1. A system for monitoring a condition of a patient's heart, the system comprising: a hardware processor that is configured to: receive a plurality of images of a first wall of the patient's heart, the plurality including a first image captured at a time t 1 and a second image captured at a time t 2 ; determine, based on the plurality of images, a first characteristic of movement of at least a wall portion of the first wall during a time period spanning time t 1 and time t 2 , the first characteristic of movement being determined by using one or more image processing techniques, and the first characteristic of movement being based on at least one of: (i) a shape of the wall portion in the first image and a shape of the wall portion in the second image, and (ii) a location of the wall portion in the first image and a location of the wall portion in the second image; and output an indication of the first characteristic of movement.