The P wave
Andrew R Houghton in Making Sense of the ECG, 2019
After determining the heart rate, rhythm and axis, examine each wave of the electrocardiogram (ECG) in turn, beginning with the P wave. Atrial depolarization is therefore normally so regular that it is easy to predict when the next P wave is going to appear. A lack of coordinated atrial depolarization occurs in atrial fibrillation, and this is the commonest reason for P waves to be truly absent from the ECG. Even in sinus tachycardia, at high heart rates the P waves may start to overlap with the T waves of the previous beats, making them hard to identify. The wave of depolarization normally spreads through the atria from the sinoatrial node to the atrioventricular node. The P wave becomes broad because the enlarged left atrium takes longer than normal to depolarize. Prolongation of P wave duration and also increased P wave dispersion have been identified as predictors of risk for the development of atrial fibrillation.
The P wave
Andrew R Houghton, David Gray in Making Sense of the ECG, 2014
The only normal circumstance in which the P wave rate is variable is sinus arrhythmia, which is usually only seen in patients below the age of 40 years. After determining the heart rate, rhythm and axis, examine each wave of the electrocardiogram (ECG), beginning with the P wave. There are two reasons why P waves may be absent from the ECG. The first is that there is no coordinated atrial depolarization so that P waves are not being formed. The second is that P waves are present, but are just not obvious. Search the ECG carefully for evidence of P waves before concluding that they are absent, as P waves will often be hidden by any rapid tachycardia. P waves can just be discerned as a small deflection immediately after the end of the QRS complexes in some leads.
Conduction impairment
Romeo J Vecht in ECG Diagnosis Made Easy, 2003
Sinus arrhythmia is normal in children. It is abnormal in adults but not indicative of specific pathology. The heart accelerates during inspira- tion and slows during expiration (ECG 90). Wandering pacemaker Wandering pacemaker is seen usually with sinus arrhythmia, with the same clinical significance. The sinus pacemaker may move location within the SA node from beat to beat. This shows up as a change in P wave size and PR interval.
Electrocardiographic diagnosis of left atrial enlargement in patients with mitral stenosis: the value of the P-wave area
Published in Acta Cardiologica, 2003
Chunlai Zeng, Tiemin Wei, Ruiying Zhao, Chunming Wang, Liping Chen, Lexin Wang
Objective — To investigate the value of the P-wave area in diagnosing left atrial enlargement in patients with mitral stenosis. Methods — We measured the P-wave area from lead II of a standard 12-lead ECG in 136 consecutive patients with mitral stenosis.We also measured the left atrial diameter with two-dimensional echocardiography. Results — Left atrial enlargement was identified in 120 (88.2%) patients. There was an excellent correlation between P-wave area and left atrial diameter in these patients (r = 0.739, p = 0.001). A P-wave area of ≥4 ms•mv had an 85.8% sensitivity and 93.7% specificity for left atrial enlargement. There was also a smaller but significant correlation between left atrial diameter and the total P-wave duration (r = 0.635, p < 0.01) or P-wave amplitude (r = 0.683, p
Increased P-wave dispersion a risk for atrial fibrillation in adolescents with anorexia nervosa
Published in Eating Disorders, 2016
İlker Ertuğrul, Sinem Akgül, Orhan Derman, Tevfik Karagöz, Nuray Kanbur
ABSTRACT Studies have shown that a prolonged P-wave dispersion is a risk factor for the development of atrial fibrillation. The aim of this study was to evaluate P-wave dispersion in adolescents with anorexia nervosa at diagnosis. We evaluated electrocardiographic findings, particularly the P-wave dispersion, at initial assessment in 47 adolescents with anorexia nervosa. Comparison of P-wave dispersion between adolescents with anorexia nervosa and controls showed a statistically significant higher P-wave dispersion in patients with anorexia nervosa (72 ± 16.3 msec) when compared to the control group (43.8 ± 9.5 msec). Percent of body weight lost, lower body mass index, and higher weight loss rate in the patients with anorexia nervosa had no effect on P-wave dispersion. Due to the fact that anorexia nervosa has a high mortality rate we believe that cardiac pathologies such as atrial fibrillation must also be considered in the medical evaluation.
Gaussian modeling of the P-wave morphology time course applied to anticipate paroxysmal atrial fibrillation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2015
Arturo Martínez, Raúl Alcaraz, José Joaquín Rieta
This paper introduces a new algorithm to quantify the P-wave morphology time course with the aim of anticipating as much as possible the onset of paroxysmal atrial fibrillation (PAF). The method is based on modeling each P-wave with a single Gaussian function and analyzing the extracted parameters variability over time. The selected Gaussian approaches are associated with the amplitude, peak timing, and width of the P-wave. In order to validate the algorithm, electrocardiogram segments 2 h preceding the onset of PAF episodes from 46 different patients were assessed. According to the expected intermittently disturbed atrial conduction before the onset of PAF, all the analyzed Gaussian metrics showed an increasing variability trend as the PAF onset approximated. Moreover, the Gaussian P-wave width reported a diagnostic accuracy around 80% to discern between healthy subjects, patients far from PAF, and patients less than 1 h close to a PAF episode. This discriminant power was similar to those provided by the most classical time-domain approach, i.e., the P-wave duration. However, this newly proposed parameter presents the advantage of being less sensitive to a precise delineation of the P-wave boundaries. Furthermore, the linear combination of both metrics improved the diagnostic accuracy up to 86.69%. In conclusion, morphological P-wave characterization provides additional information to the metrics based on P-wave timing.