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The question of the existence of low-frequency modes in accretion disks is reexamined through use of a recently developed formalism for treating adiabatic perturbations of rapidly rotating systems. It is argued that this formalism is more accurate than those used in other analyses. The present analysis includes a simple prescription for estimating nonbarotropic corrections, associated with nonadiabatic temperature gradients, to barotropic modes. It is found that in certain cases one-armed low-frequency modes do exist in the inner regions of disks, with frequencies much less than the rotation angular velocity. It is shown that modest nonadiabatic gradients have only small effects on the frequencies.
