Role of Left Atrial Size in Risk Stratification and Prognosis of Patients Undergoing Stress Echocardiography

Left atrium volume and function changes during stress in patients with primary mitral regurgitation and preserved left ventricular ejection fraction

INTRODUCTION

Patients with primary mitral regurgitation (MR) usually remain asymptomatic for a long time due to compensatory mechanisms and an adequate treatment could be delayed. Stress echocardiography and speckle-tracking analysis could help to evaluate impaired left atrium (LA) function before the manifestation of clinically significant myocardial changes in asymptomatic patients with primary MR and preserved left ventricular (LV) ejection fraction (EF).

METHODS

This study prospectively enrolled 91 patients with preserved LV EF (≥60%) at rest, of which 60 patients had moderate-to-severe MR and 31 were healthy controls. Rest and stress (bicycle ergometry) echocardiography and speckle-tracking offline analysis were performed.

RESULTS

In MR group LA volume indices were higher at rest and during stress, while LA reservoir, conduit, and contractile fractions were decreased (p < .005). LA deformation parameters at rest were similar in both groups. During maximum stress LA conduit, contractile fractions and reservoir strain were lower (p < .05) in patients with MR. Indices of LA volume were related to SPAP at rest and during stress. Higher NT-proBNP concentrations was associated with higher LA volume indices, decreased contractile and reservoir functions during peak stress (p < .05). LA volume indices, LA EF, and filling index at rest could predict exercise-induced pulmonary hypertension (EIPH) (p < .05).

CONCLUSIONS

In patients with primary MR and preserved LV EF, LA parameters are related to SPAP and NT-pro-BNP concentration. LA volume indices, LA EF and LA filling index are predictors of EIPH.

Effect of different alcohol consumption levels on the left atrial size: A cross-sectional study in rural China

OBJECTIVE

Previous studies have investigated the relationship between alcohol and ventricular structure; however, few studies have evaluated the relation between alcohol consumption and the atrium size. In this study, we aimed to test the association between alcohol consumption and left atrium (LA) size in the general population.

METHODS

A population-based sample of 10,211 subjects aged ≥35 years and free from hypertension at baseline were followed from January 2012 to August 2013. Left atrial enlargement (LAE) was defined as the ratio of LA diameter to body surface area exceeding 2.4 cm/m2 in both the sexes. Independent factors for LAE were estimated by multiple logistic regression analyses.

RESULTS

The study included 10,211 participants (4,751 men and 5,460 women). Left atrial diameter/body surface area (LAD/BSA) was higher in the moderate and heavy alcohol consumption groups than in the non-drinker group (non-drinker, 20.5±0.03 cm/m2; moderate, 20.8±0.09 cm/m2; and heavy, 20.6±0.06 cm/m2; p<0.001). Both the groups of moderate and heavy drinkers had a higher incidence of LAE than the non-drinker group (6.9% of non-drinkers, 9.9% of moderate drinkers, and 8.4% of heavy drinkers; p<0.001). After adjusting for related risk factors, multiple logistic regression analyses showed that moderate drinkers had an approximately 1.4-fold higher risk of LAE [odds ratio (OR): 1.387, 95% confidence interval (CI) 1.056-1.822, p=0.019] compared with the non-drinkers, and the heavy drinkers had an approximately 1.2-fold higher risk of LAE (OR: 1.229, 95% CI: 1.002-1.508, p=0.047) compared with that of the non-drinkers.

CONCLUSION

Both heavy and moderate drinkers had increased odds for LAE compared with participants with no alcohol consumption in the general population.

Prognostic value of left atrial size in hypertensive African Americans undergoing stress echocardiography

BACKGROUND

Left atrial (LA) enlargement is a marker of increased risk in the general population undergoing stress echocardiography. African American (AA) patients with hypertension are known to have less atrial remodeling than whites with hypertension. The prognostic impact of LA enlargement in AA with hypertension undergoing stress echocardiography is uncertain.

AIM

To investigate the prognostic value of LA size in hypertensive AA patients undergoing stress echocardiography.

METHODS

This retrospective outcomes study enrolled 583 consecutive hypertensive AA patients who underwent stress echocardiography over a 2.5-year period. Clinical characteristics including cardiovascular risk factors, stress and echocardiographic data were collected from the electronic health record of a large community hospital. Treadmill exercise and Dobutamine protocols were conducted based on standard practices. Patients were followed for all-cause mortality. The optimal cutoff value of antero-posterior LA diameter for mortality was assessed by receiver operating characteristic analysis. Cox regression was used to determine variables associated with outcome.

RESULTS

The mean age was 57 ± 12 years. LA dilatation was present in 9% (54) of patients (LA anteroposterior ≥ 2.4 cm/m²). There were 85 deaths (15%) during 4.5 ± 1.7 years of follow-up. LA diameter indexed for body surface area had an area under the curve of 0.72 ± 0.03 (optimal cut-point of 2.05 cm/m²). Variables independently associated with mortality included age [P = 0.004, hazard ratio (HR) 1.34 (1.10-1.64)], tobacco use [P = 0.001, HR 2.59 (1.51-4.44)], left ventricular hypertrophy [P = 0.001 , HR 2.14 (1.35-3.39)], Dobutamine stress [P = 0.003, HR 2.12 (1.29-3.47)], heart failure history [P = 0.031, HR 1.76 (1.05-2.94)], LA diameter ≥ 2.05 cm/m² [P = 0.027, HR 1.73 (1.06-2.82)], and an abnormal stress echocardiogram [P = 0.033, HR 1.67 (1.04-2.68)]. LA diameter as a continuous variable was also independently associated with mortality but LA size ≥ 2.40 cm/m² was not.

CONCLUSION

LA enlargement is infrequent in hypertensive AA patients when traditional reference values are used. LA enlargement is independently associated with mortality when a lower than “normal” threshold (≥ 2.05 cm/m²) is used.

Real time three-dimensional echocardiographic quantification of left atrial volume in orthotopic heart transplant recipients: Comparisons with cardiac magnetic resonance imaging

INTRODUCTION

The accuracy of real time three-dimensional echocardiography (RT-3DE) in evaluating left atrial volume (LAV) of heart transplant recipients against cardiac magnetic resonance (CMR) has not been reported. The aim of this study was to compare LAV with RT-3DE with respect to CMR in heart transplant recipients.

METHODS

Thirty-one heart transplant recipients who received echocardiogram and CMR examination on the same day were prospectively enrolled. The maximal LAV, minimal LAV by RT-3DE, and two-dimensional echocardiography (2DE) were compared with CMR measurements. Inter-technique comparisons included Pearson's correlation coefficient and Bland-Altman analysis. Reproducibility of 2DE and RT-3DE technique was assessed by intra-class correlation coefficient (ICC).

RESULTS

RT-3DE-derived LAV values showed higher correlation with CMR than 2DE measurements in heart transplant recipients (r = .93 vs r = .76 for maximal LAV; r = .91 vs r = .81 for minimal LAV). Two-dimensional echocardiography underestimated maximal LAV by 10 ± 31 mL and minimal LAV by 26 ± 26 mL. Although RT-3DE underestimated minimal LAV 15 ± 19 mL, no significant difference between RT-3DE and CMR was observed in maximal LAV (RT-3DE: 86 ± 22 mL; CMR: 89 ± 23 mL, P = .079), with a negligible bias of 3 mL. Inter-observer and intra-observer agreement were excellent for 2DE and RT-3DE parameters.

CONCLUSION

Compared with CMR reference, RT-3DE-derived LAV measurements are more accurate than 2DE-based analysis in heart transplant recipients, especially with regard to the assessment of maximal LAV. RT-3DE may be a valid alternative to CMR for quantification LAV in heart transplant recipients.

Relationship of left atrial expansion index to exercise tolerance, pretest probability of restenosis, and positive predictive value of treadmill test in coronary artery disease

BACKGROUND

Whether left atrial (LA) expansion index is associated with coronary restenosis, and exercise capacity (EC) reduction in coronary artery disease has not been established.

METHODS

This study analyzed 342 consecutive patients who had received a coronary stent implant. A treadmill exercise test (TET) was administered in all participants. The LA expansion indices were measured immediately before and after TET. Maximal EC measured on a breath-by-breath basis by a metabolic cart with gas analyzers and recorded as metabolic equivalent task. All patients with positive TET results received angiography, and those with restenosis received complete revascularization by either percutaneous coronary intervention (PCI) or bypass surgery. The LA expansion index and EC before and 1 month after PCI were then compared.

RESULTS

Out of 342 patients, 74 had positive TET results, and 54 had restenosis in angiography. Low LA expansion index was associated with poor EC. In patients with LA expansion index > 200%, only 5% had restenosis with 38.5% positive predictive value (PPV) of TET. In patients with LA expansion index < 100%, however, 64.3% had restenosis with 94.7% PPV of TET. Restenosis induced low pre-TET LA expansion index and further decline during TET. The LA expansion index significantly (P .001) improved from 133 ± 64% before PCI to184 ± 86% after PCI, and the improvement corresponded with EC recovery. A 10% reduction in LA expansion index was associated with a 15% increase in pretest probability of restenosis.

CONCLUSION

The LA expansion index is associated with EC, pretest probability of restenosis, and PPV of TET. Revascularization improves both EC and LA expansion index.

Endocardial Changes in Nonvalvular Atrial Fibrillation Without Atrial Thrombus-Thrombomodulin and Tissue Factor Pathway Inhibitor

Atrial fibrillation (AF) is a well-known cause for thromboembolism. Although blood stasis in the left atrium and hypercoagulable state of the blood have been emphasized as important mechanisms, limited attention has been paid to the endocardial changes in maintaining the balance of local coagulation, which may also contribute to the thrombus formation in AF. In the present study, left atrial appendage samples were obtained at heart surgery from nonvalvular AF and non-AF patients without atrial thrombus. Immunohistochemistry for endocardial markers including thrombomodulin (TM) and tissue factor pathway inhibitor (TFPI) was performed and semiquantitatively graded. In immunohistochemistry analysis, decreased expression of TM was found in patients with nonvalvular AF compared with those without AF ( P < .001). There was no difference in TFPI expression between the 2 groups ( P = .213). Patients with TM score of 0 or 1 seemed to have larger left atrial diameter (LAD) than those with TM score of 2 or 3 (44.0 (7.9) vs 40.6 (3.9); P = .009), while no relationship between LAD and TFPI expression was found (43.4 (7.0) vs 42.9 (7.8); P = .485). In conclusion, TM expression in the atrial endocardium is decreased in nonvalvular AF without atrial thrombus, while TFPI expression is not. Downregulated TM expression might be associated with enlarged LAD.

Biomass fuel smoke exposure was associated with adverse cardiac remodeling and left ventricular dysfunction in Peru

While household air pollution from biomass fuel combustion has been linked to cardiovascular disease, the effects on cardiac structure and function have not been well described. We sought to determine the association between biomass fuel smoke exposure and cardiac structure and function by transthoracic echocardiography. We identified a random sample of urban and rural residents living in the high-altitude region of Puno, Peru. Daily biomass fuel use was self-reported. Participants underwent transthoracic echocardiography. Multivariable linear regression was used to examine the relationship of biomass fuel use with echocardiographic measures of cardiac structure and function, adjusting for age, sex, height, body mass index, diabetes, physical activity, and tobacco use. One hundred and eighty-seven participants (80 biomass fuel users and 107 non-users) were included in this analysis (mean age 59 years, 58% women). After adjustment, daily exposure to biomass fuel smoke was associated with increased left ventricular internal diastolic diameter (P=.004), left atrial diameter (P=.03), left atrial area (four-chamber) (P=.004) and (two-chamber) (P=.03), septal E' (P=.006), and lateral E' (P=.04). Exposure to biomass fuel smoke was also associated with worse global longitudinal strain in the two-chamber view (P=.01). Daily biomass fuel use was associated with increased left ventricular size and decreased left ventricular systolic function by global longitudinal strain.

Left Atrial Volume Assessed by Coronary Computed Tomography in Mid Ventricular Diastasis Predicts Adverse Events

PURPOSE

Previous studies have demonstrated that left atrial (LA) volume has incremental prognostic value in predicting major adverse cardiac events (MACE). However, the predictive ability of LA volume in mid diastasis has not been investigated. We determined the incremental predictive value of LA volume indexed to body surface area (LAVi) measured in mid ventricular diastasis.

MATERIALS AND METHODS

A total of 96 patients with MACE (all-cause mortality and nonfatal myocardial infarction) were matched to 96 controls without adverse events on follow-up. Coronary computed tomographic angiography images were reconstructed at the 75% phase (mid ventricular diastasis). LA volumes were measured and indexed to the body surface area. The predictive value of LAVi was assessed using Cox proportional hazard models for the MACE.

RESULTS

LAVi was significantly larger (P<0.001) in the cases with adverse clinical outcomes (63.8±2.1 mL/m) versus the controls (50.3±1.2 mL/m). In a multivariate analysis, both significant coronary artery disease (defined as >70% stenosis in at least 1 coronary artery) and LAVi emerged as significant predictors of MACE with P-values of 0.0022 and 0.0001, respectively.

CONCLUSIONS

A significantly larger LAVi was associated with MACE. LAVi was an incremental predictor to traditional clinical variables for MACE. The assessment of LAVi may be considered during coronary computed tomographic angiography and could potentially be incorporated into risk stratification and decision-making strategies.

The emerging role of Cardiovascular Magnetic Resonance in the evaluation of hypertensive heart disease

BACKGROUND

Arterial hypertension is the commonest cause of cardiovascular death. It may lead to hypertensive heart disease (HHD), including heart failure (HF), ischemic heart disease (IHD) and left ventricular hypertrophy (LVH).

MAIN BODY

According to the 2007 ESH/ESC guidelines, the recommended imaging technique is echocardiography (echo), when a more sensitive detection of LVH than that provided by ECG, is needed. Cardiovascular Magnetic Resonance (CMR), a non-invasive, non-radiating technique, offers the following advantages, beyond echo: a) more reliable and reproducible measurements of cardiac parameters such as volumes, ejection fraction and cardiac mass b) more accurate differentiation of LVH etiology by providing information about tissue characterisation c) more accurate evaluation of myocardial ischemia, specifically if small vessels disease is present d) technique of choice for diagnosis of renovascular, aortic tree/branches lesions and quantification of aortic valve regurgitation e) technique of choice for treatment evaluation in clinical trials. The superiority of CMR against echocardiography in terms of reproducibility, operator independency, unrestricted field of view and capability of tissue characterization makes the technique ideal for evaluation of heart, quantification of aortic valve regurgitation, aorta and aortic branches.

CONCLUSIONS

CMR has a great potential in early diagnosis, risk stratification and treatment follow up of HHD. However, an international consensus about CMR in HHD, taking under consideration the cost-benefit ratio, expertise and availability, is still warranted.

CHA2DS2-VASc score, left atrial size and atrial fibrillation as stroke risk factors in the Tromsø Study

Objective

CHA₂DS₂-VASc score, left atrial (LA) size and atrial fibrillation (AF) have individually been associated with stroke risk. Our aim was to investigate the predictive ability of combinations of these factors for the odds of incident stroke in a population-based cohort study.

Methods

We followed 2844 participants from the Tromsø Study from 1994 to 2012. Information on LA size and CHA₂DS₂-VASc score (age, sex, congestive heart failure, hypertension, vascular disease, stroke and diabetes) were obtained at baseline. AF status was recorded from medical records. The outcome measure was all strokes. The association between covariates and stroke was investigated by means of multivariate logistic regression analysis.

Results

A total of 325 participants (45% women, mean age at baseline 59.3 years) had a stroke. Incidence rates for stroke were 6.4 in women and 8.4 in men per 1000 person-years. Participants with CHA₂DS₂-VASc ≥1 and LA size <2.8 had ∼4 times (95% CI 2.6 to 5.3) increased odds of stroke, whereas participants with CHA₂DS₂-VASc ≥1 and LA size ≥2.8 had ∼9 times (95% CI 5.3 to 16.4) increased odds of stroke, compared with participants with CHA₂DS₂-VASc score 0, irrespective of AF status. Adjustment for significant covariates had minimal impact on the OR estimates.

Conclusions

Combining CHA₂DS₂-VASc score ≥1 and enlarged LA size identified participants with high odds of stroke regardless of AF status.

Cardiac Function and Diastolic Dysfunction in Behcet's Disease: A Systematic Review and Meta-Analysis

Background. Cardiovascular involvement in Behcet's disease (BD) is reported and has variable manifestations. It is not clear if diastolic dysfunction (DD) is increased in BD. Our objective was to evaluate the existing literature to determine if cardiac dysfunction, particularly DD, was more prevalent in these patients. Methods. A systematic review and meta-analysis of the available studies analyzing the echocardiographic findings in BD was conducted using a random-effects model. Mean differences were used to calculate the effect sizes of the echocardiographic parameters of interest. Results. A total of 22 studies with 1624 subjects were included in the analysis. Patients with BD had statistically significantly larger mean left atrial dimension (0.08, p = 0.0008), greater aortic diameter (0.16, p = 0.02), significantly reduced ejection fraction (−1.08, p < 0.0001), significantly prolonged mitral deceleration time (14.20, p < 0.0001), lower E/A ratio (−0.24, p = 0.05), and increased isovolumetric relaxation time (7.29, p < 0.00001). Conclusion. DD is increased in patients with BD by the presence of several echocardiographic parameters favoring DD as compared to controls. The meta-analysis also identified that LA dimension is increased in BD patients. EF has also been found to be lower in BD patients. Aortic diameter was also increased in BD patients as compared to controls.

Association between diastolic dysfunction and future atrial fibrillation in the Tromsø Study from 1994 to 2010

Objective

To investigate the association between echocardiographic measurements with emphasis on diastolic dysfunction and risk of atrial fibrillation (AF) in a population-based cohort study.

Methods

We followed 2406 participants from the Tromsø Study from 1994 to 2010. Left atrial (LA) size and mitral Doppler indices as measured by echocardiography were used for evaluating diastolic dysfunction. Information concerning age, systolic blood pressure, height, heart rate, body mass index, total and high-density lipoprotein cholesterol, self-reported use of alcohol, smoking, coffee, physical activity, antihypertensive treatment, prevalent coronary heart disease, valvular heart disease, heart failure, hypertrophy, diabetes and palpitations were obtained at baseline. The outcome measure was clinical AF, documented by an ECG.

Results

AF was detected in 462 subjects (193 women). Mean age at baseline was 62.6 years. Incidence rate of clinical AF was 12.6 per 1000 person-years. In multivariable Cox proportional hazards regression analysis, moderately enlarged LA was associated with 60% (95% CI 1.2 to 2.0) increased risk of AF. Severely enlarged LA had HR for AF of 4.2 (95% CI 2.7 to 6.5) with p value for linear trend <0.001, and the association was similar in both sexes. Abnormal mitral Doppler flow adjusted for predictor variables did not show a statistically significant association with AF risk. However, when LA size was also adjusted for, the risk of AF increased by 30% (95% CI 1.0 to 1.6).

Conclusions

Our findings suggest that enlarged LA as a measure for diastolic dysfunction is a significant risk factor for AF in both sexes, and adding measures of abnormal diastolic flow increased the predictive ability significantly.

Elevated left ventricular filling pressure estimated by E/E' ratio after exercise predicts development of new-onset atrial fibrillation independently of left atrial enlargement among elderly patients without obvious myocardial ischemia

OBJECTIVE

To determine whether elevated left ventricular (LV) filling pressure estimated by raised Doppler E velocity to tissue Doppler E' velocity ratio (E/E') after exercise is associated with increased risk of new-onset atrial fibrillation (AF) in non-ischemic elderly patients.

BACKGROUND

Prognostic importance of exercise induced LV diastolic dysfunction remains uncertain.

PATIENTS AND METHODS

We studied 147 elderly patients (73 ± 5 years) who underwent treadmill stress echocardiography. Patients with exercise induced LV wall motion abnormality were not included. Doppler and tissue Doppler measurements were done before treadmill exercise and immediately after the post-stress image acquisition, and E/E' ratio was measured. Raised E/E' was defined as E/E'≥ 15, and left atrial (LA) enlargement was defined as LA volume index ≥ 34 ml/m(2). Using Cox proportional hazards regression analysis, predictor of new-onset AF was determined. Using Kaplan-Meier analysis, we evaluated association between raised post-exercise E/E' or LA enlargement with new-onset AF.

RESULTS

During the follow-up period (median=67 months), there were 25 new-onset AF. Cox proportional hazards regression analysis demonstrated that male gender [hazard ratio (HR) 3.294; p=0.0117], LA enlargement (HR 3.576; p=0.0017), and raised post-exercise E/E' (HR 3147; p=0.0068) were the best predictors of new-onset AF. Kaplan-Meier survival plot demonstrated that patients with both LA enlargement and raised post-exercise E/E' developed new-onset AF most frequently. There was no significant difference in outcome between patients with isolated raised post-exercise E/E' or isolated LA enlargement.

CONCLUSIONS

Raised E/E' ratio after exercise provides significant prognostic information for predicting new-onset AF in non-ischemic elderly patients. This prognostic value of raised post-exercise E/E' is independent of and incremental to the LA enlargement.

Left ventricular diastolic function and long-term outcomes in patients with normal exercise echocardiographic findings

The objective of the present study was to determine whether diastolic dysfunction (DD) is associated with outcomes in the absence of myocardial ischemia. We studied 2,835 patients undergoing exercise echocardiography from January 2006 through December 2006 who had normal systolic function (ejection fraction ≥50%) and an absence of exercise-induced wall motion abnormalities. Diastolic function was graded as normal, mild DD, or moderate to severe DD. Medical records review and patient contact were undertaken to determine mortality, cardiovascular events (i.e., death, myocardial infarction, or stroke), incident heart failure (HF), and hospitalization. The mean ± SD age was 58.9 ± 12.8 years, and 54.0% were women. DD was present in 40.0% of the participants, with mild DD in 28.2% and moderate to severe DD in 11.8%. During a median follow-up of 4.4 years, 81 deaths and 114 cardiovascular events occurred, and DD was associated with greater rates of mortality, cardiovascular events, and HF events or hospitalizations (all p <0.001). On multivariate analysis, mild or moderate to severe DD (referent, normal function) was associated with HF or hospitalization (hazard ratio 1.45, 95% confidence interval 1.18 to 1.78, p <0.001 for mild DD; hazard ratio 1.75, 95% confidence interval 1.37 to 2.24, p <0.001 for moderate to severe DD) but was not independently associated with death or cardiovascular events. The diastolic index of filling pressure (E/e') was independently associated with mortality, cardiovascular events, and HF or hospitalization. In conclusion, among patients without demonstrable myocardial ischemia, left ventricular DD was associated with greater event rates during long-term follow up but did not independently predict hard end points other than HF or hospitalization. E/e' was independently associated with the clinical outcomes and might be an important echocardiographically derived parameter to identify in patients undergoing exercise echocardiography.

Real-time 3D echocardiographic quantification of left atrial volume: multicenter study for validation with CMR

OBJECTIVES

We studied in a multicenter setting the accuracy and reproducibility of 3-dimensional echocardiography (3DE)-derived measurements of left atrial volume (LAV) using new, dedicated volumetric software, side by side with 2-dimensional echocardiography (2DE), using cardiac magnetic resonance (CMR) imaging as a reference.

BACKGROUND

Increased LAV is associated with adverse cardiovascular outcomes. Although LAV measurements are routinely performed using 2DE, this methodology is limited because it is view dependent and relies on geometric assumptions regarding left atrial shape. Real-time 3DE is free of these limitations and accordingly is an attractive alternative for the evaluation of LAV. However, few studies have validated 3DE-derived LAV measurements against an accepted independent reference standard, such as CMR imaging.

METHODS

We studied 92 patients with a wide range of LAV who underwent CMR (1.5-T) and echocardiographic imaging on the same day. Images were analyzed to obtain maximal and minimal LAV: CMR images using standard commercial tools, 2DE images using a biplane area-length technique, and 3DE images using Tomtec LA Function software. Intertechnique comparisons included linear regression and Bland-Altman analyses. Reproducibility of all 3 techniques was assessed by calculating the percentage of absolute differences in blinded repeated measurements. Kappa statistics were used to compare 2DE and 3DE classification of normal/enlarged against the CMR reference.

RESULTS

3DE-derived LAV values showed higher correlation with CMR than 2DE measurements (r = 0.93 vs. r = 0.74 for maximal LAV; r = 0.88 vs. r = 0.82 for minimal LAV). Although 2DE underestimated maximal LAV by 31 ± 25 ml and minimal LAV by 16 ± 32 ml, 3DE resulted in a minimal bias of -1 ± 14 ml for maximal LAV and 0 ± 21 ml for minimal LAV. Interobserver and intraobserver variability of 2DE and 3DE measurements of maximal LAV were similar (7% to 12%) and approximately 2 times higher than CMR (4% to 5%). 3DE classified enlarged atria more accurately than 2DE (kappa: 0.88 vs. 0.71).

CONCLUSIONS

Compared with CMR reference, 3DE-derived LAV measurements are more accurate than 2DE-based analysis, resulting in fewer patients with undetected atrial enlargement.

A transoesophageal echocardiographic image acquisition protocol for wide-view fusion of three-dimensional datasets to support atrial fibrillation catheter ablation

PURPOSE

The aim of this paper is to propose a transoesophageal echocardiography (TOE) image acquisition protocol which provides a systematic manner of acquiring a minimal number of overlapping 3D TOE datasets allowing the reconstruction of a wide 3D view of the left atrium (LA) with anatomical landmarks that are important for atrial fibrillation catheter ablation.

METHODS

In eight cardiac surgical patients, 3D TOE datasets were acquired with a six-step protocol. In the protocol, step 1 aims to acquire the central view of the mitral valve (MV), aortic valve (AV) and left atrial appendage (LAA). Step 2 was developed to acquire the left pulmonary veins (PVs) and step 3 to acquire the right PVs. Steps 4, 5 and 6 were developed to create a sufficient overlap between different datasets. 3D TOE datasets were registered and fused manually in end diastole.

RESULTS

The image acquisition protocol was feasible in all patients. In the fused 3D dataset, a wide 3D view of the LA is shown, and left and right PVs could be seen simultaneously. The LAA, MV, AV and fossa ovalis (FO) were visualised clearly in the 3D TOE datasets. The PV ostia, which are located at the edges of the 3D datasets, suffered more from the artefact of echo loss. The volume overlaps between neighbouring TOE datasets were 50-75 %.

CONCLUSION

The major part of the LA anatomy incorporating the PVs, LAA, MV, AV and FO as important anatomical landmarks can be reconstructed by registering and fusing 3D datasets acquired with the six-step TOE image acquisition protocol.

Cardiovascular magnetic resonance in systemic hypertension

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension.

Left atrial volume by echocardiography in patients with false positive myocardial perfusion scans

A stress-induced myocardial perfusion abnormality (MPS), in the absence of angiographically significant epicardial coronary artery disease, is considered a "false-positive" test result. We hypothesized that echocardiography would provide complementary prognostic and pathophysiologic data relevant to the management of patients with MPS and normal coronary angiograms. Accordingly, left atrial volume index (LAVi) was assessed by echocardiography in 38 patients with false positive MPS as defined by normal coronary angiograms and 26 patients with true negative MPS from a total of 1,356 patients stressed from July 2006-May 2008. Pathologically abnormal elevation of LAVi (≥ 32 mL/m(2)) was observed in 16 of 19 women (84%) and 11 of 19 men (58%) in the false positive MPS (FPMPS) group while none of the patients in the true negative MPS (TNMPS) group had elevated LAVi. In the FPMPS group mean LAVi was significantly higher in women than men (40.64 ± 11.4 mL/m(2) versus 32.6 ± 10.5 mL/m(2), P = 0.01). The mean LAVi in the FPMPS group was significantly different from the TNMPS group (36.6 ± 11.6 versus 21 ± 7 mL/m(2), P = 0.000). A stepwise logistic regression determined BSA, LAV and LAVi as useful in predicting false positive and true negative MPS. All three were significant predictors (P < 0.01) and the area under the ROC curve was 0.91. Our findings in this relatively small cohort suggest that patients with false positive MPS have a greater increased LAVi.

Cardiothoracic ratio from postero-anterior chest radiographs: a simple, reproducible and independent marker of disease severity and outcome in adults with congenital heart disease

OBJECTIVE

The wide spectrum of intracardiac anatomy and reparative surgery available for adults with congenital heart disease (ACHD) makes uniform measurement of cardiac size and disease severity challenging. The aim of this study was to assess the prognostic potential of cardiothoracic ratio, a simple marker of cardiomegaly, in a large cohort of ACHD.

PATIENTS AND SETTING

Chest radiographs from 3033 ACHD patients attending our institution between 1998 and 2007 and 113 normal controls of similar age were analyzed blindly.

DESIGN

Cardiothoracic ratio derived from plain postero-anterior chest radiographs, was compared between ACHD patients and controls, different diagnostic subgroups and different functional classes. Relationship between cardiothoracic ratio and survival was assessed using Cox regression.

RESULTS

Average cardiothoracic ratio in ACHD was 52.0±7.6% (over 50% in 56.4%), significantly higher in all ACHD diagnostic subgroups compared to controls (42.3±4.0%, p<0.0001) and highest in the "complex" cardiac anatomy, Ebstein's anomaly and Eisenmenger subgroups. Cardiothoracic ratio related to functional class, but was high even in asymptomatic patients. During a median follow-up of 4.2years, 164 patients died. Patients with a cardiothoracic ratio >55% had an 8-fold increased risk of death compared to those in the lowest tertile (<48%). Even patients with mildly increased cardiothoracic ratio (48-55%) had an adjusted 3.6-fold increased mortality compared to the lowest tertile.

CONCLUSIONS

Cardiothoracic ratio derived from postero-anterior chest radiographs is a simple, and reproducible marker, which relates to functional class and predicts independently mortality risk in ACHD patients.

Left atrial dimension and risk of stroke in women without atrial fibrillation: the Chin-Shan Community Cardiovascular Cohort study

BACKGROUND

Evidence on the relationship between left atrial dimension and cardiovascular events is inconclusive. We explored the association between left atrial dimension and stroke and all-cause death in an ethnic Chinese population.

METHODS

We recruited 1,937 subjects undertaking echocardiographic examination without prior atrial fibrillation/stroke in the Chin-Shan Community Cardiovascular Cohort study. Left atrial dimension indexed by body mass index was used as left atrial dimension index (LADI) for analysis. The end points were stroke and all-cause death. A multivariate Cox regression analysis was used to estimate the relative risks between participants stratified by tertile of LADI within each gender.

RESULTS

During a median follow-up of 11.9 years, 21,733 person-years were accrued and 114 subjects with stroke and 364 all-cause deaths were identified. The adjusted relative risk of stroke was 2.44 (95% CI, 1.11 to 5.36, P for trend = 0.029) among women in the upper tertile of LADI compared with women in the lower tertile of LADI. Further adjusting for left ventricular mass index attenuated the relationship of LADI to stroke (adjusted relative risk 2.11, 95% CI, 0.88 to 5.02, P for trend = 0.09). In men, tertile of LADI was not associated with stroke. LADI was not associated with risk of all-cause death in both genders.

CONCLUSIONS

We found an association between increased LADI and incident stroke in women but not in men in this ethnic Chinese population. LADI was not associated with all-cause death in both genders.

Left atrial size and risk for all-cause mortality and ischemic stroke

BACKGROUND

Limited data are available on the relation between left atrial size and outcome among patients referred for clinically indicated echocardiograms. Our aim was to assess the association of left atrial size with all-cause mortality and ischemic stroke in a large cohort of patients referred for echocardiography.

METHODS

Left atrial diameter was measured in 52 639 patients aged 18 years or older (mean age 61.8 [standard deviation (SD) 16.3] years; 52.9% men) who underwent a first transthoracic echocardiogram for clinical reasons at our institution between April 1990 and March 2008. The outcomes were all-cause mortality and nonfatal ischemic stroke.

RESULTS

Based on the criteria of the American Society of Echocardiography, 50.4% of the patients had no left atrial enlargement, whereas 24.5% had mild, 13.3% had moderate and 11.7% had severe left atrial enlargement. Over a mean follow-up period of 5.5 (SD 4.1) years, 12 527 patients died, and 2314 patients had a nonfatal ischemic stroke. Cumulative 10-year survival was 73.7% among patients with normal left atrial size, 62.5% among those with mild enlargement, 54.8% among those with moderate enlargement and 45% among those with severe enlargement (p < 0.001). After adjustment in multivariable Cox proportional hazard analysis, left atrial diameter remained a predictor of all-cause mortality in both sexes (hazard ratio [HR] per 1-cm increment in left atrial size 1.17, 95% confidence interval [CI] 1.12-1.22, p < 0.001 in women, and HR 1.09, 95% CI 1.05-1.13, p < 0.001 in men) and of ischemic stroke in women (HR 1.25, 95% CI 1.14-1.37, p < 0.001).

INTERPRETATION

Left atrial diameter has a graded and independent association with all-cause mortality in both sexes and with ischemic stroke in women.

Left atrial volume and index by multi-detector computed tomography: comprehensive analysis from predictors of enlargement to predictive value for acute coronary syndrome (ROMICAT study)

OBJECTIVES

We aimed to identify the predictors of left atrial (LA) enlargement by multi-detector computed tomography (CT) and determine its association and predictive value for acute coronary syndrome (ACS).

BACKGROUND

LA enlargement is associated with myocardial ischemia and coronary artery disease (CAD) and is a strong predictor for cardiovascular events. These studies were performed primarily with echocardiography. With the rise of cardiac CT, LA volume can be readily measured.

METHODS

In 377 emergency department patients with chest pain, we performed 64-slice CT for coronary artery assessment. We derived LA volumes (LAV(max), LAV(min)) and indices (LAVI(max), LAVI(min)) using a threshold-based volumetric method.

RESULTS

Subjects, with cardiac risk factors or CAD by CT, had larger LA (ΔLAV(max) 9.1 ml, p=0.004; ΔLAV(min) 8.1 ml, p=0.001; ΔLAVI(max) 3.3 ml/m(2), p=0.03; ΔLAVI(min) 3.4 ml/m(2), p=0.006) than controls. Predictors of LA enlargement were related to risk factors for diastolic dysfunction. ACS risk was greater in patients with top quartile LAV(max) (odds ratio [OR] 3.4, p=0.02) and LAV(min) (OR 4.7, p=0.01) than lowest quartile, but not when indexed. Similarly, the predictive values of LA volumes were incrementally better when added to CT finding of indeterminate stenosis (LAV(max): C statistic 0.62 to 0.70, p=0.046; LAV(min): C statistic 0.65 to 0.73, p=0.008), but not when indexed.

CONCLUSIONS

Risk factors related to diastolic dysfunction are independent predictors of LA enlargement. LA enlargement by volumes are associated with a 3-5 fold increase risk for ACS and have incremental value for predicting ACS when added to the CT finding of indeterminate stenosis.

The changing paradigm of stress echocardiography: risk stratification, prognosis, and future directions

The use of stress echocardiography has undergone considerable evolution in the past 3 decades. Although stress echocardiography was first introduced as a noninvasive diagnostic tool for determining the presence or absence of coronary artery disease (CAD), it later served a prognostic role as well. The importance of stress echocardiography in risk stratification and prognosis is substantially undervalued by clinicians. The identification of patients at risk for future cardiac events has become a primary objective in noninvasive evaluation of patients with suspected or known CAD. In particular, the ability of stress echocardiography to identify patients at low (< 1%), intermediate (1%-5%), or high (> 5%) risk for future cardiac events is essential to decision making in patient management. Moreover, previous studies have conclusively demonstrated the incremental prognostic value of stress echocardiography over clinical and treadmill exercise data in predicting future cardiac events. This article presents a primarily single-center experience of retrospective and observational studies that address the current role of stress echocardiography and summarize its use for risk stratification, prognosis, and determining clinical outcomes, as well as cost-effective integration of such information in patient management decision making.

Prognostic value of left atrial volume in patients who underwent dobutamine stress echocardiography for known or suspected coronary artery disease

BACKGROUND

Left atrial volume indexed (LAVI) has been reported as a predictor of cardiovascular events. We sought to determine the prognostic value of LAVI for predicting the outcome of patients who underwent dobutamine stress echocardiography (DSE) for known or suspected coronary artery disease (CAD).

METHODS

From January 2000 to July 2005, we studied 981 patients who underwent DSE and off-line measurements of LAVI. The value of DSE over clinical and LAVI data was examined using a stepwise log-rank test.

RESULTS

During a median follow-up of 24 months, 56 (6%) events occurred. By univariate analysis, predictors of events were male sex, diabetes mellitus, previous myocardial infarction, left ventricular ejection fraction (LVEF), left atrial diameter indexed, LAVI, and abnormal DSE. By multivariate analysis, independent predictors were LVEF (relative risk [RR] = 0.98, 95% CI 0.95-1.00), LAVI (RR = 1.04, 95% CI 1.02-1.05), and abnormal DSE (RR = 2.70, 95% CI 1.28-5.69). In an incremental multivariate model, LAVI was additional to clinical data for predicting events (chi(2) 36.8, P < .001). The addition of DSE to clinical and LAVI yielded incremental information (chi(2) 55.3, P < .001). The 3-year event-free survival in patients with normal DSE and LAVI < or =33 mL/m(2) was 96%; with abnormal DSE and LAVI < or =33 mL/m(2), 91%; with normal DSE and LAVI >34 mL/m(2), 83%; and with abnormal DSE and LAVI >34 mL/m(2), 51%.

CONCLUSION

Left atrial volume indexed provides independent prognostic information in patients who underwent DSE for known or suspected CAD. Among patients with normal DSE, those with larger LAVI had worse outcome, and among patients with abnormal DSE, LAVI was still predictive.