  Using an exactly solvable model of the Wigner-Weisskopf atom it is shown that
an unstable quantum state cannot be recovered completely by the procedure
involving detection of the decay products followed by creation of the time
reversed decay products state, as proposed in \cite{Son}. The universal lower
bound on the recovery error is approximately equal to $5% $ of the \emph{error
per cycle} - the dimensionless parameter characterizing decay process in the
Markovian approximation. This result has consequences for the efficiency of
quantum error correction procedures which are based on syndrome measurements
and corrective operations.
