1. A method for acquiring two-dimensional ultrasound images of a heart for display in a three-dimensional orientation, the heart having a heart cycle, the method comprising: locating an instrument in the heart, the instrument having an axis and carrying a transducer; establishing a three-dimensional spatial coordinate system in the heart; acquiring, with the transducer, a sequence of images during a single heart cycle, wherein each image of the sequence is acquired at a different rotational orientation of the transducer about the axis; acquiring positional data of the transducer at the time an image in the sequence is acquired; and associating the positional data with the image.