Impaired transport function of the left atrium in patients with lone paroxysmal atrial fibrillation

Background: Although lone paroxysmal atrial fibrillation (LPAF) is clinically defined as an arrhythmia that occurs in the absence of structural heart disease, it has been suggested that the presence of anatomical substrate is related to LPAF. The aim of the present study is to determine whether structural and functional remodeling of the left atrium (LA) occurs in patients with LPAF, and to identify whether frequent episodes of atrial fibrillation (AF) contribute to LA remodeling. Methods and Results: Forty‐five patients who diagnosed as LPAF and age‐, gender‐, and body mass index‐matched healthy control subjects (n = 45) were enrolled. Patients were grouped based on the frequency of AF episodes. An echocardiography was performed >2 weeks after last episode of AF without antiarrhythmic drugs. There were no statistical differences in left ventricular (LV) diastolic and systolic functions as well as baseline characteristics between patients and controls, whereas, patients had significantly larger LA volume (LAV), lower active LA emptying fraction (LAEF_active, P = 0.009) and total LAEF (LAEF_total, P = 0.005) compared with controls. Passive LAEF (LAEF_passive) was not different between patients and controls (P = 0.664). LAEF_active was significantly depressed in patients with frequent episodes of AF than the others (P = 0.034). Conclusions: Compared with healthy controls, patients with LPAF had increased LAV and depressed LAEF_active and LAEF_total without accompanying compensatory increase in LAEF_passive. LAEF_active was influenced by frequent episodes of AF. These findings may support the hypothesis that LPAF is “not‐so‐lone AF” and related to the concealed cardiac dysfunctions. (Echocardiography 2011;28:44‐51)     

Predictors of arrhythmia recurrence in patients with lone atrial fibrillation.

AIMS: The need for antiarrhythmic drugs (AAD) after a first episode of atrial fibrillation (AF) is determined by the probability of recurrence. The aim of this study was to asses the probability of relapse and the predictors of recurrence in patients with idiopathic AF. METHODS AND RESULTS: A cohort of 98 consecutive patients younger than 65 years admitted at the emergency room because of an episode of symptomatic idiopathic (lone) AF was included in this study. On admission, a complete medical history was taken, and an echocardiogram and 24-h Holter monitoring were performed. Patients were seen at 3 and 6 months after the index episode. There were 35 (35.7%) patients with a new-onset AF episode and 63 (64.3%) with a recurrent AF episode. A majority of them were male (71%), with a mean age of 48+/-11 years. Patients with new-onset AF episodes did not receive AAD. At 6 month follow-up, 57% of all patients suffered at least one symptomatic AF relapse. Patients with AF relapses belong more often to the recurrent group vs. new-onset group of AF (65.1 vs. 34.9%, respectively, P = 0.03); they had larger LA diameter indexed for body surface area (BSA) (22.6+/-3.7 vs. 19.8+/-3.2 mm/m(2), P = 0.001), larger left ventricular end-systolic diameter (18.4+/-3.1 vs. 17.2+/-2.5 mm/m(2), P = 0.05) and a tendency towards a higher proportion of atrial tachycardia runs on Holter (66.7 vs. 50%, P = 0.09). Logistic regression analysis showed that the presence of previous episodes of AF (OR: 3.2; 95% CI; 1.0-8.0, P = 0.04) and a larger anteroposterior LA diameter (OR: 1.3; 95% CI; 1.1-1.6, P = 0.001) were independent predictors of AF recurrences at 6 months. CONCLUSIONS: The recurrence rate in lone AF patients is high. The presence of previous episodes and a mildly enlarged anteroposterior LA diameter increase the probability of relapse of lone AF.     

Left ventricular diastolic dysfunction in patients with so-called lone atrial fibrillation

Lone atrial fibrillation (AF) is defined by the absence of identifiable causes of AF, but its hemodynamics have not been investigated. Twenty-eight patients with lone AF were compared with 14 control patients referred for Wolff-Parkinson-White ablation. Transthoracic and transesophageal echocardiography were performed to rule out structural heart disease, followed by transseptally performed complete hemodynamic evaluation of the left heart systolic and diastolic function. There was no evidence of diastolic dysfunction according to echocardiographic criteria in AF and control patients. There was no difference in echocardiographic measurements, except for a significantly higher inferosuperior left atrial dimension seen in the four-chamber apical view in AF patients (51+/-10 vs 40+/-6 mm, P = 0.03). Hemodynamic evaluation showed that end-diastolic left ventricular pressure and the nadir of the left atrial Y descent were significantly higher in lone AF patients versus controls: 13+/-5 versus 8+/-3 mmHg (P = 0.001) and 6.7+/-3 versus 4.6+/-2.7 mmHg (P = 0.05). Our results demonstrated the presence of diastolic left heart dysfunction in patients with so-called lone AF.     

Predicting new onset atrial fibrillation post acute myocardial infarction: Echocardiographic assessment of left atrial size

Background

Atrial fibrillation (AF) commonly occurs following acute myocardial infarction (AMI). Left atrial (LA) size has been reported to predict new onset AF in this cohort, however, the optimal metric of left atrial size for risk stratification following AMI is unknown.

Methods

Patients presenting to a tertiary hospital with incident AMI (NSTEMI or STEMI) and no history of AF were recruited. All patients underwent guideline-based workup and management for AMI, including transthoracic echocardiographic assessment. Three alternative metrics of left atrial size were determined: LA area, maximal and minimal LA volume indexed to body surface area (LAVImax and LAVImin). The primary endpoint was new onset AF diagnoses.

Results

Four hundred thirty three patients were included in the analysis, of which 7.1% had a new diagnosis of AF within a median follow-up of 3.8 years. Univariate predictors of incident AF included age, hypertension, revascularization with CABG, NSTEMI presentation, right atrial area, and all three metrics of LA size. Among three multivariable models created for the prediction of new onset AF utilizing alternate metrics of LA size, LAVImin was the only LA size metric found to be an independent predictor.

Conclusions

LAVImin is an independent predictor of new onset AF post AMI. LAVImin outperforms echocardiographic assessment of diastolic dysfunction and alternative metrics of LA size (including LA area and LAVImax) for risk stratification. Further studies are needed to validate our findings in post AMI patients, and evaluate whether LAVImin holds similar advantages over LAVImax in other cohorts.     

Association of atrial fibrillation in patients with interatrial block over prospectively followed controls with comparable echocardiographic parameters

Interatrial block (IAB) (P wave >or=110 ms) is a potential risk of atrial fibrillation (AF). However, few investigations have assessed the relevance of echocardiographic parameters, particularly the contribution of its known correlate, left atrial enlargement in this regard. We identified 32 consecutive patients with comparable echocardiographic parameters, such as left atrial dimension and left ventricular ejection fraction. Patients were evaluated for IAB and followed for 15 months for cardiovascular events (heart failure, transient ischemic attacks, and stroke), atrial tachyarrhythmias (AF/atrial flutter), and death. Preexisting AF and IAB (p = 0.02) were significantly associated with future AF events. However, logistic regression analysis indicated that IAB was not an independent predictor of future AF, only preexisting atrial tachyarrhythmias was (hazard ratio 39.5, 95% confidence interval 2.7 to 576.3, p = 0.007). In conclusion, in patients with comparable echocardiographic parameters, such as left atrial size and left ventricular ejection fraction, IAB remained associated with AF after a 15-month follow-up. Additional investigation is needed to confirm the extent of the association.     

Previously known and newly diagnosed atrial fibrillation: a major risk indicator after a myocardial infarction complicated by heart failure or left ventricular dysfunction

AIMS: To characterize the relationship between known and newly diagnosed atrial fibrillation (AF) and the risk of death and major cardiovascular (CV) events in patients with acute myocardial infarction (MI) complicated by heart failure (HF) and/or left ventricular systolic dysfunction (LVSD). METHODS: The VALIANT trial enrolled 14,703 individuals with acute MI complicated by HF and/or LVSD. AF was assessed at presentation and at randomization (median 4.9 days after symptom onset). Primary outcomes were risk of death and major CV events 3 years following acute MI. RESULTS: A total of 1812 with current AF (AF between presentation and randomization), 339 patients with prior AF (history of AF without current AF), and 12,509 without AF were enrolled. Patients with AF were older; had more prior HF, angina, and MI, and received beta-blockers and thrombolytics less often than those without AF. Three-year mortality estimates were 20% in those without AF, 37% with current AF, and 38% with prior AF. Compared with patients without AF, the multivariable adjusted HR of death was 1.25 (1.03-1.52; p=0.03) for prior AF and 1.32 (1.20-1.45; p<0.0001) for current AF. HR for major CV events was 1.15 (0.98-1.35; p=0.08) and 1.21 (1.12-1.31; p<0.0001). CONCLUSION: AF is associated with greater long-term mortality and adverse CV events with acute MI complicated by HF or LVSD.     

Maintenance of Sinus Rhythm after Cardioversion of Atrial Fibrillation in Patients with Lone Atrial Fibrillation and Patients with Hypertension

Background: The success rate and prognosis of cardioversion of atrial fibrillation (AF) in patients with organic heart disease is well known. In contrast, little data exist about cardioversion success and maintenance of sinus rhythm (SR) in patients with lone AF and in patients with hypertension as the only underlying cardiovascular disease. Methods: In a prospective cardioversion registry 148 of 181 patients (81.8%) with lone AF (age 58 ± 13 years, duration of AF 7.6 ± 19 weeks) and 120 of 148 patients (81.1%) with hypertension (age 62 ± 10 years, duration of AF 6.6 ± 21 weeks) had successful cardioversion and were followed for 7.7 ± 1.9 months. Results: At follow-up, 120 patients (81.1%) with lone AF were in SR, and 18 of these patients had had repeated cardioversion during follow-up (AF total recurrence rate 31.1%). In stepwise regression analysis, the number of previous cardioversions was predictive of rhythm at follow-up (P = 0.0453). Rhythm at follow-up did not differ between patients who were or were not on antiarrhythmic drugs. At follow-up 96 patients (80%) with hypertension were in SR, and 9 of these had had repeated cardioversion during follow-up (AF total recurrence rate 27.5%). As in lone AF, the recurrence rate of AF did not differ between patients with or without antiarrhythmic drug treatment, and in multivariate regression analysis, the number of previous cardioversions was the only clinical predictor of rhythm at follow-up (P = 0.0284). Conclusions: Even in patients with such benign conditions as lone AF or hypertension as the only underlying disease, the prognosis of cardioversion in terms of maintenance of SR is poor. Future studies of rhythm control versus rate control need to include not only patients with organic heart disease but also patients with lone AF and patients with hypertension, since the long-term benefits of these two strategies remain unclear even in these subsets of patients.     

左房容积与心房颤动导管消融术后患者复发的关系

目的探讨左房容积(LAV)与心房颤动(简称房颤)消融术后房颤复发的相关性。方法 104例房颤患者。术前应用64排容积CT扫描,在advantage workstation4.2图像工作站中重建左房,测量LAV,术中通过三维标测系统(CARTO)指导行射频消融术,术后3个月评定治疗效果,并随访6个月。结果随访6个月结束,104例中有20例(19%)房颤复发。单因素分析结果显示,复发组平均LAV比未复发组的大[117.6±28.9cm3,95%可信区间(CI)104.1~131.1cm3vs97.1±16.8cm3,95%CI93.5~100.8cm3,P=0.006]。多因素分析显示LAV是独立的预测导管消融术后复发的指标(P(0.05,相对风险度=1.044,95%CI1.018~1.071)。结论房颤射频消融术后房颤复发与LAV大小相关。     

Clinical characteristics of persistent lone atrial fibrillation in the RACE study

In the RAte Control versus Electrical cardioversion for persistent atrial fibrillation (RACE) study, 522 patients were randomized to either rate or rhythm control therapy. Lone atrial fibrillation (AF) was present in 89 patients. Demographics, cardiovascular mortality and morbidity, and quality of life were compared between patients with lone AF and those with underlying structural heart disease. Patients with lone AF were significantly younger (65 +/- 10 vs 69 +/- 8 years) and had fewer complaints of fatigue (p = 0.01) and dyspnea (p = 0.005). With lone AF, quality-of-life scores were higher on almost all 8 Medical Outcomes Study Short-Form health survey questionnaire subscales, and comparable to healthy, age- and gender-matched controls. Mean follow-up was 2.3 +/- 0.6 years. Cardiovascular end points occurred in 9 patients with lone AF (10%), consisting of death (all bleedings) 3%, thromboembolic complications in 3%, nonfatal bleeding in 2%, and pacemaker implantation in 2%, but no heart failure and severe adverse effects due to antiarrhythmic drugs occurred. End points occurred in 95 patients (22%) with underlying diseases. Heart failure and severe adverse effects from drugs did not occur in patients with lone AF in this study. Despite the absence of demonstrable cardiovascular and cerebrovascular disease, lone AF is associated with bleeding and thromboembolism.     

Latent Arterial Hypertension in Apparently Lone Atrial Fibrillation

Introduction. Longitudinal studies on lone AF are rare and the incidence of hypertension in this population unknown. This study aimed at investigating the incidence of arterial hypertension in patients with apparently lone atrial fibrillation (AF). Methods and Results. Out of 292 consecutive patients presented with permanent or paroxysmal AF, 32 patients were diagnosed as having lone AF according to strict criteria. Three patients were subjected to ablation of the ligament of Marshall, 14 patients to pulmonary vein isolation, and the remainder were treated with beta blockade. Patients were followed-up for a 1–3 year period. During follow-up, 14 patients were diagnosed as having arterial hypertension. Thirteen of them had recurrent AF despite ligament of Marshall ablation (1 patient), pulmonary vein isolation (4 patients) and beta blockade (8 patients). Cox regression analysis revealed that the only significant predictor of development of hypertension was complete or partial response to antiarrhythmic therapy (beta = 3.82, S.E. = 1.22, exp(b) = 45.63, 95% C.I. = 4.17–499.2, p = 0.001), independent of age (beta = −0.01, p = 0.74), sex (beta = −0.91, p = 0.28), left ventricular ejection fraction (beta = 0.06, p = 0.52), left atrial size (beta = 0.58, p = 0.7) and kind of antiarrhythmic therapy (ablation or drug therapy) (beta = 1.36, p = 0.09). In patients with lone AF that did not respond at all to antiarrhythmic therapy, there was a 45.6 times higher risk of diagnosing hypertension during the next 3 years as compared to responders. Conclusion. Approximately 44% of patients with an initial diagnosis of lone AF may represent occult cases of arterial hypertension. In these patients hypertension may affect AF recurrence and treatment outcomes, regardless of the mode of antiarrhythmic therapy used.     

左心房容积与冠状动脉旁路移植术后心房颤动相关性的研究

目的:评价冠状动脉旁路移植术(CABG)前,二维超声心动图估测左心房容积指数(LAVI)与术后心房颤动发生的相关性。方法:入选北京同仁医院2010年1月至2012年6月期间,入院实施CABG术的冠心病患者106例进行前瞻性分析。将患者分为术后心房颤动组和术后未发生心房颤动组。采用多因素Logistic回归分析,评价术前通过二维超声心动图估测的LAVI值与术后心心房颤动动发生的相关性。结果:CABG术后发生心房颤动患者19例,术后心房颤动发生率为17.9%。术后心房颤动组的LAVI值显著高于术后未发生心房颤动组[(22.1±4.1)vs.(18.1±5.1)m L/m2,P=0.018]。多元logistic回归分析显示,年龄(OR=1.015,95%CI:1.017~1.0323,P=0.026)、高血压病史(OR=1.053,95%CI:1.019~1.087,P=0.009)、既往心房颤动病史(OR=2.273,95%CI:1.207~3.340,P=0.010)、LAV值(OR=1.784,95%CI:1.181~2.487,P=0.003)是CABG后心房颤动发生的独立危险因素。结论:CABG术前通过二维超声心动图估测的LAVI值是冠心病患者CABG术后心房颤动发生的独立危险因素,对于预测CABG术后心房颤动发生并进行危险分层具有一定参考价值。     

Indexed left atrial volume is superior to left atrial diameter in predicting nonvalvular atrial fibrillation recurrence after successful cardioversion: a prospective study

Background: Although indexed left atrial volume (iLAV) is the most accurate measure of left atrial size, it has not been evaluated prospectively as predictor of recurrence of atrial fibrillation (AFib) after successful cardioversion (CV). Methods: We prospectively selected 76 patients (mean age 66.1 ± 13.6 years, 65.8% men) with AFib who underwent successful CV. Baseline clinical and echocardiographic characteristics were obtained before CV. LAV was measured using Simpson's method and indexed to body surface area. All patients were scheduled for follow‐up visit at 1, 6, 12 months, and then annually. A 24‐hour Holter ECG was performed within 6 months and each time the patients reported symptoms suggestive of arrhythmia. Results: The 52 patients (68.4%) with AFib recurrence had larger iLAV (35.5 ± 8.9 mL/m² vs 27.0 ± 6.7 mL/m², P < 0.001). Anteroposterior LA diameter was not associated with AFib relapse (OR 1.08, 95% CI: 0.96–1.21, P = 0.09). Each unit increase in iLAV was associated with a 1.15‐fold increased risk of recurrence (OR 1.15, 95% CI: 1.06–1.25, P < 0.001). In a multivariable model, iLAV remained the only independent predictor of relapse (adjusted OR 1.14, 95% CI: 1.02–1.28, P = 0.02). The area under ROC curves, generated to compare LA diameter, and iLAV as predictors of AFib recurrence were 0.56 (SE 0.07) versus 0.78 (SE 0.05), respectively (P = 0.003). Conclusion: This is the first prospective study to show that larger iLAV, as a more accurate measure of LA remodeling than anteroposterior diameter, is strongly and independently associated with a higher risk of AFib recurrence after CV. (Echocardiography 2012;29:276‐284)     

Ibutilide: efficacy and safety in atrial fibrillation and atrial flutter in a general cardiology practice.

BACKGROUND: Published experience with ibutilide (IB) in randomized clinical trials reveals that conversion to sinus rhythm (SR) occurs in 31% of patients with atrial fibrillation (AF) and in 63% of patients with atrial flutter. HYPOTHESIS: The study was undertaken to test the efficacy and safety of IB in patients with AF and with atrial flutter and to compare them with those reported in previous studies. METHODS: In a general cardiology practice, 54 consecutive patients with AF or atrial flutter, no contraindication to IB, and a normal QTc interval, were treated with intravenous IB (0.4-2.0 mg). Duration of arrhythmia, left atrial (LA) size, ejection fraction (EF), time to conversion, QTc interval, and adverse drug events were determined. Patients were observed for a minimum of 6 h. Successful cardioversion was defined as arrhythmia termination within 6 h. RESULTS: Twenty-four of 34 (70.6%) patients with AF and 15 of 20 (75%) patients with atrial flutter converted to SR. Conversion of AF to SR was more likely to occur if duration of AF was approximately 96 h compared with > 96 h (81 vs. 17%, respectively; p = 0.006). The mean time to arrhythmia termination was 68.8 min. Left atrial size, determined by echocardiogram, was 44 +/- 13 mm in 43 patients. Patients with LA size approximately 45 mm had a conversion rate of 55% in both AF and flutter, compared with a conversion rate of 72% in patients with LA size < 45 mm. Ejection fraction was not a predictor of drug success. The QTc intervals were significantly prolonged after IB administration, with a mean change of 47.1 ms for successfully treated patients. Sustained polymorphic ventricular tachycardia occurred in one patient within 1 min of IB infusion, requiring electrical cardioversion to SR. This patient's serum electrolytes and QTc interval were normal prior to IB infusion; however, the QTc increased by 160 ms (from 387 to 547 ms) during drug infusion. No systemic or pulmonary emboli occurred. CONCLUSION: The efficacy of IB for conversion of AF to SR in this prospective observational study was considerably better than previously reported. Duration of AF remains an important predictor of conversion to SR. Complications are rare and without long-term adverse effects.     

Left atrial volume is associated with inflammation and atherosclerosis in patients with kidney disease

BACKGROUND: Left atrial volume (LAV) is an independent echocardiographic predictor of cardiovascular events in the general population. We evaluated predictors of LAV in patients with advanced chronic kidney disease (CKD). Hypothesis: Increasing LAV identifies increased cardiovascular risk in patients with CKD. METHODS: Transthoracic echocardiography was performed in CKD patients undergoing cardiovascular evaluation prior to listing for renal transplantation. LAV was measured using the biplane area-length formula and indexed for body surface area. Carotid intima-media thickness was assessed by B-mode ultrasound. Lipoproteins were measured by nuclear magnetic resonance spectroscopy. Values are presented as mean (standard deviation). Relationships with LAV were evaluated using univariate and multivariable regression analyses. RESULTS: There were 99 participants (80% white, 68% male). Their mean age was 55.7 (9.3) years. Significant correlates of LAV were systolic blood pressure (r = 0.24), C-reactive protein (r = 0.29), carotid intima-media thickness (r = 0.29), peak transmitral E-wave (r = 0.38), and severity of mitral regurgitation (r = 0.23, P < 0.05 for all). LAV also was higher among individuals with a history of stroke (45 mL/m2 vs 36.3 mL/m2, P = 0.04) and with >75% stenosis on coronary angiography (38.4 mL/m2 vs 31.8 mL/m2, P = 0.03). In regression models, high sensitivity CRP (hs-CRP), the transmitral E-wave velocity, and a history of stroke independently predicted LAV (P < or = 0.05). CONCLUSION: In individuals with advanced CKD, LAV is associated with inflammation, increased early transmitral filling velocities, and atherosclerosis. These findings may indicate increased cardiovascular risk with increasing LAV in patients with CKD.     

前瞻队列研究节段性肺静脉电隔离与胺碘酮及胺碘酮联合氯沙坦治疗孤立性阵发性心房颤动

目的比较节段性肺静脉电隔离和胺碘酮及胺碘酮联合氯沙坦对孤立性阵发性心房颤动（房颤）患者维持窦性心律（窦律）的疗效。方法选择154例孤立性阵发性房颤患者分为节段性肺静脉电隔离治疗组（Ⅰ组,n=51）、胺碘酮组（Ⅱ组,n=52）、胺碘酮＋氯沙坦组（Ⅲ组,n=51）。治疗随访时间为1年,研究的一级终点为12导联心电图和24小时Hoher证实的持续30秒以上的症状性房性快速性心律失常复发。结果在12个月的随访期间,Ⅰ、Ⅱ、Ⅲ组分别有11例（21．6％）、24例（46．2％）、12例（23．5％）到达了一级终点（P〈0．05）。Kaplan—Meier生存分析显示,Ⅰ组和Ⅲ组对窦律维持率均高于Ⅱ组（P=0．009和0．018,log—rank检验）;Ⅰ组和Ⅲ组对窦律的维持率差异无统计学意义（P：0．814）。同Ⅱ组相比,Ⅲ组降低了54％的房颤复发风险（RR=0．46,95％可信区间0．225～0．953,P：0．036）,Ⅰ组降低了59％的房颤复发风险（RR=0．41,95％可信区间0．200～0．848,P：0．016）。三组间不良事件的发生率分别为3．9％、9．6％和7．8％,差异无统计学意义（P〉0．05）。结论节段性肺静脉电隔离和胺碘酮联合氯沙坦对孤立性阵发性房颤患者窦律的维持疗效相当,均明显优于单用胺碘酮治疗。     

Left atrial volume predicts the risk of atrial fibrillation after cardiac surgery: a prospective study.

OBJECTIVES: This study sought to identify preoperative predictors of postoperative atrial fibrillation (POAF) among patients undergoing cardiac surgery. BACKGROUND: Postoperative atrial fibrillation is frequent after cardiac surgery and is associated with increased morbidity, mortality, prolonged hospital stay, and increased costs. Left atrial volume (LAV), a marker of chronically elevated left ventricular filling pressure, is a predictor of atrial fibrillation (AF) in the nonsurgical setting. METHODS: A total of 205 patients (mean age 62 +/- 16 years; 35% women) undergoing cardiac surgery were prospectively enrolled. Clinical risk factors were obtained by detailed medical record review and patient interview. Preoperative transthoracic echocardiograms were performed for assessment of LAV, left ventricular ejection fraction, and diastolic function. Follow-up was complete. Detection of POAF was based on documentation of AF episodes by continuous telemetry throughout hospitalization. RESULTS: Postoperative atrial fibrillation occurred in 84 patients (41.4%) at a median of 1.8 days after cardiac surgery. The LAV was significantly larger in patients in whom AF developed (49 +/- 14 ml/m2 vs. 39 +/- 16 ml/m2, p = 0.0001). Patients with LAV >32 ml/m2 had an almost five-fold increased risk of POAF, independently of age and clinical risk factors (adjusted hazard ratio 4.84, 95% confidence interval 1.93 to 12.17, p = 0.001). Age and LAV were the only independent predictors of POAF. The area under the receiver-operator characteristics curve to predict POAF was 0.729 for LAV and 0.768 for the combination of LAV and age (both p < 0.0001). CONCLUSIONS: The LAV is a strong and independent predictor of POAF. Risk stratification using LAV and age enables clinicians to identify high-risk patients before cardiac surgery.     

Relation of recurrence of atrial fibrillation after non-ST-elevation acute myocardial infarction to left atrial abnormality

Atrial fibrillation (AF) is common during the course of acute myocardial infarction and is associated with left atrial (LA) dilatation. However, the role of LA depolarization abnormality on the electrocardiogram (ECG) in the setting of LA dilatation was not studied in this context. Patients admitted with non-ST-segment elevation myocardial infarction (NSTEMI) who developed new-onset AF (International Classification of Diseases, Ninth Revision code 427.31) were prospectively identified. Baseline ECGs and echocardiograms before the admission event were reviewed. Follow-up was directed toward pertinent cardiovascular events, atrial tachyarrhythmias, and death as end points. Of 101 patients with NSTEMI who had new-onset AF, 88 had current echocardiograms and 69 had LA dilatation (78%). Total follow-up was 24 months (mean 21.4). Prolonged P-wave duration (> or =110 ms) and decreased left ventricular fractional shortening were most significant in those with LA dilatation and were independently associated with AF. In those with LA dilatation, the prevalence of such abnormal atrial depolarization on ECGs was 56%. AF (43% vs 15%; p = 0.03) and heart failure (63% vs 35%; p = 0.03) occurred more often in this subset, but there was no difference in mortality. However, the overall prevalence of late cardiovascular complications in this subset was higher (71% vs 45%; p = 0.02) compared with that of immediate complications (20% vs 26%; p = 0.60). In conclusion, there is higher recurrence of AF in patients with NSTEMI who have a combination of electrocardiographic and echocardiographic LA abnormalities compared with those without.     

P-wave morphology correlation with left atrial volumes assessed by 2-dimensional echocardiography

To correlate prespecified P-wave morphologies with echocardiographically derived left atrial volumes (LAVs), we studied a convenience sample of 71 patients with predominantly normal left ventricular systolic function (mean ejection fraction = 58.2% +/- 6.6%) who underwent concurrent 2-dimensional echocardiogram and 12-lead electrocardiogram. Left atrial volume was calculated from apical end-systolic images by the biplane method of disks and was indexed for body surface area (BSA). Electrocardiograms were assessed manually with calipers, measuring leading edge to leading edge. Patients included 34 men and 37 women with a mean age of 53 +/- 14 years. P-wave duration/PR-segment duration in lead II and depth and duration of terminal P wave in lead V1 (P terminal force) correlate poorly with LAV and provided only modest predictive power (area under receiver operating characteristic curve = 0.466-0.619 and r = 0.30-0.42, P = .014-.021). Total P-wave duration in lead II correlated moderately (r = 0.47, P < .001) and predicted LAV (LAV/BSA = 8.0 + 0.2 [P-wave duration in lead II]), as did P-wave area in lead II (r = 0.49, P < .001) (LAV/BSA = 18.6 + 1.7 [P-wave duration in lead II]). The 4 P-wave morphologies were found to be poorly sensitive but highly specific for left atrial enlargement.     

Prevalence and significance of focal sources of atrial arrhythmia in patients undergoing cardioversion of persistent atrial fibrillation

INTRODUCTION: Recent reports have high-lighted the importance of focal atrial arrhythmias as a curable cause for a group of patients with frequently recurrent paroxysmal atrial fibrillation (AF). The importance of this arrhythmia mechanism in the general population of patients with persistent AF is unknown. METHODS AND RESULTS: After successful internal cardioversion of 50 consecutive patients with persistent AF (mean age 60 years, mean duration of AF 26 months), endocardial activity in the immediate postcardioversion period was analyzed for the presence of focal atrial activity. Postcardioversion atrial arrhythmias were considered to be focal if there was evidence of a localized source of repetitive early atrial activation, either in the form of (1) self-terminating monomorphic atrial tachycardia (at least five beats) or (2) recurrences of AF with an initial atrial activation sequence (first five beats) that was both monomorphic and reproducible with repeated recurrences. Evidence for a focal atrial arrhythmia was present in 20 of the total group of 50 patients (40%). Multivariate analysis of clinical characteristics revealed the diagnosis of lone AF as the only independent predictor of a focal source of AF (P = 0.028). Thirty-nine patients were discharged from hospital in sinus rhythm. At 1-month follow-up, 25 (64%) of these 39 patients had suffered AF recurrence. The only significant predictor of AF recurrence was evidence of a focal source of atrial arrhythmia immediately after cardioversion, with a relative risk of 1.73 (range 1.1 to 2.7; P = 0.015). CONCLUSION: Focal atrial arrhythmias are common in patients presenting with "idiopathic" persistent AF, suggesting a possible causative role in the generation of this common arrhythmia.     

Relation of C-reactive protein to long-term risk of recurrence of atrial fibrillation after electrical cardioversion

The aim of this study is to assess the role of C-reactive protein (CRP) in predicting long-term risk of atrial fibrillation (AF) recurrence after electrical cardioversion. CRP levels are associated with the presence of AF and failure of electrical or pharmacologic cardioversion, but no previous study has assessed their predictive role in long-term follow-up after successful electrical cardioversion. One hundred two consecutive patients (age 67 +/- 11 years; 58 men) with nonvalvular persistent AF who underwent successful biphasic electrical cardioversion were studied. High-sensitivity CRP was measured immediately before cardioversion. Follow-up was performed up to 1 year in all cases. Patients were divided into 4 groups according to CRP quartiles. Patients in the lowest CRP quartile (<1.9 mg/L) had significantly lower rates of AF recurrence (4% vs 33% at 3 months in the other 3 groups combined, p = 0.007, and 28% vs 60% at 1 year, p = 0.01). The 4 groups were similar in age, gender, ejection fraction, and left atrial size. Survival analysis confirmed that patients in the lowest CRP quartile had a lower recurrence rate (p = 0.02). Cox regression analyses using age, gender, hypertension, diabetes, ejection fraction, left atrial diameter, use of antiarrhythmic drugs, angiotensin-converting enzyme inhibitors or angiotensin II antagonists, and statins, and CRP quartiles as covariates showed that only CRP was independently associated with AF recurrence during follow-up (hazard ratio 4.98, 95% confidence interval 1.75 to 14.26, p = 0.003). In conclusion, low CRP is associated with long-term maintenance of sinus rhythm after cardioversion for nonvalvular AF.