Is my understanding about the ECG waveform is correct or not

Question

I need to design an amplifier for an ECG signal.The signal specification is given below.

BW = 0.47Hz..40Hz (-3dB) – Limited by the system

Signal amplitude max. 10mVPV (peak-to-valley), DC offset max ±300mV

Sample rate = 256Hz

Assume the noise level of the system (referred to input) = 50uVPV (peak-to-valley)

I have some confusion about interpreting the amplitude.

My understanding is given in the below figure.

May I know my interpretation of the amplitude specification

(Signal amplitude max. 10mVPV (peak-to-valley), DC offset max ±300mV) is correct or not.

What you mean by peak to valley

Answer 1

May I know my interpretation [...] is correct or not.

It is. The ECG signal will "surf" along a low frequency signal (see example below, image from myself, with two leads). The specs refer to it as "DC Offset" but you will also find references to "baseline wander".

What you mean by peak to valley

Similar to peak-to-peak, as correctly shown in your pictures, but since both limits may be positive or both negative, it's a way to avoid this confusion.