Predictive value of a comprehensive atrial assessment with cardiac magnetic resonance in non-ischemic cardiomyopathy: keep it simple

Cardiac magnetic resonance (CMR) can provide a multi-parametric evaluation of left atrial (LA) size and function. A complete CMR-based LA assessment might improve the risk stratification of patients with non-ischemic dilated cardiomyopathy (DCM). We performed a comprehensive CMR-based evaluation of LA size and function, in order to assess the prognostic impact of specific LA parameters in DCM. Secondary analysis of a prospective registry (UHSM-CMR study, NCT02326324) including 648 consecutive patients with DCM and CMR evaluation of LA area and LA length. Of these, 456 had complete LA assessment covering reservoir, conduit and booster pump function and including LA reservoir strain evaluated with feature tracking. The heart failure (HF) endpoint included HF hospitalizations, HF death and heart transplant. The arrhythmic endpoint included ventricular arrhythmias (VA) (sustained or treated by implantable defibrillator) and sudden death (SD). At median follow-up of 23 months, 34 patients reached the HF endpoint; in a multivariable model including NYHA class and LVEF, LA length had incremental predictive value. LA length ≥ 69 mm was the best cut-off to predict HF events (adjusted HR 2.3, p = 0.03). Among the 456 patients with comprehensive LA assessment, only LA length was independently associated with the HF endpoint after adjusting for LVEF and NYHA class. By contrast, no LA parameter independently predicted the arrhythmic risk. In DCM patients, LA length is an independent predictor of HF events, showing stronger association than other more complex parameters of LA function. No atrial parameter predicts the risk of VA and SD.

Predictors of New Onset Atrial Fibrillation Burden in the Critically Ill

INTRODUCTION

Atrial fibrillation (AF) is common in the intensive care unit (ICU) setting and has been associated with adverse outcomes. In this context, there is increasing research interest in AF burden as a predictor of subsequent adverse events. However, the pathophysiology and drivers of AF burden in the ICU are poorly understood. This study sought to evaluate the predictors of AF burden in critical illness-associated new-onset AF (CI-NOAF).

METHODS

Out of 7,030 admissions in a tertiary general ICU between December 2015 and September 2018, 309 patients developed CI-NOAF. AF burden was defined as the percentage of monitored time in AF, as extracted from hourly interpretations of continuous ECG monitoring. Low and high AF burden groups were defined relative to the median AF burden. Clinical, laboratory, and echocardiographic parameters were extracted, and multivariable modelling with binary logistic regression was performed to evaluate for independent associations with AF burden.

RESULTS

The median AF burden was 7.0%. Factors associated with increased AF burden were age, dyslipidaemia, chronic kidney disease, increased creatinine, CHA2DS2-VASc score, ICU admission diagnosis category, amiodarone administration, and left atrial area (LAA). Factors associated with lower AF burden were previous alcohol excess, burden of ventilation, the use of inotropes/vasopressors, and beta blockers. On multivariate analysis, increased LAA, chronic kidney disease, and amiodarone use were independently associated with increased AF burden, whereas beta blocker use was associated with lower AF burden.

CONCLUSION

Left atrial size and chronic cardiovascular comorbidities appear to be the primary drivers of CI-NOAF burden, whereas factors related to acute illness and critical care intervention paradoxically did not appear to be a substantial driver of arrhythmia burden. Further research is needed regarding drivers of AF and the efficacy of rhythm control intervention in this unique setting.

Anthracycline Treatment and Left Atrial Function in Children: A Real-Time 3-Dimensional Echocardiographic Study

Anthracycline (AC) therapy is associated with left ventricular (LV) dysfunction. Left atrial (LA) size and function are used to assess LV diastolic function in heart failure in adults. Data on LA size and function following AC therapy in children is limited. We hypothesized that LA size and function will be abnormal in children following AC chemotherapy. This retrospective review included patients who received AC for pediatric cancers. Controls had normal echocardiograms performed for evaluation of chest pain, murmur, or syncope. Real-time three-dimensional echocardiography was performed to evaluate LA reservoir, conduit, and booster pump function parameters. In addition to LA volume data, LV shortening fraction, spectral and tissue Doppler variables assessing diastolic function as well as myocardial performance index was obtained. Groups with and without AC therapy were compared by student t-test and chi-square test. We evaluated 136 patients, 55 (40.4%) had received AC. There was no significant difference between the groups in LV shortening fraction, diastolic as well as global function indices. LA reservoir and conduit function parameters were significantly lower in AC group compared to controls. The booster function parameters showed variable results. It is intriguing that AC-treated children have smaller LA reservoir and abnormal booster function. We speculate that these findings may reflect early changes in LA compliance associated with AC exposure. Assessment of LA volumes and function as prognostic markers of AC-induced cardiotoxicity in children is warranted.

Different associations between left atrial size and 2.5-year clinical outcomes in patients with anterior versus non-anterior wall ST-elevation myocardial infarction

Objective

To investigate associations between left atrial diameter (LAD) and long-term outcomes in patients with anterior or non-anterior wall ST-elevation myocardial infarction (STEMI).

Methods

Patients with STEMI were included in this secondary analysis of data from a prospective cohort study in which the primary outcome was major adverse cardiovascular event (MACE) occurrence during a 2.5-year follow-up. A LAD cut-off value was obtained through receiver operating characteristic curve analysis. Kaplan-Meier curve and Cox regression analyses were applied. Subgroup Cox regression analysis was also performed, with patients stratified based on left ventricular diastolic diameter (LVEDD, > 55 mm and ≤55 mm). The relationship between LAD and outcomes in patients with anterior or non-anterior wall STEMI was explored using restricted cubic spline functions.

Results

Out of 464 patients, adjusted Cox regression showed that dichotomous (>40 mm) LAD was significantly associated with MACE (hazard ratio 2.978, 95% confidence interval 1.763, 5.030) in patients with anterior wall but not non-anterior wall STEMI. The association was not different between normal and enlarged LVEDD groups.

Conclusions

A left atrium > 40 mm may indicate higher risk of MACE in patients with anterior wall STEMI, even in patients with normal left ventricular structure. This relationship was not observed in patients with non-anterior wall STEMI.

Prognostic importance of left atrial size measured by non-contrast cardiac computed tomography - A DANCAVAS study

BACKGROUND

Enlargement of left atrium (LA) is a valuable marker of cardiovascular events, and LA size is readily available while performing non-contrast cardiac computed tomography (NCCT) for preventive purposes. We aimed to evaluate the predictive value of a single LA area from NCCT in a population-based cohort.

METHOD

Mainly men aged 60-75 years from DANCAVAS were included. Traditional risk factors were recorded, and an NCCT scan performed at baseline. Coronary artery calcifications (CAC) score and the largest LA area were measured. LA was indexed to body surface area and categorised into four groups. Data on incident atrial fibrillation (AF), thromboembolic events, heart failure (HF) and death were obtained from Danish national registries.

RESULTS

In total, 14,557 individuals were eligible, excluding those without LA measurement (N = 232) and with heart valve replacement (N = 197). Known AF or HF were respectively excluded from follow-up. Median follow-up time was 2.1 to 3.4 years. In total, 304 developed AF, 149 had thromboembolism, 129 developed HF and 482 died. In adjusted analysis, LA enlargement was associated with AF (HR (95% CI): large 1.99 (1.46-2.71) and very large LA 3.77 (2.31-6.14)) and HF (large 2.40 (1.50-3.85) and very large LA 6.54 (4.07-10.51)). A very large LA significantly increased mortality (HR: 2.01 (1.44-2.82)), and was associated with a two-fold increased risk of thromboembolism; however, not significantly in adjusted analysis (p = 0.09).

CONCLUSION

We demonstrated that determination of LA area from NCCT was an important predictor of AF, HF and death. This knowledge could inform current risk assessment beyond CAC score.

Heart to spine measurements to detect left atrial enlargement in dogs with mitral insufficiency

Background

Radiography is useful to determine left atrial (LA) size when echocardiography is not available. Recently, the authors have described Radiographic Left Atrial Dimension (RLAD) as a new radiographic measurement to assess LA size. The objective of this study was to assess the clinical usefulness of 2 new radiographic measurements to detect and quantify left atrial enlargement (LAE) compared to RLAD and using left atrium to aortic root (LA/Ao) ratio as gold standard. These new measurements, bronchus-to-spine (Br-Spine) and RLAD-to-spine (RLAD-Spine) may be more precise in cases were LA boundaries are not well defined. Fifty dogs, 25 with and 25 without LAE were recruited. Reference LA/Ao ratio was assessed by 2D echocardiography and LAE was considered if LA/Ao > 1.6. Br-spine was measured as a straight vertical line from the main stem bronchus to the ventral border of the vertebra situated immediately dorsal to the heart base. RLAD-Spine was measured from RLAD endpoint perpendicularly to spine. The correlation of RLAD, Br-Spine and RLAD-Spine methods with LA/Ao and their sensitivity and specificity for detecting LAE were calculated. Receiver Operating Characteristic (ROC) curves were used to estimate the optimal cut-off for each method.

Results

Correlations between Br-Spine, RLAD-Spine, RLAD and LA/Ao ratio were - 0.66, - 0.76 and 0.89 respectively (P < 0.001). Sensitivity at the optimal cut-off values for detecting LAE were 32.0, 64.0 and 96.0%, respectively. Specificity was 96.0% in all cases.

Conclusion

Br-Spine and RLAD-Spine were less sensitive radiographic measurements than RLAD in detecting LAE in dogs. Both Br-Spine and RLAD-Spine may not be good alternatives to RLAD.

Prognostic Value of Left Atrial Size and Functional Indices Measured by 3-Dimensional Speckle-Tracking Analysis

BACKGROUND

The prognostic value of indices for left atrial volumes (LAV) and reservoir function measured by 3D speckle-tracking analysis (3DSTA) has not been determined. Methods and Results: LA maximal and minimal volume indices (LAVImax, LAVImin), and LA emptying fraction (LAEmpF) were measured via 2D echocardiography (2DE) and 3DSTA in 514 patients (62% male, mean age: 66±15 years) with various cardiovascular diseases. Two cutoff values using normal±2SD (cutoff criterion 1) and receiver-operating characteristic analysis (cutoff criterion 2) were evaluated. During a mean follow-up of 720±383 days, MACE (cardiac death, nonfatal myocardial infarction, stroke and admission for heart failure) occurred in 98 patients. Kaplan-Meier survival analysis showed both cutoff criteria measured by 2DE and 3DSTA had significant predictive power for MACE (P<0.001). For cutoff criterion 1, 3DSTA measurements yielded higher hazard ratios than 2DE by Cox proportional hazard model. Cutoff criterion 2 using 3DSTA had higher average treatment effect values than 2DE by matching propensity scores on the outcome. Further, a regression model that included clinical variables, left ventricular ejection fraction and cutoff criterion 2 using 3DSTA-derived LAEmpF had significantly higher prognostic power than 2DE.

CONCLUSIONS

LA indices measured by 3DSTA had greater prognostic power for future MACE than 2DE. In particular, 3DSTA-derived LAEmpF has the potential to be a valuable prognostic tool in clinical settings.

A radiographic measurement of left atrial size in dogs

Background

The dimensions of the left atrium in cases with mitral regurgitation are an indirect measurement of its severity. The objective of this study was to evaluate the value of a new radiographic measurement, the radiographic left atrial dimension (RLAD), for detecting left atrial enlargement (LAE) in dogs. Thirty one dogs without LAE and 46 dogs with LAE were recruited in a prospective fashion. Reference left atrium dimension was measured by standard left atrium to aorta ratio (LA/Ao) by 2D echocardiography. LAE was considered if LA/Ao > 1.6. Left atrium dimension was then quantified on lateral radiographs by measuring RLAD. Vertebral heart size (VHS) was measured and RLAD was obtained by drawing a line bisecting the 90 degrees angle defined by the long and short cardiac axes lines of the VHS, up to the dorsal edge of the left atrium and comparing its length to T4’s vertebral body length. The correlation of VHS and RLAD methods with LA/Ao was estimated, as well as their sensitivity and specificity for detecting LAE. Receiver Operating Characteristic (ROC) curves were used to estimate the optimal decision criteria for each method.

Results

A positive correlation was observed between RLAD and LA/Ao (r = 0.82). RLAD’s sensitivity and specificity for detecting LAE when evaluated at the optimal cut-off value, 1.8 vertebrae, were 93.5 and 96.8% respectively. RLAD showed high reproducibility and repeatability.

Conclusion

RLAD appears to be a clinically useful radiographic measurement for evaluating left atrial dimensions. RLAD would provide clinicians with a simple and cost-effective tool for evaluating and monitoring LAE.

Relation between left atrial measurements and thromboembolic risk markers assessed by echocardiography in patients with nonvalvular atrial fibrillation: A cross-sectional study

Background

Left atrium (LA) dilatation has been associated with adverse cardiovascular outcomes in patients with sinus rhythm and atrial fibrillation (AF).

Aim of the study

We aimed to evaluate the accuracy of left atrial (LA) size to predict transesophageal echocardiographic (TEE) markers of increased thromboembolic risk left atrial appendage (LAA) thrombus, low LAA velocities and dense spontaneous echocardiographic contrast (SEC), and also to assess the best method to evaluate LA size.

Patients and methods

Cross-sectional study included 64 patients with nonvalvular AF undergoing transthoracic and transesophageal echocardiographic (TTE and TEE) evaluation. LA size was measured on TTE by several methods including the following: anteroposterior diameter (AP), LA area in four and two apical chamber views and volumes by ellipsoid, single plane (1P) and biplane area-length (2P) formulas. All these measures were indexed to the body surface area (BSA). Thromboembolic markers including LAA thrombus, low LAA velocities, dense SEC and LA abnormality (LA ABN) which means the presence of one or more of the previous three parameters were evaluated by TEE.

Results

There was statistically significant increase in indexed and non-indexed LA parameters in patients with LA ABN compared to patients without LA ABN. According to ROC curve, the study found that all indexed LA parameters were predictive for LAA thrombus with the highest AUC was indexed LA 1P area length volume (AUC 0.91, CI 95% 0.81-1.01, p < 0.000), for LAA low flow velocity were indexed and non-indexed LA AP diameters with the highest AUC was indexed LA AP diameter (AUC 0.89, CI 95% 0.80-0.98, p < 0.000), for LA dense SEC were indexed LA ellipsoid volume (AUC 0.78, CI 95% 0.66-0.96, p = 0.002) and indexed LA 1P area length volume (AUC 0.78, CI 95% 0.66-0.90, p = 0.002) and for LA ABN were all LA parameters with the highest AUC was indexed LA 1P area length volume (AUC 0.87, CI 95% 0.79-0.96, p < 0.000). On multivariate logistic regression analysis of TEE parameters, the study found that the most predictive LA measurement for LAA thrombus was indexed LA AP diameter with cutoff 3 cm/m² (OR 7.5, 95% CI 1.24-45.2, p = 0.02), for LAA low flow velocity was LA AP diameter with cutoff 6 cm (OR 17.6, 95% CI 3.23-95.84, p = 0.001), for LA dense SEC was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 6.5, 95% CI 1.32-32.07, p = 0.02), and for LA ABN was indexed LA ellipsoid volume with cutoff 42 cm³/m² (OR 10.45, 95% CI 2.18-51.9, p = 0.008).

Conclusion

LA enlargement is suitable to predict thromboembolic markers in patients with non-valvular AF. The indexed and non-indexed LA AP diameter and indexed LA ellipsoid volume were the most accurate parameters for predicting thromboembolic markers.

Validation of Left Atrial Volume Estimation by Left Atrial Diameter from the Parasternal Long-Axis View

BACKGROUND

Measurement of left atrial (LA) volume (LAV) is recommended for quantification of LA size. Only LA anteroposterior diameter (LAd) is available in a number of large cohorts, trials, or registries. The aim of this study was to evaluate whether LAV may be reasonably estimated from LAd.

METHODS

One hundred forty consecutive patients referred to our outpatient clinics were prospectively enrolled to measure LAd from the long-axis view on two-dimensional echocardiography. LA orthogonal dimensions were also taken from apical four- and two-chamber views. LAV was measured using the Simpson, area-length, and ellipsoid (LAV_e) methods. The first 70 patients were the learning series and the last 70 the testing series (TeS). In the learning series, best-fitting regression analysis of LAV-LAd was run using all LAV methods, and the highest values of F were chosen among the regression equations. In the TeS, the best-fitting regressions were used to estimate LAV from LAd.

RESULTS

In the learning series, the best-fitting regression was linear for the Spearman method (r² = 0.62, F = 111.85, P = .0001) and area-length method (r² = 0.62, F = 112.24, P = .0001) and powered for the LAV_e method (r² = 0.81, F = 288.41, P = .0001). In the TeS, the r² value for LAV prediction was substantially better using the LAV_e method (r² = 0.89) than the Simpson (r² = 0.72) or area-length (r² = 0.70) method, as was the intraclass correlation (ρ = 0.96 vs ρ = 0.89 and ρ = 0.89, respectively). In the TeS, the sensitivity and specificity of LA dilatation by the estimated LAV_e method were 87% and 90%, respectively.

CONCLUSIONS

LAV can be estimated from LAd using a nonlinear equation with an elliptical model. The proposed method may be used in retrospective analysis of existing data sets in which determination of LAV was not programmed.

Prognostic value of CT-derived left atrial and left ventricular measures in patients with acute chest pain

PURPOSE

To determine which left atrial (LA) and left ventricular (LV) parameters are associated with future major adverse cardiac event (MACE) and whether these measurements have independent prognostic value beyond risk factors and computed tomography (CT)-derived coronary artery disease measures.

MATERIALS AND METHODS

This retrospective analysis was performed under an IRB waiver and in HIPAA compliance. Subjects underwent coronary CT angiography (CCTA) using a dual-source CT system for acute chest pain evaluation. LV mass, LV ejection fraction (EF), LV end-systolic volume (ESV) and LV end-diastolic volume (EDV), LA ESV and LA diameter, septal wall thickness and cardiac chamber diameters were measured. MACE was defined as cardiac death, non-fatal myocardial infarction, unstable angina, or late revascularization. The association between cardiac CT measures and the occurrence of MACE was quantified using Cox proportional hazard analysis.

RESULTS

225 subjects (age, 56.2±11.2; 140 males) were analyzed, of whom 42 (18.7%) experienced a MACE during a median follow-up of 13 months. LA diameter (HR:1.07, 95%CI:1.01-1.13permm) and LV mass (HR:1.05, 95%CI:1.00-1.10perg) remained significant prognostic factor of MACE after controlling for Framingham risk score. LA diameter and LV mass were also found to have prognostic value independent of each other. The other morphologic and functional cardiac measures were no significant prognostic factors for MACE.

CONCLUSION

CT-derived LA diameter and LV mass are associated with future MACE in patients undergoing evaluation for chest pain, and portend independent prognostic value beyond traditional risk factors, coronary calcium score, and obstructive coronary artery disease.

Left atrial volume and function in dogs with naturally occurring myxomatous mitral valve disease

OBJECTIVE

Myxomatous mitral valve disease (MMVD) induces progressive left atrial (LA) enlargement. The LA modulates left ventricular filling and performance through its reservoir, conduit, and contractile function. Assessment of LA size and function may provide valuable information on the level of cardiac compensation. Left atrial function in dogs with naturally occurring MMVD remains largely unexplored. The objective of this study was to evaluate LA volume and function in dogs with naturally occurring MMVD.

ANIMALS

This prospective study included 205 client-owned dogs of different breeds, 114 healthy dogs, and 91 dogs with MMVD of different disease severities.

METHODS

Using two-dimensional echocardiography, the biplane area-length method was applied to assess LA volume and calculate volumetric indices of LA reservoir, conduit, and contractile function.

RESULTS

Left atrial volume and LA stroke volume increased, whereas LA reservoir and contractile function decreased with increasing disease severity. A maximal LA volume <2.25mL/kg was the optimal cut off identified for excluding congestive heart failure in dogs with chronic MMVD with a sensitivity of 96% and a specificity of 100%. An active LA emptying fraction <24% and/or a LA expansion index <126% were suggestive of congestive heart failure in dogs with chronic MMVD with a sensitivity of 77% and a specificity of 89% and a sensitivity of 82% and a specificity of 82%, respectively.

CONCLUSION

Dogs with MMVD appear to have larger LA volumes with poorer LA function. Deteriorating LA function, characterized by a decreasing reservoir and active contractile function, was evident in dogs with MMVD with increasing disease severity.

Steerable versus non-steerable sheaths during pulmonary vein isolation: impact of left atrial enlargement on the catheter-tissue contact force

PURPOSE

The influence of left atrial (LA) enlargement on the efficacy of steerable sheath usage during pulmonary vein (PV) isolation is poorly understood. Here, we compared the catheter-tissue contact force (CF) and clinical outcomes between steerable and non-steerable sheaths among patients with different severities of LA enlargement.

METHODS

In this prospective observational study, 90 consecutive atrial fibrillation patients scheduled for PV isolation (paroxysmal, 67 %) were enrolled and divided into tertiles of the LA volume (LA1, <124 cm³; LA2, 124 to 145 cm³; LA3, ≥146 cm³). An ipsilateral PV isolation was completed using either a steerable (n = 57) or non-steerable sheath (n = 33).

RESULTS

The average CF of each ipsilateral PV was lower in the LA3 group (right 13.8 ± 5.8 g; left 9.7 ± 5.2 g) than LA1 (right 15.6 ± 6.8 g, p = 0.005; left 12.5 ± 5.6 g, p < 0.0001) or LA2 (right 15.2 ± 7.3 g, p = 0.04; left 12.6 ± 5.3 g, p < 0.0001) groups. In total, the average CF around the left PVs was significantly higher with steerable sheaths than without (12.7 ± 5.5 vs. 10.2 ± 4.9 g, p = 0.03). Subgroup analysis revealed that a tendency toward higher CF around the left PVs was observed in the LA3 group (12.3 ± 7.3 vs. 8.5 ± 3.9 g, p = 0.08) but was not in the LA1 and LA2 groups. Further, in the LA3 group, steerable sheath usage showed better clinical outcomes: shorter procedural (55 ± 29 min vs. 81 ± 39 min, p = 0.04) and fluoroscopic times (27 ± 11 min vs. 37 ± 17 min, p = 0.045) and a tendency toward a lower 1-year AF recurrence rate (39 vs. 12 %, p = 0.09).

CONCLUSIONS

The beneficial effects of using steerable sheaths were more prominent in patients with severe LA enlargement.

Reductions of left ventricular mass and atrial size following renal denervation: a meta-analysis

BACKGROUND

Renal denervation (RDN), a novel therapy for resistant hypertension, has been shown to have an effect on cardiac remodeling in several small studies. We aimed to pool currently available data to assess the effects of RDN on left ventricular hypertrophy (LVH) and left atrial (LA) enlargement.

METHODS AND RESULTS

Two investigators independently searched PubMed, EMBASE and Cochrane Library Central Register of Controlled Trials database for studies reporting change in left ventricular mass index (LVMI) or LA size before and after RDN. Twelve publications met our pre-defined inclusion criteria. Echocardiographic data showed that RDN markedly reduced both LVMI [weighted mean difference (WMD) = -15.77 g/m(2); 95 % confidence interval (CI) -22.51 to -9.02 g/m(2)] and LA diameter [WMD = -2.48 mm; 95 % CI -4.12 to -0.83 mm] after 6 months. Data from cardiac magnetic resonance also showed a significant reduction in LVMI [WMD = -5.43 g/m(2), 95 % CI -10.01 to -0.35 g/m(2)) at 6 months. Changes in LVH and LA size at 12 months were more pronounced than those at 6 months. Meta-regression analysis failed to demonstrate a significant relationship between RDN-induced LVMI reduction and BP lowering at 6 months.

CONCLUSIONS

RDN led to significant regressions of both LVH and LA enlargement at 6 months, which were sustained at least up to 12 months.

Atrial fibrillation ablation by single ring isolation versus wide antral isolation: Effects on left atrial size and function

BACKGROUND

Pulmonary vein isolation (PVI) by single ring isolation (SRI) has been demonstrated to reduce recurrence of atrial fibrillation (AF) compared to the standard technique of wide antral isolation (WAI). In this study, we examine the differential effect of these techniques on left atrial size and function.

METHODS

We examined left atrial (LA) size (LA maximum and LA minimum volumes) and function (LA emptying fraction and LA expansion index) over a period of 6 months following PVI as measured by transthoracic echocardiography in 187 patients that were enrolled in a randomised controlled trial of SRI vs WAI.

RESULTS

Compared to pre-ablation, at 6 months post-PVI, there was a small decrease in the LA maximum volume in the WAI group (67.3 vs 62.7 mL, p=0.02). The LA size did not change significantly over 6 months in the SRI group. Patients who underwent SRI had a small reduction in the LA expansion index at 6 months post-PVI compared to baseline (80.6 vs 66.6%, p=0.02). LA function did not change significantly over 6 months in the WAI group. However, at 6 months, there was no difference in any measure of LA size or function between the SRI and WAI groups.

CONCLUSIONS

SRI, whilst previously demonstrated to be more effective than WAI in preventing AF recurrence, is associated with minimal adverse effects on left atrial function at medium term follow-up despite the isolation of a larger region of LA myocardium.

Left atrial dimension and traditional cardiovascular risk factors predict 20-year clinical cardiovascular events in young healthy adults: the CARDIA study

AIMS

We investigated whether the addition of left atrial (LA) size determined by echocardiography improves cardiovascular risk prediction in young adults over and above the clinically established Framingham 10-year global CV risk score (FRS).

METHODS AND RESULTS

We included white and black CARDIA participants who had echocardiograms in Year-5 examination (1990-91). The combined endpoint after 20 years was incident fatal or non-fatal cardiovascular disease: myocardial infarction, heart failure, cerebrovascular disease, peripheral artery disease, and atrial fibrillation/flutter. Echocardiography-derived M-mode LA diameter (LAD; n = 4082; 149 events) and 2D four-chamber LA area (LAA; n = 2412; 77 events) were then indexed by height or body surface area (BSA). We used Cox regression, areas under the receiver operating characteristic curves (AUC), and net reclassification improvement (NRI) to assess the prediction power of LA size when added to calculated FRS or FRS covariates. The LAD and LAA cohorts had similar characteristics; mean LAD/height was 2.1 ± 0.3 mm/m and LAA/height 9.3 ± 2.0 mm(2)/m. After indexing by height and adjusting for FRS covariates, hazard ratios were 1.31 (95% CI 1.12, 1.60) and 1.43 (95% CI 1.13, 1.80) for LAD and LAA, respectively; AUC was 0.77 for LAD and 0.78 for LAA. When LAD and LAA were indexed to BSA, the results were similar but slightly inferior. Both LAD and LAA showed modest reclassification ability, with non-significant NRIs.

CONCLUSION

LA size measurements independently predict clinical outcomes. However, it only improves discrimination over clinical parameters modestly without altering risk classification. Indexing LA size by height is at least as robust as by BSA. Further research is needed to assess subgroups of young adults who may benefit from LA size information in risk stratification.

Prognostic implications of left atrial dilation evaluated by echocardiographic volume in patients with normal left atrial antero-posterior dimensions

BACKGROUND

The purpose of this study was to clarify the clinical characteristics and prognostic implications of left atrial (LA) dilation evaluated echocardiographic volume in patients with normal LA dimension (LAD).

METHODS

A total of 140 consecutive patients (81 men, mean age: 57 ± 18 years) with normal LAD (<39 mm for women and <41 mm for men) who underwent conventional echocardiography and tissue Doppler imaging were enrolled. LA volume (LAV) ≥29 ml/m(2) was defined as abnormal LAV. Hospitalization for heart failure (HF) and cardiac death were defined as cardiac events.

RESULTS

Eighty-seven (62%) of the patients had LA dilation, defined as a normal LAD but an abnormal LAV. Patients with LA dilation were significantly older and had a significantly higher left ventricular (LV) mass index (LVMI) and incidences of hypertension and HF than did patients with both normal LAD and normal LAV. Logistic regression analysis revealed that increased LVMI was an independent (p < 0.01) determinant of LA dilatation. During a follow-up period of 16 ± 10 months, ten patients had cardiac events. Patients with cardiac events had a higher incidence of LA dilation than those without cardiac events (100 vs. 59%, p < 0.05). A Kaplan-Meier survival curve showed that patients with LA dilation had a significantly lower survival rate than those with both normal LAD and normal LAV (log rank 6.1, p = 0.014).

CONCLUSIONS

LV hypertrophy is an independent determinant of LA dilation in patients with normal LAD. Assessment of LA morphology using LAV can contribute to risk stratification in patients with normal LAD.

Atrial conduction delay and its association with left atrial dimension, left atrial pressure and left ventricular diastolic dysfunction in patients at risk of atrial fibrillation

BACKGROUND

Atrial conduction delay and its association with left atrial dimension, left atrial pressure and left ventricular (LV) diastolic dysfunction in patients at risk of atrial fibrillation (AF) may be assessed by high-resolution electrocardiography of P wave.

OBJECTIVES

To determine how left atrial size, left atrial pressure and LV diastolic dysfunction, measured noninvasively by transthoracic echocardiography, influence atrial conduction time.

METHODS

Signal-averaged electrocardiography of P wave and echocardiogram were performed on 70 patients (average age of 63+/-10 years; 37 male and 33 female), divided into three groups: group A, patients with paroxysmal AF (n=29); group B, patients with type 2 diabetes mellitus and arterial hypertension, but without AF (n=23); and group C, healthy control patients (n=18). Standard statistical methods were used.

RESULTS

Filtered P wave duration, measured by signal-averaged electrocardiography, was significantly prolonged in group A and group B compared with control group C (138+/-12 ms and 125+/-9 ms versus 117+/-8 ms; P </= 0.001 and P </= 0.01, respectively). Left atrial diameter, area and volume were significantly increased in group A compared with group C (P </= 0.01, P </= 0.05 and P </= 0.001, respectively), but no significant differences were found in these dimensions between group B and group C. Left atrial pressure, determined with the Doppler echocardiographic parameter ratio of early diastolic transmitral velocity to mitral annular early diastolic velocity, was significantly higher in group A, as well in group B, than group C (P </= 0.05, P </= 0.01). As well, impaired LV relaxation was present more often in group A (42%) and group B (50%).

CONCLUSION

Atrial conduction delay in patients at risk of AF (patients with diabetes and hypertension in group B) was associated with increased left atrial pressure and impaired LV relaxation. Patients with paroxysmal AF (group A) presented left atrial dilation, increased left atrial pressure and impaired LV relaxation, and these factors were associated with more significantly prolonged atrial conduction in group A than in group B.