During a transthoracic echocardiogram, you will change into a medical gown and lie down on an examination table or bed at your doctor’s office or hospital. The technician will apply adhesive patches with electrodes to your body that measure your heart’s electrical currents. Before using the transducer, the ultrasound technician will spread a gel over the heart area that improves sound wave emission. They will then move the transducer back and forth over the chest to generate a live image of your heart.