This paper presents an adaptive coherent averaging structure capable of removing broad-band interference from the electrocardiogram (ECG) while preserving the morphological features of the signal. The proposed structure improves the signal-to-noise ratio (SNR) of the adaptive line enhancer (ALE) while maintaining robustness to quasi-periodic signals. The least mean-square (LMS) and recursive least-square (RLS) adaptive algorithms are implemented. Analysis and comparison of the results is provided, leading to an optimized hybrid implementation. The cascade nature of the proposed structure is both scalable and suitable for implementation in real-time hardware.