  Eccentric binaries known as heartbeat stars experience strong dynamical tides
as the stars pass through periastron, providing a laboratory to study tidal
interactions. We measure the rotation periods of 24 heartbeat systems, using
the Kepler light curves to identify rotation peaks in the Fourier transform.
Where possible, we compare the rotation period to the pseudosynchronization
period derived by Hut 1981. Few of our heartbeat stars are pseudosynchronized
with the orbital period. For four systems, we were able to identify two sets of
rotation peaks, which we interpret as the rotation from both stars in the
binary. The majority of the systems have a rotation period that is
approximately 3/2 times the pseudosynchronization period predicted by Hut 1981,
suggesting that other physical mechanisms influence the stars' rotation, or
that stars typically reach tidal spin equilibrium at a rotation period slightly
longer than predicted.
