How can chose threshold for an ECG signal

[m_eh_62]

In R-detection algorithm I get to this signal and I want to eliminte the red marked segment.
how can i chose a threshold to eliminating the red marked section.

my signal source is:

 

[andre_luis]

m_eh_62,

When I worked with ECG signal, the way to detect peak, was not by threshold, but by derivative detection. The reason is that sometimes, the offset of the real life signal turn around 0v level.


+++

 

[m_eh_62]

m_eh_62,

When I worked with ECG signal, the way to detect peak, was not by threshold, but by derivative detection. The reason is that sometimes, the offset of the real life signal turn around 0v level.


+++

What do you mean "by derivate detection"?
Can you explain it?
thanks.