Nov. 9, 2006 Difficulties in the heart's ability to fill with blood are common causes of heart failure -- and appear to be as significant in placing a heart patient at risk of death as are deficiencies in the heart's ability to pump blood, new research from Mayo Clinic shows.
As a result of these findings, heart failure -- a leading and urgent public health problem in the United States and elsewhere -- can likely be managed more effectively to identify and treat those at highest risk of dying from heart disease, the Mayo Clinic researchers say. Their report appears in the current Journal of the American Medical Association.
Significance of the Mayo Study
The Mayo study is the first large, community-based study to clarify the role of filling deficiencies -- known as diastolic dysfunction -- in heart failure. In the past, literature shows that heart failure is too often conceived as a pumping problem, known as systolic dysfunction. Systolic dysfunction is an inability to effectively move blood out of the heart. But to pump effectively, the heart also has to have a healthy filling phase.
"Our findings help support the growing understanding that heart failure is a disease with several faces -- and that's the first step to improving treatment," explains Mayo Clinic cardiologist Veronique Roger, M.D., M.P.H., the study's lead author. "Specifically, our results highlight the diverse nature of heart failure as a syndrome in which defects in both the pumping and the filling phases need to be considered for optimal patient management. It is not a case of one or the other."
To clarify the role of diastolic dysfunction in heart failure, Dr. Roger and colleagues recruited 556 patients with heart failure in Olmsted County, Minn., from 2003 to 2005. They tested both heart-pumping and heart-filling functions with Doppler echocardiography. This technique is a form of ultrasound based on the Doppler shift variation in sound wave frequency to determine normal and abnormal blood flow status in the heart. Results showed that of the 556 heart patients, 44 percent had filling abnormalities that had never before been detected. This means that a significant number of patients' heart problems had not been adequately described because the prevailing methods tested only for pumping problems -- not for filling problems. The researchers conclude that this finding suggests filling problems are frequently undiagnosed. To adequately evaluate most patients with heart failure, using tests that can evaluate filling problems is essential and can likely improve heart patient care.
Implications and Applications
The Mayo data suggest that physicians should test for abnormalities in the heart's filling phase, just as they are vigilant about detecting abnormalities in the pumping phase. Wider use of Doppler echocardiography to detect diastolic dysfunction could improve risk stratification and management of heart failure patients. While Doppler echocardiography is common practice, this testing to detect filling problems is not uniformly performed everywhere.
"Our results suggest that if you are a patient who has been diagnosed with heart failure, you should be evaluated for filling abnormalities," Dr. Roger says. "Whether the primary problem is a pumping or a filling defect, both can have a negative impact on survival and need to be managed."
Summary: Key Findings At A Glance
The Mayo Clinic study is important because it:
- clarifies long-standing confusion over the role of diastolic dysfunction in heart failure. In the past, heart failure has generally been conceived as systolic dysfunction -- a pumping problem, with uncertainties about the role of filling deficiencies.
- is the first community approach to the assessment of the role of diastolic dysfunction in heart failure. It therefore presents a more accurate portrait of heart failure risk in the general population, not just in a heart specialist's practice or hospital, as referral studies have done.
- expands the concept of what heart failure is: a syndrome encompassing both filling and pumping phases, with multiple, diverse, causes -- and, therefore, multiple paths to treatment.
- underscores the importance of new strategies to evaluate heart patients -- especially those whose pumping errors cannot be detected. By newly documenting the prevalence and risk of diastolic dysfunction in heart failure patients who show no signs of systolic dysfunction, results support wider use of Doppler echocardiography to detect diastolic dysfunction and improve treatment.
Collaboration and Support
Other Mayo Clinic researchers include: Francesca Bursi, M.D., M.Sc.; Susan Weston, M.S.; Margaret Redfield, M.D.; Steven Jacobsen, M.D., Ph.D.; Serguei Pakhomov, Ph.D.; Vuyisile Nkomo, M.D.; and Ryan Meverden. Their work was supported by grants from the U.S. Public Health Service, the National Institutes of Health and the American Heart Association.
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