Symbolic analysis (SA) is usually applied for the assessment of cardiac control from spontaneous variability of heart period (HP). However, SA does not account for the amplitude of HP changes because patterns featuring small and large variations are included in the same class. The aim of this study is to propose an amplitude SA (ASA) approach accounting for pattern amplitudes. The adopted SA method was grounded on a uniform 6-bin quantization, on the construction of length-3 patterns and on their grouping into four families according to the number and sign of the variations between adjacent symbols. The percentages of patterns belonging to a given class were computed. ASA assessed the variance of the pattern over the original HPs and averaged it within each class. SA and ASA were applied during a pharmacological challenge inducing central sympathetic inhibition and vagal enhancement in 8 healthy male volunteers (age range: 25-46 yrs). We found that both SA and ASA suggest a shift toward vagal activation with a greater presence of patterns featuring fast changes and larger variations. Remarkably, SA and ASA indexes computed over the same class were found to be uncorrelated, thus suggesting that they can capture different features of the HP dynamics and complementary aspects of the cardiac control.