Association of P-wave duration, dispersion, and terminal force in relation to P-wave axis among outpatients
Laxman Prajapat1, Vignendra Ariyarajah, Mary E Frisella
1Department of Medicine, Saint Vincent Hospital, Worcester, MA, USA.
Insights
P-wave duration (P-dur), P-wave dispersion (P-disp), and P-wave terminal force in lead V1 (PTFV1) show a significant tripartite association, especially within the normal P-wave axis range of 0 to +60 degrees. Evaluating these P-wave markers together offers optimal clinical assessment for cardiac impulse propagation.
Area of Science:
- Cardiology
- Electrocardiography
- Cardiac Electrophysiology
Background:
- P-wave duration (P-dur) and dispersion (P-disp) may reflect sinus cardiac impulse propagation abnormalities.
- The relationship between P-dur, P-disp, and P-wave terminal force in lead V1 (PTFV1) in relation to P-wave axis (P-axis) requires further study.
Purpose of the Study:
- To investigate the association between P-dur, P-disp, and PTFV1.
- To determine the significance of these P-wave characteristics in relation to the P-axis.
Main Methods:
- Analysis of 428 electrocardiograms (ECGs) from outpatients.
- Manual measurement of P-dur and P-disp to the nearest 10 ms.
- Assessment of PTFV1 positivity (> or = 40 mm2 terminal deflection) and P-axis (0 to +75 degrees).
Main Results:
- P-dur strongly associated with P-disp (P < 0.0001), though correlation was weak (r = 0.42).
- P-dur showed significance with P-axis within the normal range (0 to +60 degrees, P < 0.0001).
- PTFV1 (present in 47% of 380 ECGs) significantly associated with P-dur (P < 0.0001), P-disp (P < 0.0001), and P-axis (P = 0.002).
Conclusions:
- P-dur, P-disp, and PTFV1 exhibit a significant tripartite association.
- This association is particularly evident within the normal P-axis range (0 to +60 degrees).
- Clinical assessment benefits from evaluating these P-wave markers collectively in relation to the normal P-axis.
Background:
While P-wave duration (P-dur) and dispersion (P-disp) could both reflect fractionated and inhomogeneous propagation of sinus cardiac impulses, and may therefore be associated with each other, a clear relationship has not been extensively studied. We studied these markers as well as the significance of P-wave terminal force in lead V1 (PTFV1) in relation to the P-wave axis (P-axis).
Methods:
We appraised our previously studied sample of 500 consecutively numbered, otherwise unselected, electrocardiograms (ECGs) of outpatients from the University of Massachusetts, Worcester, Massachusetts, for the foregoing P-wave characteristics. P-disp, defined as the difference of the duration between the widest and narrowest P wave, and the greatest P-dur after a 12-lead ECG search, was measured manually to the nearest 10 ms. PTFV1 was considered positive when > or = 40 mm2 terminal deflection was present on biphasic P waves on lead V1. Normal P-axis was considered 0 degrees to +75 degrees by manually constructing the mean frontal plane electrical P-axis from standard limb leads.
Results:
After excluding those with atrial arrhythmias, paced rhythms, errors in lead placement, P waves with low amplitude or overall technically poor tracing, 428 ECGs formed our final sample. P-dur was strongly associated with P-disp (P < 0.0001), but the correlation remained weak (r = 0.42). Overall, P-dur was not significantly associated with P-axis but when divided into tertiles and quintiles, the significance was evident within the range of the normal P-axis, particularly 0 degrees to +60 degrees (P < 0.0001). In a subanalysis of 380 ECGs that had appreciable biphasic P waves on lead V1, PTFV1 was noted on 178 (47%) ECGs and was significantly associated with P-dur (P < 0.0001), P-disp (P < 0.0001), and P-axis (P = 002). When considering P-axis in tertiles and quintiles, P-dur was greater in patients with a positive PTFV1 and significant within the normal range of the P-axis, especially from 0 degrees to +60 degrees .
Conclusion:
P-dur, P-disp, and PTFV1 appear to share a significant tripartite association in relation to the normal P-axis, particularly when P-axis ranges 0 degrees to +60 degrees . Therefore, for optimal clinical assessment, these markers should be evaluated in relation to the normal P-axis.
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