  The orbital periods of most eclipsing cataclysmic binaries are not undergoing
linear secular decreases of order a few parts per billion as expected from
simple theory. Instead, they show several parts per million increases and
decreases on timescales of years to decades, ascribed to magnetic effects in
their donors, triple companions, or both. To directly test the triple companion
hypothesis, we carried out a speckle imaging survey of six of the nearest and
brightest cataclysmic variables. We found no main sequence companions earlier
than spectral types M4V in the separation range 0.02" - 1.2", corresponding to
projected linear separations of 2 - 100 AU, and periods of 3 - 1000 years. We
conclude that main sequence triple companions to CVs are not very common, but
cannot rule out the presence of the faintest M dwarfs or close brown dwarf
companions.
