Atrial fibrillation after coronary artery bypass grafting in elderly patients: incidence and risk factor analysis

OBJECTIVE: New-onset atrial fibrillation (AF) is the most frequent arrhythmic complication after coronary artery bypass grafting (CABG). Elderly patients who undergo this operation may have a different risk profile from the general population. The aim of this study was to identify risk factors for post-CABG AF in the elderly population. METHODS: Between September 2001 and December 2005, 426 elderly patients (age >/= 65 years) underwent CABG at our center. Ninety-one developed post-CABG AF (AF group), and the other 335 (no-AF group) did not develop this complication. Multivariate analysis (odds ratio, +/- 95 % CI, P value) was used to identify independent clinical predictors of post-CABG AF. RESULTS: The incidence of post-CABG AF in elderly patients during the study period was 21.4 %. Multivariate analysis identified age (OR 1.07, P < 0.009), age >/= 75 years (OR 1.77, P < 0.042), preoperative renal insufficiency (OR 5.09, P < 0.035), EuroSCORE (OR 1.18, P < 0.038), and cross-clamping time (OR 1.02, P < 0.012) as predictors of AF occurrence. The AF group had a significantly longer mean intensive care unit (ICU) stay (3.8 +/- 4.7 vs. 2.5 +/- 1.3 days for AF vs. no-AF; P = 0.0001), and a significantly higher proportion of patients with prolonged (>/= 6 days) ICU stays (8.8 % vs. 3.2 %, respectively; P = 0.033). Hospital mortality was 3.2 % in the no-AF group and 2.2 % in the AF group ( P = 0.74). CONCLUSION: This study of elderly patients reveals some novel predictors of post-CABG AF, most notably preoperative renal insufficiency and EuroSCORE. It is important to identify risk factors for post-CABG AF in all patient groups as this knowledge might lead to better prevention of this problem and its potential consequences.     

Role of atrial electrophysiology and autonomic nervous system in patients with supraventricular tachycardia and paroxysmal atrial fibrillation

Objectives. The purposes of this study were to evaluate the atrial electrophysiology and autonomic nervous system in patients who had paroxysmal supraventricular tachycardia (PSVT) associated with paroxysmal atrial fibrillation (PAF).Background. PAF frequently appeared in patients with PSVT. However, the critical determinants for the occurrence of PAF were not clear.Methods. This study population consisted of 50 patients who had PSVT with (n = 23) and without (n = 27) PAF. Atrial pressure, atrial size, atrial effective refractory periods (AERPs), and AERP dispersion were evaluated during baseline and PSVT, respectively. Twenty-four hour heart rate variability and baroreflex sensitivity (BRS) were also examined.Results. There was greater baseline AERP dispersion in patients with PAF than in those without PAF. The atrial pressure, atrial size, AERPs in the right posterolateral atrium and distal coronary sinus, and AERP dispersion were increased during PSVT as compared with those during baseline. Patients with PAF had greater AERP dispersion than those without PAF during PSVT. The differences of atrial size, right posterolateral AERP, and AERP dispersion between baseline and PSVT were greater in patients with PAF than in those without PAF. BRS, but not heart rate variability, was higher in patients with PAF than in those without PAF. Univariate analysis showed that higher BRS (>4.5 ms/mm Hg, p = 0.0002, odds ratio = 16.1), AERP dispersion during PSVT (>40 ms, p = 0.0008, odds ratio = 9.7), and increase of right atrial area during PSVT (>2 cm², p = 0.016, odds ratio = 10.7) were significantly correlated with the occurrence of PAF in patients with PSVT.Conclusions. Disturbed atrial electrophysiology and higher vagal reflex could play important roles in the genesis of PAF in patients with PSVT.     

Value of preoperative echocardiography in the prediction of postoperative atrial fibrillation following isolated coronary artery bypass grafting

The value of echocardiography, especially tissue Doppler imaging (TDI), in the assessment of risk of postoperative atrial fibrillation (AF) after coronary artery bypass grafting (CABG) is not clear. One hundred two consecutive patients (80 men; mean age 61 +/- 10 years) who underwent elective isolated CABG were included in the study. All patients underwent conventional transthoracic echocardiography and TDI of the left and right heart before surgery. Also, 24-hour Holter recordings were obtained for all patients. The study end point was the development of postoperative AF. The surgical mortality rate was 2%. Postoperative AF occurred in 18 patients (18%). Patients with postoperative AF have been significantly older than patients without postoperative AF (73 +/- 7 vs 58 +/- 9 years, respectively; p <0.001). Compared with patients without postoperative AF, a significantly higher proportion of patients with postoperative AF experienced paroxysmal AF before surgery (6% vs 33%, respectively; p = 0.001). Patients with postoperative AF had a significantly larger mean left atrial diameter compared with patients without postoperative AF (37 +/- 3 vs 35 +/- 3 mm, respectively; p = 0.012). Multivariate logistic regression analysis identified age as the most significant predictor of postoperative AF (odds ratio 1.254, 95% confidence interval 1.127 to 1.396; p <0.001). Of the echocardiographic variables, only left atrial diameter was identified as a significant predictor of postoperative AF (odds ratio 1.250, 95% confidence interval 1.055 to 1.562; p = 0.047). In conclusion, in the prediction of postoperative AF after isolated CABG, preoperative transthoracic echocardiography, including both conventional echocardiography and TDI, is of little value.     

N-acetylcysteine for the prevention of postoperative atrial fibrillation: a prospective, randomized, placebo-controlled pilot study.

AIMS: Oxidative stress has recently been implicated in the pathophysiology of atrial fibrillation (AF). The aim of the present study was to evaluate the effects of antioxidant agent N-acetylcysteine (NAC) on postoperative AF. METHODS AND RESULTS: The population of this prospective, randomized, double-blind, placebo-controlled study consisted of 115 patients undergoing coronary artery bypass and/or valve surgery. All the patients were treated with standard medical therapy and were randomized to NAC group (n = 58) or placebo (saline, n = 57). An AF episode >5 min during hospitalization was accepted as endpoint. During follow-up period, 15 patients (15/115, 13%) had AF. The rate of AF was lower in NAC group compared with placebo group (three patients in NAC group [5.2%] and 12 patients in placebo group [21.1%] had postoperative AF; odds ratio [OR] 0.20; 95% confidence interval [CI] 0.05 to 0.77; P = 0.019). In the multivariable logistic regression analysis, independent predictors of postoperative AF were left atrial diameter (OR, 1.18; 95% CI, 1.06-1.31; P = 0.002) and the use of NAC (OR, 0.20; 95% CI, 0.04-0.91; P = 0.038). CONCLUSION: The result of this study indicates that NAC treatment decreases the incidence of postoperative AF.     

Usefulness of P-wave dispersion in standard twelve-lead electrocardiography to predict transition from paroxysmal to persistent atrial fibrillation

A prospective study was conducted to investigate the validity of the hypothesis that P-wave dispersion (Pd) may be a clinically useful predictor of progression from paroxysmal to persistent atrial fibrillation (AF). Two hundred four consecutive patients with a diagnosis of paroxysmal AF were studied. Standard 12-lead electrocardiography and echocardiography were performed on all patients at the time of entry into the study. Pd was measured as the difference between maximum and minimum P-wave duration in any of the 12 leads. Mean follow-up was 66 +/- 8 months. Group I included patients (n = 132) in whom paroxysmal AF did not progress to persistent AF, and group II included those (n = 72) who developed persistent AF. In group II, age, percentage of men, percentage of patients with diabetes mellitus, maximum P-wave duration, Pd, and left atrial dimension were significantly higher than in group I (p <0.05). Multivariate logistic regression analysis using these 6 factors identified age (odds ratio 2.18, 95% confidence interval 1.41 to 3.41, p <0.01) and Pd (odds ratio 1.91, 95% confidence interval 1.51 to 2.44, p <0.01) as independent predictors of a transition to persistent AF. Pd >or=40 ms predicted progression to persistent AF with sensitivity of 71%, specificity of 77%, positive predictive value of 63%, negative predictive value of 83%, and accuracy of 75%. In conclusion, Pd was a clinically useful predictor of progression from paroxysmal to persistent AF.     

Association of inflammation with atrial fibrillation in hyperthyroidism

Objectives The aim of this study was to evaluate the relationship between inflammation and development of atrial fibrillation (AF) in patients with hyperthyroidism. Methods A total of 65 patients with newly diagnosed hyperthyroidism, 35 of whom were in sinus rhythm and 30 of whom in AF. Thirty five age- and gender-matched patients in a control group were included in the study. Factors associated with the development of AF were evaluated by multivariate regression analysis. Results Factors associated with AF in multivariate analysis included high sensitivity C reactive protein [(HsCRP); odds ratio (OR): 11.19; 95% confidence interval (95% CI): 1.80-69.53; P = 0.003], free T4 (OR: 8.76; 95% CI: 2.09–36.7; P = 0.003), and left atrial diameter (OR: 1.25; 95% CI: 1.06–1.47; P = 0.008). Conclusions The results of the present study suggest that high sensitivity C reactive protein, an indicator of inflammation, free T4 and left atrial diameter are associated with the development AF in patients with hyperthyroidism.     

Supervulnerable phase immediately after termination of atrial fibrillation

INTRODUCTION: Recent studies with the implantable atrial cardioverter have shown that atrial fibrillation (AF) recurs almost immediately after successful cardioversion in about 27% of cases. In the present study, we determined the electrophysiologic properties of the caprine atrium immediately after spontaneous termination of AF both before and after 48 hours of AF-induced electrical remodeling. METHODS AND RESULTS: In eight goats, atrial effective refractory period (AERP), intra-atrial conduction velocity, and atrial wavelength were measured during sinus rhythm both before (t = 0) and after 48 hours (t = 48) of electrically maintained AF (baseline). After baseline, a 5-minute paroxysm of AF was induced, during which the refractory period (RPAF) was determined. AERP, conduction velocity, and atrial wavelength also were measured immediately after spontaneous restoration of sinus rhythm (post-AF values). Both in normal and remodeled atria, immediately after AF, AERP and conduction velocity were markedly decreased compared with baseline (P < 0.01). In normal atria, post-AF AERP (107+/-14 msec) gradually prolonged from its AF value (114+/-17 msec) to its baseline value (138+/-13 msec). Conduction velocity decreased from 130+/-9 cm/sec to 117+/-9 cm/sec. After 48 hours of AF, AERP had shortened to 74+/-8 msec. RPAF was 89+/-9 msec. Surprisingly, immediately after termination of AF, AERP shortened further to 58+/-6 msec (P < 0.01). Post-AF conduction velocity decreased from 136+/-11 cm/sec to 122+/-10 cm/sec (P < 0.01). As a result, the post-AF atrial wavelength became as short as 7.1+/-1 cm. These changes were transient, and all parameters gradually returned to baseline within 1 to 2 minutes after conversion of AF. CONCLUSION: Due to a combined decrease in AERP and conduction velocity, marked shortening of the atrial wavelength occurs during the first minutes after conversion of AF. In electrically remodeled atria, this results in a transient ultrashort value of AERP (<60 msec) and atrial wavelength (7.1 cm). These observations imply a highly vulnerable substrate for reentry immediately after termination of AF. During this supervulnerable phase, both early and later premature beats reinitiated immediate recurrences of AF.     

Impairment of left atrial function predicts post-operative atrial fibrillation after coronary artery bypass graft surgery.

AIMS: Despite the prevalence of atrial fibrillation (AF) occurring after cardiac surgery, its pathophysiology is incompletely understood. Specifically, whether left atrial (LA) structural remodelling occurs, contributing to a decrement in atrial function and AF has not been previously determined. This study sought to determine the relationship between LA function and post-operative AF. METHODS AND RESULTS: Three hundred patients undergoing elective coronary artery bypass graft surgery were monitored with intraoperative transoesophageal echocardiography to determine LA function and dimensions. Post-operative AF was monitored with continuous telemetry until hospital discharge. The relationship between clinical factors versus LA function and dimension was assessed using multi-variate logistic regression. By univariate analysis, patients who subsequently developed post-operative AF had a larger LA area and LA appendage area, and lower LA ejection fraction measured in the pre-bypass period compared to those without subsequent AF. By multivariable analysis, in addition to clinical data including age (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05-1.16, P<0.0001), body surface area (OR 13.31, 95% CI 1.87-94.5, P=0.0097) and white race, post-bypass atrial systolic function (atrial filling fraction 0.36, OR 2.51, 95% CI 1.03-6.13, P=0.04) and abnormal relaxation of the left ventricle (E duration 270 ms) (OR 2.89, 95% CI 1.34-6.24, P=0.0067) independently increased the risk of post-operative AF. CONCLUSION: These results demonstrate that some of the structural and functional changes in the atria common to chronic AF in the elderly population are also prevalent in surgical patients who develop post-operative AF, suggesting that post-operative and chronic AF may have similar pathophysiology.     

Prognostic value of preoperative atrial fibrillation in patients with aortic stenosis and low ejection fraction having aortic valve replacement

Aortic valve replacement in severe aortic stenosis (AS) with a low left ventricular ejection fraction (EF) is associated with high perioperative mortality. The aim of this study was to assess the prognostic value of preoperative atrial fibrillation (AF) in patients with AS and low EFs who undergo aortic valve replacement. Eighty-three consecutive patients with severe AS (area <1 cm2) and low EFs (< or =35%) were prospectively included. Perioperative mortality was 12%. Twenty-nine patients (35%) had preexisting paroxysmal or permanent AF. Perioperative mortality was higher in the AF group than in the non-AF group (24% vs 5.5%, p = 0.03). Preoperative AF was identified as an independent predictor of perioperative mortality (odds ratio 7.5, 95% confidence interval 1.19 to 47.06, p = 0.03). Five-year overall survival was lower in the AF group than in the non-AF group (47% vs 77%, p = 0.0017). Associated multivessel coronary artery disease and preoperative AF were identified as 2 independent predictors of overall mortality. In conclusion, in patients with AS with low left ventricular EFs, preoperative AF is associated with higher operative risk and lower postoperative survival. The presence of AF in patients with severe AS and low EFs should be taken into account for operative risk stratification, along with low pressure gradient and associated multivessel coronary artery disease.     

室上速并发心房颤动的电生理研究

目的探讨室上速并发心房颤动(房颤)的电生理特性及其发生机制。方法对38例室上速患者,根据有无房颤史分为两组,即房颤组18例,无房颤组20例。分别测量两组室上速周长、心房内压、心房各部位有效不应期、心房不应期离散度、心房最大不应期与室上速周长的比值,所有对象均行射频消融术治疗室上速,并行为期半年的随访,观察两组病人房颤的发生情况。结果房颤组与无房颤组的室上速周长分别为（326±9）ms,（331±11）ms,P>0.05。在窦性心律与室上速发作时,房颤组的心房不应期离散度均较无房颤组增加,房颤组的心房最大不应期与室上速周长的比值比无房颤组明显增加（P<0.05）。房颤组的心房最大不应期比无房颤组增加（P<0.05）,但却发生在心房的不同部位。结论(1)室上速合并房颤与室上速周长无明显关系。(2)心房不应期离散度是室上速合并房颤发生和维持的一个重要机制。(3)心房最大不应期与室上速周长的比值可能是室上速诱发房颤的另一个机制。     

Clinical and Prognostic Significance of Atrial Fibrillation in Acute Myocardial Infarction

The clinical significance of the time of onset of atrial fibrillation (AF) was investigated in patients with acute myocardial infarction (AMI). Among 1,039 patients with AMI, 100 (9.6%) had AF. These patients were divided into 3 groups: AF group 1 (n = 45), who developed AF within 24 hours of the onset of AMI; AF group 2 (n = 41), who developed AF>24 hours after the onset of AMI; and AF group 3 (n = 14), who developed AF before the onset of AMI. The infarct-related lesion was most frequent (67%) in the proximal right coronary artery in AF group 1 (p <0.01). Right atrial pressure was most significantly increased in AF group 1. The left atrial dimension and pulmonary arterial wedge pressure were most significantly increased, and left ventricular ejection fraction was most significantly decreased in AF group 2. In the acute phase, the frequencies of heart failure, cardiogenic shock, and in-hospital mortality were higher for all 3 AF groups than the sinus group (p <0.01). The long-term survival rate was significantly lower in AF group 1 and AF group 2 than in the sinus group. AF was an independent predictor of cardiac death in both AF group 1 (odds ratio 2.5; 95% confidence interval 1.2 to 5.0; p = 0.0012) and AF group 2 (odds ratio 3.7; 95% confidence interval 1.8 to 7.5; p = 0.0005), but not in AF group 3. The onset time of AF appears to be a useful parameter for evaluating the cardiac status and prognosis of patients with AMI.     

风心病慢性房颤心外膜标测心房有效不应期的对比研究

目的:研究风心病慢性房颤的电生理特征。方法:对29例风心病伴或不伴慢性房颤的病人在行二尖瓣置换术时,采用心外膜标测技术测定左、右心房各部位的有效不应期(AERP)及右房内和房间的传导时间。结果:风心病慢性房颤组左、右心房AERP比窦性心律明显缩短(P<0.05),左、右心房各部分的AERF,之间有明显差异(P< 0.01),即存在明显离散性;慢性房颤组的右房和房间传导时间在转复为窦性心律和缩短刺激右房高位问期时均显著长于正常对照组(P<0.05)。结论:风心病慢性房颤心房各部位AERP的差异反映了其AERP的离散性,而AERP 的离散性在房颤的诱发和维持过程中起着重要作用。     

Left atrial size may predict exercise capacity and cardiovascular events in patients with heart failure

Our aim was to investigate, in patients with heart failure, the relationship between left atrial size and exercise capacity and cardiovascular events. Seventy-five patients (67 men and 8 women; mean age, 53.4 +/- 8.8 yr) with left ventricular ejection fractions of < or =0.45 (New York Heart Association functional classes I-III) were matched by age and sex with 20 healthy control subjects. Echocardiographic examinations were performed, as was exercise testing by the modified Bruce protocol. Patients were monitored for a period of 330 to 480 days for cardiac death or for heart failure that required hospitalization. The indexed left atrial diastolic size (beta level = -0.534, P <0.001) and left ventricular late diastolic filling velocity (beta level = 0.247, P <0.017) were the most important values in predicting low exercise capacity. The only independent predictor of low exercise capacity (<5 METS) was the indexed left atrial diastolic size (odds ratio, 1.428; 95% confidence interval, 1.09-1.702; P <0.001). Every 1 mm/m2 increase in indexed left atrial diastolic dimension caused a 42.8% increase in the risk of severe heart failure (exercise capacity, <5 METS). Independent predictors for cardiovascular events were indexed as left atrial systolic size (odds ratio, 1.383; 95% confidence interval, 1.145-1.671; P <0.001) and left ventricular early diastolic/late diastolic filling velocity (odds ratio, 1.096; 95% confidence interval, 1.010-1.189; P <0.027). Indexed left atrial diastolic and left atrial systolic size predict exercise capacity and cardiovascular events, respectively, in New York Heart Association functional class I through III heart failure patients.     

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.     

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.     

Verapamil prevents stretch-induced shortening of atrial effective refractory period in langendorff-perfused rabbit heart

INTRODUCTION: Atrial dilation and rapid pacing reduce atrial effective refractory periods (AERPs), thereby increasing the susceptibility to sustained atrial fibrillation (AF) in Langendorff-perfused rabbit hearts. It is unclear whether similar pathophysiologic mechanisms are operative in short-term electrophysiologic changes caused by dilation and rapid pacing. Therefore, we analyzed whether both forms of short-term electrophysiologic changes are similarly affected by pharmacologic interventions acting on different potential mechanisms underlying these changes. METHODS AND RESULTS: Thirty Langendorff-perfused rabbit hearts underwent a protocol with stepwise increase of intra-atrial pressure from 0 to 12 cm H2O followed by 10 minutes of rapid pacing at 4 cm H2O. The protocol was repeated after addition of glibenclamide (10 micromol/L, n = 7), cariporide (1 micromol/L, n = 7), or verapamil (1 micromol/L, n = 9). In the basal state, increase of intra-atrial pressure from 0 to 12 cm H2O decreased AERPs from 85 +/- 11 to 55 +/- 9 msec (P < 0.01), rapid pacing at low intra-atrial pressure (4 cmH2O) decreased AERP to a similar extent, from 81 +/- 11 to 60 +/- 10 (P < 0.01). At higher intra-atrial pressure, decrease of AERP was more pronounced (10 cm H2O: 37 +/- 2 msec) (n = 7). Addition of verapamil decreased basal AERP from 86 +/- 10 msec to 68 +/- 11 msec (P < 0.05). Short-term electrophysiologic changes due to atrial dilation were abolished; changes due to rapid pacing were reduced but still present. Glibenclamide and cariporide had no significant effect. CONCLUSION: Langendorff-perfused rabbit heart is a suitable model for studying short-term electrophysiologic changes due to both rapid pacing and atrial dilation. AERPs are shortened to a similar extent by both mechanisms, whereas a combination of the two leads to more pronounced AERP reduction. Calcium overload plays a crucial role in short-term electrophysiologic changes caused by atrial dilation, whereas atrial ischemia or acidosis has no significant impact.     

Enhanced dispersion of atrial refractoriness as an electrophysiological substrate for vulnerability to atrial fibrillation in patients with paroxysmal atrial fibrillation.

Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been related to an increase in heterogeneity of atrial refractoriness that facilitates the occurrence of multiple reentry wavelets and vulnerability to AF. AIM: To examine the relationship between dispersion of atrial refractoriness (Disp_A) and vulnerability to AF induction (A_Vuln) in patients with clinical paroxysmal AF (PAF). METHODS: Thirty-six patients (22 male; age 55+/-13 years) with > or =1 year of history of PAF (no underlying structural heart disease--n=20, systemic hypertension--n=14, mitral valve prolapse--n=1, surgically corrected pulmonary stenosis--n=1), underwent electrophysiological study (EPS) while off medication. The atrial effective refractory period (AERP) was assessed at five different sites--high (HRA) and low (LRA) lateral right atrium, high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus--during a cycle length of 600 ms. AERP was taken as the longest S1-S2 interval that failed to initiate a propagation response. Disp_A was calculated as the difference between the longest and shortest AERP. A_Vuln was defined as the ability to induce AF with 1-2 extrastimuli or with incremental atrial pacing (600-300 ms) from the HRA or dCS. The EPS included analysis of focal electrical activity based on the presence of supraventricular ectopic beats (spontaneous or with provocative maneuvers). The patients were divided into group A--AF inducible (n=25) and group B--AF not inducible (n=11). Disp_A was analyzed to determine any association with A_Vuln. Disp_A and A_Vuln were also examined in those patients with documented repetitive focal activity. Logistic regression was used to determine any association of the following variables with A_Vuln: age, systemic hypertension, left ventricular hypertrophy, left atrial size, left ventricular function, duration of PAF, documented atrial flutter/tachycardia and Disp_A. RESULTS: There were no significant differences between the groups with regard to clinical characteristics and echocardiographic data. AF was inducible in 71% of the patients and noninducible in 29%. Group A had greater Disp_A compared to group B (105+/-78 ms vs. 49+/-20 ms; p=0.01). Disp_A was >40 ms in 50% of the patients without A_Vuln and in 91% of those with A_Vuln (p=0.05). Focal activity was demonstrated in 14 cases (39%), 57% of them with A_Vuln. Disp_A was 56+/-23 ms in this group and 92+/-78 ms in the others (p=0.07). Using logistic regression, the only predictor of A_Vuln was Disp_A (p=0.05). CONCLUSION: In patients with paroxysmal AF, Disp_A is a major determinant of A_Vuln. Nevertheless, the degree of nonuniformity of AERP appears to be less important as an electrophysiological substrate for AF due to focal activation.     

Chronic obliterative arterial disease of the lower limbs in the coronary patient: prevalence and prognostic incidence. The Monica Toulouse register]

PURPOSE: This study was aimed at evaluating the prevalence of peripheral arterial disease of the lower extremities and its prognostic value in a population of patients from the Haute-Garonne department, who were hospitalized for acute coronary artery disease. METHODS: Between 1985 and 1991, four thousands three hundred and sixty-eight patients (3,680 males and 688 females) presenting with acute coronary artery disease were included in the study. RESULTS: The prevalence of peripheral arterial disease of the lower extremities was 13.4%, increasing with age and being higher in male patients. In regard to patients hospitalized for acute myocardial infarction (n = 2,417), independent relationships were observed between the 28-day mortality and the following: patient's age (odds ratio: 1.02; 95% confidence interval: 1.01-1.04; P < 0.0005), female gender (odds ratio: 1.32; 95% confidence interval: 1.17-1.54; P < 0.002), inclusion in the study (odds ratio 0.95; 95% confidence interval: 0.90-0.99; P < 0.02), previous coronary artery disease (odds ratio: 2.88; 95% confidence interval: 2.32-3.48; P < 0.0001), and peripheral arterial disease (odds ratio: 1.61; 95% confidence interval: 1.26-2.06; P < 0.0001). CONCLUSION: The prevalence of peripheral arterial disease of the lower extremities is high in patients with acute coronary artery disease in both genders, whatever the age. This disease is therefore an independent marker of mortality for acute myocardial infarction. Easy diagnosis of peripheral arterial disease of the lower limbs by measurement of the ankle pressure index allows identification of patients prone to death from acute myocardial infarction.     

Plasminogen activator inhibitor-1 in patients with atrial arrhythmias during acute myocardial infarction, treated with streptokinase.

Atrial arrhythmias (AA), especially atrial fibrillation (AF), during acute myocardial infarction (AMI) are often associated with increased mortality and heart failure. Impaired fibrinolysis with elevated plasminogen activator inhibitor-1 (PAI-1) activity is associated with resistance to fibrinolytic therapy in AMI patients, but it is also found in patients with AF. Our aim was a prospective study of the role of pre-treatment PAI-1 levels for the presence of AA in AMI patients and the influence of AA on in-hospital mortality. In 116 AMI patients, treated with streptokinase, pre-treatment PAI-1 levels were estimated by the chromogenic method (normal levels, 0.3-3.5 U/ml) and in-hospital AA were assessed as atrial fibrillation, flutter and/or tachycardias. Between patients with and without AA, a significant difference was observed in mean pre-treatment PAI-1 levels, in several in-hospital complications and mortality (24 versus 4.4%; P < 0.01; odds ratio, 6.45; 95% confidence interval, 1.66-25.0). The PAI-1 level > 7 U/ml was the most significant independent pre-treatment risk factor for AA (P < 0.05; odds ratio, 3.5; 95% confidence interval, 1.15-10.6). We conclude that AA were a significant risk for in-hospital mortality of AMI patients, treated with streptokinase. A pre-treatment PAI-1 level > 7 U/ml was the most significant pre-treatment risk for AA in these patients.     

Predictors of early recurrence and delayed cure after segmental pulmonary vein isolation for paroxysmal atrial fibrillation without structural heart disease

Background Early recurrence of atrial fibrillation (ERAF) and delayed cure are commonly observed after atrial fibrillation (AF) ablation. The purpose of this study was to determine the predictors of ERAF and delayed cure after a single pulmonary vein isolation (PVI) performed in paroxysmal AF patients without structural heart disease.Methods and results In 108 consecutive patients (93 men, 15 women; mean age 51 ± 8 years) with paroxysmal AF and no structural heart disease, segmental PVI guided by a Lasso catheter was performed. Forty-one percent (44/108) AF patients had ERAF after a single PVI. Univariate analysis revealed that left atrial diameter (p = 0.004), age (p = 0.024) and P-wave dispersion (p = 0.045) were significantly related to ERAF. Logistic regression analysis revealed that left atrial enlargement was the only independent predictor of ERAF (odds ratio [OR] 1.17; 95% confidence interval [CI] 1.04–1.30, p = 0.006). Delayed cure occurred in 32% (14/44) patients with ERAF. P-wave dispersion (p = 0.001), left atrial diameter (p = 0.008) were significantly related to delayed cure. P-wave dispersion was the only independent predictive factor of delayed cure (OR 0.91; 95% CI 0.85–0.97, p = 0.004).Conclusions Elderly patients with left atrial enlargement and a high dispersion of P wave are susceptible to ERAF after a single PVI. Left atrial enlargement is the only independent predictor of ERAF. Among patients with ERAF, those with less P-wave dispersion and less left atrial diameter have a higher probability of delayed cure. P-wave dispersion can independently predict delayed cure.This study was supported by National Natural Science Foundation of China. (NSFC No.30470704). There is not any potential conflict of interest.