Left atrial volume as an index of left atrial size: a population-based study

OBJECTIVES: We studied left atrial volume (LAV) as an index of atrial size. BACKGROUND: Increased left atrial dimension (LAD) measured by M-mode echocardiography is a risk factor for atrial fibrillation, stroke, and death. METHODS: A random sample of residents of Olmsted County, Minnesota, age > or =45 years (n = 2,042) underwent Doppler echocardiography with assessment of LAD and LAV. A subgroup of the population (n = 767) with no cardiovascular disease and normal systolic and diastolic function was used to develop reference ranges for LAD and LAV. In the total population, the prevalence of left atrial enlargement and the association between cardiovascular disease and left atrial size as determined by both indexes were assessed. RESULTS: In the normal subgroup, both indexes were associated with gender and body size, thus models controlling for body size were used to determine gender-specific reference ranges for LAD and LAV. In the total population, left atrial enlargement was common, with a prevalence of 18% (men) and 12% (women) using LAD/body surface area (BSA) and of 16% (men and women) using LAV/BSA. The agreement between the indexes was only fair (kappa = 0.53). Adjusting for age and gender, LAV/BSA was more strongly associated with the presence of cardiovascular diseases than LAD/BSA. CONCLUSIONS: We described a simple technique of measuring LAV, examined methods for indexing LAV, and described its normal range in a large, healthy reference cohort. Further, we find that in the community, left atrial enlargement is common and reflects the burden of cardiovascular disease.     

Correlation of Left Atrial Diameter by Echocardiography and Left Atrial Volume by Computed Tomography

Introduction: For patients undergoing catheter ablation of atrial fibrillation (AF), left atrial size is a predictor of recurrence of AF during follow-up. For this reason, major clinical trials have used a left atrial diameter (LAD) of more than 5.0 or 5.5 cm, assessed by echocardiography, as an exclusion criterion for patients deemed candidates for ablation of AF. However, whether LAD accurately reflects true left atrial size has not been systematically investigated. Therefore, the purpose of this study was to test the hypothesis that LAD, measured by echocardiography, accurately correlates to left atrial volume measured by computed tomography (CT).
Methods and Results: We included 50 patients (mean age 56 ± 12 years, five female) with symptomatic AF (40% paroxysmal, 60% persistent), referred for catheter ablation. In each patient, transthoracic echocardiography was performed. Additionally, all patients underwent CT using a 64-slice CT scanner. Left atrial volume was calculated by manually tracing left atrial area on each CT cross-sectional image. Patients had a mean LAD measured by echocardiography of 4.5 ± 0.7 cm, ranging from 2.9 to 5.7 cm. Left atrial volume measured by CT ranged from 67 mL to 270 mL with a mean value of 146 ± 49 mL. A poor correlation was noted between LAD and left atrial volume, r = 0.49 (P < 0.001).
Conclusion: LAD measured by echocardiography correlates poorly with left atrial volume measured by CT in patients with AF. As a result, selecting patients with AF for treatment with catheter ablation should not be based on an echocardiographic-derived LAD alone.     

Identification and Quantification of Cardiovascular Structures From CCTA: An End-to-End,Rapid, Pixel-Wise,Deep-Learning Method

ObjectivesThis study designed and evaluated an end-to-end deep learning solution for cardiac segmentation and quantification.BackgroundSegmentation of cardiac structures from coronary computed tomography angiography (CCTA) images is laborious. We designed an end-to-end deep-learning solution.MethodsScans were obtained from multicenter registries of 166 patients who underwent clinically indicated CCTA. Left ventricular volume (LVV) and right ventricular volume (RVV), left atrial volume (LAV) and right atrial volume (RAV), and left ventricular myocardial mass (LVM) were manually annotated as ground truth. A U-Net−inspired, deep-learning model was trained, validated, and tested in a 70:20:10 split.ResultsMean age was 61.1 ± 8.4 years, and 49% were women. A combined overall median Dice score of 0.9246 (interquartile range: 0.8870 to 0.9475) was achieved. The median Dice scores for LVV, RVV, LAV, RAV, and LVM were 0.938 (interquartile range: 0.887 to 0.958), 0.927 (interquartile range: 0.916 to 0.946), 0.934 (interquartile range: 0.899 to 0.950), 0.915 (interquartile range: 0.890 to 0.920), and 0.920 (interquartile range: 0.811 to 0.944), respectively. Model prediction correlated and agreed well with manual annotation for LVV (r = 0.98), RVV (r = 0.97), LAV (r = 0.78), RAV (r = 0.97), and LVM (r = 0.94) (p < 0.05 for all). Mean difference and limits of agreement for LVV, RVV, LAV, RAV, and LVM were 1.20 ml (95% CI: −7.12 to 9.51), −0.78 ml (95% CI: −10.08 to 8.52), −3.75 ml (95% CI: −21.53 to 14.03), 0.97 ml (95% CI: −6.14 to 8.09), and 6.41 g (95% CI: −8.71 to 21.52), respectively.ConclusionsA deep-learning model rapidly segmented and quantified cardiac structures. This was done with high accuracy on a pixel level, with good agreement with manual annotation, facilitating its expansion into areas of research and clinical import.     

Using traditional measurements of the left atrial diameter to predict the left atrial volume index

BACKGROUND: Left atrial enlargement by echocardiography is associated with adverse cardiovascular outcomes, yet the best method for assessing left atrial size has not been established. We sought to correlate the traditional left atrial diameter (LAD) measured in the parasternal view with the recently characterized left atrial volume index (LAVI). METHODS: 100 routine clinical patients who received a transthoracic echocardiogram for customary indications were studied. The LAD and LAVI were measured in each patient. RESULTS: The mean LAVI was 32.8 milliliters per square meter (ml/m(2)) and the LAD was 46.8 millimeters (mm). LAD > 4.7 centimeters (cm) was predictive of LAVI > 32 ml/m(2) (P < 0.001; OR 17.33; 95% CI = 5.96-50.44). CONCLUSION: LAD > 4.7 cm via the traditional method can be used to indicate left atrial enlargement. However, a LAD < or = 4.7 cm does not correlate well with the LAVI, and in such patients, extreme caution should be employed when using the LAD to estimate cardiac prognosis.     

Biatrial volume ratio predicts low voltage areas in atrial fibrillation

BackgroundLeft atrial volume (LAV) and low voltage areas (LVAs) are acknowledged markers for worse rhythm outcome after ablation of atrial fibrillation (AF). Some studies reported the importance of increased right atrial volume (RAV) as a predictor for arrhythmia recurrences in AF patients.ObjectiveTo investigate association between the LAV/RAV ratio and LVAs presence.MethodsPatients undergoing first AF ablation were included. LVAs were assessed peri‐procedurally using high‐density 3D maps and defined as <0.5 mV. All patients underwent pre‐procedural cardiovascular magnetic resonance imaging. LAV (biplane) and RAV (monoplane 4‐chamber) were assessed prior to ablation, and the LAV/RAV ratio was calculated.ResultsThe study population included 189 patients (age mean 63 ± 10 years, 33% women, 57% persistent AF, 22% LVAs). There were 149 (79%) patients with LAV > RAV. In univariable analysis LAV > RAV was associated with LVAs (OR 6.803, 95%CI 1.395–26.514, p = .016). The association remained robust in multivariable model after adjustment for persistent AF, CHA₂DS₂‐VASc score, and heart rate (OR 5.981, 95%CI 1.256–28.484, p = .025). Using receiver operator curve analysis, LAV > RAV (AUC 0.668, 95%CI 0.585–0.751, p = .001) was significant predictor for LVAs. In multivariable analysis, after adjustment for age, persistent AF, and renal function, RAV≥LAV was threefold higher in males (OR 3.040, 95%CI 1.050–8.802, p = .04).ConclusionsLAV > RAV is useful for the prediction of electro‐anatomical substrate in AF. LAV > RAV was associated with LVAs presence, while male sex remained associated with RAV≥LAV and less LVAs.     

Signal averaged P wave compared with standard electrocardiography or echocardiography for prediction of atrial fibrillation after coronary bypass grafting.

OBJECTIVE: To define the clinical value of the signal averaged P wave (SAPW) and to compare it with the standard electrocardiogram (ECG), echocardiogram, and clinical assessment for the prediction of atrial fibrillation after coronary bypass grafting (CABG). DESIGN: Prospective validation cohort study. SETTING: Regional cardiothoracic centre. PATIENTS: 201 unselected patients undergoing first elective CABG were recruited over six months. Patients requiring concomitant valve surgery were excluded. MAIN OUTCOME MEASURES: Age, sex, cardiothoracic ratio, and cardioactive drugs were noted. P wave specific SAPW recordings, ECG, and M mode echocardiograms from which left atrial diameter was measured were performed within 24 hours of surgery. Filtered P wave duration (SAPWD), spatial velocity, and energy were calculated from the SAPW. From the ECG, lead II P wave duration, P terminal force in lead V1, total P wave duration, and isoelectric interval were measured. Patients had Holter monitoring for 48 hours postoperatively and daily ECGs until discharge. RESULTS: Two patients died (1%) and 10 were unsuitable for analysis (5%). Of the remaining 189, 51 (27%) had atrial fibrillation (AF) lasting > 1 hour at a mean of 2 (0.5 to 7) days after CABG. Of the variables examined, only SAPWD (AF group 148 (SD 12), v 142 (14) ms, P = 0.008) and male sex (AF group 96%, v 78%, P < 0.01) were significantly different. A prospectively defined SAPWD of > 141 ms predicted atrial fibrillation with positive and negative predictive accuracies of 34% and 83%. Logistic regression analysis identified both male sex and SAPWD as significant independent predictors of postoperative atrial fibrillation. CONCLUSIONS: Signal averaged P wave duration was a better predictor of atrial fibrillation after coronary bypass grafting than standard electrocardiographic or echocardiographic criteria. The predictive value of this test is such that it is likely to be useful in the design of prospective trials of prophylactic antiarrhythmic treatment but is of limited use using current techniques in the clinical management of individual patients.     

Underestimation of left atrial volume by three-dimensional echocardiography validated by magnetic resonance imaging: a meta-analysis and investigation of the source of bias

Background: Left atrial volume (LAV) is a fundamental prognostic factor in a variety of cardiac diseases including atrial fibrillation, heart failure, and valvular diseases. Developing a repeatable, noninvasive, and accurate method of measuring LAV is crucial. Three‐dimensional echocardiography (3DE) has achieved better estimation of LAV than two‐dimensional echocardiography. However, underestimation of LAV by 3DE has often been reported and no previous study has synthesized these data. The present study aimed at revealing existence and extent of bias in LAV measurement by 3DE and investigating related factors affecting the bias. Methods: Studies comparing LAV between 3DE and magnetic resonance imaging published before August 15, 2011 were eligible. A meta‐analysis with random effects model was performed to evaluate the systematic bias. Factors affecting the bias were investigated by univariate followed by multivariate analysis. Results: A total of 14 studies including 395 subjects revealed underestimation of LAV by 3DE (?9.4 mL; 95% confidence interval, ?13.2 to ?5.6mL; P < 0.00001, Fig. 2 ). Existence of cardiac disease led to more underestimation, whereas increasing the number of plane included in the analysis counteracted the underestimation (P < 0.00001 for each comparison). Conclusions: Only by synthesizing a number of small studies as a meta‐analysis could we display underestimation of LAV by 3DE and factors influencing the systematic bias. These data provide a more detailed basis for analyzing and improving the accuracy of 3DE, an indispensable step toward further clinical application in LAV assessment. (Echocardiography 2012;29:385‐390)

Figure 2 Open in figure viewer PowerPoint Meta‐analysis of difference in left atrial volume between 3D‐echocardiography and magnetic resonance imaging. Note the significant underestimation of left atrial volume by 3D‐echocardiography. 3DE = three‐dimensional echocardiography; CI = confidence interval; Max = maximal volume; Min = minimal volume; MRI = magnetic resonance imaging; Nl = normal subjects; pl = planes; Pt = patients.     

Left atrial volume is associated with inflammation and atherosclerosis in patients with kidney disease

BACKGROUND: Left atrial volume (LAV) is an independent echocardiographic predictor of cardiovascular events in the general population. We evaluated predictors of LAV in patients with advanced chronic kidney disease (CKD). Hypothesis: Increasing LAV identifies increased cardiovascular risk in patients with CKD. METHODS: Transthoracic echocardiography was performed in CKD patients undergoing cardiovascular evaluation prior to listing for renal transplantation. LAV was measured using the biplane area-length formula and indexed for body surface area. Carotid intima-media thickness was assessed by B-mode ultrasound. Lipoproteins were measured by nuclear magnetic resonance spectroscopy. Values are presented as mean (standard deviation). Relationships with LAV were evaluated using univariate and multivariable regression analyses. RESULTS: There were 99 participants (80% white, 68% male). Their mean age was 55.7 (9.3) years. Significant correlates of LAV were systolic blood pressure (r = 0.24), C-reactive protein (r = 0.29), carotid intima-media thickness (r = 0.29), peak transmitral E-wave (r = 0.38), and severity of mitral regurgitation (r = 0.23, P < 0.05 for all). LAV also was higher among individuals with a history of stroke (45 mL/m2 vs 36.3 mL/m2, P = 0.04) and with >75% stenosis on coronary angiography (38.4 mL/m2 vs 31.8 mL/m2, P = 0.03). In regression models, high sensitivity CRP (hs-CRP), the transmitral E-wave velocity, and a history of stroke independently predicted LAV (P < or = 0.05). CONCLUSION: In individuals with advanced CKD, LAV is associated with inflammation, increased early transmitral filling velocities, and atherosclerosis. These findings may indicate increased cardiovascular risk with increasing LAV in patients with CKD.     

Evaluation of left atrial size in patients with atrial arrhythmias: comparison of standard 2D versus real time 3D echocardiography

AIM: Two-dimensional echocardiography may not correctly indicate size in nonspherical atria. The present study compares different parameters of left atrial size evaluated by standard two-dimensional echocardiography with left atrial volume measured using three-dimensional echocardiography (3DE). METHODS AND RESULTS: One hundred seventy consecutive patients with a history of atrial arrhythmias were studied by standard two-dimensional and by real time 3DE. Of these 166 (98%) recordings were of sufficient quality for interpretation by both imaging techniques. The following parameters of left atrial size were measured: parasternal long axis diameter (PLAX), apical 4-chamber short-axis diameter (4CH short axis), apical 4-chamber (4CH long axis), and 2-chamber long-axis diameters and planimetry areas. Two-dimensional-derived left atrial volumes were calculated by using both single plane (4CH area-length) and biplane area-length methods. The 2D parameters were then correlated with left atrial volume measured by 3D echocardiography. Linear regression analysis showed moderate correlation for 4-chamber planimetry area (r = 0.76, P < 0.0001) and 2D-derived volume calculations (r of 4CH single plane area-length LA volume = 0.74 and biplane area-length LA volume = 0.78, P < 0.0001). Diameters correlated less well with 3DE volume (r of PLAX = 0.67, 4CH short axis = 0.68, 4CH long axis = 0.63, P < 0.0001 respectively). CONCLUSION: The results demonstrate that measurements of dimensions using standard echocardiography are of limited accuracy to assess left atrial volume. If 3DE is not available, 4-chamber planimetry area is a valid simple parameter for evaluating left atrial size in clinical practice. Two-dimensional-derived volume by biplane area-length method was only slightly better correlated with 3DE volume than 4-chamber planimetry area.     

Assessment of echocardiographic left atrial size: accuracy of M-mode and two-dimensional methods and prediction of diastolic dysfunction

Background: Despite the American Society of Echocardiography recommendation to use left atrial volume indexed for body surface area (LAVI) for quantification of left atrial size, a variety of methods are used in clinical practice. Our objectives were to evaluate the accuracy of M‐mode and two‐dimensional (2D) echocardiographic LA size estimates to LAVI and to determine their ability to predict left ventricular diastolic dysfunction. Methods: In 150 consecutive patients, LA diameter (LAD), LA diameter indexed for body surface area (LADI), LA area in the apical two‐ and four‐chamber views (LAA 2c and LAA 4c), biplane area–length LA volume (LAV), and LAVI were obtained. The accuracy of these methods to quantify LA enlargement by LAVI, correlation with clinical parameters, and ability to act as a surrogate for diastolic dysfunction were determined using Pearson correlation coefficients along with univariate and multiple logistic analysis. Results: The true degree of LA size (with LAVI as standard) was identified by LAD in 45%, LADI in 42%, LAA 4c in 43%, and LAA 2c in 41%. All methods showed positive correlation with age, E/E′, mitral regurgitation, and right atrial size and negative correlation with ejection fraction. LAVI was the strongest method to predict any (c = 0.655, P = 0.012) or moderate–severe (P = 0.856 and P < 0.001) diastolic dysfunction. All methods have greater capacity to identify moderate or severe diastolic dysfunction than any degree of diastolic dysfunction alone. Conclusions: One‐dimensional and 2D methods inaccurately quantify LA size and are inferior to LAVI to predict diastolic dysfunction. (Echocardiography 2012;29:379‐384)     

老年原发性高血压患者左心房/左心室容量比值的变化

目的本文旨在探讨老年原发性高血压患者左心房容量／左心室容量比值变化的临床意义。方法老年正常对照组32例。老年原发性高血压无室壁肥厚患者35例，老年原发性高血压患者伴室壁肥厚者33例。应用实时三维三平面显像方式测量左房、左室容量，对3组病人的左房容量，左房内径，左房容量指数和左心房容量／左心室容量比值进行分析。结果左房容量，左房内径，左房容量指数和左心房容量／左心室容量比值在高血压室壁肥厚组与对照组之间均存在极显著差异（P〈0．01），但左房内径在原发高血压无室壁肥厚组与对照组之间无显著差异（P〉0．05）。左房容量、左房容量指数在原发高血压无室壁肥厚组与对照组之间差异有显著性（P〈0．05），左心房容量／左心室容量比值在原发高血压无室壁肥厚组与对照组之间差异更为显著（P〈0．01）且变异性最小。结论左心房容量／左心室容量比值是一种新的参数，能够灵敏地反映老年原发性高血压患者舒张功能减低的血流动力学改变。     

Evaluation of right atrial size in patients with atrial arrhythmias: comparison of 2D versus real time 3D echocardiography

Aim: This study compares different parameters of right atrial size evaluated by two-dimensional (2D) echocardiography with right atrial volume measured using three-dimensional echocardiography (3DE). Methods and Results: One hundred sixty-three consecutive patients with a history of atrial arrhythmias were studied by standard two-dimensional and by real time 3DE. Of these 142 (87%) recordings were of sufficient quality for interpretation of the right atrium by both imaging techniques. The following parameters of right atrial size were measured: apical four-chamber short-axis diameter (4CH short axis), apical four-chamber long axis diameter (4CH long axis), and apical four-chamber planimetry area. The 2D-derived right atrial volume was calculated by using the single plane area-length method (4CH area-length). The 2D parameters were then correlated with right atrial volume measured by real time 3DE. Linear regression analysis showed moderate correlation for four-chamber planimetry area (r = 0.72, P < 0.001) and 2D-derived volume calculation (r of 4CH single plane area-length RA volume = 0.70, P < 0.001). Diameters correlated clearly less well with 3DE volume (r of 4CH short axis = 0.61, 4CH long axis = 0.59, P < 0.001 respectively). Conclusion: Real time 3DE is highly feasible for right atrial volume determination. The results demonstrate that measurements of dimensions using 2D echocardiography may not accurately assess right atrial size. If 3DE is not available, apical 4CH planimetry area is a simple alternative that may be used for evaluating right atrial size in clinical practice. The 2D-derived right atrial volume by single plane area-length method was not better correlated with 3DE volume than four-chamber planimetry area.     

Three-dimensional echocardiographic analysis of right atrial volume in normal and abnormal hearts: comparison of biplane and multiplane methods

Background: Although right atrial size has clinical and prognostic importance, few data exist regarding the optimal three‐dimensional echocardiography (3DE) method for assessing right atrial volume (RAV). While measuring RAV in multiple planes may improve the accuracy, it also increases analysis time. The purpose of this study was to determine the minimum number of planes required for optimal assessment of RAV, using eight‐plane 3DE measurements as a reference standard. Methods: 3DE was performed in 70 subjects (35 normal and 35 abnormal). 3DE RAV was obtained from three methods by tracing right atrial endocardial borders at ventricular end‐systole in two orthogonal planes (two‐plane), four equiangular planes (four‐plane), and eight equiangular planes (eight‐plane) in each subject. The time required for analysis was recorded for each method. Results: Based on eight‐plane RAV, mean RAV was 41±13 mL in the normal group, and 82±35 mL in the abnormal group. The average time for two‐plane, four‐plane, and eight‐plane analysis was 69 ± 29, 118 ± 29, and 203 ± 37 s, respectively (P < 0.001 for comparisons between all groups). Four‐plane approach had close agreement with eight‐plane (2.6% underestimation for total group), while two‐plane measurement underestimated RAV by an average of 19% for the total group, compared to eight‐plane. Conclusion: Four‐plane measurement of RAV shows good agreement with eight‐plane measurement, while reducing the time required for analysis. Compared to eight‐plane analysis, biplane measurement of RAV can result in underestimation of RAV, particularly in abnormal subjects with right atrial enlargement and remodeling. (Echocardiography 2012;29:608‐613)     

Clinical and echocardiographic correlates of plasma B-type natriuretic peptide levels in patients with aortic valve stenosis and normal left ventricular ejection fraction

Background: Several studies suggest that BNP testing may help define the timing of aortic valve surgery in patients with aortic valve stenosis (AVS) prior onset of overt LV systolic dysfunction. The aim of this study was to identify clinical and echocardiographic correlates of plasma BNP levels in a large cohort of patients with AVS and preserved LV ejection fraction. Method and results: One hundred thirty‐five consecutive patients were prospectively included in the present study (Mean age 73 ± 13 years old, 66 (49%) male). Eighty‐nine patients (66%) had severe AVS (aortic valve area <0.6 cm²/m² BSA). Plasma BNP levels, clinical and comprehensive Doppler echocardiography evaluation was performed in all patients. Independent clinical correlates of plasma BNP levels (R²= 0.19) were older age (P < 0.0001) and presence of AVS symptoms (P = 0.004). Independent echocardiographic correlates of plasma BNP levels (R²= 0.38) were E/Ea ratio (P = 0.01), LV mass index (P = 0.018), left atrial surface (P < 0.0001) and systolic pulmonary artery pressure (sPAP; P = 0.004). Overall, independent correlates of plasma BNP levels (R²= 0.47) were older age (P = 0.001), known coronary artery disease (P = 0.047), increased LV mass index (P = 0.001), left atrial enlargement (P = 0.002), and increased sPAP (P = 0.003). Conclusions: In patients with AVS and normal LV ejection fraction, plasma BNP predominantly reflects the clinical and echocardiographic consequences of afterload burden imposed on the left ventricle rather than the severity of valve stenosis, per se. (Echocardiography 2011;28:695‐702)     

Left atrial filling volume can be used to reliably estimate the regurgitant volume in mitral regurgitation

Objectives. The objective was to analyze the accuracy and diagnostic value of the estimated regurgitant volume of mitral regurgitation using 1) left atrial volume variation during ventricular systole (left atrial filling volume) and 2) the percent of systolic pulmonary vein velocity integral compared with its total.Background. Left atrial filling volume (LAfill), which represents the atrial volume variation during ventricular systole, has been used for the assessment of mitral regurgitation severity. A good correlation with invasive semiquantitative evaluation was found, but with an unacceptable overlapping among grades. The reason could be the absence of information concerning the contribution of blood entering into the left atrium from the pulmonary veins.Methods. Doppler regurgitant volume (Dpl-RVol) (mitral stroke volume − aortic stroke volume) was measured in 30 patients with varying degrees and etiological causes of mitral regurgitation. In each patient atrial volumes were measured from the apical view, using the biplane area-length method. The systolic time-velocity integral of pulmonary vein flow was expressed as a percentage of the total (systolic-diastolic) time-velocity integral (PVs%). These parameters were used in this group of patients to obtain an equation whose reliability in estimating Dpl-RVol was tested in a second group of patients.Results. In the initial study group, with linear regression analysis the following parameters correlated with Dpl-RVol: end-systolic left atrial volume (R²= 0.37, p = 0.0004); LAfill (R²= 0.45, p < 0.0001); PVs% (R²= 0.56, p < 0.0001). In multiple regression analysis the combination of LAfill and the percent of the systolic pulmonary vein velocity integral (PVs%) provided a more accurate estimate of regurgitant volume (R²= 0.88; SEE 10.6; p < 0.0001; Dpl-RV = 6.18 + (1.01 × LAfill) − (0.783 × PVs%). The equation was subsequently tested in 54 additional patients with mitral regurgitation with a mean Dpl-RVol 27 ± 37 ml. Estimated regurgitant volume and Dpl-RVol correlated well with each other (R²= 0.90; SEE 12.1; p < 0.0001). In the test population, the equation was 100% sensitive and 98% specific in detecting a regurgitant volume higher than 55 ml.Conclusions. Left atrial filling volume and pulmonary vein flow give a reliable estimate of regurgitant volume in mitral regurgitation.     

Agreement Between Automatic and Manual Measurement of Atrial and Ventricular Signal‐Averaged Electrocardiograms in Healthy Subjects

Background: Although prolonged duration of the signal‐averaged (SA) P wave has been proposed as a noninvasive marker of atrial arrhythmias, clinical value of atrial SAECG is limited, largely due to the difficulty with detection of the onset and offset of the high gain P wave. The aim of this study was to assess the reliability of automatic measurement of the atrial SAECG. Methods: Fifty‐one healthy volunteers (30 men; 32 ± 8 years) underwent a session of 3 atrial and 3 ventricular SAECG recordings. Automatically detected onset and offset of SA QRS complex (QRS_tot) and SA P wave (P_tot) were subsequently‐corrected by two independent observers. For ventricular SAECG, three conventional time‐domain parameters were calculated. For atrial SAECG, the following five parameters were measured: P_tot, root mean square voltages of the entire P_tot (RMS‐P) and of the terminal 40, 30, and 20 ms of P_tot. Relative errors of the different pairs of measurements were used to assess the interobserver and observer‐computer variability. The Bland‐Altman method was applied to express the agreement between measurements. Results: Although the mean interobserver relative errors were low for QRS_tot and P_tot (1.1% vs 1.5%), the observer‐computer error was significantly higher for P_tot than for QRS_tot (1.7% vs 7.1%; P < 0.0001). For the voltage parameters, the lowest interobserver and observer‐computer relative errors were found for RMS‐P (6.6% vs 7.3%, P = ns). For RMS voltages of the terminal 40–20 ms of P_tot, relative errors exceeded 10%, but the interobserver error was significantly lower than the observer‐computer error (P < 0.0001). Conclusion: Automatic detection of the SA P‐wave onset and offset is unreliable and the atrial SAECG requires manual correction. Given a good interobserver agreement, such a correction is unlikely to introduce any significant observer‐dependent bias. A.N.E. 2000; 5(2):133–138     

Plasma levels of brain natriuretic peptide increase in patients with idiopathic bilateral atrial dilatation

Idiopathic bilateral atrial dilatation (IBAD) is an extremely rare anomaly and is usually associated with atrial fibrillation. Plasma levels of atrial natriuretic peptide (ANP) have been shown to increase in patients with atrial fibrillation. However, secretion of ANP and brain natriuretic peptide (BNP) in patients with IBAD remains unclear. We investigated the clinical features of 9 patients with IBAD and 16 age- and sex-matched patients with lone atrial fibrillation (LAF). Plasma levels of ANP and BNP were measured, and echocardiographic parameters were followed. Left (LAV) and right atrial volumes (RAV) were significantly higher in patients with IBAD than in patients with LAF (both p < 0.01). There were no differences between patients with IBAD and LAF in other echocardiographic parameters. The percent increases in LAV and RAV in patients with IBAD exceeded those in patients with LAF (both p < 0.01). Plasma levels of BNP and the BNP/ANP ratios in patients with IBAD were significantly higher than those in patients with LAF (both p < 0.01), but there was no significant difference in plasma levels of ANP. Regarding the clinical course of the patients with IBAD compared with those with LAF, the atrial volume increased gradually, and plasma levels of BNP were significantly higher. These findings suggested that IBAD was not only influenced by long-term atrial fibrillation, but also by subclinical left ventricular dysfunction.     

Left Atrial Volume Determinants in Patients with Non-Ischemic Dilated Cardiomyopathy

Background

Left atrial volume (LAV) is a predictor of prognosis in patients with heart failure.

Objective

We aimed to evaluate the determinants of LAV in patients with dilated cardiomyopathy (DCM).

Methods

Ninety patients with DCM and left ventricular (LV) ejection fraction ≤ 0.50 were included. LAV was measured with real-time three-dimensional echocardiography (eco3D). The variables evaluated were heart rate, systolic blood pressure, LV end-diastolic volume and end-systolic volume and ejection fraction (eco3D), mitral inflow E wave, tissue Doppler e´ wave, E/e´ ratio, intraventricular dyssynchrony, 3D dyssynchrony index and mitral regurgitation vena contracta. Pearson´s coefficient was used to identify the correlation of the LAV with the assessed variables. A multiple linear regression model was developed that included LAV as the dependent variable and the variables correlated with it as the predictive variables.

Results

Mean age was 52 ± 11 years-old, LV ejection fraction: 31.5 ± 8.0% (16-50%) and LAV: 39.2±15.7 ml/m². The variables that correlated with the LAV were LV end-diastolic volume (r = 0.38; p < 0.01), LV end-systolic volume (r = 0.43; p < 0.001), LV ejection fraction (r = -0.36; p < 0.01), E wave (r = 0.50; p < 0.01), E/e´ ratio (r = 0.51; p < 0.01) and mitral regurgitation (r = 0.53; p < 0.01). A multivariate analysis identified the E/e´ ratio (p = 0.02) and mitral regurgitation (p = 0.02) as the only independent variables associated with LAV increase.

Conclusion

The LAV is independently determined by LV filling pressures (E/e´ ratio) and mitral regurgitation in DCM.     

Evaluation of the Relationship between Atrial Septal Aneurysm and Cardiac Arrhythmias via P‐Wave Dispersion and Signal‐Averaged P‐Wave Duration

Objective: The aim of the study was to investigate the relationship between atrial septal aneurysms (ASAs) and cardiac arrhythmias via signal‐averaged P‐wave duration (SAPWD) and P‐wave dispersion (Pd). Methods: Sixty‐six patients with ASA served as the study group (group 1; 28 men and 38 women; mean age, 34 ± 10 years) and 62 healthy volunteers served as the control group (group 2; 29 men and 33 women; mean age, 31 ± 8 years) in the current study. ASAs were diagnosed by transthoracic echocardiography based on the criteria of a minimal aneurysmal base of ≥15 mm; and an excursion of ≥10 mm. All subjects were evaluated by 24‐hour Holter monitoring, 12 lead body surface electrocardiogram for P‐wave analysis, and signal‐averaged electrocardiogram for P‐wave duration (PWD). Results: There was no significant difference between the study and control groups in terms of age, gender, left atrium diameter, and left ventricular ejection fraction. Supraventricular arrhythmias (SVAs) were detected in 29 patients with ASA (43.9%) and 5 controls (8.1%; P < 0.001). The mean Pd in patients with ASA was significantly longer compared to the control group (14.1 ± 8 ms vs 7.0 ± 2.9 ms; P < 0.001). Similarly, the mean SAPWD in group 1 was significantly longer compared to group 2 (127.4 ± 17.6 ms vs 99.8 ± 12.3 ms; P < 0.001). Conclusion: Prolonged SAPWD and Pd were determined to indicate electrical disturbances in the atrial myocardium, and predict the increase in the prevalence of SVA in patients with ASA. Ann Noninvasive Electrocardiol 2010;15(2):157–164     

The signal-averaged P-wave duration is longer in hypertensive patients with history of paroxysmal atrial fibrillation as compared to those without

BACKGROUND: Onset of atrial fibrillation in hypertensive patients is usually associated with a high occurrence of cardiovascular complications. Therefore, it is important to assess non-invasively the risk of developing paroxysmal atrial fibrillation (PAF) in hypertensive patients during sinus rhythm. This study was undertaken to determine if hypertensive patients with history of PAF could be identified while in sinus rhythm by measurement of signal-averaged ECG P-wave duration. METHODS: Signal-averaged electrocardiography (SAECG) P-wave recording was performed in 44 hypertensive patients (30 men and 14 women; mean age 60+/-11 years, group A) who had a history of paroxysmal AF and in 50 hypertensive patients without history of AF (33 men and 17 women; mean age 57+/-12, group B). All patients were also evaluated by using echocardiography to measure left ventricular ejection fraction (LVEF) and left atrial diameter (LAD). RESULTS: SAECG P-wave duration was found to be significantly higher in group A than in group B (146+/-14 ms vs. 128+/-11 ms, p<0.001). Left atrial diameter was not significantly different (40.1+/-3.4 mm vs. 39.3+/-3.0 mm, p>0.05), whereas LVEF was significantly lower in group A than group B (63+/-5% vs. 67+/-4%, p=0.03). There was a correlation between SAECG P-wave duration and age (r=0.32, p<0.05). In univariate analysis, SAECG P-wave duration and LVEF were significant predictors of PAF, but only SAECG P-wave duration remained a significant independent predictor of PAF in multivariate analysis. CONCLUSION: The results of this study indicate that hypertensive patients with history of PAF can be detected while in sinus rhythm by signal-averaged ECG P-wave duration.