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_re

3 ch records

mgh001, mgh007, 30000, 30001, 30002, 30003, 30004, 30005, 30006, 30007

Validation result:

Sensitivity:                       95.42%

Positive predictivity:         97.16%