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.     

Left atrial dimension and atrial fibrillation in surgical heart disease patients

Objective The effect of left atrial (LA) dimension on the occurrence of atrial fibrillation (AF) has been examined in some small studies.Less is known about the relationship of LA dimension,hemodynamic with AF during echocardiographic evaluation,especially,the flow dynamics in LA poorly described.The objective of this study was to investigate the relationship between LA dimension and the occurrence of AE Methods Two hundred and forty-five consecutive patients with heart disease scheduled to undergo open heart surgery were prospectively enrolled in the study.Patients were divided into 2 groups according to atrial fibrillation:AF group (n=148,99 men and 49 women,with a mean age 59.3+8.4 years),and no-AF group (n= 97,60 men and 37 womem).Echocardiography was performed before surgery.All measurements were performed following the American Society of Echocardiography recommendations.Results There were more patients with congestive heart failure in AF group than in no-AF group (45.9% vs 39.1%,P ＜0.05).The mean LA volume was 49.2±12.2 ml/m2 in AF group and 33.1±10.8 ml/m2 in no-AF group.There were also significant differences between two groups in left atrial end systolic dimension (LAESD) (50±13mm vs 27±14mm),left atrial end diastolic dimension (LAEDD) (79±17mm vs 53±13mm),PA pressure ( 41.3+11.6 mmHg vs 37.5±10.4 mmHg),and ratio of mitral E velocity and septal mitral annulus motion velocity (E/E') .The percentage of abnormal diastolic function grades (DGF) was also higher in AF than in no-AF group (89.9% versus 59.8% );.Conclusion Atrial fibrillation is associated more frequently with an increased LA dimension and more severe atrial hemodynamics disorder.(J Geriatr Cardiol 2008;5:11-4)     

左心房/肺静脉重构在孤立性心房颤动进展中的作用

目的 探讨孤立性心房颤动（房颤）进展过程中左心房/肺静脉重构的作用.方法 连续47例孤立性房颤患者在房颤心律下接受左心房/肺静脉CT检查,其中25例为阵发性房颤,22例为新发持续性房颤.通过对两组间有差异的CT指标进行Logistic回归分析,确定孤立性房颤进展的预测指标.结果 新发持续性房颤组的平均房颤持续时间为1～12（6.4±4.3）周.与阵发性房颤组比较,新发持续性房颤组呈现如下的左心房/肺静脉重构特征：（1）左心房非对称扩张;（2）左心房容积显著增大;（3）肺静脉开口扩张.经Logistic回归分析,左心房容积（P=0.003,OR=1.139,95%可信区间：1.046～1.240）是预测孤立性房颤进展最强的独立指标.左心房容积≥108 ml预测孤立性房颤由阵发性进展为持续性的敏感性为68.2%,特异性为88%.结论 孤立性房颤在由阵发性进展为持续性的过程中伴随有显著的左心房和肺静脉重构;左心房容积显著增加是该过程的独立预测指标.     

Left atrial enlargement as a predictor of recurrences in lone paroxysmal atrial fibrillation

BACKGROUND: A mild increase in left atrial (LA) size predicts arrhythmia onset and adverse events in patients with lone paroxysmal atrial fibrillation (LPAF). However, the role of LA size as a predictor of LPAF recurrences is still controversial. OBJECTIVE: The potential role of LA size in affecting the frequency of recurrent episodes in patients with LPAF was investigated. METHODS: Fifty-one patients who were admitted for a first episode of LPAF and presenting with one recurrence (group A, n=20), two or three recurrences (group B, n=18), or four or more recurrences (group C, n=13) during an average follow-up period of two years were retrospectively selected. The M-mode LA anteroposterior diameter (LAAPd) was used as an echocardiographic surrogate of LA size. RESULTS: At baseline, LA size was normal or borderline in the control group, group A and group B, but significantly increased in group C. At two years' follow-up, a significant further LA enlargement from baseline was observed in group B (LAAPd 40+/-1.1 mm versus 40.7+/-1.2 mm, P<0.01) and in group C (LAAPd 41.4+/-1.6 mm versus 42.7+/-1.7 mm, P<0.001), while LA size remained substantially unchanged in the control group and in group A. CONCLUSIONS: Observations confirmed the association of increased LA size and LPAF onset, and provide the first evidence for a potential role of LA progressive enlargement as a predictor of arrhythmic recurrences.     

孤立性心房颤动患者左右心室功能的研究

目的应用定量组织速度成像技术(QTVI)联合二尖瓣环收缩期位移(MAD)及三尖瓣环收缩期位移(TAPSE)评价孤立性心房颤动(LAF)患者左、右心室功能。方法 LAF组为36例患者(左、右心室结构正常),对照组为30名健康成年人,应用M型超声测量左、右心室结构常规参数,MAD及TAPSE;应用多普勒超声测定二、三尖瓣瓣口舒张期峰值血流速度E;应用QTVI测量左心室侧壁二尖瓣环处、右心室侧壁三尖瓣环处收缩期峰值速度Vs,舒张期峰值速度Ve,并计算E/Ve。结果与对照组相比,LAF组左心室E、E/Ve升高,Ve、Vs、MAD减低(均为P<0.05),LAF组右心室E、E/Ve升高,Ve、Vs、TAPSE值减低(均为P<0.05),IVSTd、LVPWTd、LVEDD、LVESD、LVEF、RVD1、RVD2、RVD3、RVAW、RVEF各组间差异无统计学意义(均为P>0.05)。结论 LAF组较对照组左、右心室功能均受损。     

Left ventricular diastolic dysfunction in lone atrial fibrillation determined by Doppler tissue imaging of mitral annular motion

In this study, we sought evidence for an underlying atrial or ventricular myopathy in patients with paroxysmal lone atrial fibrillation using standard echocardiographic parameters in addition to Doppler tissue imaging of mitral annular motion. No impairment in atrial contractile function was found, but there was evidence for impaired diastolic function in these patients.     

Left ventricular relaxation abnormality is detectable by analysis of the relaxation time constant in patients with atrial fibrillation.

Left ventricular (LV) contractility is constantly changing during atrial fibrillation (AF), which is dependent on the force-interval relationships. However, no information has been available on LV relaxation in patients with both AF and impaired LV systolic function. LV pressure was measured with a catheter-tipped micromanometer and the time constant of isovolumic LV pressure decline (tau(bf)) was calculated with best exponential fitting from more than 10 consecutive beats. Patients with AF (5 with mitral valvular disease, 6 with idiopathic dilated cardiomyopathy, and 1 with no underlying disease) were subdivided into 2 groups: group A, with ejection fraction (EF) <0.5 (n=7); and group B, with EF > or =0.5 (n=5). Linear correlation coefficients (r) between tau and RR2, RR2/RR1, LV peak systolic pressure (peak LVP) were calculated. Although tau did not show a discrepancy between the 2 groups, tau(bf) correlated better with RR2/RR1 only in the group A patients. The relation between tau and peak LVP showed a good correlation with a steep slope (R, Deltatau/Deltapeak LVP) only in the group A patients (accentuated afterload-dependence). R was significantly different between the 2 groups. Thus, a beat-to-beat analysis of tau may be a practical and feasible way for detecting LV relaxation abnormality in patients with AF.     

Left atrial function and ventricular filling in hypertensive patients with paroxysmal atrial fibrillation

Objectives. We evaluated left atrial dimensions and function, as well as left ventricular structure and filling, in hypertensive patients with paroxysmal atrial fibrillation.Background. In hypertensive patients, left atrial dilation and enhanced volume transport may facilitate arrhythmias.Methods. Left ventricular two-dimensional and M-mode echocardiograms and pulsed Doppler echocardiography of transmitral flow were performed in 17 consecutive primary hypertensive patients with paroxysmal atrial fibrillation (group EHf) and in 34 patients with high blood pressure without this arrhythmia (group EH). Seventeen normal subjects (group N) were also investigated. Groups were matched for age and gender.Results. The EH and EHf groups had similar systolic arterial pressures ([mean ± SD] group EH 185 ± 27, group EHf 173 ± 25 mm Hg, p = NS) and left ventricular mass index (group EH 154 ± 55, group EHf 131 ± 57.8 g/m², p = NS), and their M-mode left ventricular systolic wall stress and fractional shortening were comparable to those of normal subjects. M-mode left atrial maximal (group N 37.8 ± 6, group EH 37.9 ± 4.6, group EHf 44.6 ± 6.7 mm, p < 0.05 for group EHf vs. groups N and EH) and minimal diameters and the diameter preceding atrial contraction (group N 31 ± 3.6, group EH 34.5 ± 5, group EHf 40.4 ± 6.9 mm, p < 0.001 for group EHf vs. group N; p < 0.05 for group EHf vs. group EH) were greater in group EHf than in group EH and group N subjects, whereas only the latter diameter was increased in group EH (p < 0.05 vs. group N), so that left atrial fractional shortening was higher than normal only in group EH (group N 10.8 ± 4.4%, group EH 14.6 ± 5.5%, group EHf 9.3 ± 5.3%; group EH vs. group N, p < 0.05; group EHf vs. group EH, p < 0.05). The pulsed Doppler ratio of early to late transmitral flow rates (E and A wave velocity/time integrals × mitral annulus area) was lower than normal in group EH (group N 2.9 ± 2.2, group EH 1.75 ± 0.8, group EHf 2.8 ± 0.8; group EH vs. group N, p < 0.05; group EHf vs. group EH, p < 0.001; group EHf vs. group N, p = NS) and was “normalised” in group EHf, early flow being increased in this group (group N 42 ± 13, group EH 39 ± 29, group EHf 60 ± 17 ml; group EHf vs. group N, p < 0.05; group EHf vs. group EH, p < 0.05).Conclusions. These results suggest that the occurrence of paroxysmal atrial fibrillation in hypertension is associated with enlargement of the left atrium, depression of its contractile function and “normalization” of the pattern of left ventricular filling and is independent of left ventricular hypertrophy and systolic wall stress. The mechanisms linking these variables remain undefined.     

Left atrial volume predicts cardiovascular events in patients originally diagnosed with lone atrial fibrillation: three-decade follow-up

We read with great interest the study of Osranek et al.¹on the left atrial volume as a     

Left atrial volume predicts cardiovascular events in patients originally diagnosed with lone atrial fibrillation: three-decade follow-up.

AIMS: The objectives of this study were to determine the long-term outcome and the predictors of adverse events in patients originally diagnosed with lone atrial fibrillation (AF). METHODS AND RESULTS: This population-based historical cohort study comprised 46 residents of Olmsted County, MN, USA, with well-documented, clinically defined lone AF and a complete two-dimensional echocardiographic examination. The original echocardiographic videotape recordings were analysed in a blinded fashion for left atrial volume (LAV) and left ventricular ejection fraction. With 1296 person-years of follow-up, the median duration of AF was 27 (first quartile=24, third quartile=33) years. Twenty-three (50%) patients developed events. Cerebral infarction occurred in seven patients, myocardial infarction in 11, and congestive heart failure in 16. In a multivariable analysis, patients with indexed LAV >or=32 mL/m(2) had a significantly worse event-free survival (adjusted HR, 4.46; 95% CI, 1.56-12.74; P=0.005). All cerebral infarctions occurred in patients with an indexed LAV >32 mL/m(2). CONCLUSION: Patients originally diagnosed with benign lone AF follow divergent courses based on LAV. Those originally diagnosed with lone AF and normal sized atria had a benign clinical course throughout the long-term follow-up. Patients with increased LAV at diagnosis or later during the follow-up experienced adverse events.     

C-Reactive protein in lone atrial fibrillation

An inflammatory cause of atrial fibrillation (AF) has been proposed on the basis of the presence of lymphocytic infiltrates in the biopsy results of patients with lone AF, alterations of C-reactive protein (CRP) and interleukin-6 levels in subjects with AF, and the time course of postoperative AF. Many previous studies exploring inflammatory factors in AF have been confounded by concomitant medical illnesses. Subjects with lone AF provide a unique opportunity to eliminate the effects of associated conditions. We therefore sought to determine CRP levels in homogenous cohorts of patients with lone AF or AF and hypertension. One hundred twenty-one subjects with lone AF, 52 subjects with AF and hypertension, and 75 control subjects were enrolled and studied. Plasma CRP levels were determined using a commercially available immunoassay. There was no significant difference in CRP levels between subjects with lone AF and controls (1.34 vs 1.21 mg/L, p = 0.18). CRP levels in subjects with AF and hypertension were elevated compared with those of controls and those of subjects with lone AF, although this difference was attributable to increased body mass indexes. CRP levels were not elevated in subjects with lone AF compared with controls. In conclusion, these findings clarify previous observations of elevations in CRP levels in subjects with AF and suggest that this marker of systemic inflammation is associated not with the arrhythmia per se, but rather with underlying cardiovascular disease.     

Changes in left atrial size in patients with lone atrial fibrillation

A retrospective analysis was performed on 23 subjects with lone atrial fibrillation who were followed for an average of 6.2 years (1.1-12.8 years). In all patients, underlying organic heart disease was excluded based on history, physical exam, electrocardiogram, echocardiogram, and Doppler ultrasound interrogation. All patients had at least two echocardiographic studies during the period of observation. Atrial fibrillation was chronic in 11 subjects and paroxysmal in 12. All echocardiographic measurements were obtained by averaging the measurements of two blinded investigators. Left atrial size increased an average of 5.6 mm which translates into a 14.7% increase over the baseline measurement. This increase in size was not associated with a change in left ventricular mass or fractional shortening as determined by echocardiography. Subjects with chronic atrial fibrillation had a larger percent increase than subjects with paroxysmal atrial fibrillation (18.9 vs. 10.8%), although this relative change in size failed to reach statistical significance. The only variable which significantly contributed to the change in left atrial size was the duration of follow-up. We conclude that atrial fibrillation occurring in patients with lone atrial fibrillation may cause a slow and progressive increase in left atrial size independent of changes in left ventricular size or function.     

Left ventricular function in atrial fibrillation during overdrive pacing

Objective Our purpose was to measure the effect of ventricular pacing in patients with atrial fibrillation (AF) on stroke volume and cardiac output. Background Unceasing variation in cycle length in AF decreases stroke volume and cardiac output. Because ventricular-inhibited pacing after atrioventricular node ablation has been reported to improve left ventricular performance, we tested the hypothesis that overdrive pacing would produce a similar benefit by regularizing cycle length. Methods and Results We studied 18 patients with chronic AF and permanent pacemakers. The aortic time velocity integral (TVI) was measured with continuous-wave Doppler and was used as a surrogate measure of stroke volume (stroke volume = TVI × aortic valve area, and aortic valve area is constant whether in AF or during pacing). For each patient, the linear relation between preceding cycle length and TVI in AF was used to estimate relative stroke volume (TVI compared within each patient) at a preceding cycle length of 666 ms in AF, and a similar comparison between AF and pacing was made at the minimum allowable pacing rate. Relative stroke volume in AF was then compared with relative stroke volume at both the fixed cycle (666 ms) and the minimum allowable rate. During pacing at 666 ms, relative stroke volume increased significantly by 18% (t = 2.8, P = .048), but there was no difference in cardiac output during pacing at the minimum possible rate and the corresponding preceding cycle length in AF. Conclusion Our data suggest that regularization of ventricular rhythm by overdrive pacing in patients with AF only improves stroke volume (and by extension, cardiac output) at pacing rates at the outer limit of and above the normal physiologic range. (Am Heart J 2002;143:827-32.)     

Left atrial mechanical responses to right ventricular pacing in heart failure patients: implications for atrial fibrillation

Left Atrial Function During Right Ventricular Pacing. Background: RV pacing (RVP), even with preserved atrioventricular (AV) synchrony, may lead to left atrial (LA) enlargement and atrial fibrillation. However, inciting events are unknown. We hypothesized that RVP acutely impairs LA function by mechanisms affecting atrial contraction and/or ventricular diastole. Methods: LA function in ICD patients (n = 31, LVEF ≤ 40%) and controls (n = 14, LVEF > 50%) was contrasted between intrinsic conduction versus RVP during asynchronous (ICD, n = 17, control, n = 7), and synchronous (ICD, n = 14, control, n = 14) pacing at long (LAVd, 107 ±16 ms) and short (SAVd, 31 ± 5 ms) AV delays. LA maximal volume (LA_Max), minimal volume (LA_Min), and emptying fraction {LA_EmF = (LA_Max–LA_Min)/LA_Max} were measured echocardiographically. Six‐segment mean mitral annular tissue doppler E′ (global E′) assessed diastolic recoil during baseline and LAVd. Results: In the ICD group, LA_Min increased by 42% (P < 0.0009) during VVI, by 31% (P = 0.0002) during SAVd, and by 17% (P < 0.0007) during LAVd. LA_EmF decreased by 44% (P < 0.0008), 27% (P < 0.0001), and by 15% (P = 0.003) during VVI, SAVd, and LAVd respectively. LA_Max was unaltered. Global E′ was reduced by 12%. In control, LA_Min increased and LA_EmF decreased significantly during VVI (82 and 58%) and SAVd (46 and 41%), but not during LAVd. Conclusion: In patients with LV dysfunction, RVP acutely impaired LA emptying, and increased minimal volume, most prominently when atrial contraction was impeded (VVI, DDD‐SAVd) but also when completed (DDD‐LAVd), indicating impaired diastolic recoil as an important mechanism. When LV function was normal, similar changes were present when atrial filling is impeded (VVI, SAVd), but not when completed (LAVd) . (J Cardiovasc Electrophysiol, Vol. 22, pp. 866‐874, August 2011)