Eyes May Be Window to Heart Risk

Atrial fibrillation risk may rise with damage in small blood vessels of retina and kidneys

(RxWiki News) High blood pressure can harm the vessels supplying blood to the retina. Small vessel changes in the eye — as well as the kidneys — may also signal increased likelihood of abnormal heart rhythm.

More than 2.5 million American adults have atrial fibrillation (AFib), the most common sustained irregular heartbeat (or arrhythmia). AFib raises a person’s risk for having a stroke or heart failure.

Scientists recently discovered that if the small blood vessels of the retina (part of the eye) and kidneys become damaged, it could signal a greater likelihood for getting AFib.

"See a doctor regularly to keep track of your heart health."

Sunil Agarwal, MD, a general internal medicine fellow at Johns Hopkins Medicine in Baltimore, led this research following 10,009 middle-aged people for an average 13.6 years. Participants were from the Atherosclerosis Risk in Communities Study (ARIC).

Dr. Agarwal and his team evaluated the rate that atrial fibrillation developed in these individuals in terms of person-years (a measurement combining the number of persons and their time contribution in a study).

AFib causes the top chambers of the heart (atria) to flutter (fibrillate) as fast as 300 to 400 times per minute, instead of the normal 60 to 80 times a minute. People with AFib are five times more likely to have a stroke, according to the National Stroke Association.

Dr. Agarwal and colleagues observed that 7.1 percent of participants had retinopathy (both retinal hemorrhage and micro-aneurysms where blood vessels bleed) and 7.2 percent had micro-albuminuria (a condition of vessel damage in the kidneys, allowing tiny amounts of protein to be released into their urine).

These researchers found that those who had no retina or kidney changes had the fewest incidences of AFib at 5.7 per 1,000 person-years.

Among those with small vessel damage in the retina, such as micro-bleeds or micro-aneurysms, there were 8.9 incidences per 1,000 person-years.

Those who had micro-albuminuria had almost three times the rate of AFib compared to those who had no retina or kidney harm. Their rate of AFib was 16.8 incidences per 1,000 person-years.

Those with both acute or persistent damage to the retina (retinopathy) and micro-albuminuria had an AFib rate of 24.4 incidences per 1,000 person-years.

Dr. Agarwal told dailyRx News, “Several factors such as non-specific inflammation, high glucose levels, and high blood pressure affect small vessels in multiple organ systems. We are able to detect micro-vessel changes in eyes by imaging and in the kidneys by checking urine for leakage of proteins and kidney function. These changes in other organ systems may correlate with micro-vessel damage in the heart too, and this remains to be studied.”

He added that micro-vessel damage in the heart may cause difficultly for the heart to relax (diastolic dysfunction) and also reduce its pumping capacity. This micro-vessel damage, if occurring in the upper chambers of the heart, may lead to changes in both electrical and mechanical nature of tissue of atria thus leading to atrial fibrillation, according Dr. Agarwal.

“Whether micro-vessel changes in the eyes are related to micro-vessel changes in the coronaries needs study,” he told dailyRx News. “Whether few available treatments such as statin and ACE inhibitors known to prevent or reverse some of the microvascular changes are useful in reducing the risk of [AFib] in individuals without traditional indication remains unclear and needs to be studied.”

"This is another observational study demonstrating the ever mounting evidence that uncontrolled high blood pressure leads to a significant increase in long term cardiovascular complications. This study demonstrates patients with microvascular damage in the eye, kidney or both are two, three, and four times more likely to develop atrial fibrillation and increased risk of stroke," David Brown, MD, an interventional cardiologist at The Heart Hospital Baylor Plano where he is director of interventional cardiology and co-director of cardiovascular research and the structural heart program, told dailyRx News.

Dr. Brown continued with, "Individuals with any indication of or tendency towards high blood pressure should clearly have regular blood-pressure checks."

This study was presented November 18 at American Heart Association's Scientific Sessions 2013. The ARIC study is funded by the National Heart, Lung, and Blood Institute; National Institutes of Health.

Review Date: 
November 17, 2013