Common Cause of Dizziness May Spell Heart Trouble

Blood Pressure That Falls When You Stand May Be a Clue to Coming Heart Failure

By Brenda Goodman, MA
WebMD Health News

Reviewed by Laura J. Martin, MD

March 19, 2012 -- Blood pressure that drops when a person stands up may signal a higher risk for heart failure, a new study shows.

If further research supports the study's findings, a simple test that measures blood pressure change as a person gets to their feet may one day help doctors spot heart failure early, when it is most manageable.

The study followed more than 12,000 middle-aged adults for nearly two decades.

At the start of the study, researchers measured blood pressure while people were lying down and then several times over a two-minute period after they stood.

"If the top number, the systolic number, fell by 20 or more points, or the bottom number, the diastolic blood pressure, fell by 10 or more points, then it was defined as orthostatic hypotension," says Christine D. Jones, MD, an internist and resident in preventive medicine at the University of North Carolina at Chapel Hill.

In orthostatic hypotension, the blood pressure drops when the body is in an upright standing position, as compared to a reclining position. Sometimes the sudden dip causes a brief dizzy spell or head rush. In severe cases it may cause a person to faint.

"Sometimes people can have it and not feel a thing," Jones says.

Dropping Blood Pressure and Heart Failure

About 600 people had the telltale blood pressure shift at the start of the study.

Researchers found that those with orthostatic hypotension were about 50% more likely than those who didn't experience the changes to go on to develop heart failure.

Some of that extra risk appeared to be explained by high blood pressure.

People with orthostatic hypotension were also more likely to have high blood pressure, which is known to contribute to heart failure.

But when researchers excluded people with high blood pressure from their analysis, those whose blood pressure dropped when they stood were still 34% more likely to develop heart failure.

In heart failure, the heart loses its ability to pump blood effectively to the rest of the body. Medications and lifestyle changes can help control the condition if it's spotted early.

The risk appeared to be highest for younger adults. Those who were younger than 55 when they were diagnosed with the positional change in blood pressure were nearly twice as likely as those with steady blood pressure to go on to develop heart failure.

Researchers caution that their study can only show associations. It doesn't prove that falling blood pressures cause heart failure or even explain how the two problems may be linked.

What's most likely, they think, is that a common disease process, like atherosclerosis, which causes arteries to become hard and stiff, may be behind both.

When arteries harden, they can't contract as easily to raise blood pressure. Stiff arteries around the heart muscle can weaken its ability to pump.

"Maybe this is an [indicator] of early atherosclerotic disease," Jones says.

The study is published in the journal Hypertension.

Advice to Patients

Experts who were not involved in the research say the findings were interesting but preliminary.

"I don't think that everybody who gets lightheaded or dizzy occasionally in their life should be concerned that they are going to get heart failure," says David Frid, MD, a cardiologist at Cleveland Clinic in Ohio.

Rather, he says people who feel dizzy frequently or nearly every time they stand might want to mention the problem to their doctors.

"Maybe if they have a lot of risk factors for [heart] disease, but haven't shown any true disease, maybe this is a sign that we need to evaluate it further and be more aggressive in managing their risk factors," Frid says.

Those risk factors might include high blood pressure, diabetes, high cholesterol, or a family history of heart disease.

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SOURCES: Jones, C. Hypertension, March 19, 2012.News release, American Heart Association. Christine D. Jones, MD, internist and resident in preventive medicine, University of North Carolina at Chapel Hill. David Frid, MD, staff cardiologist, Cleveland Clinic, Ohio.

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