This is an ultrasonogram of a massive pericardial effusion. IN A CAT!The piece de resistance of the piece de resistance is pulsus paradoxus! When they breathe in, their pulses decrease in height and width and when they breathe out their pulses return to baseline. This is very difficult to appreciate if they are very tachypnoeic but if their resp. rates are 30ish then you will usually have 6 beats per breath if their heart rates are 180. Pulsus paradoxus happens to a greater or lesser degree with all dogs in tamponade.