A Study Testing a New Heart Scan Method to Improve Pacemaker Treatment for Heart Failure

Cardiac resynchronization therapy (CRT) is a device treatment for patients with heart failure which cannot be managed by medications alone. CRT can help the heart contract more efficiently and improve the pumping function. However, many patients do not benefit from this treatment. Therefore, a better selection tool will help us to determine the most suitable patients to receive this treatment. A new measure of pumping function of the heart called: first-phase ejection fraction or EF1 has been shown a good tool to select suitable patients for CRT. EF1 is a sensitive measurement of heart function and can be easily measured by echocardiography (an ultrasound heart scan). The purpose of this study is to examine whether this new measurement (EF1) can predict outcomes and response to CRT treatment.