Theory of the #P_wave_ detection
The algorithm first finds the  the possible positive and negative wave peaks
based on zero transition searching, then validates them with comparing
to reference P waves.

The P wave detection needs high amplitude resolution. This value is better,
than 0.6 uV / bit in the Cardiospy system.  With this resolution and
the effective filter system which uses wavelet transformation,
the Cardiospy system is able to detect P waves less than 50 uV of amplitude. 

Validation of the P wave detector
The validation is carried out on 10 pcs 12 channel and 10 pcs 3 channel ECG
reference records. The reference records include the P wave  annotation.  12
of the 20 records are taken from the MitBih database, 8 records are
taken from the Labtech database (30000 – 30007). 
12 ch records
s0014lre, s0292lre, s0302lre, s0331lre, s0364lre, s0422_re, s0431_re,
s0437_re, s0549_re, s0550_re3 ch records

mgh001, mgh007, 30000, 30001, 30002, 30003, 30004, 30005, 30006, 30007Validation result:Sensitivity:                       95.42%Positive predictivity:         97.16%