How can I remove Baseline wander from ECG signal using cubic Spline method?

could you please help me in writing a code to remove baseline wander from ecg signal using Spline method. I know that the best way is to locate knots in PR segment ( 1 knot for each beat) and then using spline interpolation to connect these points. in this way the baseline will be estimated. but I cannot write MATLAB code to do this.