Left Atrial Volume Reduction Research Articles

Association of Heart Rhythm With Exercise Capacity After Operation for Chronic Mitral Regurgitation

Although atrial fibrillation (AF) and decreased exercise capacity are common in chronic mitral regurgitation patients, the relationship between rhythm status and exercise capacity after corrective surgery is largely unknown. Seventy-one patients undergoing repair or replacement of mitral valve for chronic severe mitral regurgitation were examined with preoperative and 6 months' postoperative cardiopulmonary exercise test and two-dimensional echocardiography. Patients were divided into three groups according to preoperative versus postoperative rhythm (sinus/sinus, SS [n=42]; AF/sinus, AS [n=17]; AF/AF, AA group [n=12]). Preoperative maximal oxygen consumption was lower and ventilatory efficiency was higher in the AS and AA groups compared with the SS group. However, maximal oxygen consumption improved only in the AS group at 6 months' postoperative cardiopulmonary exercise test (24.0±6.9 versus 24.6±6.1 mL·kg(-1)·min(-1) in the SS group, 19.3±5.9 versus 23.2±6.4 mL·kg(-1)·min(-1) in the AS group, 19.8±5.4 versus 18.8±5.1 mL·kg(-1)·min(-1) in the AA group; p=0.016 for maximal oxygen consumption by analysis of covariance) as well as ventilatory efficiency. Echocardiography verified more significant reduction of left atrial volume in the SS and AS groups than in the AA group (172.2±68.0 versus 96.7±31.0 mL in the SS group, 247.5±77.8 versus 129.2±25.7 mL in the AS group, 316.7±210.0 versus 192.0±95.0 mL in the AA group; p=0.001 for left atrial volume by analysis of covariance) as well as pulmonary artery systolic pressure. When analyzed for significant predictors of postoperative maximal oxygen consumption, being in the AS group but not the SS group was a significant positive predictor when compared with the AA group (β=5.475; p=0.006). Successful sinus conversion of AF, preferably by maze operation, in patients undergoing surgical correction of chronic severe mitral regurgitation confers improved exercise capacity. Reduction of left atrial volume and pulmonary artery pressure may contribute to this improvement.

Assessing the Immediate and Sustained Effectiveness of Circular Epicardial Surgical Ligation of the Left Atrial Appendage

Obliterating the left atrial appendage from systemic circulation in patients with atrial fibrillation has been proposed to reduce thromboembolic events. The goal of this study was to assess the effectiveness of a circular method of epicardial surgical ligation in obliterating the left atrial appendage and maintaining sustained exclusion. Patients with permanent atrial fibrillation and an indication for elective cardiac surgery were enrolled. All patients underwent preoperative cardiac gated computerized tomography (CT) and transesophageal echocardiography (TEE). During the cardiac procedure circular ligation of the appendage was performed. Twelve patients, mean (SD) age 65 (12) years completed the study. Intraoperative TEE demonstrated all patients (12/12) had complete postligation occlusion of the left atrial appendage. At three-month follow-up, cardiac gated CT demonstrated that 75% (9/12) of the patients had communication of contrast dye from the left atrial appendage to body of left atrium. Left atrial appendage orifice area and volume were reduced from mean (SD) (5.5 cm(2) [1.8] to 0.5 cm(2) [0.4] p = 0.002) and (14.0 cm(3) [8.3] to 2.7 cm(3) [1.3] p = .005) postligation, respectively. No clinically significant thromboembolic events were reported. Epicardial suture ligation of the left atrial appendage resulted in successful intra-operative exclusion on TEE; however, a significant portion of patient's demonstrated communication of contrast on CT. This is suggestive of incomplete long-term exclusion. The clinical significance of reduction in left atrial appendage orifice area and volume with a persistent communication requires further study.

Left Atrial Reduction Plasty: A Novel Technique

We describe a novel technique of left atrial volume reduction in a patient presenting with severe dyspnea from severe mitral insufficiency, giant left atrium, and compressive symptoms of dysphagia and dysphonia. Resection involved circumferential excision of the left atrium anterior to the pulmonary venous vestibule and posterior to the mitral valve and fossa ovalis, including the left atrial appendage. A chordal-sparing bioprosthetic mitral valve replacement, tricuspid valve annuloplasty, and coronary bypass were also performed. Significant reduction of left atrial volume by 50% was achieved and clinical resolution of compressive symptoms was seen at 6-month follow-up.

Initial experience with Pomerantzeff´s technique for reduction of the size of giant left atrium

The most common indication for surgical correction of giant left atrium is associated with mitral valve insufficiency with or without atrial fibrillation. Several techniques for this purpose are already described with varying results. To present the initial experience with the tangential triangular resection technique (Pomerantzeff). From 2002 to 2010, four patients underwent mitral valve operation with reduction of left atrial volume by the technique of triangular resection tangential in our service. Three patients were female. The age ranged from 21 to 51 years old. The four patients presented with atrial fibrillation. Ejection fraction of left ventricle preoperatively ranged from 38% to 62%. The left atrial diameter ranged from 78mm to 140mm. After treatment of mitral dysfunction, the left atrium was reduced by resecting triangular tangential posterior wall between the pulmonary veins to avoid anatomic distortion of the mitral valve or pulmonary veins, reducing tension in the suture line. Average hospital stay was 21.5 ± 6.5 days. The mean cardiopulmonary bypass time was 130 ± 30 minutes. There was no surgical bleeding or mortality in the postoperative period. All patients had sinus rhythm restored in the output of cardiopulmonary bypass, maintaining this rate postoperatively. The average diameter of the left atrium was reduced by 50.5% ± 19.5%. The left ventricular ejection fraction improved in all patients. Initial results with this technique have shown effective reduction of the left atrium.

Prediction of Left Atrial Fibrosis With Speckle Tracking Echocardiography in Mitral Valve Disease: A Comparative Study With Histopathology

Background and ObjectivesLeft atrial (LA) fibrosis is a main determinant of LA remodeling and development of atrial fibrillation. However, non-invasive prediction of LA fibrosis is challenging. We investigated whether preoperative LA strain as measured by speckle tracking echocardiography could predict the degree of LA fibrosis and LA reverse remodeling after mitral valve (MV) surgery.Subjects and MethodsSpeckle tracking echocardiography and LA volume measurements were performed in 50 patients one day before MV surgery. LA tissues were obtained during the surgery, and the degrees of their interstitial fibroses were measured. LA volume measurements were repeated within 30 days after surgery (n=50) and 1-year later (n=39).ResultsLeft atrial global strain was significantly correlated with the degree of LA fibrosis (r=-0.55, p<0.001), and its correlation was independent of age, underlying rhythm, presence of rheumatic heart disease and type of predominant MV disease (B=-1.37, 95% confidence interval -2.32 - -0.41, p=0.006). The degree of LA fibrosis was significantly correlated with early (r=-0.337, p=0.017) and 1-year (r=-0.477, p=0.002) percent LA volume reduction after MV surgery, but LA global strain was not significant.ConclusionLeft atrial strain as measured by speckle tracking echocardiography might be helpful for predicting the degree of LA fibrosis in patients with MV disease.

Cardiac Resynchronization Therapy Reduces Left Atrial Volume and the Risk of Atrial Tachyarrhythmias in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy)

We hypothesized that reductions in left atrial volume (LAV) with a cardiac resynchronization therapy-defibrillator (CRT-D) would translate into a subsequent reduction in the risk of atrial tachyarrhythmias (AT). There is limited information regarding the effect of CRT-D on the risk of AT. Percent reduction in LAV at 1 year following CRT-D implantation (pre-specified as low [lowest quartile: <20% reduction in LAV] and high [≥20% reduction in LAV] response to CRT-D) were related to the risk of subsequent AT (comprising atrial fibrillation, atrial flutter, atrial tachycardia, and supraventricular tachyarrhythmias) among patients enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy). The cumulative probability of AT 2.5 years after assessment of echocardiographic response was lowest among high LAV responders to CRT-D (3%) and significantly higher among both low LAV responders to CRT-D (9%) and implantable cardioverter-defibrillator-only patients (7%; p = 0.03 for the difference among the 3 groups). Consistently, multivariate analysis showed that high LAV responders to CRT-D experienced a significant 53% (p = 0.01) reduction in the risk of subsequent AT as compared with implantable cardioverter-defibrillator-only patients, whereas low LAV responders did not derive a significant risk reduction with CRT-D therapy (hazard ratio [HR]: 1.05 [95% confidence interval (CI): 0.54 to 2.00]; p = 0.89). Patients who developed in-trial AT experienced significant increases in the risk for both the combined endpoint of heart failure or death (HR: 2.28 [95% CI: 1.45 to 3.59]; p < 0.001) and the separate occurrence of all-cause mortality (HR: 1.89 [95% CI: 1.08 to 3.62]; p = 0.01). In the MADIT-CRT study, favorable reverse remodeling of the left atrium with CRT-D therapy was associated with a significant reduction in risk of subsequent AT. (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).

Hemodynamic and Clinical Impact of Prosthesis–Patient Mismatch After Transcatheter Aortic Valve Implantation

This study examined the mid-term hemodynamic and clinical impact of prosthesis-patient mismatch (PPM) in patients undergoing transcatheter aortic valve implantation (TAVI) with balloon-expandable valves. PPM can be observed after aortic valve surgery. However, little is known about the incidence of PPM in patients undergoing TAVI. Echocardiography and clinical assessment were performed in 165 patients at baseline, before hospital discharge, and at 6 months after TAVI. PPM was defined as an indexed effective orifice area ≤0.85 cm(2)/m(2). Thirty patients (18.2%) showed PPM before hospital discharge. At baseline, patients with PPM had a larger body surface area (1.84 ± 0.18 m(2) vs. 1.73 ± 0.18 m(2), p = 0.003) and a greater severity of aortic stenosis (indexed valve area 0.35 ± 0.09 cm(2)/m(2) vs. 0.40 ± 0.10 cm(2)/m(2), p = 0.005) than patients without PPM. Patients with PPM demonstrated a slower and smaller reduction in mean transaortic gradient, limited left ventricular (LV) mass regression, and left atrial volume reduction over 6 months compared with patients without PPM. LV filling pressure, measured by E/e', tended to remain elevated in patients with PPM. Importantly, a higher proportion of patients with PPM did not improve in New York Heart Association functional class compared with patients without PPM (36.7% vs. 1.5%, p < 0.001), although major adverse valve-related and cardiovascular events did not differ between the 2 groups. PPM may be observed after TAVI and when present may be accompanied by less favorable changes in transvalvular hemodynamics, limited LV mass regression, persistent elevated LV filling pressure, and less improvement in clinical functional status.

Outcomes After Transcatheter Aortic Valve Implantation: Transfemoral Versus Transapical Approach

Transcatheter aortic valve implantation is commonly implanted through a transfemoral (TFA) or transapical approach (TAA) for patients with severe aortic stenosis. This study aimed to describe the clinical and echocardiographic outcomes of TFA versus TAA. Clinical and echocardiographic evaluations were performed at baseline, post-TAVI (transcatheter aortic valve implantation), at 6 and 12 months follow-up in 107 consecutive patients who underwent TAVI with balloon-expandable valves. The TFA was performed in 44% and the remaining patients underwent TAA. Although procedural complications were not significantly different in both approaches, more vascular complications were observed in the TFA group (18% vs 5%, p = 0.053). Patients with TAA required shorter fluoroscopy time (median 5 vs 12 min, p < 0.001), less contrast volume (median 80 vs 173 mL, p < 0.001), and similar length of hospitalization, as compared with TFA. Importantly, the early 30-day mortality (TFA: 11.1% vs TAA: 8.5%, p = 0.74) were not significantly different between the 2 approaches. Midterm survival at 6 months and 1 year was comparable between TFA and TAA (6 months: 88.9% vs 85.7% and 1 year: 80.2% vs 85.7%). All patients achieved immediate and sustained improvements in transvalvular hemodynamics, together with significant left ventricular mass regression (137 ± 39 vs 113 ± 30 g/m(2), p < 001) and left atrial volume reduction (48 ± 17 vs 34 ± 14 mL/m(2), p < 0.001) at 6 months or less. Early, midterm, clinical, and echocardiographic outcomes were comparable in both approaches. However, TAA has the additional benefit of reducing radiation exposure and contrast use intraoperatively without prolonging the length of hospital stay.

Reduction of Left Atrial Volume as a Predictor for the Recurrence of Atrial Fibrillation after Pulmonary Vein Isolation

Background: Recent technological advances have improved the outcome of the pulmonary vein isolation (PVI). However, the predictors of atrial fibrillation (AF) recurrence after PVI are not completely understood. The aim of this study was to investigate the predictors for AF recurrence after PVI. Methods: Thirty three consecutive patients with drug-refractory chronic AF were treated with PVI under Carto-merge guidance. Left atrial (LA) volume and left ventricular function were assessed with multislice computed tomography (CT), echocardiography and plasma brain natriuretic peptide (BNP) before and 3 months after PVI. Moreover, the rate of change in ejection fraction, LA volume index, CT LA volume and BNP were measured. Several parameters of patients with maintained sinus rhythm and were compared with those with recurrent AF. Results: Of 33 patients, 19 patients had recurrent AF during follow up. Only the rate of change in CT LA volume was predictive of AF recurrence (0.70±0.10 vs 0.87±0.12, P=0.002). Conclusions: The reduction rate of CT LA volume can be used as the predictor for AF recurrence after PVI.

Left Atrial Strain Predicts Reverse Remodeling After Catheter Ablation for Atrial Fibrillation

The purpose of this study was to assess left atrial (LA) strain during long-term follow-up after catheter ablation for atrial fibrillation and to find predictors for LA reverse remodeling. The association between LA reverse remodeling and improvement in LA strain after catheter ablation has not been investigated thus far. In 148 patients undergoing catheter ablation for atrial fibrillation, LA volumes and LA strain were assessed with echocardiography at baseline and after a mean of 13.2 ± 6.7 months of follow-up. The study population was divided according to LA reverse remodeling at follow-up: responders were defined as patients who exhibited 15% or more reduction in maximum LA volume at long-term follow-up. Left atrial systolic (LAs) strain was assessed with tissue Doppler imaging. At follow-up, 93 patients (63%) were classified as responders, whereas 55 patients (37%) were nonresponders. At baseline, LAs strain was significantly higher in the responders as compared with the nonresponders (19 ± 8% vs. 14 ± 6%; p = 0.001). Among the responders, a significant increase in LAs strain was noted from baseline to follow-up (from 19 ± 8% to 22 ± 9%; p < 0.05), whereas no change was noted among the nonresponders. LAs strain at baseline was an independent predictor of LA reverse remodeling (odds ratio: 1.813; 95% confidence interval: 1.102 to 2.982; p = 0.019). In the present study, 63% of the patients exhibited LA reverse remodeling after catheter ablation for atrial fibrillation, with a concomitant improvement in LA strain. LA strain at baseline was an independent predictor of LA reverse remodeling.

Effect of acute high-intensity interval exercise on postexercise biventricular function in mild heart failure

We studied the acute effect of high-intensity interval exercise on biventricular function using cardiac magnetic resonance imaging in nine patients [age: 49 ± 16 yr; left ventricular (LV) ejection fraction (EF): 35.8 ± 7.2%] with nonischemic mild heart failure (HF). We hypothesized that a significant impairment in the immediate postexercise end-systolic volume (ESV) and end-diastolic volume (EDV) would contribute to a reduction in EF. We found that immediately following acute high-intensity interval exercise, LV ESV decreased by 6% and LV systolic annular velocity increased by 21% (both P < 0.05). Thirty minutes following exercise (+30 min), there was an absolute increase in LV EF of 2.4% (P < 0.05). Measures of preload, left atrial volume and LV EDV, were reduced immediately following exercise. Similar responses were observed for right ventricular volumes. Early filling velocity, filling rate, and diastolic annular velocity remained unchanged, while LV untwisting rate increased 24% immediately following exercise (P < 0.05) and remained 18% above baseline at +30 min (P < 0.05). The major novel findings of this investigation are 1) that acute high-intensity interval exercise decreases the immediate postexercise LV ESV and increases LV EF at +30 min in patients with mild HF, and this is associated with a reduction in LV afterload and maintenance of contractility, and 2) that despite a reduction in left atrial volume and LV EDV immediately postexercise, diastolic function is preserved and may be modulated by enhanced LV peak untwisting rate. Acute high-intensity interval exercise does not impair postexercise biventricular function in patients with nonischemic mild HF.

Time course of markers of tissue repair after ablation of atrial fibrillation and their relation to left atrial structural changes and clinical ablation outcome

BackgroundRadiofrequency ablation of atrial fibrillation (AF) creates left atrial (LA) tissue damage with a subsequent healing process. We sought to prospectively assess the time course of biomarkers of tissue repair after ablation and to evaluate their association with clinical variables. Methods30 consecutive patients (57.9±1.7yrs, 63% males) with paroxysmal AF underwent a CARTO-guided LA circumferential ablation, Lasso-guided segmental pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Matrix metalloproteinase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1), both key regulators of tissue repair, and the aminoterminal propeptide of type III procollagen (PIIINP), reflecting collagen synthesis, were determined in blood samples before and 6h, 1, 2, 7, 30, 90 and 180days post-ablation. ResultsAll markers showed a significant ablation-induced up-regulation (MMP-9: 1.8±0.1-fold, TGF-β1: 2.4±0.4-fold, PIIINP: 1.3±0.1-fold). MMP-9 was significantly up-regulated until day 90, TGF-β1 only on day 2. PIIINP increased from day 2 to 7. The area under the curve (AUC) of MMP-9 and TGF-β1 correlated with the ablation-induced reduction of LA volume (both p<0.05). The AUC of MMP-9 was additionally associated with the amount of radiofrequency energy delivered during ablation (p<0.05). At 12months of follow-up 57% of patients were free of AF off antiarrhythmic drugs. The AUC of PIIINP independently predicted recurrent AF (p<0.05). ConclusionsMarkers of healing showed a significant up-regulation after AF ablation detectable for up to 90days. A more pronounced up-regulation of MMP-9 or TGF-β1 is associated with a greater reduction of LA size. High PIIINP levels after ablation predict a poor ablation outcome.

The Responsibility of Left Atrial Size and Wall Contraction Velocity to Left Atrial Active Emptying in Relation to the Mitral Flow Velocity Pattern

The aim of this study was to investigate the role and limitations of left atrial (LA) preload or contractility as determinants of active LA emptying in patients with heart failure. In 56 healthy individuals (controls) and 30 patients with heart failure, the LA volume before atrial contraction (LAV(pre) I), the LA volume reduction (LASVI) and LA wall contraction velocity (LAWV) during atrial contraction, and the transmitral peak flow velocities during early diastole (E) and atrial contraction (A) were determined using two-dimensional pulsed Doppler or tissue Doppler echocardiography. LAV(pre) I and LASVI were positively correlated in patients whose A/E ratio was ≥1 (r = 0.58) and negatively correlated in those whose A/E ratio was <1 (r =-0.63). LAWV was significantly lower in those with heart failure than in the controls 2.2 (1.2) cm/sec, versus 3.3 (0.8) cm/sec; mean (standard deviation) and negatively correlated with left ventricular end-diastolic pressure (r =-0.37). LAWV and LASVI were significantly correlated (r = 0.71). This correlation was stronger in the patients whose A/E ratio was <1 than in those whose A/E ratio was ≥1. Multivariate regression analysis showed that LAWV was the only factor affecting LASVI. In patients with heart failure and an A/E ratio of <1, the contribution of LA dilatation to active LA emptying may be limited, and LAWV may be the most important determinant of active LA emptying, even if this velocity is decreased because of elevated left ventricular diastolic pressure.

088 Is there any improvement in 3D and 2D echocardiography determined left atrial volume following continuous positive airway pressure treatment in patients with obstructive sleep apnoea?: Abstract 088 Table 1

Background Previous studies have reported a higher incidence of diastolic dysfunction indices in obstructive sleep apnoea (OSA). Chronic diastolic dysfunction causes structural and functional remodelling of left atrium resulting in increase in left atrial volume (LAV). Long-term continuous positive airway pressure (CPAP), an accepted treatment for OSA, has been shown to lead to improvement in diastolic function in OSA. However, it is still not known if long term CPAP treatment causes reduction in LAV (representing chronic diastolic dysfunction) in such patients. Methods Accordingly, a total of 27 patients with moderate to severe OSA (aponea-hypopnoea index>15) were recruited. All patients underwent 3D echocardiography (3DE) for end-systolic LA volume calculation prior to CPAP treatment. LA volume was also calculated using conventional 2D echocardiography (2DE) methods (ie, elliptical and biplane area length). All OSA patients were then treated by CPAP (>20 weeks). 3DE and 2DE LAV measurements were repeated following successful CPAP treatment. Results Mean duration of CPAP therapy was 20 weeks. Significant reduction in LAV was noted by all three methods following CPAP therapy (abstract 088 table 1). Conclusion Long term successful CPAP treatment results in significant reduction in LAV, a marker for adverse prognosis, determined by 3D and 2DE techniques.

Atrial asynchrony and function before and after electrical cardioversion for persistent atrial fibrillation

The relation between left atrial (LA) electrical and mechanical activity is a challenging field of investigation. The availability of echocardiographic strain analysis techniques has enhanced our ability to non-invasively assess LA wall mechanical synchrony and performance. The aim of our study was to investigate how new strain analysis tools describe the improvement in LA mechanical function after sinus rhythm (SR) restoration as a result of electrical cardioversion (CV) and how such improvement mirrors endocrine profile changes. Seventy-three patients, with persistent atrial fibrillation (AF) who underwent successful electrical CV, were prospectively studied with transthoracic echocardiography 1 week before CV and 1 month after SR. Speckle-tracking 2D-strain evaluation and asynchrony quantification were performed according to the standard deviation of time-to-peak (TP-SD) of deformation of six segments automatically located along the perimeter of the LA cavity, as imaged in an apical four-chamber view. We also calculated classic echocardiograhic parameters such as mitral regurgitation (MR) jet area, LA volume, LV diastolic and systolic volumes, as well as E-wave velocity and deceleration time (DT) on transmitral pulsed wave Doppler. Specimens for plasmatic brain natriuretic peptide (BNP) were also obtained before and 1 month after CV. After 1 month of SR, we detected a significant reduction in TP-SD (from 17.5 +/- 7.4 to 15.2 +/- 7.5%, P = 0.022), this being the expression of improved LA asynchrony, together with a marked increase in LA deformation (peak strain from 11.4 +/- 5.2 to 17.2 +/- 7.5%, P < 0.001) and a reduction in LA volume (-4.5 +/- 36%, P = 0.012). BNP decreased by one-third (from 127 +/- 96 to 86 +/- 89 pg/mL, P = 0.01). We also noticed improved ventricular pump performance [LV ejection fraction (EF) from 53 +/- 10 to 57 +/- 8%, P = <0.001] due to a 20 +/- 42% (P < 0.001) increase in LV diastolic volume (without variations in LV systolic volume and mass), a better diastolic profile (DT 34 +/- 64%, P = 0.003), and a reduction in MR jet area (-1.0 +/- 2.0 cm(2), P < 0.001). These findings are compatible with reverse LA remodelling secondary to SR maintenance, with a favourable effect on LV function that appears modulated by the atrium itself. A significant correlation (r = 0.40, P < 0.001) was demonstrated between TP-SD and peak strain data pre-post CV. At multivariate analysis, a significant capacity for the TP-SD/peak strain ratio to predict AF recurrence at 1-year follow-up (P = 0.013) was shown. Our novel noninvasive approach appears to be able to describe the LA mechanical behaviour during AF and how this ameliorates after 1 month of SR, together with an improved endocrine profile. LA mechanical data pre-CV can predict AF recurrence 1-year post CV.

Impact of left atrial volume reduction concomitant with atrial fibrillation surgery on left atrial geometry and mechanical function

Left atrial geometry and mechanical functions exert a profound effect on left ventricular filling and overall cardiovascular performance. We sought to investigate the perioperative factors that influence left atrial geometry and mechanical functions after the Maze procedure in patients with refractory atrial fibrillation and left atrial enlargement. Seventy-four patients with atrial fibrillation and left atrial enlargement (diameter > or = 60 mm) underwent the Maze procedure in association with mitral valve surgery. The maximum left atrial volume and left atrial mechanical functions (booster pump, reservoir, and conduit function [%]) were calculated from the left atrial volume-cardiac cycle curves obtained by magnetic resonance imaging. A stepwise multiple regression analysis was performed to determine the independent variables that influenced the postoperative left atrial geometry and function. The multivariate analysis showed that left atrial reduction surgery concomitant with the Maze procedure and the postoperative maintenance of sinus rhythm were predominant independent variables for postoperative left atrial geometry and mechanical functions. Among the 58 patients who recovered sinus rhythm, the postoperative left atrial geometry and function were compared between patients with (VR group) and without (control group) left atrial volume reduction. At a mean follow-up period of 13.8 months, sinus rhythm recovery rate was better (85% vs 68%, P < .05) in the VR group and maximum left atrial volume was less (116 +/- 25 mL vs 287 +/- 73 mL, P < .001) than in the control group. The maximum left atrial volume reduced with time only in the VR group (reverse remodeling). Postoperative booster pump and reservoir function in the VR group were better than in the control group (25% +/- 6% vs 11% +/- 4% and 34% +/- 7% vs 16% +/- 4%, respectively, P < .001), whereas the conduit function in the VR group was lower than in the control group, indicating that the improvement of the booster pump and reservoir function compensated for the conduit function to left ventricular filling. Left atrial reduction concomitant with the Maze procedure helped restore both contraction (booster pump) and compliance (reservoir) of the left atrium and facilitated left atrial reverse remolding. Left atrial volume reduction and postoperative maintenance of sinus rhythm may be desirable in patients with refractory AF and left atrial enlargement.

Fate of Left Atrial Function as Determined by Real-Time Three-Dimensional Echocardiography Study After Radiofrequency Catheter Ablation for the Treatment of Atrial Fibrillation

Radiofrequency catheter ablation has been demonstrated to be effective in the treatment of patients with atrial fibrillation. However, its impact on left atrial (LA) function has not been widely studied. The purpose of the present study was to evaluate the impact of radiofrequency catheter ablation on LA function in patients with atrial fibrillation. Thirty-eight patients with symptomatic drug-refractory atrial fibrillation were treated with circumferential pulmonary vein ablation (CPVA). LA volumes and function were assessed with real-time 3-dimensional echocardiography before and 6 months after the procedure. The effectiveness of CPVA was evaluated at 6-month follow-up. Recurrence of the arrhythmia was defined as any documented (clinically or on 24-hour Holter electrocardiography) atrial tachyarrhythmia lasting>30 seconds after the first 12 weeks after the procedure. CPVA induced a reduction of maximum LA volume (from 55+/-15 to 48+/-16 ml, p<0.001), without impairment in LA function, measured as the active emptying percentage of total volume (32+/-29% vs 39+/-33%, p=NS). At follow-up, 21 patients (61.8%) had no recurrences. Maximum LA volumes were significantly larger in patients who presented with recurrences compared with those who did not (64+/-18 vs 50+/-11 ml, p=0.01). In conclusion, CPVA induces a reduction in LA volume without a deleterious impact on function, and, of importance, real-time 3-dimensional echocardiography is a useful noninvasive imaging tool to follow up LA remodeling and function in these patients.

Factors Determining Early Left Atrial Reverse Remodeling After Mitral Valve Surgery

This study aimed to investigate the factors determining early left atrial (LA) reverse remodeling after mitral valve (MV) surgery. The left atrium is frequently dilated in patients with mitral stenosis (MS) or mitral regurgitation (MR). MV surgery usually results in LA volume reduction. However, the factors associated with LA reverse remodeling after MV surgery are not clearly defined. One hundred thirty-eight patients (51 men, 87 women; mean age, 53 years) underwent transthoracic echocardiography before and after MV surgery. Maximal LA volume was measured using the prolate ellipsoid model. The percentage of LA volume change was calculated. The patients were grouped according to age (<50 vs >or=50 years), predominant lesion (pure MR vs some degree of MS), type of surgery (MV repair vs MV replacement), and preoperative rhythm (sinus rhythm vs atrial fibrillation). LA volume decreased from 147+/-93 to 103+/-43 ml (p<0.001) after surgery. LA reverse remodeling was more prominent in patients who were <50 years old (percentage of LA volume change -31.2+/-17.4 vs -18.4+/-19.2, p<0.001), had pure MR (percentage of LA volume change -30.4+/-18.6 vs -17.3+/-18.2, p<0.001), and had a preoperative sinus rhythm (percentage of LA volume change -28.5+/-17.7 vs -20.5+/-20.0, p=0.019). In conclusion, on stepwise multiple regression analysis, preoperative LA volume, predominant lesion, age, and cardiac rhythm were significant predictors of LA reverse remodeling. A larger preoperative LA volume, MR rather than MS, younger age at the time of surgery, and sinus rhythm were important predictors of LA reverse remodeling after MV surgery.

Reduction in Left Atrial Volume Following Percutaneous Transluminal Septal Myocardial Ablation for Severe Hypertrophic Obstructive Cardiomyopathy

Reduction in Left Atrial Volume Following Percutaneous Transluminal Septal Myocardial Ablation for Severe Hypertrophic Obstructive Cardiomyopathy

Evolution of Left Atrial Systolic and Diastolic Functions in Different Stages of Hypertension: Distinct Effects of Blood Pressure Control

Background: To evaluate the left atrial (LA) volume, and LA systolic (contractile) and diastolic (expansion) functions in different stages of hypertension with or without atrial fibrillation (AF), as well as the effects of good blood pressure control. Methods: A prospective observational study. Individuals including 22 normotensive controls, 23 patients with mild hypertension, 20 with severe hypertension, and 17 with hypertension and paroxysmal AF were recruited for paired echocardiography studies at baseline and 6 months after control of hypertension. Results: With increasing severity of hypertension, left ventricular (LV) diastolic function deteriorated with decreasing LV septal E′/A′ and increasing E/E′ ratios. LA expansion index was reduced in parallel. LA expansion index was correlated positively with LV E′/A′ (r = 0.43, p = 0.022) and inversely with LV E/E′ (r = 0.49, p = 0.009). Significant improvement of LV diastolic function and LA expansion index preceded the reduction of LA volume after blood pressure control. In patients with paroxysmal AF, LA volume reduction was more evident in patients receiving angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers. Conclusions: With progressive LV diastolic dysfunction in hypertension, there was a corresponding deterioration in LA diastolic function. Effective blood pressure control for 6 months improved LA diastolic function.