Tatyana Remley — an equestrian who pleaded guilty to plotting to have her estranged husband murdered — committed suicide last week … and TMZ has video of responders attempting to save her life.

Watch the just-released video … you can see police huddled over her body while one performs rhythmic compressions on Tatyana’s lifeless chest last Thursday. Her body is lying on a walkway adjacent to what seems to be the outdoor seating of a restaurant.

Passersby gawk at the scene as police try valiantly to save her life, but to no avail. TMZ can confirm Tatyana died of a self-inflicted gunshot wound to the head outside a San Diego bar.

People reports, Mark said Tatyana offered a mutual friend $2 million to kill him, but the friend declined and went to the police. The tip launched the sting operation, which eventually nailed her.

Tatyana served time after being sentenced to 3 years and 8 months in prison.