Detection of hypertensive patients at risk for paroxysmal atrial fibrillation during sinus rhythm by computer-assisted P wave analysis.

OBJECTIVE AND METHODS: To determine whether hypertensive patients at risk for paroxysmal atrial fibrillation (AF) could be detected while in sinus rhythm, a computer-based 12-lead surface electrocardiogram was recorded in 50 hypertensive patients with history of paroxysmal AF (group A) and in 60 hypertensive patients without history of AF (group B). The maximum P-wave duration (P(maximum)), the minimum P-wave duration (P(minimum)), P-wave dispersion (Pdispersion = Pmaximum Pminimum), adjusted P-wave dispersion (APdispersion = Pdispersion/square root of the number of measurable leads), mean P-wave duration (mean P) and the standard deviation of the P-wave duration in all measured leads (SDP) were calculated. RESULTS: Pdispersion, APdispersion and SDP were significantly higher in group A than in group B (Pdispersion, 52 +/- 19 versus 41 +/- 15 ms, P< 0.001; APdispersion, 15.2 +/- 5.5 versus 11.9 +/- 4.6 ms, P< 0.001; SDP, 16 +/- 5 versus 13 +/- 5 ms, P < 0.001). P(minimum), mean P and left ventricle ejection fraction (LVEF) were significantly lower in group A than in group B (Pminimum, 79 +/- 18 versus 91 +/- 13 ms, P < 0.001; mean P, 108 +/- 18 versus 116 +/- 13 ms, P= 0.005; LVEF, 64 +/- 5 versus 69 +/- 8%, P< 0.001). Pminimum, Pdispersion, mean P, SDP, APdispersion and LVEF were found to be significant univariate predictors of paroxysmal AF, whereas only Pminimum (P< 0.001) remained a significant independent predictor of paroxysmal AF in the multivariate analysis. CONCLUSION: Hypertensive patients at risk for paroxysmal AF could be detected while in sinus rhythm by computer-assisted electrocardiographic P-wave analysis.     

Changes in P-wave dispersion and P-wave duration after open heart surgery are associated with the peak incidence of atrial fibrillation

Background: Increased P-wave dispersion (P-disp) and maximum P-wave duration (P-max) predict the development of atrial fibrillation (AF) in the general population. The present study evaluates the time-dependent relationship of P-disp and P-max after open heart surgery. Methods And Results: P-disp and P-max were measured in the perioperative period of open heart surgery (one day before surgery through postoperative day 4). Compared with the baseline, P-max decreased immediately after open heart surgery (112.63 +/- 7.4 ms vs 106.9 +/- 8.2 ms, P =.005). An increase in P-disp was observed between postoperative days 1 and 2 (37.5 +/- 6.8 ms vs 43.1 +/- 4.5 ms, P <.05), and postoperative days 1 and 3 (37.5 +/- 6.8 ms vs 44.1 +/- 6.6 ms, P <.05). There was also an increase in the P-max between postoperative day 1 and 3 (103 +/- 8.3 ms vs 110 +/- 7.7 ms, P <.05). Conclusions: Nonuniform atrial conduction (P-disp) is greatest on days 2 and 3 after open heart surgery, and the longest atrial conduction time (P-max) is greatest on day 3 after open heart surgery, findings that coincide with the time of greatest risk for AF. (Heart Lung((R)) 2001;30:466-71.)     

Diurnal variation of the P-wave dispersion in chronic ischemic heart diseases

OBJECTIVE: Electrocardiographic indices like maximum P-wave duration (P(max)) and P-wave dispersion (PD) can be used to detect patients with atrial conduction disorders, myocardial ischemia and those at risk for atrial fibrillation. Considering the diurnal variation of ischemia in patients with significant coronary lesions, this study was designed to investigate the diurnal variation of eventual atrial conduction abnormalities. METHODS: Forty-eight patients (31 male) with typical angina were grouped according to coronary angiography results as group 1 - 70% or more luminal reduction in at least one of the coronary arteries (n=28), and group 2 - normal coronary arteries (n=20). The difference between the P(max) and minimum P-wave durations (P(min)) is designated as PD. The diurnal P(max), P(min) and PD values were compared between and within the groups. RESULTS: The morning P(max) value of group 1 was significantly higher than the value of group 2 (112+/-1 vs. 102+/-1 ms, P<0.001). The morning PD of group 1 was significantly higher than that of group 2 (54+/-9 vs. 48+/-1 ms, P<0.05). The morning P(max) of group 1 (112+/-1 ms) was significantly higher than its afternoon (102+/-9 ms) and night (102+/-1 ms) values (P<0.001). The morning PD of group 1 (54+/-9 ms) was higher than the afternoon (40+/-10 ms) and night (43+/-9 ms) PD (P<0.001). No significant difference was observed between the P(max), P(min) and PD values in group 2 (P>0.05). CONCLUSION: This study demonstrated that coronary heart disease patients have higher morning P(max) and PD values that may be important regarding prediction of timing and treatment of atrial conduction disorders in myocardial ischemia.     

The effect of conversion type on P wave dispersion in patients with atrial fibrillation

AIM: The aim of this study was to investigate whether conversion type of atrial fibrillation (AF) to sinus rhythm affects the P wave dispersion (PD) in patients with AF. METHODS: Based on conversion type, 95 consecutive patients with AF <3 months were divided into 3 groups: spontaneous cardioversion (SC) (N.=33, mean age: 60.6+/-11.6 years), pharmacologic cardioversion (PC) (N.=32, mean age: 59.2+/-9.6 years) and electrical cardioversion (EC) (N.= 30, mean age: 65.3+/-10.6 years). P wave duration (maximum and minimum) were measured in 12-lead ECG, and PD was calculated. RESULTS: Left atrial diameter and AF duration were significantly higher in EC (43.6+/-4.8 mm and 794.1+/-815.1 h) than SC (38.5+/-3.9 mm and 13.8+/-18.3 h) and PC (40.9+/-4.5 mm and 65.3+/-148.5 h) groups (P<0.01). P maximum was much longer in EC group compared with SC and PC group (121.6+/-9.7, 108.4+/-6.4 and 115.8+/-8.6 ms, P=0.01, respectively). There was a significant difference in PD among SC, PC and EC groups (44.4+/-9.2, 49.5+/-8.7 and 53.5+/-8.8 ms; P=0.005, respectively). PD correlated with AF duration (r=0.36, P=0.03), left atrial diameter (r=0.45, P=0.002) and conversion type (r=0.29, P=0.03). However, there was no significant association between PD and conversion type in multivariate analysis. The prolonged PD resulted from AF duration (P=0.01) and the left atrial size P=0.001). CONCLUSION: This study suggests that conversion type of AF to sinus rhythm has no effect on P wave duration and independent of AF duration and the left atrial diameter.     

Determinants and consequences of atrial fibrosis in patients undergoing open heart surgery

OBJECTIVE: Atrial fibrillation (AF) is a frequent complication following open-heart surgery (OHS). Increased atrial fibrosis may indicate the presence of an intrinsic arrhythmogenic substrate. The aim of this prospective study was to determine whether atrial fibrosis is associated with increased prevalence of AF after OHS. METHODS: Right atrial appendages were obtained from 259 patients undergoing OHS; none of the patients had a history of AF. Atrial fibrosis was quantitatively analyzed with point counting. All patients were followed prospectively until hospital discharge. None of the patients received anti-arrhythmic prophylaxis. Post-operative AF was defined as an episode of AF lasting > or = 5 min. RESULTS: Quantitation of atrial fibrosis yielded a mean volume percentage of 15.8 +/- 4.3% (V%; range 4.6-32.4%). Patient age was found to correlate with the amount of atrial fibrosis (r = 0.165; P < 0.01) and surface P-wave duration (r = 0.249; P < 0.01). The degree of fibrosis combined with P-wave duration predicted post-operative AF (P < 0.01). Age (> 60 years) and P-wave duration (> or = 100 ms) were independent predictors of post-operative AF (age: relative risk 2.20; P-wave: relative risk 2.69; P < 0.05). The patients were divided into three groups: group 1, V% = 4.6-13.8%; group 2, V% = 13.9-23.1%; group 3, V% = 23.2-32.4%. A total of 52 patients (20.1%) developed AF, which occurred least commonly in group 1 (16.3%) and group 2 (21.2%) as compared with group 3 (33.3%). CONCLUSIONS: Atrial fibrosis provides a pathophysiological substrate for post-operative AF. The results support the importance of P-wave duration as a predictor of post-operative AF, and explain the increased prevalence of AF in elderly patients after OHS.     

The signal-averaged P-wave duration is longer in hypertensive patients with history of paroxysmal atrial fibrillation as compared to those without

BACKGROUND: Onset of atrial fibrillation in hypertensive patients is usually associated with a high occurrence of cardiovascular complications. Therefore, it is important to assess non-invasively the risk of developing paroxysmal atrial fibrillation (PAF) in hypertensive patients during sinus rhythm. This study was undertaken to determine if hypertensive patients with history of PAF could be identified while in sinus rhythm by measurement of signal-averaged ECG P-wave duration. METHODS: Signal-averaged electrocardiography (SAECG) P-wave recording was performed in 44 hypertensive patients (30 men and 14 women; mean age 60+/-11 years, group A) who had a history of paroxysmal AF and in 50 hypertensive patients without history of AF (33 men and 17 women; mean age 57+/-12, group B). All patients were also evaluated by using echocardiography to measure left ventricular ejection fraction (LVEF) and left atrial diameter (LAD). RESULTS: SAECG P-wave duration was found to be significantly higher in group A than in group B (146+/-14 ms vs. 128+/-11 ms, p<0.001). Left atrial diameter was not significantly different (40.1+/-3.4 mm vs. 39.3+/-3.0 mm, p>0.05), whereas LVEF was significantly lower in group A than group B (63+/-5% vs. 67+/-4%, p=0.03). There was a correlation between SAECG P-wave duration and age (r=0.32, p<0.05). In univariate analysis, SAECG P-wave duration and LVEF were significant predictors of PAF, but only SAECG P-wave duration remained a significant independent predictor of PAF in multivariate analysis. CONCLUSION: The results of this study indicate that hypertensive patients with history of PAF can be detected while in sinus rhythm by signal-averaged ECG P-wave duration.     

P wave dispersion and short-term vs. late atrial fibrillation recurrences after cardioversion

BACKGROUND: P wave dispersion has been previously suggested as a potential tool for predicting the risk of recurrence of atrial fibrillation after electrical cardioversion. We investigated whether different P wave dispersion values are associated with recurrence of atrial fibrillation in the short (< or =1 month after cardioversion) and longer term. METHODS: In 37 patients with long-lasting persistent atrial fibrillation (mean duration 21 +/- 36 months) with (n = 19) or without (n = 18) amiodarone pretreatment as antiarrhythmic prophylaxis, maximum and minimum P wave duration and P wave dispersion were measured 1 min after internal cardioversion. RESULTS: P wave dispersion was lower in patients with amiodarone pretreatment (28.3 +/- 9.5 vs. 21.9 +/- 7.3 ms, P = 0.029). The subgroups of patients with recurrence of atrial fibrillation at 1 month or in the long-term did not differ from the rest of the study sample regarding age, sex, atrial fibrillation duration, left atrial dimensions or ejection fraction. P wave dispersion was significantly higher in patients with short-term atrial fibrillation recurrence (< or = 1 month) than in the rest of the population. Furthermore, P wave dispersion values >25 ms were associated with a higher short-term relapse rate. No significant relation was present in the long-term. CONCLUSIONS: Our results suggest that P wave dispersion analysis immediately after internal cardioversion may help predict short-term recurrences of atrial fibrillation. These findings may be related to different mechanisms and predisposing factors for short-term and late recurrences. The long-term predictive value of serial evaluations of P wave dispersion during follow-up deserves investigation.     

Long-term effects of beta blocker therapy on P-wave duration and dispersion in congestive heart failure patients: a new effect?

Atrial fibrillation (AF) is associated with heart failure in approximately 20%-50% of patients with increased morbidity and mortality. P-wave maximum duration (PWM) and P-wave dispersion (PWD) are recent ECG markers and reflect increased risk of AF. The aim of our study was to investigate the long-term effects of metoprolol on atrial conduction abnormalities as estimated by PWM and PWD, which were calculated on 12-derivation surface ECG in heart failure patients. Forty-two NYHA class 3 to 4 patients (23 males, 19 females and aged 52.9 +/- 11.2) were enrolled in the study. At the end of the 6 months, PWM and PWD values were significantly decreased (for PWM: from 115.2 +/- 12.6 to 105.4 +/- 13.5; for PWD: from 39.3 +/- 9.1 to 28.6 +/- 10.5; P <.001 for both). Metoprolol treatment is associated with a decreased duration of PWM and PWD and this may reflect a reduction in the probability of atrial fibrillation in heart failure patients.     

Seasonal variation of P-wave dispersion in healthy subjects

We studied the seasonal variability of P dispersion in 523 healthy male patients, aged 22 +/- 4 years (range, 20-26). Four seasonal 12-lead resting electrocardiograms were recorded at 2 mV/cm standardization and at 50 mm/s paper speed at intervals of three months. Electrocardiograms were recorded between the hours 10 to 12 AM. The difference between the maximum P-wave duration and minimum P-wave duration was calculated and defined as "P dispersion." There was a significant seasonal variation in the maximum P-wave duration (P = .001) and P dispersion (P = .001), with the longest maximum P-wave duration (121 +/- 16 ms) and P dispersion (41 +/- 7 ms) observed in winter and the shortest maximum P-wave duration (106 +/- 15 ms) and P dispersion (24 +/- 8 ms) observed in summer. The minimum P-wave duration did not show any significant seasonal variation. In conclusion, there exists a significant seasonal variation in the maximum P-wave duration and P dispersion in healthy patients. Seasonal variation of P dispersion resulted from the significant variation of maximum P-wave duration.     

Acute alcohol intake and P-wave dispersion in healthy men.

OBJECTIVE: P-wave dispersion (Pd), defined as the difference between the maximum and the minimum P-wave duration (Pmin), and maximum P-wave duration (Pmax) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time, respectively. The incidence of cardiac arrhythmias, particularly atrial fibrillation (AF), following acute alcohol intake has been previously reported. Prolonged P-wave duration and Pd have been reported to represent an increased risk for AF. However, the association between Pd and acute alcohol intake has not been studied previously in normal subjects. METHODS: In a randomized crossover study, 10 healthy male volunteers, aged 30.0+/-2.1 years (range 25-33 years) received either ethanol and/or placebo (juice). Alcohol group drank moderate dose ethanol; 0.97+/-0.12 g/kg body weight (range 0.80-1.25 g/kg), and the other group consumed same amount of juice in one-hour period. After 48-hours washout period, alcohol group took juice and juice group drank alcohol. Pmax, Pmin and Pd were measured as milliseconds (ms) on baseline ECG, after alcohol period (AP) and after juice period (JP). RESULTS: In comparison with baseline, Pmax values were significantly prolonged after AP but not after JP (baseline: 95.3+/-5.3 ms, after AP: 103.7+/-9.5 ms, after JP: 94+/-7 ms, p=0.027, p=0.102, respectively). Pmin values did not change significantly. And also, in comparison with baseline, Pd values were significantly prolonged after AP but not after JP (baseline: 27.0+/-7.6 ms, after AP: 42.7+/-12.8 ms, after JP: 27.0+/-6.7 ms, p=0.021, p=0.891, respectively). CONCLUSION: Acute moderate dose of alcohol intake in short time is associated with an increase in Pmax and Pd.     

Immediate recurrence of atrial fibrillation after internal cardioversion: importance of right atrial conduction variations

This study investigates the importance of right atrial conduction features in predicting of immediate recurrence of atrial fibrillation (AF) after internal cardioversion (IC). Patients with chronic AF who were resistant to external cardioversion were studied. Twenty-four patients (16 female, 8 male mean age 58 +/- 7 years) who were successfully converted to sinus rhythm (SR) by IC, and experienced recurrence of AF within 1 minute of restoration of SR were enrolled in group A. Thirty-four patients, who were converted to SR by IC and in whom SR was maintained at least 1 minute after IC, were enrolled in group B (24 female, 10 male mean age 56 +/- 6 years) as control. There was no difference in age, left atrial diameter, use of antiarrhythmic drug, etiology and duration of AF between the groups. After successful IC, His bundle electrocardiograms via placed electrode catheters, and surface electrocardiograms were recorded for 1 minute. P-A interval duration, as a marker of right atrial conduction, was measured from the onset of the earliest registered surface P wave to the onset of the atrial deflection on His-bundle catheter recording. The difference between the recorded maximum P-A duration and minimum P-A duration obtained in 1 minute after IC was described as P-A interval absolute difference. There were no differences in the maximum P-A duration and minimum P-A duration between two groups. But, the P-A absolute difference was more pronounced in group A compared to group B (16.9 +/- 7.7 ms versus 10.3 +/- 6.4 ms, P < .001) and was significantly correlated with P wave dispersion derived from the surface electrocardiogram (r = .72, P < .001) In conclusion, variations in right atrial conduction might play an important role in predicting immediate recurrence of AF in patients converted to SR by IC.     

Long-term changes in sequence of atrial activation and refractory periods: no evidence for "atrial memory".

OBJECTIVES: The purpose of this study was to test whether the spatial distribution of the atrial refractory period (AERP) and the vulnerability to atrial fibrillation (AF) are altered by long-term changes in the sequence of atrial activation. BACKGROUND: The spatial distribution of the AERP plays an important role in AF. Changes in the activation sequence have been postulated to modulate atrial repolarization ("atrial memory"). METHODS: Six goats were chronically instrumented with epicardial atrial electrodes to determine activation time and AERP at 11 different areas of the right (RA) and left (LA) atrium and the Bachmann bundle. Activation time and AERP were measured during sinus rhythm and during prolonged RA and LA pacing (1 week RA pacing, 2 weeks LA pacing, 1 week RA pacing; 150 bpm). Inducibility of AF was determined by the number of atrial sites where single premature stimuli induced AF paroxysms >1 second. RESULTS: During sinus rhythm (106 +/- 4 bpm), AERP was longest at the Bachmann bundle and shortest at the LA free wall (185 +/- 6 ms and 141 +/- 5 ms, P < .001). In five of six goats, an inverse correlation between local activation time and AERP was found during sinus rhythm (r = -0.53 +/- 0.05; P < .05). The increase in atrial rate during RA and LA pacing caused an overall shortening of AERP from 167 +/- 6 ms to 140 +/- 6 ms (P < .001). However, a switch between long-term RA and LA pacing did not significantly change AERP at any of the 11 atrial regions and had no significant effect on AF inducibility. CONCLUSIONS: During sinus rhythm, an inverse relationship exists between the sequence of atrial activation and the local refractory period. However, long-term changes in the sequence of atrial activation do not alter the spatial distribution of AERP or the inducibility of AF.     

A novel method of multisite atrial pacing, incorporating Bachmann's bundle area and coronary sinus ostium, for electrical atrial resynchronization in patients with recurrent atrial fibrillation.

AIMS: The aim of the study was to assess efficacy and safety of a novel method of multisite atrial pacing, incorporating Bachmann's bundle (BB) and coronary sinus (CS) ostium pacing, which was implemented for the first time in atrial fibrillation (AF) patients with intra-atrial conduction delay. METHODS AND RESULTS: This follow-up study included 97 patients with drug refractory symptomatic AF, sinus node dysfunction, sinus P-wave > or = 120 ms, and normal atrioventricular conduction. Pacing efficacy was assessed on the basis of two main endpoints: successful rhythm control and the absence of documented or symptomatic AF. During the mean 2.3 +/- 0.7 years of follow-up, the survival rate was 99%, pacing maintenance rate 97%, and the need for re-operation 5%. Rhythm control efficacy was 90%, and 14 patients had no evidence of recurrent AF. After implantation, the mean number of anti-arrhythmic drugs used (P < 0.0001), the need for cardioversion (P < 0.01), and the incidence (P < 0.0001) and duration (P < 0.001) of AF-related hospitalizations decreased. P-wave duration with multisite atrial pacing was shorter than during sinus rhythm, BB, and CS pacing (P < 0.0001). CONCLUSION: A novel method of multisite atrial pacing is safe, provides effective long-term rhythm control, and decreases the necessity for adjunctive therapies in patients with refractory AF and intra-atrial conduction delay.     

Effects of short-term propylthiouracil treatment on p wave duration and p wave dispersion in patients with overt hypertyroidism.

BACKGROUND: P-wave duration is defined as the time measured from the onset to the offset of the P-wave in surface electrocardiogram (ECG). Prolonged P wave duration and increased P wave dispersion (PWD) have been reported to carry an increased risk for atrial fibrillation. AIM: Our aim was to evaluate the role of hyperthyroidism on P wave duration and dispersion, to investigate the effect of anti-thyroid therapy on P wave duration and dispersion. MATERIAL AND METHODS: A total of 44 consecutive subjects (22 patients with newly diagnosed overt hyperthyroidism and 22 randomly selected euthyroid healthy subjects) were enrolled in the study. Transthoracic echocardiography, 12 lead surface ECG and thyroid hormone levels were studied at the time of enrollment, in the first and third months of the 6-8 mg/kg/day propylthiouracil therapy. Patients were followed-up for 3 months. RESULTS: Patient and control groups were consisted of age and sex matched subjects. Baseline left atrial diameter was similar between the patient and control groups (3.4+/-0.3 cm and 3.4+/-0.3 cm respectively, p=0.813). The maximum P-wave duration (P maximum) was 113.1+/-6.6 and 105.7+/-4.1 ms in patient and control groups (p=0.001). PWD was 31.5+/-9.5 and 25.2+/-5.9 ms in patient and control groups respectively (p=0.015). At the third month of propylthiouracil treatment P maximum and PWD were decreased in the patient group at statistically significant level and returned back in normal limits (p<0.001 and p=0.001). CONCLUSION: P wave duration and PWD are found prolonged in hyperthyroid patients and propylthiouracil treatment decreased them effectively. This mechanism may establish how the anti-thyroid treatment may prevent the development of atrial fibrillation in hyperthyroid patients.     

Comparison of effects of nebivolol and atenolol on P-wave dispersion in patients with hypertension

BACKGROUND: P-wave dispersion has been shown to be a noninvasive electrocardiographic predictor for development of atrial fibrillation . Thus it may be possible to attenuate atrial fibrillation risk through normalization of P-wave variables and improvement in P-wave dispersion may be an important goal in treatment of hypertension. OBJECTIVE: To compare the effects of nebivolol, a new b-blocker that have additional vasodilating activity via acting on endothelium and nitric oxide release, and atenolol on P-wave duration and dispersion in patients with mild-to-moderate hypertension. METHODS: A total of 34 newly-diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either nebivolol (5 mg) or atenolol (50 mg). P-wave durations (Pmin and Pmax) and P-wave dispersion were measured before and one month after treatment. RESULTS: While Pmin increased (50,6 +/- 11,2 ms to 54,7 +/- 9,1 ms, p=0,05), Pmax decreased (111,9 +/- 9,1 ms to 104,0 +/- 12,4 ms, p=0,003) and P-wave dispersion decreased (62,5 +/- 10,6 ms to 51,3 +/- 8,9 ms, p < 0,001) with nebivolol, Pmin increased (44,4 +/- 9,8 ms to 58,0 +/- 15,5 ms, p=0,02), Pmax didn t change (106,1 +/- 13,8 ms to 107,0 +/- 11,6 ms, p=NS) and P-wave dispersion decreased (61,7 +/- 15,0 ms to 49,0 +/- 13,7 ms, p < 0.001) with atenolol. However, there was no statistical difference between pre- and post-treatment values of two groups. CONCLUSIONS: Both nebivolol and atenolol are effective in improvement of P-wave dispersion in patients with hypertension and there s no significant difference between them.     

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     

Investigation of the predictors of transition to persistent atrial fibrillation in patients with paroxysmal atrial fibrillation

BACKGROUND: Until now, no clinically useful indicators have existed that predict the transition from paroxysmal to persistent atrial fibrillation (AF). HYPOTHESIS: The current prospective study was conducted for identifying predictors of progression to persistent AF over the long term. METHODS: We studied 102 consecutive patients (mean age: 55 +/- 10 years: 75 men and 27 women) diagnosed with paroxysmal AF. Standard 12-lead electrocardiography, echocardiography, and P-wave-triggered signal-averaged electrocardiography (P-SAECG) were performed on all patients at the time of their entry into the study. RESULTS: The mean follow-up period was 61 +/- 13 months. Group 1 (n = 66) comprised patients in whom paroxysmal AF did not progress to persistent AF, and Group 2 (n = 36) comprised those who developed persistent AF. In Group 2 the patients were significantly older, and P-wave dispersion, filtered P-wave duration (FPD), and left atrial dimension were significantly higher than in Group 1 (p < 0.05). The root mean square voltage for the last 30 ms of the filtered P-wave was also significantly lower in Group 2 (p < 0.05). Multivariate logistic regression analysis using these five factors identified left atrial dimension (odds ratio [OR] 2.29; 95% confidence interval [CI] 1.16-4.54; p = 0.02) and FPD (OR 2.71; 95% CI 1.78-4.13; p < 0.01) as independent predictors of transition to persistent AF. Left atrial dimension > or = 40 mm predicted progression to persistent AF with a sensitivity of 64%, specificity of 76%, positive predictive value of 59%, negative predictive value of 79%, and an accuracy of 71%. An FPD > or = 150 ms predicted persistent AF with a sensitivity of 81%, specificity of 91%, positive predictive value of 88%, negative predictive value of 90%, and an accuracy of 87%. Filtered P-wave duration was a significantly more sensitive and specific predictor than left atrial dimension (p < 0.05). CONCLUSION: We conclude that FPD is a clinically useful predictor of progression from paroxysmal to persistent AF over the long term.     

Effect of ethnicity and hypertension on atrial conduction: evaluation with high-resolution P-wave signal averaging

BACKGROUND: Measurements by P-wave signal-averaged electrocardiogram (P-SAECG) of P-wave duration and P-wave voltage integral are higher in patients with atrial fibrillation (AF) than in those with sinus rhythm. Hypertension is perhaps the most common cardiovascular antecedent cause of AF, and particularly a disproportionate cause of morbidity and mortality among blacks. The purpose of this study was to examine the effect of hypertension and ethnicity on P-SAECG parameters in patients without AF. HYPOTHESIS: It was hypothesized that P-SAECG parameters can identify hypertensives, and are disproportionately higher in hypertensive blacks. METHODS: In all, 234 normotensives and 84 hypertensives underwent P-SAECG analysis. In an ancillary study group of 34 hypertensive black men, the relationship between severity of hypertension and measured parameters of P-SAECG was evaluated. RESULTS: Mean filtered P-wave duration and total P-wave voltage integral for normotensives of both ethnic groups were similar. Hypertensive blacks had greater increase in P-wave duration (138 +/- 16 vs. 132 +/- 12ms;p < 0.01, N42:42) and total P-wave voltage integral (922 +/- 285 vs. 764 +/- 198 microV-ms; p < 0.001) than white hypertensives. Filtered P-wave duration and total P-wave voltage integral increased with severity of hypertension. CONCLUSIONS: Patients at very early stages of hypertension have demonstrable evidence of prolonged atrial conduction by P-SAECG and, thus, cardiac electrical remodeling. P-wave duration and total P-wave voltage integral increase with severity of hypertension. Hypertensive blacks manifest a greater increase in P-SAECG parameters than whites. This may portend an increased cardiovascular risk for black patients with hypertension.     

Predictors of atrial fibrillation after coronary artery bypass surgery

OBJECTIVE: Atrial fibrillation is one of the most common arrhythmias associated with not only increased morbidity after coronary artery bypass grafting but also increased healthcare costs. Many factors are associated with atrial fibrillation onset after coronary artery bypass grafting. We prospectively examined which factors could predict atrial fibrillation after coronary artery bypass grafting. METHODS: Fifty-seven consecutive patients (37 men, mean age=60.2+/-12 years) with sinus rhythm before coronary artery bypass grafting are included the study. Clinical, demographic, laboratory and echocardiographic characteristics are all evaluated prospectively. The maximum and minimum P-wave duration (P(max) and P(min)) were measured from the 12-lead surface electrocardiogram. The difference between the P(max) and the P(min) was calculated and defined as P-wave dispersion. Preoperative venous blood samples were taken for N-terminal proBrain natriuretic peptide level analysis. RESULTS: Ten (17%) patients had postoperative atrial fibrillation. Patients with postoperative atrial fibrillation were older (69.4+/-6 versus 58.2+/-12 years, P=0.01), had lower ejection fraction (44.1+/-8.9% versus 54.3+/-9; P=0.002), higher proBrain natriuretic peptide levels (538+/-136 pg/ml versus 293+/-359 pg/ml; P=0.03), longer P(max) (142.2+/-13.7 ms versus 120.8+/-21.2 ms; P=0.006) and longer P-wave dispersion (55.0+/-8.2 ms versus 41.3+/-14.3 ms; P=0.008) compared with the patients without atrial fibrillation. Univariate analysis showed that increased age (P=0.01), lower ejection fraction (P=0.02), enlargement of left atrium (P=0.02), increased P(max) (P=0.006) and increased P-wave dispersion (P=0.008) and increased level of preoperative proBrain natriuretic peptide (P=0.03) were associated with postoperative atrial fibrillation. Positive correlation was seen between the age and level of proBrain natriuretic peptide (r=0.322 and P=0.015). In multivariate analysis, age (P=0.05), lower ejection fraction (P=0.03), left atrial enlargement (P=0.05), longer P(max) (P=0.01) and P-wave dispersion (P=0.01) were found to be independent predictors of postoperative atrial fibrillation. CONCLUSION: Age, poor left ventricular functions, P(max) and P-wave dispersion are found to be independent predictors of atrial fibrillation after coronary artery bypass grafting.     

The effect of atrial preference pacing on atrial fibrillation electrophysiological substrate in Myotonic Dystrophy type 1 population

P-wave dispersion is a non invasive indicator of intra-atrial conduction heterogeneity producing substrate for reentry, which is a pathophysiological mechanism of atrial fibrillation. The relationship between P-wave dispersion (PD) and atrial fibrillation (AF) in Myotonic dystrophy type 1 (DM1) patients is still unclear. Atrial Preference Pacing (APP) is an efficient algorithm to prevent paroxysmal AF in patients implanted with dual-chamber pacemaker. Aim of our study was to evaluate the possible correlation between atrial preference pacing algorithm, P-wave dispersion and AF burden in DM1 patients with normal cardiac function underwent permanent dual-chamber pacemaker implantation.We enrolled 50 patients with DM1 (age 50.3 ± 7.3; 11 F) underwent dual-chamber pacemaker implantation for various degree of atrioventricula block. The study population was randomized following 1 months stabilization period to APP algorithm features programmed OFF or ON. Patients were assessed every 3 months for the first year, and every 6 months thereafter up to 3 years. At each follow-up visit, we counted: the number of premature atrial beats, the number and the mean duration of AF episodes, AF burden and the percentage of atrial and ventricular pacing.APP ON Group showed lower number of AF episodes (117 ± 25 vs. 143 ± 37; p = 0.03) and AF burden (3059 ± 275 vs. 9010 ± 630 min; p < 0.04) than APP OFF Group. Atrial premature beats count (44903 ± 30689 vs. 13720 ± 7717 beats; p = 0.005) and Pwave dispersion values (42,1 ± 11 ms vs. 29,1 ± 4,2 ms, p = 0,003) were decreased in APP ON Group. We found a significant positive correlation between PD and AF burden (R = 0,8, p = 0.007).Atrial preference pacing algorithm, decreasing the number of atrial premature beats and the P-wave dispersion, reduces the onset and perpetuator factors of AF episodes and decreases the AF burden in DM1 patients underwent dual chamber pacemaker implantation for various degree of atrioventricular blocks and documented atrial fibrillation.Key words: atrial fibrillation, Myotonic Dystrophy, atrial preference pacing