Interval-force relation is unaffected by the presence of cardiomyopathy or coronary artery disease in patients with atrial fibrillation.

BACKGROUND: We tested the hypothesis that cycle length-dependent cardiac contractility in atrial fibrillation is primarily governed by the negative interval-force relation in patients with normal and depressed systolic function. METHODS AND RESULTS: We performed two-dimensional guided M-mode echocardiography in 41 patients (mean age, 69 +/- 4 years; range, 48 to 92 years; 19 men, 11 women). Twelve patients had objective evidence of left ventricular systolic dysfunction (CMP; mean ejection fraction, 37% +/- 7%) in the absence of coronary artery disease (CAD), 13 patients had documented CAD (mean ejection fraction, 43% +/- 6%), and 16 patients had normal resting left ventricular systolic function (mean ejection fraction, 58% +/- 7%). Simultaneous beat-to-beat blood pressure, end-systolic and end-diastolic dimension, circumferential velocity of fiber shortening (Vcf), and end-systolic wall stress (ESWS) were calculated for all patients. All three groups showed a significant linear relation between beat-to-beat Vcf and Vcf corrected for afterload (represented as the Vcf/ESWS ratio) and preceding cycle length. There was, however, no significant difference in the relation between either of these variables and cycle length among the three groups. There was also no difference in the rate of change in either Vcf or Vcf corrected for afterload (Vcf/ESWS ratio) from beat-to-beat among the three groups. Control patients with normal systolic function showed greater Vcf at any given cycle length compared with patients with CMP or CAD. CONCLUSION: Our data show that, for each beat in atrial fibrillation, Vcf and Vcf/ESWS ratio are decreased after shorter cycle lengths and increased after long cycles, but there is no significant attenuation of this effect in patients with systolic dysfunction with or without coronary disease compared with controls. Thus, the negative interval-force relation, the predominant determinant of beat-to-beat variation in contractility in atrial fibrillation, is preserved in patients with CAD or reduced left ventricular systolic function.     

Analysis of left ventricular contractile behaviour during atrial fibrillation

SummaryObjectives The purpose of this study was to explore the physiology underlying the beat-to-beat variations of ventricular function during atrial fibrillation (AF).Methods Left ventricular pressure, and its first derivative (LVdP/dt_max, an index of contractility, and aortic blood velocity (and its integral AVI, an ejection index), were recorded using cathetermounted transducers in 15 patients with AF during cardiac catheterisation. Transfer function modelling was used to examine the influence of preceding intervals on LVdP/dt_max, and of LVdP/dt_max on AVI. The technique also allowed simulation of the behaviour of LVdP/dt_max in response to specific manipulations of interval.Results The variations in LVdP/dt_max recorded from the AF patients were shown to be dependent on up to six preceding intervals; a maximum of 91 % of the variation was explicable in this way. The influences of mechanical restitution (MR, the relationship between preceding interval and contractility), postextrasystolic potentiation (PESP, the inverse relationship between pre-preceding interval and contractility) and the decay of that potentiation were all demonstrated. These influences collectively appeared to be powerful determinants of AVI. Simulations of LVdP/dt_max, following single interval perturbations, were entirely consistent with these interval force effects.Conclusions The cardiac interval force relationship in man is an important determinant of the beat-to-beat variations of contractile and ejection function during AF: the beat-to-beat variations in contractile (or inotropic) function are independent of changes in ventricular filling or fibre-length.     

Left ventricular relaxation in lone atrial fibrillation and atrial fibrillation with heart disease]

Atrial fibrillation with organic heart disease shows a steady value for the time constant of left ventricular isovolumetric relaxation (TC), whereas left ventricular contractility varies from beat to beat. However, there is no report on left ventricular relaxation in lone atrial fibrillation. This study assessed left ventricular relaxation in 5 patients with lone atrial fibrillation, 3 with ischemic heart disease and one with hypertrophic cardiomyopathy. Left ventricular pressure was recorded at 3 msec intervals, with a high fidelity micromanometer-tipped catheter. Maximal positive dP/dt (dP/dtmax) and TC of isovolumetric left ventricular relaxation period [P(t) = (P0-P infinity) exp (-t/TC) + P infinity] were measured as indices of left ventricular contractility and left ventricular relaxation, respectively. Correlation coefficients of dP/dtmax and TC versus the ratio of the preceding to the pre-preceding RR-interval (RR2/RR1) were calculated. A good correlation was found between dP/dtmax and RR2/RR1 in all patients (r = 0.71-0.84, p < 0.0001). No correlation between TC and RR2/RR1 was found in patients with atrial fibrillation with organic heart disease, but a good correlation was found between TC and RR2/RR1 in patients with lone atrial fibrillation (r = 0.74-0.95, p < 0.0001). The correlation between TC and RR2/RR1 is well preserved in lone atrial fibrillation. The mechanism of the variation of TC with the RR2/RR1 interval in lone atrial fibrillation may be similar to the change of TC in postextrasystolic potentiation, which is attributed to the change of intracellular Ca2+ concentration. Absence of correlation between TC and RR2/RR1 interval may indicate that left ventricular relaxation is disturbed in patients with atrial fibrillation with organic heart disease.     

Left ventricular beat to beat performance in atrial fibrillation: dependence on contractility, preload, and afterload

OBJECTIVE—To assess independent determinants of beat to beat variation in left ventricular performance during atrial fibrillation.
DESIGN—Prospective study.
SETTING—University hospital.
PATIENTS—Seven patients with chronic non-valvar atrial fibrillation.
INTERVENTIONS—Invasive and non-invasive haemodynamic variables were assessed using a non-imaging computerised nuclear probe, a balloon tipped flow directed catheter, and a non-invasive fingertip blood pressure measurement system linked to a personal computer.
MAIN OUTCOME MEASURES—Left ventricular ejection fraction, left ventricular volume, ventricular cycle length, pulmonary capillary wedge pressure, and measures of left ventricular afterload (end systolic pressure/stroke volume) and contractility (end systolic pressure/end systolic volume) were calculated on a beat to beat basis during 500 consecutive RR intervals. A statistical model of the beat to beat variation of the ejection fraction containing these variables was constructed by multiple regression analysis.
RESULTS—Positive independent relations with ejection fraction were found for preceding RR interval, contractility, and end diastolic volume, while inverse relations were found for afterload, preceding end systolic volume, and preceding contractility (all variables, p < 0.0001). A relatively strong interaction was found between end diastolic volume and afterload, indicating that ejection fraction was relatively more enhanced by preload in the presence of low afterload.
CONCLUSIONS—The varying left ventricular systolic performance during atrial fibrillation is independently influenced by beat to beat variation in cycle length, preload, afterload, and contractility. Beat to beat variation in preload shows its effect on ventricular performance mainly in the presence of a low afterload.


Keywords: atrial fibrillation; contractility; haemodynamic variables     

Correction for preload in assessment of myocardial contractility in aortic and mitral valve disease. Application of the concept of systolic myocardial stiffness

With single-beat analysis, the new concept of systolic myocardial stiffness is applied to provide a new approach for the assessment of myocardial contractility in aortic and mitral valve disease. Seventy patients underwent diagnostic right and left heart catheterization. Twenty-six patients had aortic stenosis, 18 had aortic insufficiency, and 26 had mitral regurgitation. Patients with aortic stenosis were divided into two groups on the basis of left ventricular mass index less than 172 g/m2 (AS1) and mass index greater than or equal to 172 g/m2 (AS2). The mitral regurgitation patients were divided into those in normal sinus rhythm (MR1) and those in atrial fibrillation (MR2). Nine patients without significant coronary or cardiovascular disease served as controls. Thirteen patients with aortic stenosis and eight with aortic insufficiency were evaluated (average, approximately 18 months) after successful aortic valve replacement. With simultaneous left ventricular pressure and cineangiographic methods, myocardial contractility was assessed by the conventional ejection fraction-afterload relation (uncorrected for preload) and by two new methods that permit the correction of the ejection fraction for preload. Assessments of the contractile state by these two new methods differed from those by the conventional method in 20-40% of the cases studied. Contractile state improved postoperatively in aortic stenosis and aortic insufficiency even in patients with preoperative depressed contractile states. In patients with mitral regurgitation, there was considerable heterogeneity of contractile function preoperatively. Severe left ventricular hypertrophy in aortic stenosis was not a marker for postoperative outcome since contractility was normal postoperatively in AS1 and AS2 in equal numbers. This study demonstrates that preload correction is important in a preoperative assessment of contractility in aortic and mitral valve disease but that it is less important postoperatively, presumably because of reductions in the preload.     

Effect of rhythm regularization on left ventricular contractility in patients with atrial fibrillation

In 10 patients with atrial fibrillation, echocardiographic measures of left ventricular function-interval relations were used to assess contractility and to test the hypothesis that rhythm regularization produces a higher contractile state than is seen when the rhythm is irregular. Regularization, following direct-current cardioversion, did not augment ventricular contractility above that seen during atrial fibrillation.     

Evaluation of ventricular contractility indexes in the dog with left ventricular dysfunction induced by rapid atrial pacing

Eight dogs were studied by simultaneous invasive hemodynamic and two-dimensional echocardiographic methods to determine whether left ventricular contractility is altered by 2 weeks of rapid atrial pacing. Additionally, this study evaluated the response of three ventricular contractility indexes to both the pacing intervention and acute load alteration. The indexes compared were ejection fraction, peak systolic pressure to end-systolic volume index ratio (SBP/ESVI) and end-systolic wall stress to end-systolic volume index ratio (ESWS/ESVI). After 2 weeks of pacing at 265 +/- 20 min-1 (mean +/- SD), cardiac index and ejection fraction were reduced to 73 +/- 38 ml/kg per min and 22 +/- 6%, respectively, from 161 +/- 22 and 46 +/- 7 before pacing (both p less than 0.001). Concomitantly, SBP/ESVI and ESWS/ESVI were reduced to 34 +/- 10 mm Hg/ml per kg and 54 +/- 19 g/cm2 per ml per kg, respectively, from 84 +/- 29 and 121 +/- 36 before pacing (both p less than 0.005). There were high correlations for the changes in SBP/ESVI and ejection fraction (r = 0.94, p less than 0.001) and ESWS/ESVI and ejection fraction (r = 0.89, p less than 0.003). Acute afterload alteration with phenylephrine depressed ejection fraction but not SBP/ESVI or ESWS/ESVI. Therefore, this study demonstrates 1) that left ventricular contractility is markedly depressed in the dog by 2 weeks of rapid atrial pacing, and 2) that SBP/ESVI and ESWS/ESVI are superior to ejection fraction as ventricular contractility indexes because these ratios accurately measure contractility changes but are influenced less by after-load conditions.     

Determination of left ventricular residual function by analysis of post-extrasystolic beat in mitral stenosis.

Residual function of the left ventricle was assessed in 25 patients with mitral stenosis and a normal left ventriculogram. The post-extrasystolic beat (R2) in sinus rhythm (nine patients) and the first beat after an early beat (R2) in atrial fibrillation (16 patients) were analysed angiocardiographically. Five subjects with a normal heart (controls) were also studied. The results are expressed as percentage changes in left ventricular contractility from the beat preceding the extra beat (R1) to the beat R2. In the control group the mean changes from R1 to R2 were: end diastolic volume +68.3% (increase), end systolic volume -21.7% (decrease), ejection fraction +36.2%, mean systolic ejection rate +22.1%, and mean velocity of circumferential fibre shortening +31%. A significant increase in proportional systolic shortening of all left ventricular axes was found in R2 compared with R1. In five patients with sinus rhythm and nine with atrial fibrillation the results fell within the normal range. In the remaining patients the beat R2 indicated signs of poor left ventricular function. The mean changes from R1 to R2 in the patients with sinus rhythm and those with atrial fibrillation were respectively: end diastolic volume +47.8% and +36.6%, end systolic volume +20% and +27%, ejection fraction +12.5% and +6.2%, mean systolic ejection rate -23.3% and -30.2%, and mean velocity of circumferential fibre shortening -25.5% and -39.2%. The increase in the left ventricular axial systolic shortening was not significant. Thus analysing a post-extrasystolic beat in sinus rhythm of the beat following an early beat with a long diastole in atrial fibrillation is a valuable method of determining the residual function in patients with mitral stenosis who have a normal left ventriculogram in basic rhythm.     

Predictors of left atrial appendage clot: a transesophageal echocardiographic study of left atrial appendage function in patients with severe mitral stenosis

BACKGROUND: The purpose of this study was to prospectively evaluate a large group of consecutive, non-anticoagulated patients with severe rheumatic mitral stenosis and to analyze the left atrial appendage function in relation to left atrial appendage clot and spontaneous echo contrast formation. METHODS AND RESULTS: We prospectively studied left atrial appendage function in 200 consecutive patients with severe mitral stenosis who underwent transesophageal echocardiography and correlated it with spontaneous echo contrast and left atrial appendage clot. The mean age was 30.2 +/- 9.4 years. Fifty-five (27.5%) patients were in atrial fibrillation. Left atrial appendage clot was present in 50 (25%) patients and 113 (56.5%) had spontaneous echo contrast. The older age, increased duration of symptoms, atrial fibrillation, spontaneous echo contrast, larger left atrium, depressed left atrial appendage function and type II and III left atrial appendage flow patterns correlated significantly (p<0.05) with the left atrial appendage clot. Left atrial appendage ejection fraction was significantly less in patients with clot (21.8 +/- 12.8% v. 39.1 +/- 13.2%, p<0.0001) and in those with spontaneous echo contrast (30.3 +/- 16.2 % v. 40.3 +/- 11.8%, p<0.001). Left atrial appendage filling (18.0 +/- 11.7 v. 27.6 +/- 11.8 cm/s, p <0.0001) and emptying velocities (15.4 +/- 7.0 v. 21.5 +/- 9.6 cm/s, p<0.001) and filling (1.4 +/- 1.0 v. 2.5 +/- 1.4 cm, p<0.0001) and emptying (1.5 +/- 1.2 v. 2.1 +/- 1.2 cm, p <0.05) velocity time integrals were also significantly lower in patients with clot as compared to those without clot. On multivariate regression analysis, atrial fibrillation (odds ratio 6.68, 95% CI 1.85-24.19, p=0.003) and left atrial appendage ejection fraction (odds ratio 1.06, 95% CI 1.00 - 1.11, p=0.04) were the only two independent predictors of clot formation. Incidence of clot was 62.59% in patients with left atrial appendage ejection fraction < or = 25% as compared to 10.4% in those having left atrial appendage ejection fraction >25%. Similarly patients with spontaneous echo contrasthadlower filling (21.7 +/- 11.5 v. 29.4 +/- 12.7 cm/s, p<0.0001) and emptying (17.0 +/- 8.1 v. 23.9 +/- 10.9 cm/s, p<0.0001) velocities, as well as filling (1.9 +/- 1.3 v. 2.7 +/- 1.3 cm, p<0.01) and emptying (1.7 +/- 1.0 v. 2.3 +/- 1.4 cm, p<0.01) velocity time integrals as compared to patients without spontaneous echo contrast. In a subgroup of the patients with normal sinus rhythm, the left atrial appendage ejection fraction was significantly less in patients with clot compared to those without clot (31.2 +/- 13.2 v. 41.3 +/- 11.5 %, p<0.01). CONCLUSIONS: In the patients with severe mitral stenosis, besides atrial fibrillation, a subgroup of patients in normal sinus rhythm with depressed left atrial appendage function (left atrial appendage ejection fraction < or = 25%) had a higher risk of clot formation in left atrial appendage and these patients should be routinely anticoagulated for prevention of clot formation.     

Changes in systemic and intracardiac hemodynamics during bicycle ergometry in patients with fibrillation arrhythmia treated with allapinin before and after sinus rhythm recovery

In atrial fibrillation, allapinine was shown to enhance rhythm by 7% and to increase cardiac output (p less than 0.05), as well as to slightly lower mean blood pressure and peripheral vascular resistance at rest. With exercise, both in atrial fibrillation, and sinus rhythm, there was a decrease in end-diastolic and end-systolic volumes of the left ventricle (p less than 0.05), a slight drop in ventricular ejection, that was statistically significant only with sinus rhythm (p less than 0.05). Physical exercise was not followed by an apparent additional aggravation of myocardial contractility, which makes allapinine preferable for long-term application to preserve sinus rhythm in patients without evident signs of heart failure.     

Impact of congestive heart failure and left ventricular systolic function on the prognostic significance of atrial fibrillation and atrial flutter following acute myocardial infarction

BACKGROUND: Reports on the prognostic importance of atrial fibrillation following myocardial infarction have provided considerable variation in results. Thus, this study examined the impact of left ventricular systolic function and congestive heart failure on the prognostic importance of atrial fibrillation in acute myocardial infarction patients that might explain previous discrepancies. METHODS: The study population was 6676 patients consecutively admitted to hospital with acute myocardial infarction. Information on the presence of atrial fibrillation/flutter, left ventricular systolic function and congestive heart failure were prospectively collected. Mortality was followed for 5 years. RESULTS: In patients with left ventricular ejection fraction<0.25, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.8 (1.1-3.2); p<0.05) but not an increased 30-day mortality. In patients with 0.250.35. In patients with congestive heart failure, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.5 (1.2-1.9); p<0.001) and increased 30-day mortality (OR=1.4 (1.1-1.7); p<0.001) but not in patients without congestive heart failure. In hospital survivors, atrial fibrillation/atrial flutter was associated with an increased long-term mortality in all subgroups except those with left ventricular ejection fraction<0.25. CONCLUSIONS: Atrial fibrillation/atrial flutter is primarily associated with increased in-hospital mortality in heart failure patients. Long-term mortality is increased in all subgroups except those with left ventricular ejection fraction<25%.     

心房纤颤对左心室射血分数正常的心力衰竭患者的影响

目的分析心房纤颤在左心室射血分数正常的心力衰竭（HFPEF）患者中的比例及其临床特征。方法选取HFPEF患者86例。依照是否存在心房纤颤病史或人院时心电图检查是否存在心房纤颤分为房颤组、非房颤组,并比较两组的特征。结果HFPEF患者心房纤颤的发生率为34．9％。房颤组平均年龄高于非房颤组[（71．6±8．97）岁与（62．71±17．79）岁]。多元线性回归分析表明室间隔厚度、肾功能不全和感染性疾病依次与血浆氨基末端脑钠肽前体水平相关。心房纤颤与左房内径相关性较好。结论心房纤颤是HFPEF患者常见的心律失常,左心房容积增大是房颤的主要临床特征。心房纤颤可能是HFPEF重要发病机制之一。     

Serial evaluation of left atrial dimension after cardioversion for atrial fibrillation and relation to atrial function

The size of the left atrium is usually increased during atrial fibrillation (AF). The aim of the present study was to evaluate changes in left atrial (LA) dimension after cardioversion for AF, and the relation between LA dimension and atrial function. The initial study population included 171 consecutive patients. Patients who had spontaneous cardioversion to sinus rhythm (56 patients) were compared with patients who had random cardio-version with drugs (50 patients) or direct-current (DC) shock (50 patients). Echocardiographic evaluations included LA size and volume. LA passive and active emptying volumes were calculated, and LA function was assessed. Atrial stunning was observed in 18 patients reverted with DC shock and in 7 patients reverted with drugs. The left atrium was dilated in all patients during AF (48 +/- 5 mm). The size of the left atrium decreased after restoration of sinus rhythm in all patients with spontaneous reversion to sinus rhythm, in 73% of patients reverted with drugs, and in 50% of patients reverted with DC shock. The comparison between patients with a normal mechanical atrial function and patients with reduced atrial function showed that a higher atrial ejection force was associated with a more marked reduction in LA size after restoration of sinus rhythm. A relation between LA volumes and atrial ejection force was observed in the group of patients with depressed atrial mechanical function (r = -0.78; p <0.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. Thus, a depressed atrial mechanical function after cardioversion for AF was associated with a persistence of LA dilation.     

Hemodynamic abnormalities in the left atrial appendage in patients with paroxysmal atrial fibrillation, with special reference to albumin-contrast echocardiographic aspects

AIM: We assessed the prolonged dysfunction of the left atrial appendage caused by paroxysmal atrial fibrillation. METHODS AND RESULTS: Transesophageal echocardiography with intravenous albumin-microspheres (Albunex, 0.2 ml/kg) was performed in 100 consecutive patients (44 patients in sinus rhythm without previous paroxysmal atrial fibrillation: 13 patients in sinus rhythm who had had previous episodes of paroxysmal atrial fibrillation; and 43 patients with sustained atrial fibrillation). We compared the left atrial appendage ejection fraction and degree of opacification in the left atrial appendage with Albunex in the groups. Patients with previous paroxysmal atrial fibrillation had lower left atrial appendage ejection fractions than patients in sinus rhythm without paroxysmal atrial fibrillation (33 +/- 14 vs. 47 +/- 14%, p < 0.001). More than half of the patients (7/13 [54%]) with previous paroxysmal atrial fibrillation showed delayed and incomplete opacification of the left atrial appendage with Albunex. CONCLUSION: We conclude that paroxysmal atrial fibrillation causes left atrial appendage stunning, at least in some patients.     

心房颤动合并肺动脉高压的临床特征与危险因素

目的 探讨肺动脉高压(pulmonary arterial hypertension,PAH)在心房颤动(atrial fibrillation,AF)患者中的临床特征与危险因素.方法 纳入于2016年11月～2019年11月连续入院的292名确诊AF的患者,根据临床分类分为两组:①阵发性AF组167例(发作后在7天内...     

60例老年心房颤动患者资料的临床分析

目的：探讨老年心房颤动（简称房颤）的病因及临床特点。方法：对我院老年病房2003年1月～2007年6月期间住院的60例男性房颤患者的临床资料进行回顾性分析。结果：患者中阵发性房颤、持续性和永久性房颤分别占12％、22％、66％；冠心病、高血压和糖尿病是引起房颤的主要病因（发病率分别占65％、52％、47％）；持续性／永久性房颤心功能明显差于阵发性房颤心功能（P〈0.01）；其左房内径显著大于阵发性房颤患者的左房内径，而射血分数显著低于阵发性房颤的射血分数（P均〈0.01）；慢性房颤患者均合并有不同类型的其它心律失常（如病窦综合征，房室传导阻滞等）；60例老年房颤患者均用过抗凝剂，仅有5例患者使用过华法林，24例患者发生脑栓塞，2例患者发生下肢或上肢动脉栓塞。结论：冠心病、高血压和糖尿病是引起房颤的主要病因；随着房颤的发展，左房内径增大、心功能逐渐恶化、左室射血分数降低；房颤常合并其它形式的心律失常；脑栓塞发生较高．应加强防治。     

Factors associated with early atrial fibrillation after ablation of common atrial flutter. A single centre prospective study.

BACKGROUND: The occurrence of early atrial fibrillation (< or = 6 months) after ablation of common atrial flutter is of clinical significance. Variables predicting this evolution in ablated patients without a previous atrial fibrillation history have not been fully investigated. OBJECTIVES: The aim of the present study was: (1) to identify predictive factors of early atrial fibrillation (< or = 6 months) in the overall population following atrial flutter catheter ablation; (2) to identify predictive variables of early atrial fibrillation following (< or = 6 months) atrial flutter catheter ablation within a subgroup of patients without documented prior atrial fibrillation. METHODS: This study prospectively included 96 consecutive patients (age 65 +/- 13 years; 18 women) over a 12-month period. Their counterclockwise flutter was ablated by radiofrequency, by the same operator, with an 8-mm-tip catheter. Clinical, electrophysiological and echocardiographic data were collected and 27 variables were retained for analysis: age; gender; type of atrial flutter (permanent vs paroxysmal); symptom duration (months +/- SD); pre-ablation history of atrial fibrillation; structural heart disease; left ventricular ejection fraction (%); left atrial size (mm); cava--tricuspid isthmus dimension; septal isthmus dimension; systolic pulmonary pressure > or < or = 30 mmHg; right atrial area; left atrial area; isthmus block; number of radiofrequency applications (+/- SD); antiarrhythmic drugs at discharge; left ventricular diastolic diameter; left ventricular systolic diameter; left ventricular telediastolic volume; left ventricular telesystolic volume; A-wave velocity (cm . s(-1)); E-wave velocity (cm . s(-1)); E/A; isovolumetric relaxation time; E-wave deceleration time; significant mitral regurgitation and flutter cycle length (ms). RESULTS: Of the 96 consecutive ablated patients, early atrial fibrillation was documented in 16 patients (17%). Atrial fibrillation occurred 30 +/- 46 days (range 1 to 171 days) after ablation. Univariate analysis associated an early occurrence of atrial fibrillation with: atrial fibrillation history, left ventricular ejection fraction, left atrial size, left ventricular telesystolic volume, A-wave velocity, significant mitral regurgitation and flutter cycle length. Multivariate analysis using a Cox model found that the only independent predictors of early atrial fibrillation were left ventricular ejection fraction and pre-ablation history of atrial fibrillation. In the subgroup without prior atrial fibrillation history (n=63; 66%), the only independent predictor of early atrial fibrillation was the presence of a significant mitral regurgitation. CONCLUSIONS: In a subgroup of patients without atrial fibrillation history, 8% of patients revealed an early atrial fibrillation. Mitral regurgitation is a strong predictive factor of early atrial fibrillation occurrence with 80% sensitivity, 78% specificity and 98% negative predictive value. These data should be considered in post-ablation management.     

心房颤动患者血尿酸水平的研究

目的：比较阵发性心房颤动（房颤）、持续性房颤及无房颤患者的血清尿酸水平。方法：入选102例房颤患者,其中阵发性房颤组患者47例（男性25例）,持续性房颤组患者55例（男性26例）。52例无房颤的患者（男性27例）为对照组。收集患者一般临床资料,检测血常规和生化指标,超声心动图测量左房内径、舒张期左室内径、左室射血分数。以房颤是否发生为因变量,进行多因素logistic回归分析。结果：与对照组比较,阵发性及持续性房颤组的左室射血分数都降低、而C反应蛋白和尿酸水平显著升高（P＜0．05）。多元logistic回归分析显示,高尿酸、高C反应蛋白和左房内径增大是房颤发生的危险因素。结论：房颤患者血清尿酸水平升高,高尿酸是房颤发生的危险因素之一。     

Beat-to-beat left ventricular performance in atrial fibrillation: radionuclide assessment with the computerized nuclear probe

There is wide beat-to-beat variability in cycle length and left ventricular performance in patients with atrial fibrillation. In this study, left ventricular ejection fraction and relative left ventricular volumes were evaluated on a beat-to-beat basis with the computerized nuclear probe, an instrument with sufficiently high sensitivity to allow continuous evaluation of the radionuclide time-activity curve. Of 18 patients with atrial fibrillation, 5 had mitral stenosis, 6 had mitral regurgitation, and 7 had coronary artery disease. Fifty consecutive beats were analyzed in each patient. The mean left ventricular ejection fraction ranged from 17 to 51%. There was substantial beat-to-beat variation in cycle length and left ventricular ejection fraction in all patients, including those with marked left ventricular dysfunction. In 14 patients who also underwent multiple gated cardiac blood pool imaging, there was an excellent correlation between mean ejection fraction derived from the nuclear probe and gated ejection fraction obtained by gamma camera imaging (r = 0.90). Based on beat-to-beat analysis, left ventricular function was dependent on relative end-diastolic volume and multiple preceding cycle lengths, but not preceding end-systolic volumes. This study demonstrates that a single value for left ventricular ejection fraction does not adequately characterize left ventricular function in patients with atrial fibrillation. Furthermore, both the mean beat-to-beat and the gated ejection fraction may underestimate left ventricular performance at rest in such patients.     

Echo Doppler guidance for atrial fibrillation ablation: recognition of primary electropathy

Atrial fibrillation (AF) is a multivariable disease. Young patients with paroxysmal AF without structural cardiac abnormality (“lone AF”) likely have a primary electropathy with excellent results from radiofrequency ablation. However, with persistent AF with cardiac abnormalities, including left atrial enlargement and systolic ventricular dysfunction (ejection fraction percent), the electropathy is considered secondary and ablation results poor. We describe a case with persistent AF, depressed systolic function, and marked left atrial enlargement but without echo Doppler evidence of diastolic dysfunction. At electrophysiology study, findings were consistent with a primary electropathy, and the patient did well following ablation.