This paper presents a method for efficient coding at high spectral efficiency using parallel concatenated trellis coded modulation (PCTCM) with symbol interleaving. The constituent encoders are optimized for symbol-wise free distance, and each has an infinite symbol-wise impulse response. In many cases of practical interest, the optimal structure for these constituent encoders connects the memory elements in a single row. Simulation results show that the performance is as close as 0.5 dB to the constrained capacity.