A noise-suppressing electrocardiograph (ECG) adapter having a first end, a second end, and a noise-suppression element is presented, together with an ECG noise-suppressing system and related methods. In an embodiment, the noise-suppressing ECG adapter includes a housing having at least one first connector disposed at a first end of the housing adapted to electrically couple with an ECG lead set, and at least one second connector adapted for coupling to an input of an ECG device. The adapter includes a noise suppression element. The noise suppression element includes a ferromagnetic element having an opening defined therein. In an embodiment the noise suppression element is internal to the adapter. In another embodiment, the noise suppression element is tethered externally to the adapter and configured to clamp around at least a portion of an ECG leadwire.