Higher Left Atrial Volume Research Articles

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).

Echocardiographic Predictors of Left Atrial Appendage Thrombus Formation

Although transesophageal echocardiography is the definitive test for the detection of left atrial (LA) appendage thrombus, transthoracic echocardiography has yet to prove useful for the determination of increased risk for LA appendage thrombus formation. The authors hypothesized that higher LA volume and/or lower left ventricular ejection fraction (LVEF) might prove valuable as markers of increased risk for LA appendage thrombus formation and tested this hypothesis in a consecutive retrospective series of patients with atrial fibrillation undergoing both transthoracic and transesophageal echocardiography. Three hundred thirty-four consecutive patients with atrial fibrillation undergoing transesophageal echocardiography for the detection of LA appendage thrombus were studied. Anticoagulation status, CHADS(2) scores, and echocardiographic parameters were catalogued. The relationship between the presence of LA appendage thrombus and covariates was analyzed using binary logistic regression. LA appendage thrombus was detected in 52 patients (15.6%). A higher CHADS(2) score (odds ratio, 1.45; P < .004), increased LA volume index (odds ratio, 1.02; P= .018), and lower LVEF (odds ratio, 1.02; P= .05) were significant predictors of LA appendage thrombus formation. LA appendage thrombus was not seen in patients with CHADS(2) scores ≤ 1, LVEFs > 55%, and a LA volume indexes < 28 mL/m(2). A ratio of LVEF to LA volume index ≤ 1.5 produced 100% sensitivity for the presence of LA appendage thrombus. The presence of LA appendage thrombus is related to both clinical and echocardiographic variables. Although no single echocardiographic variable discriminated between the presence and absence of LA thrombus, a normal LVEF and normal LA volume index were associated with the absence of LA appendage thrombus formation. For patients with atrial fibrillation with CHADS(2) scores ≤ 1, normal left ventricular systolic function and normal LA volume in combination may be a useful measure for the identification of patients at low risk for LA appendage thrombus formation.

Two-dimensional strain or strain rate findings in mild to moderate diastolic dysfunction with preserved ejection fraction

Left ventricular (LV) diastolic dysfunction with preserved ejection fraction is frequently encountered in clinical practice. However, the relations between LV filling patterns and myocardial function by using two-dimensional (2D) speckle tracking imaging are not well known. One hundred thirteen individuals (mean age 59 ± 12 years), referred for a clinically indicated echocardiogram, underwent standard and 2D strain echocardiography. The subjects were divided into groups on the basis of diastolic function by using standard Doppler indices, and we compared 2D strain/strain rate parameters between groups. Subjects with mild to moderate LV diastolic dysfunction showed a high left atrial volume index (LAVI) and early mitral inflow to annular velocity ratio. With regard to 2D strain/strain rate, the severity of diastolic dysfunction was associated with low peak strain, and low systolic and early diastolic strain rate of longitudinal, circumferential and radial deformations, whereas the late diastolic strain rate was not. In multivariate analysis, LAVI and circumferential early diastolic strain rate were most associated with the severity of diastolic dysfunction, although longitudinal and circumferential peak strains were also of significant correlation. In addition to LAVI, the circumferential early diastolic strain rate would be a useful parameter in the assessment of the severity of diastolic dysfunction with preserved ejection fraction.

Association of Left Atrial Volume With Mortality Among ESRD Patients With Left Ventricular Hypertrophy Referred for Kidney Transplantation

BackgroundLeft ventricular hypertrophy (LVH) is common in patients with end-stage renal disease (ESRD) and an independent risk factor for premature cardiovascular death. Left atrial volume (LAV), measured using echocardiography, predicts death in patients with ESRD. Cardiovascular magnetic resonance (CMR) imaging is a volume-independent method of accurately assessing cardiac structure and function in patients with ESRD.Study DesignSingle-center prospective observational study to assess the determinants of all-cause mortality, particularly LAV, in a cohort of ESRD patients with LVH, defined using CMR imaging.Setting & Participants201 consecutive ESRD patients with LVH (72.1% men; mean age, 51.6 ± 11.7 years) who had undergone pretransplant cardiovascular assessment were identified using CMR imaging between 2002-2008. LVH was defined as left ventricular mass index >84.1 g/m2 (men) or >74.6 g/m2 (women) based on published normal left ventricle dimensions for CMR imaging. Maximal LAV was calculated using the biplane area-length method at the end of left ventricle systole and corrected for body surface area.PredictorsCMR abnormalities, including LAV.OutcomeAll-cause mortality.Results54 patients died (11 after transplant) during a median follow-up of 3.62 years. Median LAV was 30.4 mL/m2 (interquartile range, 26.2-58.1). Patients were grouped into high (median or higher) or low (less than median) LAV. There were no significant differences in heart rate and mitral valve Doppler early to late atrial peak velocity ratio. Increased LAV was associated with higher mortality. Kaplan-Meier survival analysis showed poorer survival in patients with higher LAV (log rank P = 0.01). High LAV and left ventricular systolic dysfunction conferred similar risk and were independent predictors of death using multivariate analysis.LimitationsOnly patients undergoing pretransplant cardiac assessment are included. Limited assessment of left ventricular diastolic function.ConclusionsHigher LAV and left ventricular systolic dysfunction are independent predictors of death in ESRD patients with LVH.

Reduced Peak Atrial Systolic Mitral Annular Velocity Predicts the Development of Nonvalvular Atrial Fibrillation

We investigated whether the echocardiographic parameters of the left atrium (LA) can predict the development of nonvalvular atrial fibrillation (AF). Among 14,062 patients (>20 years old) who underwent an echocardiographic examination were evaluated, 2,606 patients who underwent follow-up ECG with an interval of >6 months were investigated. Newly developed AF was noted in 42 (1.6%) patients with follow-up duration of 31.8 +/- 8.9 months. Cox regression analysis revealed that a higher left atrial volume index (hazard ratio [HR]=1.06; 95% confidence interval [CI] 1.03-1.09, P < 0.001), relative wall thickness (RWT) of>or=0.407 (HR=2.74, 95% CI 1.39-5.41, P=0.004), a reduced peak atrial systolic mitral annular velocity (HR=0.845, 95% CI 0.72-0.99, P=0.037), and an advanced age (HR=1.04, 95% CI 1.01-1.07, P=0.009) were independently related to the development of nonvalvular AF. Therefore, reduced A', which is parameter of LA contractile function, might be an important predictor for the development of nonvalvular AF.

Abstract 4726: How Reliable is Left Atrial Volume in Estimating Left Atrial Pressure in Advanced Heart Failure Patients? Three-Dimensional Echocardiographic and Catheterization Studies

Previous work has suggested that left atrial (LA) size reflects LA pressure but direct correlative studies of pressure and volume are scant. Furthermore, evaluation of LA size has typically been based on 1-dimensional measures or 2D echo-derived LA area or volume. The aim of this study was to explore whether 3D LA volume could accurately indicate LA pressure in advanced heart failure (HF) patients, in whom filling pressure estimation is clinically relevant. We studied 32 patients with advanced HF both with 3D echo (3DE) performed simultaneously or close to the time of pulmonary capillary wedge pressure (PCWP) measurement by cardiac catheterization. From full volume 3D data sets of the left heart, maximum LA volume (MaxLAV) and minimum LA volume (MinLAV), and volumes indexed to body surface area (MaxMAVI and MinLAVI) were calculated. Mean PCWP was obtained from standard invasive recordings. Results: The mean LVEF was 23±8. The MaxLAV was 101±38 ml with a range of 34 to 173. MaxLAVI was 50±16 ml/m2 with a range of 19 to 81. MinLAV was 76±37 with a range of 19 to 145. MinLAVI was 38±16 ml/m2, with a range of 12 to 72. The PCWP (mm Hg) was 21±8 with a range of 2 to 34. The correlation between PCWP, and MaxLAV, MaxLAVI, MinLAV and MinLAVI were respectively r=0.193, p=0.28; r=0.25, p=0.16; r=0.24, p=0.17; and r=0.31, p=0.08. Within the group, there were some patients with normal or low PCW but with larger LA volumes (&gt;median) while some patients with high filling pressures did not necessarily have higher LA volumes. Conclusion: In advanced HF patients, maximum or minimum LA volumes do not correlate with PCWP. LA remodeling and depletion of LA volume reserve in these patients is most likely responsible for the lack of correlation. Thus, in advanced HF patients, LA volume cannot be used to assess left heart filling pressure.

Left Atrial Geometric and Functional Remodeling in Athletes

The aim of this study was to evaluate left atrial (LA) volume and its changes with the phases of atrial filling, and to examine the effect of exercise capacity on these parameters. Using two-dimensional echocardiography, LA volumes were measured in 30 male endurance runners and 30 age-matched sedentary men (controls). Maximal oxygen consumption (VO2max) was measured using a metabolic chart during exercise. LA reservoir, pump, and conduit functions, kinetic energy and force were calculated. We found that athletes had higher LA volume and volume index (except the conduit volume), LA passive emptying fraction, and LA total emptying fraction compared to control subjects. We observed positive correlations between: VO2max and LA passive emptying fraction (r=0.49, p<0.05); VO2max and LA active emptying fraction (r=0.54, p<0.05); VO2max and LA kinetic energy (r=0.61, p<0.05); and VO2max and LA force (r=0.57, p<0.05). These findings suggest that atrial function reflects exercise capacity in athletes.

Endocardial Radiofrequency Ablation During Mitral Valve Surgery: Effect on Cardiac Rhythm, Atrial Size, and Function

Restoration of sinus rhythm is thought to lead to a reduction in left atrial size and to recovery of atrial contraction. We aimed to investigate changes in atrial size and function in patients undergoing radiofrequency ablation for atrial fibrillation during mitral valve surgery. In a prospective study, 70 patients (64 +/- 10 years) with mitral valve disease and atrial fibrillation underwent mitral surgery and left atrial endocardial radiofrequency ablation. Evaluation was achieved before surgery, at 7 days, 5 months, and 22 months after surgery. Maximal right and left atrial areas, left atrial diameter, and volume were measured. Atrial filling fraction (ventricular filling related to atrial contraction to total ventricular filling ratio) was used as an index of atrial contraction. At the end of follow-up (22 +/- 10 months) most patients (91%) were in sinus rhythm. Actuarial freedom from atrial fibrillation recurrence was 62.5% after 2 years. Atrial size decreased, with a significant improvement in right (36 +/- 15 vs 10 +/- 20% preoperatively, p < 0.0001) and left (25 +/- 12 vs 7 +/- 14%, p < 0.0001) atrial filling fraction. Despite similar preoperative atrial size, at the end of follow-up atrial fibrillation recurrence was associated with a higher left atrial volume than in patients free of recurrence (41 +/- 14 vs 32 +/- 9 mL/m2, p = 0.004). Independent predictors of atrial fibrillation recurrence were previous mitral procedure (p = 0.029), left ventricular ejection fraction (p = 0.033), and mitral rheumatic lesion (p = 0.034). Left atrial radiofrequency ablation for atrial fibrillation during mitral surgery is an effective procedure restoring sinus rhythm. Right and left atrial size was significantly reduced, with a recovery in atrial contraction.