In this paper, an innovative idea of secure and energy efficient electrocardiogram steganography based on Discrete Wavelet Transform (DWT) is proposed, in which different important ECG data are steganographed with variable embedding strengths so that the reconstructed ECG signal quality is preserved. Incorporating the proposed Unequal Steganography Embedding (USE) with Unequal Error Protection (UEP), the proposed scheme further improves transmission performance in terms of ECG signal quality, ensures the confidentiality as well as reliability of a user's data, and makes the transmission more energy efficient. Simulation results demonstrate that USE attains very low distortion (WWPRD less than 0.45 %). Furthermore, high correlation between host and stego ECG and ECG data remains diagnosable after steganography. Based on our literature reviews, the reliability, robustness, and energy efficiency of this proposed method are unmatched in comparison with any other published methods.