Heart failure is a progressive disease that decreases the pumping action of the heart. This may cause a backup of fluid in the heart and may result in heart beat changes. Using a medical device like a pacemaker or a defibrillator can help the heart to pump in regular beats. However, not all patients do better with a device. Currently, there is not a way to identify which patients will benefit from the device. The purpose of this study is to determine if using medical tests, Echocardiogram, can help in predicting which patients will improve. The types of patients needed for this study are those who have been diagnosed with moderate or severe heart failure.