Test Reveals New Aspects of Heart Disorder

By Paula Rasich
Reviewed by Elizabeth Klodas, MD, FACC

(CardioSmart) August 11, 2008--New research suggests that a technique called cardiac magnetic resonance imaging (MRI) may predict risk of death associated with hypertrophic cardiomyopathy (HCM), a rare condition characterized by an abnormally thickened heart muscle.

In a multicenter trial, a team of international researchers led by Iacopo Olivotto, MD, of the Regional Referral Center for Myocardial Diseases and Radiology Unit in Florence, Italy, compared 264 men and women diagnosed with HCM by echocardiogram to 606 healthy control subjects. All study participants underwent cardiac MRI, a test that creates a detailed image of the heart.

The results of the cardiac MRI showed that the size of the left ventricle (the heart’s main pumping chamber) was normal in 21% of the HCM patients and in another 16% was only slightly increased in weight. The study authors theorize that there are different levels of heart disease risk associated with HCM that are currently unrecognized.

Up to now, a cardiac ultrasound or echocardiogram has been the standard method for diagnosing the disorder. While that technique accurately measures increased thickness of the ventricular wall at one site, wall thickness varies throughout the chamber. The overall weight, indicating how enlarged the ventricle has become, is another feature of this condition that can more accurately be assessed by cardiac MRI.

During about three years of follow up, 10 HCM-related deaths occurred. And researchers found that the weight of the heart chamber turned out to be a more powerful predictor of cardiac death than wall thickness. The researchers conclude that cardiac MRI provides additional information to help doctors pinpoint who may be at high risk for sudden death or heart failure.

“This study is a step forward in that it changes the paradigm of whom to treat aggressively and how to identify additional patients for aggressive treatment that weren’t recognized previously,” says Nathaniel Reichek, MD, director of research and education at St. Francis Hospital in Roslyn, New York. “It’s also a new tool for identifying lower risk patients who don’t have an increase in left ventricle mass or don’t have super high wall thickness.”

The study groups were not matched by age and gender. Further research is needed to confirm these results.

Sources:

Olivotto I. et al. Assessment and Significance of Left Ventricular Mass by Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy. Journal of the American College of Cardiology, August 2008.

Nathaniel Reichek, MD, Director of Research and Education at St. Francis Hospital, Roslyn, New York.

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