Evaluation of the Relationship between Atrial Septal Aneurysm and Cardiac Arrhythmias via P‐Wave Dispersion and Signal‐Averaged P‐Wave Duration

Objective: The aim of the study was to investigate the relationship between atrial septal aneurysms (ASAs) and cardiac arrhythmias via signal‐averaged P‐wave duration (SAPWD) and P‐wave dispersion (Pd). Methods: Sixty‐six patients with ASA served as the study group (group 1; 28 men and 38 women; mean age, 34 ± 10 years) and 62 healthy volunteers served as the control group (group 2; 29 men and 33 women; mean age, 31 ± 8 years) in the current study. ASAs were diagnosed by transthoracic echocardiography based on the criteria of a minimal aneurysmal base of ≥15 mm; and an excursion of ≥10 mm. All subjects were evaluated by 24‐hour Holter monitoring, 12 lead body surface electrocardiogram for P‐wave analysis, and signal‐averaged electrocardiogram for P‐wave duration (PWD). Results: There was no significant difference between the study and control groups in terms of age, gender, left atrium diameter, and left ventricular ejection fraction. Supraventricular arrhythmias (SVAs) were detected in 29 patients with ASA (43.9%) and 5 controls (8.1%; P < 0.001). The mean Pd in patients with ASA was significantly longer compared to the control group (14.1 ± 8 ms vs 7.0 ± 2.9 ms; P < 0.001). Similarly, the mean SAPWD in group 1 was significantly longer compared to group 2 (127.4 ± 17.6 ms vs 99.8 ± 12.3 ms; P < 0.001). Conclusion: Prolonged SAPWD and Pd were determined to indicate electrical disturbances in the atrial myocardium, and predict the increase in the prevalence of SVA in patients with ASA. Ann Noninvasive Electrocardiol 2010;15(2):157–164     

Effect of Obesity on P‐Wave Parameters in a Chinese Population

Objective: To study the association between obesity and P‐wave duration and dispersion (P_d) in order to evaluate the potential risk for atrial fibrillation development in Chinese subjects using the definitions applied for Asian populations. Methods: The study population consisted of 40 obese (body mass index (BMI) ≥ 25 Kg/m², according to the World Health Organization classification for the Asian population) subjects and 20 age‐ and sex‐matched normal weight controls. Maximum P‐wave duration (P_max), minimum P‐wave duration (P_min), and P_d were carefully measured using a 12‐lead electrocardiogram, while the presence of interatrial block (IAB; P ≥ 110 ms) was assessed. Results: There were no significant differences between the two groups regarding age, sex, history of hypertension or diabetes, and hyperlipidemia. Compared to controls, BMI, left atrial diameter (LAD), and interventricular septal thickness were increased, while P_max (111.9 ± 9.3 vs 101.1 ± 6.0 ms, P < 0.01) and P_d (47.9 ± 9.3 vs 31.8 ± 6.9 ms, P < 0.01) were significantly prolonged in the obese group. P_min was similar between the two groups. The prevalence of IAB was significantly greater in the obese subjects. Pearson's correlation analysis showed that there were positive correlations between P_d and BMI (r = 0.6, P < 0.001), as well as between P_d and LAD (r = 0.366, P < 0.05). Conclusion: Our data suggest that obesity is associated with increased P_max and P_d, and increased prevalence of IAB, parameters that have been associated with atrial fibrillation. The correlation of these electrocardiogram parameters with LAD indicates an association between increased BMI and atrial remodeling in Asian subjects. Ann Noninvasive Electrocardiol 2010;15(3):259–263     

P‐Wave Duration and Dispersion in Obese Subjects

Background: Although previous studies have documented a variety of electrocardiogram (ECG) abnormalities in obesity, P‐wave alterations, which represent an increased risk for atrial arrhythmia, have not been studied very well in these patients. The aim of the present study was to evaluate P‐wave duration and P dispersion (Pd) in obese subjects, and to investigate the relationship between P‐wave measurements, and the clinical and echocardiographic variables. Methods: The study population consisted of 52 obese and 30 normal weight control subjects. P‐wave duration and P‐wave dispersion were calculated on the 12‐lead ECG. As echocardiographic variables, left atrial diameter (LAD), left ventricular end‐diastolic, and end‐systolic diameters (LVDD and LVSD), left ventricular ejection fraction (LVEF), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), and left ventricular mass (LVM) of the obese and the control subjects were measured by means of transthoracic echocardiography. Results: There were statistically significant differences between obese and controls as regards to Pmax (maximum P‐wave duration) and Pd (P dispersion) (P < 0.001 and P < 0.001, respectively). Pmin (minimum P wave duration) was similar in both groups. Correlation analysis showed that Pd in the obese patients was related to any the clinical and echocardiographic parameters including BMI, LAD, LVDD, IVST, LVPWT, and LVM. Conclusion: Our data suggest that obesity affects P‐wave dispersion and duration, and changes in P dispersion may be closely related to the clinical and the echocardiographic parameters such as BMI, LAD, IVST, LVPWT, and LVM.     

Effect of Reperfusion on P‐Wave Duration and P‐Wave Dispersion in Acute Myocardial Infarction: Primary Angioplasty versus Thrombolytic Therapy

Background: Atrial fibrillation (AF) is a common arrhythmia occurring in about 10–20% of patients with acute myocardial infarction (AMI). P‐wave dispersion (PWd) and P‐wave duration (PWD) have been used to evaluate the discontinuous propagation of sinus impulse and the prolongation of atrial conduction time, respectively. This study was conducted to compare the effects of reperfusion either by thrombolytic therapy or primary angioplasty on P‐wave duration and dispersion in patients with acute anterior wall myocardial infarction. Methods: We have evaluated 72 consecutive patients retrospectively (24 women, 48 men; aged 58 ± 12 years) experiencing acute anterior wall myocardial infarction (AMI) for the first time. Patients were grouped according to the reperfusion therapy received (primary angioplasty (PTCA) versus thrombolytic therapy). Left atrial diameter and left ventricular ejection fraction (LVEF) were determined by echocardiography in all patients. Electrocardiography was recorded from all patients on admission and every day during hospitalization. Maximum (P max) and minimum (P min) P‐wave durations and P‐wave dispersions were calculated before and after the treatment. Results: There were not any significant differences between the groups regarding age, gender, left ventricular ejection fraction, left atrial diameter and volume, cardiovascular risk factors, and duration from symptom onset to treatment. P‐wave dispersions and P‐wave durations were significantly decreased after PTCA [Mean P max was 113 ± 11 ms before and 95 ± 17 ms after the treatment (P = 0.007)]. Mean PWd was 46 ± 12 ms before and 29 ± 10 ms after the treatment (P = 0.001). Also, P max and PWd were significantly lower in PTCA group (for P max 97 ± 22 ms vs 114 ± 16 ms and for PWd 31 ± 13 ms vs 55 ± 5 ms, respectively). Conclusions: Primary angioplasty reduces the incidence of AF by decreasing P max and P‐wave dispersion.     

Effects of Right Coronary Artery PTCA on Variables of P‐Wave Signal Averaged Electrocardiogram

Background: P‐wave signal averaged ECG has been used to detect atrial late potentials that were found in paroxysmal atrial fibrillation. Ischemia is supposed to trigger ventricular late potentials, which indicate an elevated risk for ventricular tachycardia. Preexistent ventricular late potentials measured by ventricular signal averaged ECG is supposed to be eliminated by successful PTCA. Methods: We examined the incidence of atrial late potentials in patients with a proximal stenosis of the right coronary artery and new onset of atrial fibrillation. Furthermore, we investigated the anti‐ischemic effect of a successful percutaneous transluminal coronary angioplasty.(PTCA) of the right coronary artery. P‐wave signal averaged ECG from 23 patients who had a PTCA of the right coronary artery (group A) were compared to age, sex, and disease‐matched control subjects (group B) one day before, one day after, and one month after PTCA. Results: A new appearance of paroxysmal atrial fibrillation was presented in eight patients before PTCA (group A1) of group A. Patients with a stenosis of the right coronary artery had a significantly higher incidence of supraventricular extrasystoles in a 24‐hour‐Holter ECG (131.1 ± 45.4 vs 17.1 ± 18.9, P < 0.0002 ). The duration of the filtered P wave was longer (124.8 ± 11.9 vs 118.5 ± 10.1 ms, P < 0.04 ) and the root mean square of the last 20 ms (RMS 20) was significantly lower in group A than in group B (2.87 ± 1.09 vs 3.97 ± 1.12 μV, P < 0.01 ). A successful PTCA caused an increase in RMS 20 (2.87 ± 1.11 vs 4.19 ± 1.19 μV, P < 0.02 ) and a decrease in filtered P‐wave duration (124.8 ± 11.9 vs 118.4 ± 10.4 ms, P < 0.04 ). Preexistent atrial late potentials were found among 15 patients before PTCA. After successful PTCA only 3 out of 15 patients were affected (P < 0.0004) after one day, as well as after one month. All patients with a history of atrial fibrillation did not suffer from an arrhythmic recurrence within the following six months after successful PTCA. Conclusion: A stenosis of the right coronary artery is associated with atrial late potentials. A successful PTCA of the right coronary artery eliminates preexistent atrial late potentials and may reduce the risk of atrial fibrillation.     

Optimal P‐Wave Duration for Bedside Diagnosis of Interatrial Block

Background: Interatrial block (IAB; P wave ≥ 110 ms) is highly prevalent and associated with atrial tachyarrhythmias, left atrial electromechanical dysfunction and is a potential risk for embolism. Investigators have often used different parameters for P‐wave duration to define IAB, and this causes confusion further adding to clinician ignorance of IAB. We therefore appraised the mode P‐wave duration in IAB and evaluated the sensitivity and specificity of using previously used durations. Methods: We prospectively evaluated 225 electrocardiograms (ECGs) of patients at a tertiary care general hospital for P‐wave duration. Of these, 49 were excluded because of severe motion artifact, errors in lead placement, absence of adequate patient identification, and atrial flutter or fibrillation. Mean, standard error of mean (SEM), standard deviation (SD), mode P‐wave duration, specificity, and sensitivity were calculated of the remaining 176 ECGs. Results: From the sample (N = 176; ages 15–95 years; mean ± SD = 69.15 ± 16.53 years, female 50.3%), measured P‐wave durations ranged from 50 ms to 230 ms (mean ± SD = 113.75 ± 30.56 ms, SEM 2.30 ms). 96 patients (54.55%) showed IAB (P wave ≥ 110 ms) with the mode P‐wave duration being 120 ms. Sensitivity and specificity of using P wave ≥ 110 ms is 100% and 88.9%, respectively (accuracy 94.31%), while P wave ≥130 ms yielded 64% and 100%, respectively (accuracy 82.38%). Conclusions: Mode P‐wave duration in IAB is 120 ms, and thus, for all practical reasons, it may be used to clinically diagnose IAB using ECGs recorded at the bedside at 25 mm/s with 10 mm/mV standardization.     

Prediction of the Recurrence of Atrial Fibrillation After Successful Cardioversion with P Wave Signal‐Averaged ECG

Background: The recurrence of atrial fibrillation (AF) was often observed after cardioversion. Methods: In our study, a P wave triggered P wave signal‐averaged ECG (P‐SAECG) was performed on 118 consecutive patients 1 day after successful electrical cardioversion in order to evaluate the utility of this method to predict AF after cardioversion. We measured the filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20). Results: During a 1‐year follow‐up, a recurrence was observed in 57 patients (48%). Patients with recurrence of AF had a larger left atrial size (41.9 ± 4.0 vs 39.3 ± 3.1 mm, P < 0.0003), a longer FPD (139.6 ± 16.0 vs 118.2 ± 14.1 ms, P < 0.0001), and a lower RMS 20 (2.57 ± 0.77 vs 3.90 ± 0.99 μV, P < 0.0001). A cutoff point (COP) of FPD ≥126 ms and RMS 20 ≤3.1 μV could predict AF with a specificity of 77%, a sensitivity of 72%, a positive value of 75%, a negative predictive value of 75%, and an accuracy of 75%. A stepwise logistic regression analysis of variables identified COP (odds ratio 9.97; 95% CI, 4.10–24.24, P < 0.0001) as an independent predictor for recurrence. Conclusions: We conclude that the probability of recurrence of AF after cardioversion could be predicted by P‐SAECG. This method seems to be appropriate to demonstrate a delayed atrial conduction that might be a possible risk factor of reinitiation of AF.     

P‐Wave Signal‐Averaged Electrocardiogram Predicts Atrial Fibrillation After Coronary Artery Bypass Grafting

Background: AF is one of the most common complications after CABG. The aim of the study was to identify the risk factors for postoperative AF. Methods: Between June and December 2000, 129 consecutive patients (72 men, 47 women; mean age 67 ± 6 years) underwent preoperative signal‐averaged electrocardiogram (SAECG) with assessment of filtered P‐wave duration (fPWD) and of the root mean square voltage of the last 10 and 20 ms of atrial depolarization (RMSV10 and RMSV20, respectively) before CABG. Results: Fifty‐six (43%) patients developed one episode of AF lasting > 30 seconds at a mean distance of 2.6 ± 1.8 days after surgery (group A), while 73 patients remained in sinus rhythm (group B). No differences between the two groups were found in terms of age, sex, P‐wave duration on the standard ECG, left atrial dimensions, and operative characteristics. In contrast, group A patients showed a significantly longer fPWD (138 ± 10 vs 111 ± 9 ms; P < 0.001) and smaller RMSV10 and RMSV20 (2.8 ± 1.0 vs 4.3 ± 1.1 μV, P < 0.001; 4.2 ± 2.1 vs 6.2 ± 2.0 μV, P < 0.001). Multivariate analysis indicated only fPWD as an independent predictor of AF (P = 0.009). With a cut‐off value of 135 ms for fPWD, the occurrence of AF could be predicted with a sensitivity of 84%, a specificity of 73%, a negative predictive value of 85%, and a positive predictive value of 70%. Conclusion: Preoperative SAECG is a simple exam that correctly identifies patients at higher risk of AF after CABG. A more widespread use of this technique can be suggested. A.N.E. 2002;7(3):198–203     

High‐Resolution Signal‐Averaged Analysis of Atrial Electromagnetic Characteristics in Patients with Paroxysmal Lone Atrial Fibrillation

Background: Abnormalities in the electromagnetic signal of the atria during sinus rhythm could serve as markers of triggering foci or substrate for atrial fibrillation (AF). We examined atrial electrophysiologic properties noninvasively by using magnetocardiographic mapping (MCG) in patients with paroxysmal lone AF to find whether any difference exists between those who have frequent triggers of AF and who don't. Methods: MCG was recorded over anterior chest during sinus rhythm in 80 patients with paroxysmal lone AF (44 ± 12 years, 61 males) and 80 matched controls. Atrial wave duration (Pd) and root mean square amplitudes of the last 40 ms (RMS40) of the averaged filtered atrial complex were determined automatically. Patients expressing atrial arrhythmias triggering AF episodes were classified as focal AF. Results: The Pd was 109 ms in patients and 104 ms in controls (P = 0.007). In focal AF (72%) the Pd was slightly prolonged and its proportion of the PR interval was larger, but RMS40 was normal compared to controls. In other patients, the Pd was close to controls, but the RMS40 was reduced (59 ± 17 vs74 ± 36 fT, P = 0.006). Pd and atrial RMS amplitudes were unrelated to duration of AF history or frequency of recurrences. Conclusion: Clinical subclasses of lone AF seem to possess distinct signal profiles of atrial depolarization. Differences in electrophysiological properties between these subclasses may reflect pathogenetic variation and could have implications on diagnostics and therapy.     

P Wave Dispersion and P Wave Duration on SAECG in Predicting Atrial Fibrillation in Patients with Acute Myocardial Infarction

Background: Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI), with reported incidence of 7% to 18%. The incidence of congestive heart failure, in‐hospital mortality, and long‐term mortality is higher in AMI patients with AF than in AMI patients without AF. P wave duration on signal‐averaged ECG (PWD) and P wave dispersion on standard ECG (Pd) are noninvasive markers of intra‐atrial conduction disturbances, which are believed to be the main electrophysiological cause of AF. Methods: In the present study we investigated prospectively whether P wave duration on SAECG and P wave dispersion on standard ECG can predict development of AF in a group of patients with AMI. One hundred and thirty patients (100 men and 30 women, aged 56.9 ± 12) with AMI were investigated. PWD, Pd, their clinical and hemodynamic characteristics were collected. Results: During the observation up to 14 days, 22 patients (16.9%) developed AF. Univariate analysis variables associated with development of AF: age > 65 years, Killip class III‐IV, PWD > 125 ms, and Pd > 25 ms. Stepwise logistic regression analysis showed that age > 65 years, PWD > 125 ms, and Pd > 25 ms were independently associated with AF. Conclusions: PWD and Pd both measured in a very early period of AMI are useful in predicting AF. A.N.E. 2002;7(4):363–368     

The Significance of P Wave Duration and P Wave Dispersion for Risk Assessment of Atrial Tachyarrhythmias in Patients with Corrected Tetralogy of Fallot

Background: The aim of the present study was to determine the potential role of P wave duration and P wave dispersion for risk assessment of atrial tachyarrhythmias in patients with corrected tetralogy of Fallot (ToF). Methods: The maximum P wave duration, minimum P wave duration, and the P wave dispersion from the 12‐lead surface electrocardiogram of the patients and controls were measured. Electrophysiological study was performed only in the patient group. Results: The study group consisted of 25 patients with corrected ToF with a mean age of 16.4 ± 4.25 years and 25 age‐matched healthy control subjects. Patients underwent repair at a mean age of 4.6 ± 3.41 years (range: 1–19), and the mean duration of follow‐up of 11.8 ± 1.7 years (range: 9–15) after surgery. On electrophysiological study sinus node dysfunction was detected in 3 patients (12%), atrial tachyarrythmias—atrial flutter or fibrillation—in 5 patients (20%), both sinus node dysfunction and atrial flutter in 1 patient (4%), and AV conduction delay in 1 patient (4%). P wave dispersion is significantly higher in patients with atrial tachyarrhythmia inducible by electrophysiological study than in other patients (P < 0.05). A P wave dispersion value of >35 ms has a high predictive accuracy (sensitivity = 83% and specificity = 89%) for inducible atrial tachyarrhythmia in patients with corrected tetralogy of Fallot. Conclusion: P wave dispersion is an easily measured electrocardiographic marker with a good sensitivity and specificity for predicting atrial arrhythmias in patients after correction of ToF.     

Prevalence of Potential Noninvasive Arrhythmia Risk Predictors in Healthy,Middle‐Aged Persons

Background : To date, prevalence and clinical significance of noninvasive arrhythmia risk predictors in apparently healthy, middle‐aged persons are largely unknown. Methods : A total of 110 apparently healthy persons 20–75 years old were enrolled in this prospective observational monocenter study and followed up for 32 ± 15 months. Baseline investigations included symptom‐limited bicycle ergometry, echocardiography, time‐domain analysis, and spectral turbulence analysis of the signal‐averaged electrocardiogram (ECG), ventricular arrhythmias, and heart rate variability on 24‐hour Holter ECG, baroreflex sensitivity, and t‐wave alternans in all persons. Results : The prevalence of an abnormal signal‐averaged ECG was 1% for spectral turbulence analysis and varied between 1% and 37% for time‐domain analysis depending upon the definition used for an abnormal time‐domain analysis. A reduced heart rate variability defined as a standard deviation of normal‐to‐normal intervals ≤105 ms, <100 ms and <70 ms was found in 12%, 9%, and 1% of persons. A baroreflex sensitivity <6 ms/mmHg and <3 ms/mmHg was present in 15% and 2% of persons. Microvolt t‐wave alternans was found to be positive in 5%, negative in 88%, and indeterminate in 7% of persons, respectively. During the 32 ± 15 months follow‐up, no arrhythmic events and no cardiovascular mortality were observed in this population. Conclusions: Abnormal findings of noninvasive arrhythmia risk stratification can be found in 1–37% of healthy, middle‐aged persons when previously reported cut‐off values are used.     

老年心血管病患者房颤反复发作的预测

目的　为明确老年心血管疾病患者窦性心律时发生阵发性房颤的危险因素并寻找反复心房颤动发作的预测因子。方法　测量 71例有阵发性房颤发作史的老年心血管疾病患者 (PAF组 )及 73例无阵发性房颤发作史的老年心血管疾病患者 (对照组 )窦性心律时的 12导联ECG ,分别测定最大P波时限 (Pmax)及最小P波时限 (Pmin)并计算其P波离散度 (Pd) ,心脏超声测量左房内径 (LAD)和左室射血分数 (LVEF) ,随访PAF组房颤反复发作情况。结果　PAF组的Pd及Pmax分别为 ( 4 7.0 7± 12 .3 5 )ms和 ( 12 1.2 5± 13 .2 4)ms,较对照组明显延长 (P <0 .0 1) ;PAF组反复房颤发作者 ,Pd≥40ms时相对危险度 3 .3 3 ,Pmax≥ 110ms时相对危险度 2 .48。结论　窦性心律时Pd、Pmax增加是预测老年心血管病患者是否发生房颤及房颤反复发作的有效且无创的临床方法     

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Objectives: Elevated beat‐to‐beat QT interval variability (QTV) has been associated with increased cardiovascular morbidity and mortality.The aim of this study was to investigate interlead differences in beat‐to‐beat QTV of 12‐lead ECG and its relationship with the T wave amplitude. Methods: Short‐term 12‐lead ECGs of 72 healthy subjects (17 f, 38 ± 14 years; 55 m, 39 ± 13 years) were studied. Beat‐to‐beat QT intervals were extracted separately for each lead using a template matching algorithm. We calculated the standard deviation of beat‐to‐beat QT intervals as a marker of QTV as well as interlead correlation coefficients. In addition, we measured the median T‐wave amplitude in each lead. Results: There was a significant difference in the standard deviation of beat‐to‐beat QT intervals between leads (minimum: lead V₃ (2.58 ± 1.36 ms), maximum: lead III (7.2 ± 6.4 ms), ANOVA: P < 0.0001). Single measure intraclass correlation coefficients of beat‐to‐beat QT intervals were 0.27 ± 0.18. Interlead correlation coefficients varied between 0.08 ± 0.33 for lead III and lead V₁ and 0.88 ± 0.09 for lead II and lead aVR. QTV was negatively correlated with the T‐wave amplitude (r =–0.62, P < 0.0001). There was no significant affect of mean heart rate, age or gender on QT variability (ANOVA: P > 0.05). Conclusions: QTV varies considerably between leads in magnitude as well as temporal patterns. QTV is increased when the T wave is small.     

Abnormal P‐Wave Morphology Is a Predictor of Atrial Fibrillation Development and Cardiac Death in MADIT II Patients

Background: Several ECG‐based approaches have been shown to add value when risk‐stratifying patients with congestive heart failure, but little attention has been paid to the prognostic value of abnormal atrial depolarization in this context. The aim of this study was to noninvasively analyze the atrial depolarization phase to identify markers associated with increased risk of mortality, deterioration of heart failure, and development of atrial fibrillation (AF) in a high‐risk population with advanced congestive heart failure and a history of acute myocardial infarction. Methods: Patients included in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) with sinus rhythm at baseline were studied (n = 802). Unfiltered and band‐pass filtered signal‐averaged P waves were analyzed to determine orthogonal P‐wave morphology (prespecified types 1, 2, and 3/atypical), P‐wave duration, and RMS20. The association between P‐wave parameters and data on the clinical course and cardiac events during a mean follow‐up of 20 months was analyzed. Results: P‐wave duration was 139 ± 23 ms and the RMS20 was 1.9 ± 1.1 μV. None of these parameters was significantly associated with poor cardiac outcome or AF development. After adjustment for clinical covariates, abnormal P‐wave morphology was found to be independently predictive of nonsudden cardiac death (HR 2.66; 95% CI 1.41–5.04, P = 0.0027) and AF development (HR 1.75; 95% CI 1.10–2.79, P = 0.019). Conclusion: Abnormalities in P‐wave morphology recorded from orthogonal leads in surface ECG are independently predictive of increased risk of nonsudden cardiac death and AF development in MADIT II patients. Ann Noninvasive Electrocardiol 2010;15(1):63–72     

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 ± 12 ms. The minimum P‐wave duration ranged from 35 to 103 ms with mean of 65 ± 10 ms. P‐wave dispersion ranged from 12 to 82 ms. The mean P‐wave dispersion was 48 ± 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. Ann Noninvasive Electrocardiol 2010;15(1):77–84     

Reference Values of Tissue Doppler Imaging and Pulsed Doppler Echocardiography for Analysis of Left Ventricular Diastolic Function in Healthy Adults

To determine reference values for tissue Doppler imaging (TDI) and pulsed Doppler echocardiography for left ventricular diastolic function analysis in a healthy Brazilian adult population. Observations were based on a randomly selected healthy population from the city of Vitória, Espírito Santo, Brazil. Healthy volunteers (n = 275, 61.7% women) without prior histories of cardiovascular disease underwent transthoracic echocardiography. We analyzed 175 individuals by TDI and evaluated mitral annulus E′‐ and A′‐waves from the septum (S) and lateral wall (L) to calculate E′/A′ ratios. Using pulsed Doppler echocardiography, we further analyzed the mitral E‐ and A‐waves, E/A ratios, isovolumetric relaxation times (IRTs), and deceleration times (DTs) of 275 individuals. Pulsed Doppler mitral inflow mean values for men were as follows: E‐wave: 71 ± 16 cm/sec, A‐wave: 68 ± 15 cm/sec, IRT: 74.8 ± 9.2 ms, DT: 206 ± 32.3 ms, E/A ratio: 1.1 ± 0.3. Pulsed Doppler mitral inflow mean values for women were as follows: E‐wave: 76 ± 17, A‐wave: 69 ± 14 cm/sec, IRT: 71.2 ± 10.5 ms, DT: 197 ± 33.3 ms, E/A ratio: 1.1 ± 0.3. IRT and DT values were higher in men than in women (P = 0.04 and P = 0.007, respectively). TDI values in men were as follows: E′S: 11± 3 cm/sec, A′S: 13 ± 2 cm/sec, E′S/A′S: 0.89 ± 0.2, E′L: 14 ± 3 cm/sec, A′L: 14 ± 2 cm/sec, E′L/A′L: 1.1± 0.4. E‐wave/ E′S ratio: 6.9 ± 2.2; E‐wave / E′L ratio: 4.9 ± 1.7. In this study, we determined pulsed Doppler and TDI derived parameters for left ventricular diastolic function in a large sample of healthy Brazilian adults. (Echocardiography 2010;27:777‐782)     

Agreement Between Automatic and Manual Measurement of Atrial and Ventricular Signal‐Averaged Electrocardiograms in Healthy Subjects

Background: Although prolonged duration of the signal‐averaged (SA) P wave has been proposed as a noninvasive marker of atrial arrhythmias, clinical value of atrial SAECG is limited, largely due to the difficulty with detection of the onset and offset of the high gain P wave. The aim of this study was to assess the reliability of automatic measurement of the atrial SAECG. Methods: Fifty‐one healthy volunteers (30 men; 32 ± 8 years) underwent a session of 3 atrial and 3 ventricular SAECG recordings. Automatically detected onset and offset of SA QRS complex (QRS_tot) and SA P wave (P_tot) were subsequently‐corrected by two independent observers. For ventricular SAECG, three conventional time‐domain parameters were calculated. For atrial SAECG, the following five parameters were measured: P_tot, root mean square voltages of the entire P_tot (RMS‐P) and of the terminal 40, 30, and 20 ms of P_tot. Relative errors of the different pairs of measurements were used to assess the interobserver and observer‐computer variability. The Bland‐Altman method was applied to express the agreement between measurements. Results: Although the mean interobserver relative errors were low for QRS_tot and P_tot (1.1% vs 1.5%), the observer‐computer error was significantly higher for P_tot than for QRS_tot (1.7% vs 7.1%; P < 0.0001). For the voltage parameters, the lowest interobserver and observer‐computer relative errors were found for RMS‐P (6.6% vs 7.3%, P = ns). For RMS voltages of the terminal 40–20 ms of P_tot, relative errors exceeded 10%, but the interobserver error was significantly lower than the observer‐computer error (P < 0.0001). Conclusion: Automatic detection of the SA P‐wave onset and offset is unreliable and the atrial SAECG requires manual correction. Given a good interobserver agreement, such a correction is unlikely to introduce any significant observer‐dependent bias. A.N.E. 2000; 5(2):133–138