PET Scan to Determine Areas of Blood Flow and Activity in the Hearts of Patients With Heart Disease Taking Beta-Blockers

The human heart is divided into four chambers. One of the four chambers, the left ventricle, is the chamber mainly responsible for pumping blood out of the heart into the circulation. Diseases of the heart like congestive heart failure (CHF), can cause the left ventricle to function improperly. Medications called beta-blockers appear to reverse the abnormalities in the left ventricle and frequently improve the function of the left ventricle in patients with different kinds of heart disease. How beta-blockers improve left ventricle function is unknown. One possible reason for improved function of the left ventricle with beta-blockers is improved blood flow to the heart muscle. When a region of the heart is active, it uses more fuel in the form of oxygen and sugar (glucose). As heart activity increases, blood flow to and from the area of activity increases also. Knowing these facts, researchers can use radioactive sugar (glucose) and positron emission tomography (PET) scans to observe what areas of the heart are receiving more blood flow. In this study researchers plan to measure glucose use in heart muscle and blood flow to the heart muscle in patients with CHF taking beta-blockers.