The function of the heartstrings is that of an information transmitter. The information transmitted is the increase and decrease of tension from the papillary muscles to the three valve cusps of the right atrioventricular (AV) valve. This information causes the valve cusps to open and close.
The heartstrings, also called the chordae tendinese, are tendons. These tendons have a string-like appearance, which explains their alternative name of heartstrings.
The right AV valve is the tricuspid by another name. The tricuspid is a valve that separates the right ventricle and the right atrium, and it allows deoxygenated blood to flow from the right atrium to the right ventricle.