P wave analysis indices in young healthy men: data from the digital electrocardiographic study in Hellenic Air Force Servicemen (DEHAS)

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

P-wave indices: derivation of reference values from the Framingham Heart Study

BACKGROUND

P-wave indices, an electrocardiographic phenotype reflecting atrial electrophysiology and morphology, may be altered in multiple disease states or by cardiovascular risk factors. Reference values for P-wave indices, providing cut points for their classification and interpretation, have not yet been established and are essential toward facilitating clinical application and comparison between studies.

METHODS

We randomly selected 20 men and 20 women from 10-year age intervals between <25 years to 76-85 years from the Framingham Heart Study Original and Offspring Cohorts, excluding subjects with prevalent cardiovascular disease, hypertension, diabetes or obesity. The total included 295 subjects; eligibility in women >75 years was limited by exclusion criteria. We used a digital measurement technique with demonstrated intrarater reproducibility to determine P-wave indices. P-wave indices examined included the maximum, mean, lead II and PR durations, dispersion, and the standard deviation of duration.

RESULTS

All P-wave indices were significantly (P < 0.0001) correlated with advancing age. Means of all P-wave indices were lower in women as compared to men. PR-interval duration was strongly correlated with maximum, mean, and lead II mean P-wave durations. In multivariable models adjusting for significant anthropometric and clinical associations risk factors, significant differences persisted by age and sex in P-wave indices.

CONCLUSIONS

In our healthy sample without cardiovascular disease, hypertension, diabetes, or obesity, men and older subjects had longer mean P-wave indices. Our description of P-wave indices establishes reference values for future comparative studies and facilitates the classification of P-wave indices.

P-wave indices, distribution and quality control assessment (from the Framingham Heart Study)

BACKGROUND

P-wave indices of maximum P-wave duration and P-wave dispersion have been examined in a broad array of cardiovascular and noncardiovascular disease states. The P-wave indices literature has been highly heterogeneous in measurement methodologies, described quality control metrics, and distribution of values. We therefore sought to determine the reproducibility of P-wave indices in a community-based cohort.

METHODS

P-wave indices were measured in sequential subjects enrolled in the Framingham Heart Study. Electrocardiograms were obtained at the 11th biennial visit of the Original Cohort (n = 250) and the initial visit of the Offspring Cohort (n = 252). We determined the mean P-wave durations, interlead correlations, and P-wave indices. We then chose 20 ECGs, 10 from each cohort, and assessed intrarater and interrater variability.

RESULTS

The maximum P-wave duration ranged from 71 to 162 ms with mean of 112 + or - 12 ms. The minimum P-wave duration ranged from 35 to 103 ms with mean of 65 + or - 10 ms. P-wave dispersion ranged from 12 to 82 ms. The mean P-wave dispersion was 48 + or - 12 ms (40-56). The intrarater intraclass correlation coefficient (ICC) was r = 0.80 for maximum P-wave duration and r = 0.82 for P-wave dispersion. The interrater ICC was 0.56 for maximum P-wave duration and 0.70 for P-wave dispersion.

CONCLUSIONS

We demonstrated excellent intrarater reproducibility and fair interrater reproducibility for calculating P-wave indices. Reproducibility is frequently lacking in studies of P-wave indices, but is an essential component for the field's growth and epidemiologic contribution.

The effects of iron deficiency anemia on p wave duration and dispersion

OBJECTIVES

The association between P wave dispersion and iron deficiency anemia has not been documented in the literature. In this study, we evaluated P wave dispersion in patients with iron deficiency anemia and the possible relationships between P wave dispersion and other echocardiographic parameters.

INTRODUCTION

The iron status of an individual may play an important role in cardiovascular health. Anemia is an independent risk factor for adverse cardiovascular outcomes. P wave dispersion is a simple electrocardiographic marker that has a predictive value for the development of atrial fibrillation. Apart from cardiovascular diseases, several conditions, such as seasonal variation, alcohol intake and caffeine ingestion, have been demonstrated to affect P wave dispersion.

METHODS

The study included 97 patients who had iron deficiency anemia and 50 healthy subjects. The cases were evaluated with a clinical examination and diagnostic tests that included 12-lead electrocardiography and transthoracic echocardiography.

RESULTS

Compared to the control group, patients with iron deficiency anemia showed significantly longer maximum P wave duration (Pmax) (91.1 ± 18.0 vs. 85.8 ± 6.7 msec, p = 0.054), P wave dispersion (PWD) (48.1 ± 7.7 vs. 40.9 ± 5.6 msec, p < 0.001), mitral inflow deceleration time (DT) (197.5 ± 27.9 vs. 178.8 ± 8.9 msec, p < 0.001) and isovolumetric relaxation time (IVRT) (93.3 ± 9.2 vs. 77.4 ± 8.2 msec, p < 0.001); they also showed increased heart rate (85.7 ± 16.1 vs. 69.0 ± 4.4, p < 0.001) and frequency of diastolic dysfunction (7 (7.2%) vs. 0). Correlation analysis revealed that PWD was significantly correlated with IVRT, DT, heart rate, the presence of anemia and hemoglobin level.

CONCLUSIONS

Iron deficiency anemia may be associated with prolonged P wave duration and dispersion and impaired diastolic left ventricular filling.

Prevalence of interatrial block in healthy school-aged children: definition by P-wave duration or morphological analysis

BACKGROUND

P waves > or = 110 ms in adults and > or = 90 ms in children are considered abnormal, signifying interatrial block, particularly in the first case.

METHODS

To evaluate the prevalence of interatrial block in healthy school-aged children, we obtained 12-lead digital ECGs (Cardioperfect 1.1, CardioControl NV, Delft, The Netherlands) of 664 healthy children (349 males/315 females, age range 6-14 years old). P-wave analysis indices [mean, maximum and minimum (in the 12 leads) P-wave duration, P-wave dispersion, P-wave morphology in the derived orthogonal (X, Y, Z) leads, as well the amplitude of the maximum spatial P-wave vector] were calculated in all study participants.

RESULTS

P-wave descriptor values were: mean P-wave duration 84.9 + or - 9.5 ms, maximum P-wave duration 99.0 + or - 9.8 ms, P dispersion 32.2 + or - 12.5 ms, spatial P amplitude 182.7 + or - 69.0 microV. P-wave morphology distribution in the orthogonal leads were: Type I 478 (72.0%), Type II 178 (26.8%), Type III 1 (0.2%), indeterminate 7 (1%). Maximum P-wave duration was positively correlated to age (P < 0.001) and did not differ between sexes (P = 0.339). Using the 90-ms value as cutoff for P-wave duration, 502 (75.6%) children would be classified as having maximum P-wave duration above reference range. The 95th and the 99th percentiles were in the overall population 117 ms and 125 ms, respectively. P-wave morphology type was not in any way correlated to P-wave duration (P = 0.715).

CONCLUSIONS

Abnormal P-wave morphology signifying the presence of interatrial block is very rare in a healthy pediatric population, while widened P waves are quite common, although currently classified as abnormal.

The effect of altitude on P-wave and QT duration and dispersion

BACKGROUND

Short-term and long-term exposure to high altitude has been reported to change the surface electrocardiogram. We aimed to compare P-wave and QT parameters between healthy people living at high altitude and sea level.

METHODS

Twelve-lead electrocardiographies of 38 healthy people living at sea level (Antalya,Turkey) and 38 healthy people living at high altitude (Van, Turkey; 1,700-1,800 m) were obtained. Minimum and maximum P-wave durations, P-wave dispersion, minimum and maximum corrected QT intervals, and corrected QT dispersion were calculated.

RESULTS

There was no significant difference between the two groups in respect to heart rate and QT variables. Mean Pminimum values were slightly but significantly lower in the high altitude group (P = 0.029). Mean Pmaximum values tended to be lower at high altitude but did not reach statistical significance (P = 0.085). However, there was no significant difference in respect to P-wave dispersion values.

CONCLUSIONS

In a sample of men and women living at high altitude in Turkey, significant reduction of Pminimum and borderline reduction of Pmaximum duration, but no significant change of P-wave and QT dispersion, were observed.

Incremental prevalence of fractionated and inhomogeneous propagation of sinus impulses with increasing atrial depolarization abnormality among outpatients

INTRODUCTION

Prolonged P-wave duration (P-dur) and excessive P-wave dispersion (P-disp) are purported arrhythmogenic substrates for atrial fibrillation. However, the extent of involvement of inhomogeneous, sinus impulse propagation demonstrated by excessive P-disp (> 40 ms) has not been evaluated in relation to increasing P-dur.

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 P-disp, P-dur and P-wave axis (P-axis). 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. Normal P-axis was considered 0 to + 75 degrees by manually constructing the mean frontal plane electrical P-axis from the 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 depicting sinus rhythm formed our final sample. P-dur was strongly associated with P-disp (p<0.0001) but the correlation remained weak (r=0.42). However, when P-dur was divided into 10 ms increments, the prevalence of abnormal P-disp rose incrementally with P-dur, with or without consideration of the P-axis. The prevalence of abnormal P-disp doubled from 30% in those with P-dur of 100 ms to > 60% in those with P-dur of 120 ms. Further, the prevalence exceeded 80% with P-dur of 130 ms and reached 100% with P-dur > 160 ms.

CONCLUSION

With increasingly prolonged atrial depolarization, the associated inhomogeneity of sinus impulse propagation across the atria increases. P-dur and P-disp are associated with each other and are consistent with abnormal atrial conduction properties.

Age-related changes in P wave morphology in healthy subjects

Background

We have previously documented significant differences in orthogonal P wave morphology between patients with and without paroxysmal atrial fibrillation (PAF). However, there exists little data concerning normal P wave morphology. This study was aimed at exploring orthogonal P wave morphology and its variations in healthy subjects.

Methods

120 healthy volunteers were included, evenly distributed in decades from 20–80 years of age; 60 men (age 50+/-17) and 60 women (50+/-16). Six-minute long 12-lead ECG registrations were acquired and transformed into orthogonal leads. Using a previously described P wave triggered P wave signal averaging method we were able to compare similarities and differences in P wave morphologies.

Results

Orthogonal P wave morphology in healthy individuals was predominately positive in Leads X and Y. In Lead Z, one third had negative morphology and two-thirds a biphasic one with a transition from negative to positive. The latter P wave morphology type was significantly more common after the age of 50 (P < 0.01). P wave duration (PWD) increased with age being slightly longer in subjects older than 50 (121+/-13 ms vs. 128+/-12 ms, P < 0.005). Minimal intraindividual variation of P wave morphology was observed.

Conclusion

Changes of signal averaged orthogonal P wave morphology (biphasic signal in Lead Z), earlier reported in PAF patients, are common in healthy subjects and appear predominantly after the age of 50. Subtle age-related prolongation of PWD is unlikely to be sufficient as a sole explanation of this finding that is thought to represent interatrial conduction disturbances. To serve as future reference, P wave morphology parameters of the healthy subjects are provided.