Ketones, Muscle Metabolism, and SGLT2 Inhibitors - Protocol 1

Within 2 weeks after the screening visit, subjects return to the Research Institute (RII) at 7:00AM for a cardiac MRI on 3.0T MRI System (TIM, Trio, Siemens Medical Solution, Malvern, PA). Cardiac output (CO) is measured using velocity encoded phase contrast MRI. The patient lies in the MRI scanner, and the imaging plane is positioned perpendicular to the ascending aorta where blood flow can be measured accurately. The MRI scan is synchronized with the patient's heartbeats using ECG gating. Two types of images are collected: magnitude images, which provide anatomical reference, phase images, which encode the speed and direction of blood flow. The system multiplies velocity by the cross-sectional area of the vessel to calculate the volume of blood passing through the vessel at each moment. Integrating the flow values over the entire cardiac cycle, the system calculates the stroke volume. Cardiac Output = Stroke Volume × Heart Rate

A measurement, expressed as a percentage, of how much blood the left ventricle pumps out with each heartbeat. It's a key indicator of heart function and can help diagnose and track heart failure. A normal EF typically falls between 55% and 70%. Values below 40% are often considered indicative of heart failure.