Screening for Asymptomatic Heart Failure

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The summary below is from the full report titled "The Epidemiology of ‘Asymptomatic’ Left Ventricular Dysfunction: Implications for Screening." It is in the 3 June 2003 issue of Annals of Internal Medicine (volume 138, pages 907-916). The authors are T.J. Wang, D. Levy, E.J. Benjamin, and R.S. Vasan.

What is the problem and what is known about it so far?

Congestive heart failure (CHF), a common, serious condition that occurs when the left side of the heart can't pump enough blood to the body, is a progressive disorder. Typically, CHF occurs when the lower chamber on the left side of the heart (left ventricle) does not fill or empty blood properly. People with CHF have symptoms such as shortness of breath, swelling of the legs, and tiredness. Before developing symptoms from CHF, many people have abnormal left ventricles that don't empty well. This condition is called asymptomatic left ventricular systolic dysfunction (LVSD).

Asymptomatic LVSD is a common precursor to CHF that often goes unnoticed. Doctors can diagnose asymptomatic LVSD with a test that uses sound waves to take pictures of the heart (echocardiography). They can also treat the disorder with drugs (angiotensin-converting enzyme inhibitors) that prevent progression of heart failure and improve survival. But whether and who doctors should routinely screen for asymptomatic LVSD is unclear.

Why did the authors do this review?

To see whether research evidence shows that routine screening for asymptomatic LVSD improves outcomes and prevents CHF.

How did the authors do this review?

They gathered published scientific studies on asymptomatic LVSD and analyzed them for information on prevalence, course, diagnosis, treatment, and outcomes.

What did the authors find?

Asymptomatic LVSD is at least as common as symptomatic CHF. They confirmed that people with asymptomatic LVSD are at an increased risk for heart failure and death. They did not find much information about what happens to people with asymptomatic ventricular dysfunction of different degrees of severity (from mild to severe). They noted that the standard test for diagnosing LVSD (echocardiography) was expensive, but found no good studies supporting simpler and less expensive ways to screen for LVSD. Some patients with asymptomatic LVSD improved with angiotensin-converting enzyme inhibitor treatment in clinical trials, but the evidence didn't show whether all people with LVSD (such as those with mild forms of the condition) should be treated and whether other agents may be effective. So, although the authors found hints that detection of asymptomatic LVSD could lead to effective treatment, too many pieces of evidence were missing for them to draw a strong conclusion about screening.

What are the implications of this review?

We need to learn more about the early identification and treatment of particular patients with asymptomatic LVSD before recommending routine screening for this disorder.