To Better Treat Heart Failure By Paula Rasich Reviewed by Elizabeth Klodas, MD, FACC  March 11, 2009--Breakthroughs in understanding the complex way our heart can get damaged will lead to more effective treatments for heart failure.  Now a new review of research sheds light on a poorly understood type of heart failure called heart failure with normal ejection fraction (HFNEF).

Heart failure does not mean that the heart stops working.  Rather, heart failure refers to a group of disorders in which the heart is unable to circulate blood around effectively enough to meet the body’s needs. 

The “ejection fraction” is one measure of heart function, and refers to the percent of its contents that the heart pumps out with every heart beat.  A normal heart pumps out somewhere between 50 and 70% of its contents with every heart beat, so a normal ejection fraction is 50-70%.

Heart failure with normal ejection fraction (HFNEF) means that despite normal pumping function, the heart is still unable to meet the body’s needs.  HFNEF affects a large number of patients and is associated with a poor outcome, but treatment options are not well defined.

In an effort to characterize this diverse group of patients, and therefore help pave the way to more innovative treatment plans in the future, David M. Kaye, MD, PhD, a heart failure cardiologist at the Alfred Hospital in Melbourne, Australia and his colleague Micha T. Maeder, MD, examined more than fifteen years worth of medical data on patients with this unique disorder.

They found that at least half of heart failure patients have HFNEF and that these individuals can experience classic symptoms of heart failure such as dizziness, fatigue and shortness of breath, despite the presence of normal heart pumping function.  Patients with HFNEF tend to be older, more likely to be women, and more likely to have a history of high blood pressure.  Other potential contributors to this disorder appear to be obesity, coronary heart disease, sleep apnea, diabetes and kidney disease,  

“Previous clinical trials of different types of medicine aimed at improving survival in this group of patients have failed,” says Dr. Kaye. “In this type of heart failure, there are multiple contributory mechanisms that need to be looked at in each patient.”

One underlying mechanism is abnormal heart muscle relaxation.  Although heart muscle can contract normally and pump out blood, that same heart muscle may not be able to relax well enough to fill up with blood in anticipation of the next heart beat.     Although there are medications that can help correct that, they are often not the whole answer.  “Clinicians should consider contributing mechanisms like coronary artery disease, arrhythmias and obesity, and then build up an overall picture of the patient,” says Dr. Kaye.

How is HFNEF diagnosed?   A physical exam, blood tests, chest X-ray, and an electrocardiogram (ECG) are routinely performed.  In addition, an echocardiogram is frequently checked in patients who present with symptoms consistent with heart failure.   An echocardiogram is a comprehensive ultrasound evaluation of the heart, which can characterize heart pumping function, provide an assessment of the ejection fraction, heart muscle relaxation, and status of the heart valves. 

Several conditions appear to contribute to HFNEF, so prevention and aggressive management of these conditions may help reduce the number of patients who develop this type of heart failure.  Adherence to a healthy lifestyle, monitoring and treating high blood pressure, losing weight, and treating sleep apnea if present, may go a long way to avoiding HFNEF.

This review is published in the March 17, 2009 issue of the Journal of the American College of Cardiology.

Sources: 

Maeder MT and Kaye DM.  Heart Failure with Normal Left Ventricular Ejection Fraction. Journal of the American College of Cardiology, 2009.

David M. Kaye, MD, PhD, Heart Failure Cardiologist, Alfred Hospital, Melbourne, Australia.