title: Filter ecg signal with wavelet
body: <p>I'm working with an ECG signal and I want to delete the drift noise.
  In Matlab it works fine this code:</p>
  
  <pre><code>[c, l]=wavedec(ecgsignal,8,'coif5'); 
  a9=wrcoef('a',c,l,'coif5',8);
  </code></pre>
  
  <p>where ecgsignal is the original signal with noise and a9 is the filtered signal.
  I'm trying to made the same in python with this code:</p>
  
  <pre><code>coeffs=pywt.wavedec(ecgsignal,'coif5', level=8)
  renc=pywt.waverec(coeffs, 'coif5')
  </code></pre>
  
  <p>but the reconstructed signal, renc, has the noise.
  Can someone help me to understand what is not correct? I use the wrong commands of the PyWavelet library?</p>