

March 8, 2012
People with rheumatoid arthritis are at a greater risk of irregular heart rhythm (known as atrial fibrillation) and stroke compared with the general population, finds a study published in the British Medical Journal today.

Atrial fibrillation associated with increased risk of death and cardiovascular events in women

May 24, 2011
Researchers at Brigham and Women's Hospital (BWH) have found that among women who are mostly healthy, those diagnosed with atrial fibrillation have an increased risk of death when compared to women without atrial fibrillation. ...

Atrial arrhythmias detected by pacemakers increase risk of stroke

January 11, 2012
An irregular heartbeat that you don't even feel but can be picked up by a pacemaker is associated with a significantly increased risk of stroke, says a new McMaster University study.

BUSM: Severe sepsis, new-onset AF associated with increased risk of hospital stroke, death

November 13, 2011
A recent study led by researchers at Boston University School of Medicine (BUSM) shows an increased risk of stroke and mortality among patients diagnosed with severe sepsis and new-onset atrial fibrillation (AF) during hospitalization.

Recommended for you

Researchers developing new tool to distinguish between viral, bacterial infections

July 28, 2017
Antibiotics are lifesaving drugs, but overuse is leading to one of the world's most pressing health threats: antibiotic resistance. Researchers at the University of Rochester Medical Center are developing a tool to help physicians ...

Finish your antibiotics course? Maybe not, experts say

July 27, 2017
British disease experts on Thursday suggested doing away with the "incorrect" advice to always finish a course of antibiotics, saying the approach was fuelling the spread of drug resistance.

Co-infection with two common gut pathogens worsens malnutrition in mice

July 27, 2017
Two gut pathogens commonly found in malnourished children combine to worsen malnutrition and impair growth in laboratory mice, according to new research published in PLOS Pathogens.

Phase 3 trial confirms superiority of tocilizumab to steroids for giant cell arteritis

July 26, 2017
A phase 3 clinical trial has confirmed that regular treatment with tocilizumab, an inhibitor of interleukin-6, successfully reduced both symptoms of and the need for high-dose steroid treatment for giant cell arteritis, the ...

A large-scale 'germ trap' solution for hospitals

July 26, 2017
When an infectious airborne illness strikes, some hospitals use negative pressure rooms to isolate and treat patients. These rooms use ventilation controls to keep germ-filled air contained rather than letting it circulate ...

Researchers report new system to study chronic hepatitis B

July 25, 2017
Scientists from Princeton University's Department of Molecular Biology have successfully tested a cell-culture system that will allow researchers to perform laboratory-based studies of long-term hepatitis B virus (HBV) infections. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.