  We address the problem of integrability of the sub-Riemannian mean curvature
of an embedded hypersurface around isolated characteristic points. The main
contribution of this note is the introduction of a concept of mildly degenerate
characteristic point for a smooth surface of the Heisenberg group, in a
neighborhood of which the sub-Riemannian mean curvature is integrable (with
respect to the perimeter measure induced by the Euclidean structure). As a
consequence we partially answer to a question posed by Danielli-Garofalo-Nhieu
in [Danielli D., Garofalo N., Nhieu D.M., Proc. Amer. Math. Soc., 2012],
proving that the mean curvature of a real-analytic surface with discrete
characteristic set is locally integrable.
