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; 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; and displaying the acquired images of the sequence as a three-dimensional, volumetric image.