Left Atrial Contractile Function Research Articles

Extensive Ablation During Pulmonary Vein Antrum Isolation Has No Adverse Impact on Left Atrial Function: An Echocardiography and Cine Computed Tomography Analysis

Although pulmonary vein antrum isolation (PVAI) may cure atrial fibrillation (AF) and improve left atrial (LA) function, the effect of extensive LA ablation on LA function is not well known. To assess the impact of PVAI on LA function remotely postablation. Consecutive patients undergoing PVAI had either transthoracic (TTE) and transesophageal (TEE) echocardiography (n = 41) or cine EBCT (n = 26) performed preablation and 6 months postablation. Only patients with paroxysmal and persistent, but not permanent, AF were included. Imaging was done in sinus rhythm for all patients. LA diameter (LAD), LA systolic and diastolic areas, and left atrial fractional area change (LFAC) were assessed by TTE. Transmitral (TMF), left atrial appendage (LAA), and pulmonary venous (PVF) Doppler flows were measured by TEE. Peak A on TMF, LAA peak emptying velocity (LAAF), and peak A reversal (AR) on PVF were used as surrogates of LA contractile function. Peak S on PV flow was used as a surrogate of reservoir function. LA areas, volumes, and LA ejection fraction (LAEF) were measured from cine EBCT. Mean radiofrequency ablation time was 45 +/- 21 minutes. All four PVs were isolated for all patients; there were no cases of PV stenosis. Echocardiography revealed a significant reduction in LAD and LA areas post-PVAI. Both peak A and peak AR were also higher post, while other variables showed strong trends toward improvement. In the subset of patients with persistent AF, post-PVAI improvements were seen in LA size, peak A, and even peak S (P = 0.04). Cine EBCT showed a significant decrease in both LA areas and volumes post-PVAI. There was also a significant improvement in LAEF post-PVAI from 17 +/- 6% to 22 +/- 5% (P = 0.01). Extensive ablation during PVAI does not cause deterioration in LA function, and may cause long-term improvement, especially in patients with higher AF burden.

Left Atrial Appendage-Flow Velocity Predicts Cardioversion Success in Atrial Fibrillation

Restoration of sinus rhythm by electrical cardioversion is a therapeutic option in appropriately selected patients with atrial fibrillation. It is important to determine predictors of electrical cardioversion outcome in patients with atrial fibrillation. Predictive value of clinical and conventional echocardiographic parameters for predicting cardioversion outcome is limited. The role of left atrial appendage (LAA) function, which may reflect left atrial contractile function, for prediction of cardioversion outcome remains unclear. We conducted a single center prospective study to evaluate the role of LAA function for prediction of cardioversion success in patients with atrial fibrillation. One hundred sixty three patients with atrial fibrillation underwent transthoracic and transesophageal echocardiography (TEE) before electrical cardioversion. LAA functions, including LAA peak flow velocity, LAA area and LAA ejection fraction, were examined. Cardioversion was successful in 133 patients and unsuccessful in 30 patients. Mean LAA peak emptying flow velocity was significantly higher in the patients with successful cardioversion than in those with unsuccessful cardioversion (0.34 +/- 0.14 vs 0.27 +/- 0.1 m/sec; p = 0.013). At multivariate logistic regression analysis, only LAA flow velocity (> 0.28 m/sec, odds ratio = 2.8 ; p = 0.03) proved to be an independent predictor of cardioversion success. LAA area (p = 0.18) and LAA ejection fraction (p = 0.52) were not different between successful and unsuccessful cardioversion groups. Therefore, measurement of LAA flow velocity provides valuable information for prediction of cardioversion outcome in patients with atrial fibrillation before TEE guided cardioversion.

Quantitative Assessment of Left Atrial Functional Changes in Patients with Atrial Fibrillation by Tissue Doppler Strain and 2-Dimensional Strain Imaging

Background and Objectives:Conservation of the normal atrial size and architecture by preventing the structural atrial remodeling that’s due to atrial fibrillation (AF) seems to be of prime importance for the management of AF patients. We attempted to assess the relevance of performing strain echocardiography for quantitatively assessing the left atrial (LA) status in AF patients. Subjects and Methods:Tissue Doppler strain and 2dimensional strain imaging were performed in 15 patients with chronic AF, in 15 patients with paroxysmal AF and in 15 healthy age-matched controls with using a GE vivid 7 dimension apparatus. The LA diameter, LA volume index and mitral inflow parameters were measured by standard echocardiography. Longitudinal peak strain and the strain rate were obtained from 2 different areas of the basal left atrial free wall and also the inter-atrial septum in the apical 4 chamber view with using the tissue Doppler strain. The mean peak systolic rate (Sm-SR), the peak early diastolic rate (Em-SR) and the peak late diastolic strain rate (Am-SR) were measured at the inter-atrial septum in the apical 4 chamber view with using the 2-dimensional strain imaging. Results:The peak strain/rate, the Sm-SR and the Em-SR were significantly reduced in the AF group as compared with the normal controls, and they were especially reduced in the chronic AF group. There were no significant differences for the LA size and A wave velocity between the paroxysmal AF group and the normal group; however, the peak systolic strain/rate, the Em-SR and the Am-SR were significantly lower in the paroxysmal AF group than in the normal controls. Conclusion:The lower values of atrial Sm-SR, Em-SR and Am-SR revealed that active contraction and passive stretching of the LA wall may be impaired in some patients suffering with paroxysmal AF even before LA enlargement occurs, and this is possibly because of reduced atrial compliance. Our results indicated that strain echocardiography enabled quantitatively precise assessment of the LA contractile function and it can provide clinically useful information concerning the early reversible atrial functional changes in patients suffering with AF, and especially in the paroxysmal AF patients. (Korean Circulation J 2006;36:786-793)

996 Can tissue Doppler imaging of the lateral mitral annulus, quantify left atrial contractile function in patients with severe mitral regurgitation due to mitral valve prolapse?

996 Can tissue Doppler imaging of the lateral mitral annulus, quantify left atrial contractile function in patients with severe mitral regurgitation due to mitral valve prolapse?

Is Functional Capacity Related to Left Atrial Contractile Function in Nonobstructive Hypertrophic Cardiomyopathy?

The mechanisms underlying reduced exercise capacity in patients with nonobstructive hypertrophic cardiomyopathy (NHCM) could include perturbations of ventricular relaxation, diastolic compliance, or compensatory atrial systolic function. We hypothesized that a loss of atrial contractility in NHCM patients leads to reduced functional capacity. To test this hypothesis, we compared resting noninvasive left atrial ejection phase indices in 49 consecutive patients with NHCM (ages 36+/-10 years; 41% female) and normal left ventricular ejection fraction (mean, 68%+/-8%) with objective metabolic exercise parameters. Left atrial active emptying fraction, ejection force, and kinetic energy failed to predict exercise capacity. Only left atrial total and active emptying volumes correlated weakly with minute volume/CO2 production slope (r=0.31 and r=0.33; p<0.05 for both). Furthermore, when subjects were stratified by New York Heart Association symptomatology, exercise parameters--but not atrial contractility--differed between groups. These data, obtained at rest, fail to suggest that NHCM-related heart failure symptoms are due to an atrial myopathy.

Excellent results for atrial fibrillation surgery in the presence of giant left atrium and mitral valve disease.

The incidence of sinus conversion in the enlarged left atrium after atrial fibrillation surgery is reported to be low. The purpose of the current study was to investigate the effects of atrial fibrillation surgery on mitral valve disease associated with a giant left atrium (GLA). From July of 1997 to February of 2002, 188 patients received mitral valve and atrial fibrillation surgery. The patients were placed in either GLA group (n = 94), or NGLA group (n = 94), based on LA size. The presence and onset of sinus rhythm and the incidence and velocity of transmitral A waves were monitored during the early postoperative period and throughout the follow up period of 42 months. The onset of postoperative sinus rhythm was slightly earlier in the NGLA group than in the GLA group at 1.3+/-0.4 days versus 3.1+/-1.2 days, respectively, (P = 0.008). The sinus conversion rates in the GLA and the NGLA groups were 91.5 and 97.9% in the early postoperative period, and 94.7 and 95.7% at 6 months after surgery, respectively. A wave appearance rates in the early postoperative period in the GLA and the NGLA groups were 62.2 and 71.7%, and continued to improve over time to 94 and 95% by 36 months, respectively. Peak A wave velocities in the early postoperative period in GLA and NGLA groups were 67.4+/-34.0 and 61.1+/-29.5 cm/s without significant change during the follow up. The results suggest that atrial fibrillation surgery is effective at inducing sinus rhythm and restoring left atrial contractile function after concomitant mitral valve surgery regardless of LA size.

Left atrial function, cytokines and soluble apoptotic markers in mitral stenosis: effects of valvular replacement

Background: Patients with mitral stenosis (MS) and heart failure (HF) are characterized by changes in the left atrial (LA) function and activation of the apoptotic process. The purpose of the present study was the evaluation of the effect of mitral valve replacement on the LA function, on inflammatory process and apoptotic markers in patients with MS and HF. Methods: We studied 30 patients with MS and HF (15 in NYHA III–IV and 15 in NYHA IV) in sinus rhythm (mean age 56.2±4.6 years), and 20 age and gender matched healthy volunteers. Blood samples were obtained before and 6 months after surgical mitral valve replacement, and plasma levels of soluble Fas/APO-1 receptor (sFas), tumor necrosis factor-alpha (TNF-a) and interleukin-6 (IL-6) were measured. Echocardiographically, LA volumes were measured at mitral valve opening (Vmax), at the onset of left atrial systole (P wave of the electrocardiogram, Vp) and at the mitral valve closure (Vmin). LA contractile function was assessed by the LA active emptying fraction (ACTEF). Results: After mitral valve replacement, TNF-a, IL-6 and sFas levels, as well as the Vmax LA volume, were significantly reduced ( p<0.05). ACTEF showed a significant postoperative decrease (0.29±0.09 vs. 0.23±0.06, p<0.01) and it was significantly correlated with sFas ( r=−0.88, p=0.001), TNF-a ( r=−0.81, p=0.001) and IL-6 ( r=−0.74, p=0.001) levels. Conclusion: The present findings indicate that mitral valve replacement in patients with mitral valve stenosis, reduces the size of the left atrium, improves left atrial contractile function and depresses inflammatory and apoptotic process.

839-6 Role of left atrial contractile function in functional capacity of patients with hypertrophic nonobstructive cardiomyopathy

839-6 Role of left atrial contractile function in functional capacity of patients with hypertrophic nonobstructive cardiomyopathy

Atrial fibrillation surgery simplified with cryoablation to improve left atrial function

Background. The Maze procedure restores atrial fibrillation to normal sinus rhythm. However, concurrent left atrial functional recovery is not always achieved. To address this limitation, a modification using linear cryo-ablation is described. Methods. Between July 1997 and December 1999, 83 patients received atrial fibrillation surgery in association with mitral valve surgery with or without additional concurrent procedures by either the conventional technique, group I (n = 30) or the modified technique, group II (n = 53). Onset of sinus conversion and echocardiographic assessment of postoperative left ventricular function, left atrial size, and mitral A-wave velocity were compared in the early postoperative period and 6 months after surgery. Results. Sinus conversion occurred significantly earlier in group II, 2.4 ± 5 days versus group I, 7.0 ± 10 days. The mean transmitral A-wave velocity and the incidence of A-wave appearance in the early postoperative period and 6 months postoperatively were greater in group II than group I. Conclusions. With the current modification, restoration of sinus rhythm and superior left atrial contractile function occurred earlier than with the standard Maze III technique.

Decreased left atrial appendage function is an important predictor of elevated left ventricular filling pressure in patients with congestive heart failure

Objective: The aim of this study was to investigate whether left atrial (LA) appendage function, as indicated by LA appendage blood flow velocities and its ejection fraction, could identify elevated left ventricular filling pressure in patients with chronic congestive heart failure. Methods: Using transesophageal echocardiography, adequate pulsed Doppler LA appendage active emptying and filling velocities could be recorded in 25 consecutive patients (16 men and 9 women, aged 57±10 years) with chronic congestive heart failure (symptom duration≥1 year). LA appendage ejection fraction calculated as (LA appendage maximal area)−(LA appendage minimal area)/(LA appendage maximal area)×100 was also determined in these patients. Left ventricular end-diastolic pressure was recorded during cardiac catheterization performed within 24 h of echocardiographic study. Results: Left ventricular end-diastolic pressure was 2 to 47 mm Hg. There were close negative correlations of LA appendage emptying velocity ( r=−0.508; P<0.0 1), filling velocity ( r=−0.429; P<0.05) and LA appendage ejection fraction ( r=−0.523; P<0.005) with left ventricular end-diastolic pressure. LA appendage active emptying velocity <30 cm/s predicted left ventricular end-diastolic pressure >25 mm Hg with a sensitivity of 72.7%, a specificity of 92.9% and a positive and negative predictive value of 88.9 and 81.3%. Conclusions: The findings suggest that measurement of LA appendage blood flow velocities and contractile function by transesophageal echocardiography can be used to predict elevated left ventricular filling pressure in patients with congestive heart failure.

Left Atrial Appendage Contractile Function in Atrial Fibrillation: Influence of Heart Rate and Cardioversion to Sinus Rhythm

A high incidence of embolic phenomena is associated with atrial fibrillation (AF) and the left atrial appendage (LAA) is frequently the source of the emboli. Thrombus formation may be due to stasis within the fibrillating and inadequately emptying LAA. Because LAA emptying in AF may be the result of mechanical compression by the adjacent left ventricle, it is possible that left ventricular diastolic filling duration will importantly influence passive emptying of the LAA. We hypothesized that the magnitude of emptying of the LAA in AF is related to the duration of left ventricular diastolic filling which is determined by the ventricular response rate in AF.The objective of our study was to determine the relationship of ventricular response rate in AF to LAA emptying and to assess the influence of sinus rhythm and heart rate on LAA emptying immediately after direct current cardioversion to sinus rhythm.To study this, we used transesophageal echocardiography to measure LAA ejection fraction ([LAAmax-LAAmin]/LAAmax x 100%) and evaluated its relationship to left ventricular response rate (VRR) in 26 patients with AF (mean age, 65 +/- 7 [1 SD] years).There was a strong inverse relationship between LAA ejection fraction and VRR in AF (r = -0.73; p < 0.001). LAA ejection fraction during AF was 26 +/- 10%, and immediately after successful cardioversion, it increased to 46 +/- 12% (p < 0.001). However, during sinus rhythm there was no relationship between LAA ejection fraction and VRR (r = 0.06; p = NS) in the subgroup of patients who were successfully converted to sinus rhythm. There were poor relationships between LAA ejection fraction and peak transmitral flow velocity (r = -0.41; p = NS) or pulmonary venous flow velocity (r = -0.03; p = NS) in AF.These results indicate that the magnitude of LAA emptying in AF is strongly and inversely influenced by ventricular rate. Direct current cardioversion to sinus rhythm is associated with an increase in the magnitude of LAA emptying that is not influenced by heart rate. The magnitude of LAA emptying may be an important factor in the formation of thromboemboli in AF. The extent to which controlling the VRR in chronic AF will prevent stasis and LAA thrombus formation remains to be determined.

Recovery of atrial function after atrial compartment operation for chronic atrial fibrillation in mitral valve disease

Objectives. We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease.Background. Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it.Methods. Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured.Results. Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for >1 week in 15 (68%) of 22 patients and >6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patents. Mean (±SD) peak atrial filling velocity of the mitral valve was 15 ± 26 cm/s at 1 week, 38 ± 39 cm/s at 2 months and 93 ± 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 ± 19 cm/s at 1 week, 33 ± 19 cm/s at 2 months and 50 ± 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months.Conclusions. Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.

Current management of atrial fibrillation.

A resurgence of interest in atrial fibrillation has led to research in several avenues. Observations on the behavior of the atrium during atrial fibrillation demonstrate that electrical activity is not entirely random and that sinus node activity persists despite surrounding fibrillation. Anticoagulation therapy for chronic atrial fibrillation is now accepted as optimal treatment, but randomized trials have excluded the majority of patients screened and the risk-benefit ratio of therapy in the average patient therefore remains unclear. This is being addressed in comparative trials of warfarin and aspirin and in an analysis of risk factors for stroke derived from a major trial. Assessment of the efficacy of therapy for the control of ventricular rate in atrial fibrillation has underscored the slow action of digoxin and raised the issue of suboptimal dosing. With the recognition that improvement of exercise capacity following cardioversion may be postponed for weeks, several studies have evaluated serial changes in ventricular function and shown that in some patients sinus rhythm is associated with an improved ejection fraction. Transesophageal echocardiography is an area of intense interest for the identification of patients at high risk of thromboembolism following cardioversion, and the significance of left atrial spontaneous echo contrast as well as the left atrial appendage contractile function are being investigated. Finally, new methods of arrhythmia termination are being evaluated and developed, and surgical approaches to atrial fibrillation are being expanded and refined.

Echocardiographie Detection of Elevated Left Ventricular End-Diastolic Pressure by Left Atrial Contractile Function

Echocardiographie Detection of Elevated Left Ventricular End-Diastolic Pressure by Left Atrial Contractile Function