Abbreviations legend: HT – arterial hypertension, DM – diabetes
mellitus, CKD – chronic kidney disease, IHD – ischemic heart disease,
HF – heart failure.
In one-way analysis it turned out that the duration of the P wave has a
statistically significant relationship with the diagnosis (AF = 0, CV =
1) as well as hypertension and chronic kidney disease. Due to the
possibility of a strong correlation between these parameters, a
multifactorial (progressive stepwise) regression analysis was performed.
As a result, the following model was obtained:
Mean P wave duration = 120.3 + 15.8 * CV + 20.2 *CKD + 9.0 * HT ± 18.5
The factors (stimulants) of longer duration of the P wave turned out to
be: belonging to the CV group, the presence of chronic kidney disease
and hypertension. All structural parameters of the model are
statistically significant (p <0.0001): F (3, 115) = 12.6; p
<0.001.
The duration of the P wave can be regarded as a parameter enabling
classification of patients into the CV or AF group. Analysis of the ROC
curve (Receiver Operating Characteristic curve) showed that for the
cut-off value P wave duration> 148 ms the diagnostic
sensitivity of the test was 67.7%, specificity 66.7% and the area
under the ROC curve, AUC = 0.700. This is not a sensational result, but
the lower confidence limit for AUC is 0.609 and is greater than 0.5 -
this indicates the diagnostic usefulness of this parameter. According to
the literature, if the AUC is in the range of 0.7 to 0.8, the classifier
is satisfactory. The graphic presentation was depicted in Figure 5.