Establishing a Non-invasive Method to Measure Your Heart's Performance

The purpose of the study is to evaluate a new way to examine cardiac function, using software developed at Caltech. The experimental device is software loaded on an iPhone. The iPhone is used to capture a pulse (waveform) by simply placing the iPhone lightly over the neck where the carotid pulse can be felt. In this study the information collected from the iPhone app is compared to cardiac function data obtained from the current gold standard for measuring cardiac function, cardiac magnetic resonance imaging (MRI). Subjects referred from cardiologists will also generally have echocardiography information available for comparison with the iPhone app. For the study, subjects will have completely non-invasive studies done in one setting: The iPhone app to capture the waveforms (over carotid and radial (wrist) arteries), tonometry (another non-invasive method using a modified stethoscope), standard pulse oximetry, followed by a 30 minute MRI examination of the heart. A second complete study will be done about 6 months after the first. The complete study session takes about 1.5 hours.