A method for producing an ECG-triggered retrospective color-flow ultrasound image comprises generating ultrasound, transmitting the ultrasound into a subject at a first location, wherein a first reference point of an ECG signal taken from the subject triggers the ultrasound transmission, receiving ultrasound reflected from the subject at the first location, transmitting the ultrasound into the subject at a second location, wherein a second reference point of an ECG signal taken from the subject triggers the ultrasound transmission receiving ultrasound reflected from the subject at the second location, processing the received ultrasound to form ultrasound color traces, and reconstructing the ultrasound color traces to form the ultrasound image.