Left atrial structure and function and clinical outcomes in the general population

Shortness of breath in clinical practice: A case for left atrial function and exercise stress testing for a comprehensive diastolic heart failure workup

The symptom cluster of shortness of breath (SOB) contributes significantly to the outpatient workload of cardiology services. The workup of these patients includes blood chemistry and biomarkers, imaging and functional testing of the heart and lungs. A diagnosis of diastolic heart failure is inferred through the exclusion of systolic abnormalities, a normal pulmonary function test and normal hemoglobin, coupled with diastolic abnormalities on echocardiography. Differentiating confounders such as obesity or deconditioning in a patient with diastolic abnormalities is difficult. While the most recent guidelines provide more avenues for diagnosis, such as incorporating the left atrial size, little emphasis is given to understanding left atrial function, which contributes to at least 25% of diastolic left ventricular filling; additionally, exercise stress testing to elicit symptoms and test the dynamics of diastolic parameters, especially when access to the "gold standard" invasive tests is lacking, presents clinical translational gaps. It is thus important in diastolic heart failure work up to understand left atrial mechanics and the role of exercise testing to build a comprehensive argument for the diagnosis of diastolic heart failure in a patient presenting with SOB.

Longitudinal association of short-term, metronome-paced heart rate variability and echocardiographically assessed cardiac structure at a 4-year follow-up: results from the prospective, population-based CARLA cohort

Aims

To assess the value of cardiac structure/function in predicting heart rate variability (HRV) and the possibly predictive value of HRV on cardiac parameters.

Methods and results

Baseline and 4-year follow-up data from the population-based CARLA cohort were used (790 men, 646 women, aged 45-83 years at baseline and 50-87 years at follow-up). Echocardiographic and HRV recordings were performed at baseline and at follow-up. Linear regression models with a quadratic term were used. Crude and covariate adjusted estimates were calculated. Missing values were imputed by means of multiple imputation. Heart rate variability measures taken into account consisted of linear time and frequency domain [standard deviation of normal-to-normal intervals (SDNN), high-frequency power (HF), low-frequency power (LF), LF/HF ratio] and non-linear measures [detrended fluctuation analysis (DFA1), SD1, SD2, SD1/SD2 ratio]. Echocardiographic parameters considered were ventricular mass index, diastolic interventricular septum thickness, left ventricular diastolic dimension, left atrial dimension systolic (LADS), and ejection fraction (Teichholz). A negative quadratic relation between baseline LADS and change in SDNN and HF was observed. The maximum HF and SDNN change (an increase of roughly 0.02%) was predicted at LADS of 3.72 and 3.57 cm, respectively, while the majority of subjects experienced a decrease in HRV. There was no association between further echocardiographic parameters and change in HRV, and there was no evidence of a predictive value of HRV in the prediction of changes in cardiac structure.

Conclusion

In the general population, LADS predicts 4-year alteration in SDNN and HF non-linearly. Because of the novelty of the result, analyses should be replicated in other populations.

Left atrial function and mortality in the oldest old

BACKGROUND

Previous studies demonstrated that left atrium (LA) size is associated with mortality in an elderly population. It remains unclear whether indices of LA function including reservoir, conduit, or booster elements of LA function provide incremental prognostic information.

HYPOTHESIS

Echocardiographic measures of the various parameters of LA function would predict 5-year mortality in a community-dwelling population of 85 to 86 year olds independently of LA volume.

METHODS

Subjects ages 85 to 86 years old underwent home echocardiography. LA volumes were assessed by the biplane Simpson's method from apical views using measurements of phasic volumes and functions of the LA, including LA expansion index. LA passive and active emptying fractions were assessed. Survival status at 5-year follow-up was assessed.

RESULTS

Two hundred eighty-two subjects were included, of whom 87 (31%) had died at follow-up. Survival of the subjects in the lowest quartile of the LA expansion index as well as LA active filling index was significantly lower. When measurements of LA volume index were added to the model, the relationship between survival and indices of LA function remained significant.

CONCLUSIONS

This study demonstrated that elderly subjects aged 85 to 86 years with significantly impaired LA function had increased 5-year mortality independently of indices of LA volume.

High sensitivity troponin T and I reflect left atrial function being assessed by cardiac magnetic resonance imaging

Background

Left atrial function (LAF) plays an interactive role between pulmonary and systemic circulation. Cardiac biomarkers, such as amino-terminal pro-brain natriuretic peptide (NT-proBNP) and troponins, might reflect cardiac function. This study aims to evaluate the association between high sensitivity troponins (hsTn) and left atrial function in patients undergoing cardiac magnetic resonance imaging (cMRI).

Methods

Patients undergoing cardiac magnetic resonance imaging (cMRI) were enrolled prospectively. Patients with right ventricular dysfunction (<50%) were excluded. Blood samples for measurements of hsTn and NT-proBNP were collected at the time of cMRI.

Results

Eighty-four patients were included. Median LVEF was 59% (IQR 51–64%). HsTn correlated inversely with LAF within multivariable linear regression models (hsTnI: Beta −0.46; T −4.44; P = 0.0001; hsTnT: Beta −0.29; T −3.06; P = 0.003). High sensitivity troponins increased significantly according to decreasing stages of impaired LAF ( P = 0.0001). High sensitivity troponins discriminated patients with impaired LAF < 55% (hsTnT: AUC = 0.80; P = 0.0001; hsTnI: AUC = 0.74; P = 0.0001) and <45% (hsTnT: AUC = 0.75; P = 0.0001; hsTnI: AUC = 0.73; P = 0.001) and were still significantly associated in multivariable logistic regression models (LAF < 55%: hsTnT: OR = 21.78; P = 0.0001; hsTnI: OR = 5.96; P = 0.009; LAF < 45%: hsTnT: OR = 10.27; P = 0.0001; hsTnI: OR = 12.56; P = 0.001).

Conclusions

This study demonstrates that hsTn are able to reflect LAF being assessed by cardiac magnetic resonance imaging.

Clinical and Echocardiographic Correlates of Left Atrial Function Index: The Framingham Offspring Study

BACKGROUND

Left atrial (LA) remodeling is a predictor of cardiovascular disease (CVD). We performed measurement of the LA function index (LAFI), a composite measure of LA structure and function, in a community-based cohort and here report the distribution and cross-sectional correlates of LAFI.

METHODS

In 1,719 Framingham Offspring Study participants (54% women, mean age 66 ± 9 years), we derived LAFI from the LA emptying fraction, left ventricular (LV) outflow tract velocity time integral, and indexed maximal LA volume. We used multivariable linear regression to assess the clinical and echocardiographic correlates of LAFI adjusting for age, sex, anthropometric measurements, and CVD risk factors.

RESULTS

The average LAFI was 35.2 ± 12.1. Overall, LAFI declined with advancing age (β = -0.27, P < .001). LAFI was significantly higher (37.5 ± 11.6) in a subgroup of participants free of CVD and CVD risk factors compared with those with either of these conditions (34.5 ± 12.2). In multivariable models, LAFI was inversely related to antihypertensive use (β = -1.26, P = .038), prevalent atrial fibrillation (β = -4.46, P = .001), heart failure (β = -5.86, P = .008), and coronary artery disease (β = -2.01, P = .046). In models adjusting for echocardiographic variables, LAFI was directly related to LV ejection fraction (β = 14.84, P < .001) and inversely related to LV volume (β = -7.03, P < .001).

CONCLUSIONS

LAFI was inversely associated with antihypertensive use and prevalent CVD and was related to established echocardiographic traits of LV remodeling. Our results offer normative ranges for LAFI in a white community-based sample and suggest that LAFI represents a marker of pathological atrial remodeling.

Left atrial phasic function and heart rate variability in patients with systemic sclerosis: A new part of the old puzzle

OBJECTIVE

We aimed to research left atrial (LA) phasic function and heart rate variability (HRV), as well as their relationship, in subjects with uncomplicated systemic sclerosis (SSc).

METHODS

The investigation involved 44 SSc patients and 33 age-matched healthy controls. All participants underwent clinical examination, serological tests, 24-hours Holter monitoring, and echocardiographic examination including strain analysis.

RESULTS

Maximum, minimum, and pre-A LA volumes and volume indices were higher in the SSc patients than in the controls. The total emptying fraction, the parameter of the LA reservoir function, as well as passive LA emptying fraction, which represents the LA conduit function, were significantly lower in the SSc patients compared to the controls. Active LA emptying fraction, the parameter of the LA booster pump function, was significantly higher in the SSc participants. There was no difference in LA reservoir function between the diffuse and the limited SSc form. LA conduit function was significantly decreased, whereas LA booster pump function was compensatory increased in the diffuse SSc form compared to the limited SSc form. Similar results were obtained by LA strain analysis. HRV indices were significantly decreased in the SSc patients. Modified Rodnan skin score, the parameter of skin involvement in SSc, and HRV indices correlated well with LA phasic function in SSc.

CONCLUSION

Left atrial (LA) phasic function, assessed by both volumetric and strain method, as well as cardiac autonomic nervous function is significantly deteriorated in SSc patients. Skin score and HRV indices correlate with LA phasic function parameters.

The relationship between nighttime hypertension and left atrial function

The authors sought to investigate the association between different hypertensive phenotypes and left atrial (LA) function assessed by the volumetric method and the strain method in patients with untreated hypertension. This cross-sectional study involved 236 untreated patients who underwent 24-hour ambulatory blood pressure monitoring and two-dimensional echocardiographic examination. Our findings showed that LA function gradually deteriorated from patients with normotension, across patients with daytime hypertension, to patients with night- and day-nighttime hypertension. LA reservoir and conduit functions were particularly deteriorated in patients with nighttime and day-nighttime hypertension compared with patients with normotension and patients with daytime hypertension, whereas LA pump function was compensatorily increased only in the participants with day-nighttime hypertension. Only nighttime hypertension and day-nighttime hypertension were independently associated with the reduced reservoir and conduit LA function. The difference between patients with daytime and nighttime hypertension was found in reservoir and conduit LA but not LA pump function.

Left atrium passive ejection fraction is the most sensitive index of type 2 diabetes mellitus-related cardiac changes

The aims of this study were to use cardiovascular magnetic resonance (CMR) cine to assess left atrium (LA) and left ventricle (LV) function and structure in normotensive type 2 diabetes mellitus (T2DM) patients and to identify the most sensitive index of those T2DM-related cardiac changes. Fifty T2DM patients with normotension (25 males, age 54.7 ± 8.7 years, duration of diabetes: 7.5 ± 5.1 years) and 35 controls (16 males, age: 52.2 ± 13.2 years) were prospectively enrolled. All patients were scanned using CMR four- and two-chamber long-axis cine to assess LA and LV structure and function. Normotensive T2DM patients were associated with decreased LA total ejection fraction (EF), passive EF and LV end diastolic volume, normal LA active EF and LV myocardial mass and increased LV mass/volume (M/V). LA total EF and passive EF correlated with body mass index, duration of diabetes and M/V. To differentiate between diabetic patients and healthy controls, area under the receiver operating characteristic (ROC) curve (AUC) values were calculated to be 0.763, 0.706, 0.647 and 0.649 for LA passive EF, total EF, LVEDV and M/V, respectively. The addition of LA total EF, LVEDV, M/V and the combination thereof did not significantly improve AUC values in a model containing LA passive EF. Normotensive T2DM patients were associated with LA decreased total ejection fraction, decreased passive EF and LV concentric remodeling. Among these indices, LA passive EF was the most sensitive to T2DM-related LA function changes.

Usefulness of Left Atrial Emptying Fraction to Predict Ventricular Arrhythmias in Patients With Implantable Cardioverter Defibrillators

Impaired left atrial emptying fraction (LAEF) is an important predictor of mortality in patients with heart failure. As it may reflect increased LV wall stress, it might predict ventricular arrhythmia (VA) specifically. This study evaluated the predictive value of LAEF assessed with cardiovascular magnetic resonance (CMR) imaging with respect to appropriate device therapy (ADT) for VA and compared its role with CMR assessed scar size and other risk factors. In total, 229 patients (68% male, 63 ± 10 years, 61% ischemic cardiomyopathy) with LV ejection fraction ≤35% who underwent CMR and implantable cardioverter defibrillator (ICD) implantation for primary prevention in 2005 to 2012 were included. CMR was used to quantify LV volumes and function. LV scar size was quantified when late gadolinium enhancement was available (n = 166). Maximum and minimum left atrial volumes and LAEF were calculated using the biplane area-length method. The occurrence of ADT and mortality was assessed during a median follow-up of 3.9 years. Sixty-two patients (27%) received ADT. Univariable Cox analysis showed that male gender, creatinine level, minimum left atrial volume, LAEF, and total scar size were significant predictors of ADT. In multivariable Cox analysis, LAEF (hazard ratio 0.75 per 10%, p <0.01), and scar size (hazard ratio 1.03 per g, p = 0.03) remained the only independent predictors of ADT. Patients with both LAEF > median and scar size < median were at low risk (13% ADT at 5 years), whereas those with LAEF < median and scar size > median experienced 40% ADT at 5 years (log-rank p = 0.01). In conclusion, LAEF independently predicts ADT in patients with primary prevention ICDs. Combined assessment of LAEF and scar size identifies a group with low risk of ADT. Therefore, LAEF assessment could assist in risk stratification for VA to select patients with the highest benefit from ICD implantation.

Reference value of left and right atrial size and phasic function by SSFP CMR at 3.0 T in healthy Chinese adults

The size and function of the left atrium (LA) and right atrium (RA) are related closely with the prognosis of cardiovascular diseases. However, their normal reference values, as measured by cardiac magnetic resonance (CMR), are not well established in Chinese populations. Healthy Chinese subjects (n = 135, 66 males, age 23–83 years) without cardiovascular risk factors were recruited. We imaged the LA and RA of all subjects using short axis and long axis slices by steady-state free precession (SSFP) sequences using a 3.0T scanner. The size and functional parameters were measured. Age and gender differences in LA were further explored. The normal reference values of atrial dimensions, volumes, and empty fractions (EFs) were provided by short axis (SAX) and area-length methods. Volumes and EFs derived by the area-length method showed correlated well with those derived by the by SAX method, but significantly underestimated the volumes (all P < 0.001) and overestimated the LA EFs (all P < 0.001). Atrial dimensions and volumes were generally larger in males. Conduit EFs and total EFs showed gender differences. Most atrial parameters correlated with age. In general, our results showed that gender and age have considerable impact on LA and RA size and function.

Impact of Left Ventricular Diastolic Property on Left Atrial Function from Simultaneous Left Atrial and Ventricular Three-Dimensional Echocardiographic Volume Measurement

Simultaneous left atrial (LA) and left ventricular (LV) 3-dimensional (3D) echocardiographic volume measurements enable the quantifying of precise LA function, by virtue of their independence on any geometric assumption and capability of measurement for net LA conduit volume. We sought to elucidate the impact of conventional Doppler LV diastolic property on LA volume and function derived from this method. Our study subjects consisted of 381 patients who underwent 3D echocardiography. From LA time-volume curve, maximum and minimum volume index (VI) and VI before atrial contraction (LAVIpre-c) were determined; subsequently, active emptying volume was calculated as LAVIpre-c - minimum LAVI. From LA and LV volume measurement, conduit volume was calculated as LV stroke VI - (maximum LAVI - minimum LAVI). LA volume increased depending on the severity of diastolic dysfunction. Compared with patients with normal diastolic function, LA booster pump function, as the contribution of active emptying volume to LV filling, was higher in those with mild diastolic dysfunction. Additionally, it gradually decreased as diastolic dysfunction was advanced from mild to moderate and moderate to severe degree (23.2 ± 15.5%, 29.5 ± 15.1%, 25.1 ± 16.2%, 14.9 ± 14.1%, respectively; p <0.001). Contrarily, conduit contribution was significantly higher in patients with severe diastolic dysfunction than in those with mild diastolic dysfunction; furthermore, conduit function tended to increase, reciprocally to booster pump function, as diastolic dysfunction grade was advanced (39.1 ± 28.8%, 36.8 ± 26.2%, 42.7 ± 25.6%, 52.9 ± 26.2%, respectively; p = 0.034). In conclusion, simultaneous LA and LV volumetric analyses through 3D echocardiography clearly demonstrate the characteristic LA functional alterations following LA dilation caused by LV diastolic dysfunction.

Factors Associated With Left Atrial Remodeling in the General Population

BACKGROUND

Although contributors to remodeling of the left ventricle (LV) have been well studied in general population cohorts, few data are available describing factors influencing changes in left atrial (LA) structure.

METHODS AND RESULTS

Maximum LA volume was determined by cardiac magnetic resonance imaging among 748 participants in the Dallas Heart Study at 2 visits a mean of 8 years apart. Associations of changes in LA volume (ΔLAV) with traditional risk factors, biomarkers, LV geometry, and remodeling by cardiac magnetic resonance imaging and detailed measurements of global and regional adiposity (by magnetic resonance imaging and dual-energy x ray absorptiometry) were assessed using multivariable linear regression. Greater ΔLAV was independently associated with black and Hispanic race/ethnicity, change in systolic blood pressure, LV mass and ΔLV mass, N-terminal probrain natriuretic peptide and change in N-terminal probrain natriuretic peptide, and body mass index (P<0.05 for each). In subanalyses, the associations of ΔLAV with LV mass parameters were driven by associations with baseline and ΔLV end diastolic volume (P<0.0001 for each) and not wall thickness (P=0.21). Associations of ΔLAV with body mass index were explained exclusively by associations with visceral fat mass (P=0.002), with no association seen between ΔLAV and subcutaneous abdominal fat (P=0.47) or lower body fat (P=0.30).

CONCLUSIONS

Left atrial dilatation in the population is more common in black and Hispanic than in white individuals and is associated with parallel changes in the LV. LA dilatation may be mediated by blood pressure control and the development of visceral adiposity.

Left atrial phasic function and heart rate variability in asymptomatic diabetic patients

AIMS

We evaluated left atrial (LA) phasic function and heart rate variability (HRV) in asymptomatic diabetic patients, and the relationship between HRV indices and LA phasic function assessed by volumes and speckle tracking imaging.

METHOD

This cross-sectional study included 55 asymptomatic patients with type 2 diabetes and 50 healthy controls without cardiovascular risk factors. All study subjects underwent laboratory analyses, complete two-dimensional echocardiography examination (2DE) and 24-h Holter monitoring.

RESULTS

Maximum, minimum LA and pre-A LA volumes and volume indexes are significantly higher in diabetic patients. Total and passive LA emptying fractions (EF), representing the LA reservoir and conduit function, are significantly lower in diabetic subjects. Active LA EF, the parameter of the LA booster pump function, is compensatory increased in diabetic patients. Similar results were obtained by 2DE strain analysis. Cardiac autonomic function, assessed by HRV, is significantly deteriorated in diabetic patients. Time and frequency-domain HRV measures are significantly lower in diabetic subjects than in controls. HbA1c, LV mass index and HRV are associated with total LA EF and longitudinal LA strain independently of age, body mass index and LV diastolic function in the whole study population.

CONCLUSIONS

LA phasic function and cardiac autonomic nervous system assessed by HRV are impacted by diabetes. HbA1c and HRV are independently associated with LA reservoir function evaluated by volumetric and strain methods in the whole study population. This study emphasizes the importance of determination of LA function and HRV as important markers of preclinical cardiac damage and autonomic function impairment in diabetic patients.

Beta-Blocker Use Is Associated With Impaired Left Atrial Function in Hypertension

Background

Impaired left atrial (LA) mechanical function is present in hypertension and likely contributes to various complications, including atrial arrhythmias, stroke, and heart failure. Various antihypertensive drug classes exert differential effects on central hemodynamics and left ventricular function. However, little is known about their effects on LA function.

Methods and Results

We studied 212 subjects with hypertension and without heart failure or atrial fibrillation. LA strain was measured from cine steady‐state free‐precession cardiac MRI images using feature‐tracking algorithms. In multivariable models adjusted for age, sex, race, body mass index, blood pressure, diabetes mellitus, LA volume, left ventricular mass, and left ventricular ejection fraction, beta‐blocker use was associated with a lower total longitudinal strain (standardized β=−0.21; P=0.008), and lower LA expansion index (standardized β=−0.30; P<0.001), indicating impaired LA reservoir function. Beta‐blocker use was also associated with a lower positive strain (standardized β=−0.19; P=0.012) and early diastolic strain rate (standardized β=0.15; P=0.039), indicating impaired LA conduit function. Finally, beta‐blocker use was associated with a lower (less negative) late‐diastolic strain (standardized β=0.15; P=0.049), strain rate (standardized β=0.18; P=0.019), and a lower active LA emptying fraction (standardized β=−0.27; P<0.001), indicating impaired booster pump function. Use of other antihypertensive agents was not associated with LA function.

Conclusions

Beta‐blocker use is significantly associated with impaired LA function in hypertension. This association could underlie the increased risk of atrial fibrillation and stroke seen with the use of beta‐blockers (as opposed to other antihypertensive agents) demonstrated in recent trials.

Predictors of Exercise-Induced Pulmonary Hypertension in Patients with Asymptomatic Degenerative Mitral Regurgitation: Mechanistic Insights from 2D Speckle-Tracking Echocardiography

Presence of exercise-induced pulmonary hypertension (EIPH) in asymptomatic degenerative mitral regurgitation (DMR) determines prognosis. This study aimed to elucidate the mechanism and predictors of EIPH in asymptomatic DMR. Ninety-one consecutive asymptomatic patients with DMR who underwent exercise stress echocardiography were prospectively included. We obtained various conventional echocardiographic parameters at rest and during peak exercise, as well as left atrial (LA) function at rest using 2-dimensional speckle-tracking analysis. The 25 patients (33.3%) with EIPH were significantly older and had a greater ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity during peak exercise than those without EIPH. LA strain (LAS)-s and LAS-e, indices of LA reservoir and conduit function, respectively, were significantly lower in those with EIPH than in those without EIPH. Multivariate analysis indicated that LAS-s was the only resting echocardiographic parameter that independently predicted EIPH, with a cut-off value of 26.9%. Furthermore, Kaplan-Meier curve analysis showed that symptom-free survival was markedly lower among those with reduced LAS-s. In conclusion, decreased LA reservoir function contributes to EIPH, and LAS-s at rest is a useful indicator for predicting EIPH in asymptomatic patients with DMR.

Changes in Left Atrial Transport Function in Patients Who Maintained Sinus Rhythm After Successful Radiofrequency Catheter Ablation for Atrial Fibrillation: A 1-Year Follow-Up Multislice Computed Tomography Study

BACKGROUND

Functional remodeling of left atrium (LA) after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been fully elucidated. This study aimed to determine the impact of RFCA on LA transport function in patients who maintained sinus rhythm (SR) after AF ablation.

METHODS AND RESULTS

A total of 96 patients (paroxysmal AF [PAF] = 52) who maintained SR during 1 year after AF ablation were enrolled. Multislice computed tomography was performed to determine LA volume (LAV) and LA emptying fraction (LAEF) at pre-RFCA and 1-year post-RFCA. Creatine kinase-MB (CK-MB) and troponin-T levels were analyzed 1-day post-RFCA. At 1-year post-RFCA, mean LAV and LAEF decreased in overall patients. Based on LAEF change (ΔLAEF) cutoff of 5.0%, LAEF reduced in 41 patients (worsened group) and improved or showed no change in 55 patients (preserved group). Compared with preserved group, worsened group had a higher proportion of PAF, higher levels of CK-MB and troponin-T, and additional LA ablation. ΔLAEF was inversely correlated with CK-MB and troponin-T levels. Subgroup analysis showed that LAEF significantly decreased in PAF patients who underwent additional LA ablation. Multivariate analysis revealed that high baseline LAEF and additional LA ablation were independent predictors for worsened LAEF.

CONCLUSIONS

Although SR was maintained for 1 year after AF ablation, LAEF as well as LAV decreased. The extent of LAEF deterioration was significantly associated with the amount of iatrogenic myocardial damage. Our data indicate that extensive atrial ablation may lead to LA functional deterioration, especially in patients with PAF.

MRI of the left atrium at 3T: evaluation of measurement reproducibility in healthy volunteers and patients with cardiovascular disease

Background Left ventricular (LV) function has traditionally been the focus for cardiac magnetic resonance imaging (MRI) investigations, but similar methods can also be applied to the left atrium (LA). Previous studies elsewhere have almost entirely involved the use of 1.5T systems, but 3T MRI can provide faster data acquisition with thinner image slices, and may be more suitable for quantifying the structure and function of the LA. Purpose To evaluate 3T-MRI for LA volume assessments in: (i) healthy volunteers (HV); (ii) patients with LV-hypertrophy and ischemia (LVHI); and (iii) patients with LV-hypertrophy and diabetes (LVHD). Material and Methods Participants were imaged using a balanced steady-state free precession sequence. Healthy volunteers were scanned twice and patients were scanned on one occasion. Volumes were segmented by two observers, and coefficients of repeatability (CoR) were derived. Results For LA volumes (indexed to body surface area), CoRs were in the range of 1.3-4.6 mL/m². The LVHI patients had enlarged LA volumes (diastolic, 46.4 mL/m²; systolic, 25.9 mL/m²) and reduced ejection fraction (EF) (44.9%) relative to the HV (diastolic, 39.0 mL/m²; systolic, 17.8 mL/m²; EF, 54.5%) and LVHD groups (diastolic, 41.4 mL/m²; systolic, 20.2 mL/m²; EF, 50.7%). LA volumes were moderately correlated with LV mass in the HV group (R²= 0.59 for LA end-systolic volume), but became weaker (R²≤ 0.17) for patient groups. Conclusion 3T-MRI derived LA volume measurements are simple and repeatable, and can elicit clear differences between LVHI patients and HVs. These MRI endpoints provide scope for improved radiological interpretation of LA structure and function, and the high degree of repeatability validates their use for longitudinal investigations where precision work is essential.

Association of chronic kidney disease with impaired left atrial reservoir function: A community-based cohort study

Background Chronic kidney disease (CKD) is an independent risk factor for atrial fibrillation, although the pathophysiological mechanisms remain unclear. This study investigated the relationship between CKD and left atrial (LA) volume and function in a sample of the general population without overt cardiac disease. Design and methods We examined 358 participants from the Cardiovascular Abnormalities and Brain Lesions study. The LA minimum volume index (LAVI_min), LA maximum volume index (LAVI_max), and LA emptying fraction (LAEF) were assessed by real-time three-dimensional echocardiography. Based on their estimated glomerular filtration rate (eGFR), the participants were divided into a CKD group (eGFR <60 ml/min/1.73 m²) and a non-CKD group (eGFR ≥60 ml/min/1.73 m²). Results Of the 358 participants, 69 (19%) were classified as having CKD and 289 (81%) as non-CKD. Participants with CKD were older, had a greater prevalence of hypertension and use of antihypertensive drugs, a larger left ventricular (LV) mass index, and a higher prevalence of diastolic dysfunction than those without CKD (all p < 0.05). There was no significant difference in LAVI_max between the CKD and non-CKD groups (23.4 ± 7.1 vs. 22.8 ± 5.8 ml/m², p = 0.47), whereas significant differences were observed for LAVI_min (13.6 ± 5.5 vs. 12.0 ± 4.6 ml/m², p = 0.01) and LAEF (42.7 ± 11.4 vs. 47.8 ± 11.5%, p = 0.001). Multivariate regression analysis revealed that the eGFR was significantly associated with LAEF independent of age, LV mass index, and diastolic dysfunction (all p < 0.05). Conclusions Participants with CKD in an unselected community-based cohort had significantly impaired LA reservoir function. Assessment of LA function may add important information in the prognostic assessment of patients with CKD even in the absence of overt cardiac disease.

Usefulness of the Atrial Emptying Fraction to Predict Maintenance of Sinus Rhythm After Direct Current Cardioversion for Atrial Fibrillation

Atrial volumes indexed to body surface area (AVI) are robust predictors of nonvalvular atrial fibrillation (AF) recurrence after direct current cardioversion (DCCV). The incremental value of atrial emptying fraction (EmF) compared with atrial volumes as a predictor for recurrent AF after DCCV has not been evaluated. We sought to compare the predictive ability of baseline left atrial (LA) EmF, right atrial (RA) EmF, LAVI, and RAVI for post-DCCV AF recurrence at 6 months. The first 95 patients enrolled in the AF Clinic Registry with adequate echocardiogram imaging constituted the study cohort. Each patient underwent echocardiogram within 6 months before cardioversion. Maximal LAVI and RAVI, LA EmF, and RA EmF were performed offline using 4-chamber single-plane Simpson's method, averaged over 5 cycles. The mean age of the study cohort was 64 ± 12 years, and 67% were men. Only 28 patients (29%) who underwent DCCV remained in sinus rhythm at 6 months of follow-up. The remaining, 67 (71%) had reverted to AF or underwent ablation during the 6 months of follow-up. The overall performance for prediction of AF recurrence was greatest for RA EmF, area under the receiver operator characteristic curve (AUC): RA EmF 0.92, LA EmF 0.89, RAVI 0.76, and LAVI 0.63. RA and LA EmF AUCs were significantly higher than for LAVI or RAVI (max p = 0.02). In conclusion, although RAVI and LAVI are strong predictors of AF recurrence after DCCV, RA and LA EmF outperformed in this cohort.

Evidence of left atrial remodeling and left ventricular diastolic dysfunction in type 2 diabetes mellitus with preserved systolic function

BACKGROUND AND AIMS

Prognosis of type 2 diabetes is associated with the occurrence of cardiovascular diseases. Left atrial (LA) size is a predictor of outcome in several diseases, including diabetes. Long duration of diabetes is an established risk factor of poor prognosis. No data are available on the relationship between LA size and duration of diabetes. The present study was aimed to investigate the relationship between LA volume index (LAVI) and the duration of diabetes to test the hypothesis that LA volume will increase as a function of diabetes duration.

METHODS AND RESULTS

Forty-four male patients with newly diagnosed and 172 male patients with established type 2 diabetes were recruited for this cross-sectional study. All patients were evaluated with a transthoracic echocardiographic Doppler. About 28.2% of patients had increased LAVI. Indices of both diastolic and systolic function were significantly lower in patients with larger left atrium. The values of LAVI increased across classes of duration of diabetes. In multivariable analysis, longer duration was a predictor of LAVI ≥34 ml/m² (odds ratio 1.65, 95% CI 1.11-2.46, p = 0.014) after adjusting for age, hemoglobin A1c, hypertension, microvascular complication status, and relevant echocardiographic parameters of systolic and diastolic function.

CONCLUSIONS

These results indicate that duration of diabetes is strongly and positively associated with larger LAVI in type 2 diabetic men with preserved systolic function. Future studies are needed to better elucidate the biological mechanisms underlying linking type 2 diabetes with abnormally increased LAVI in subjects with type 2 diabetes.

Methodological Gaps in Left Atrial Function Assessment by 2D Speckle Tracking Echocardiography

The assessment of left atrial (LA) function is used in various cardiovascular diseases. LA plays a complementary role in cardiac performance by modulating left ventricular (LV) function. Transthoracic two-dimensional (2D) phasic volumes and Doppler echocardiography can measure LA function non-invasively. However, evaluation of LA deformation derived from 2D speckle tracking echocardiography (STE) is a new feasible and promising approach for assessment of LA mechanics. These parameters are able to detect subclinical LA dysfunction in different pathological condition. Normal ranges for LA deformation and cut-off values to diagnose LA dysfunction with different diseases have been reported, but data are still conflicting, probably because of some methodological and technical issues. This review highlights the importance of an unique standardized technique to assess the LA phasic functions by STE, and discusses recent studies on the most important clinical applications of this technique.

Characterization of left and right atrial function in healthy volunteers by cardiovascular magnetic resonance

BACKGROUND

Left and right atrial function show a different pattern in advanced age in order to maintain adequate ventricular filling. It has been shown that left atrial (LA) function has a prognostic value in a number of heart conditions. Cardiovascular magnetic resonance (CMR) provides high quality images of the left and right atria using high temporal resolution steady state free precession (SSFP) cine sequences. We used SSFP cines to characterize atrial function in healthy, normotensive, volunteers.

METHODS

We measured maximum, preatrial contraction and minimum left and right atrial volumes in 120 healthy subjects after careful exclusion of cardiovascular abnormality (60 men, 60 women; 20 subjects per age decile from 20 to 80 years). Data were generated from 3-dimensional modeling, including tracking of the atrioventricular ring motion and time-volume curves analysis. With those measurements, all the usual parameters for left and right atrial function were calculated.

RESULTS

Gender had significant influence on some parameters of left and right atrial conduit and booster pump function. Age significantly influenced the majority of parameters of both left and right atrial function, with typically lower reservoir and conduit functions and higher booster pump function, both in males and females belonging to older age groups. CMR normal ranges were modelled for clinical use with normalization, where appropriate, for body surface area and gender, displaying parameters with respect to age.

CONCLUSIONS

CMR normal reference ranges for components of left and right atrial function are provided for males and females for a wide age range.

Left ventricular diastolic function is strongly correlated with active emptying of the left atrium: a novel analysis using three-dimensional echocardiography

Background

Increased left atrial (LA) dimensions are known to be a risk factor in predicting cardiovascular events and mortality and to be one key diagnostic tool to assess diastolic dysfunction. Currently, LA measurements are usually conducted using 2D-echocardiography, although there are well-known limitations. Real-time 3D-echocardiography is able to overcome these limitations, furthermore being a valid measurement tool compared to reference standards (e.g. cardiac magnetic resonance imaging).

We investigated LA function and volume and their association to left ventricular (LV) diastolic function, using newly designed and validated software for 3D-echocardiographic analysis. This software is the first to allow for a sophisticated analysis of both passive and active LA emptying.

Methods

We analyzed 2D- and 3D-echocardiographic measurements of LA volume and function in 56 subjects and compared the results between patients with normal LV diastolic function (NDF) (n = 30, 52 ± 15 years, BMI 24.7 ± 2.6 kg/m²) and patients in which diastolic dysfunction (DDF) was suspected (n = 26, 65 ± 9 years, BMI 26.7 ± 3.7 kg/m²).

Results

Volumes during LA active emptying were significantly smaller in DDF compared to NDF (active atrial stroke volume (ASV): 3.0 (0.1–4.5) vs. 5.5 (2.7–7.8) ml, p = 0.005; True-EF: 7.3(0.1–11.5) vs. 16.2 (8.1–25.4) %, p = 0.002). Furthermore, ASV showed a stronger association to E/e’_mean than all other measured LA volumes (β = − 0.35, p = 0.008). Neither total stroke LA volume, nor maximum or minimum LA volume differed significantly between the groups.

Conclusions

Diastolic LV dysfunction results in a reduction in active LA emptying, which is more strongly associated with LV filling pressure than other previously investigated LA parameters.

Determinants of Left Atrial Volume in Patients with Atrial Fibrillation

Introduction

Left atrial (LA) enlargement is an important risk factor for incident stroke and a key determinant for the success of rhythm control strategies in patients with atrial fibrillation (AF). However, factors associated with LA volume in AF patients remain poorly understood.

Methods

Patients with paroxysmal or persistent AF were enrolled in this study. Real time 3-D echocardiography was performed in all participants and analyzed offline in a standardized manner. We performed stepwise backward linear regression analyses using a broad set of clinical parameters to determine independent correlates for 3-D LA volume.

Results

We included 210 patients (70.9% male, mean age 61±11years). Paroxysmal and persistent AF were present in 95 (45%) and 115 (55%) patients, respectively. Overall, 115 (55%) had hypertension, 11 (5%) had diabetes, and 18 (9%) had ischemic heart disease. Mean indexed LA volume was 36±12ml/m². In multivariable models, significant associations were found for female sex (β coefficient -10.51 (95% confidence interval (CI) -17.85;-3.16), p = 0.0053), undergoing cardioversion (β 11.95 (CI 5.15; 18.74), p = 0.0006), diabetes (β 14.23 (CI 2.36; 26.10), p = 0.019), body surface area (BSA) (β 34.21 (CI 19.30; 49.12), p<0.0001), glomerular filtration rate (β -0.21 (CI -0.36; -0.06), p = 0.0064) and plasma levels of NT-pro brain natriuretic peptide (NT-proBNP) (β 6.79 (CI 4.05; 9.52), p<0.0001), but not age (p = 0.59) or hypertension (p = 0.42). Our final model explained 52% of the LA volume variability.

Conclusions

In patients with AF, the most important correlates with LA volume are sex, BSA, diabetes, renal function and NT-proBNP, but not age or hypertension. These results may help to refine rhythm control strategies in AF patients.

Effect of Sex Differences on the Association Between Stroke Risk and Left Atrial Anatomy or Mechanics in Patients With Atrial Fibrillation

Background—

Embolic stroke in atrial fibrillation is more prevalent in women than in men, yet the basis for this difference remains unclear. This study seeks to elucidate whether there are any sex differences in the relationships between stroke risk (CHADS 2 score, CHA 2 DS 2 -VASc score without a sex category, and estimated stroke rate) and left atrial (LA) anatomy or mechanics in patients with atrial fibrillation.

Methods and Results—

LA emptying fraction and global peak atrial longitudinal strain were assessed in 414 subjects with paroxysmal or persistent atrial fibrillation (156 women and 258 men). Linear regression models with an interaction term were performed to test the effect of sex difference on associations between the embolic risk and LA function or anatomy. Sensitivity analyses were performed in 228 age, heart rate, and rhythm-matched subjects (114 women and men). Women were older and had larger LA volumes and lower LA mechanics than men. Significant negative association between the CHADS 2 score and LA emptying fraction was only demonstrated in women with a significant interaction between sexes. Similar significant interactions were found in global peak atrial longitudinal strain but not in LA volume. These findings were corroborated in the comparisons against CHA 2 DS 2 -VASc score without a sex category and the estimated stroke rate. Sensitivity analyses in the matched subgroup also confirmed the robustness of these sex differences in LA emptying fraction, but less so in global peak atrial longitudinal strain.

Conclusions—

Significant sex interactions on the association between global LA function and risk stratification schemes exist, which may be a reason for the higher prevalence of embolic stroke in women.

Epinephrine and left atrial and left ventricular diastolic function decrease in normal subjects

BACKGROUND

We assessed the effect of epinephrine over left atrial and left ventricular diastolic function in subjects without structural heart disease.

METHODS

Twenty-seven, 34.6±17.2year-old patients without structural heart disease were included. Intravenous epinephrine (50 to 100ng/kg/min) was infused. Left atrial and ventricular functions were evaluated by means of echocardiography before and during the epinephrine infusion.

RESULTS

No complications were observed. Significant increases in heart rate and systolic blood pressure were recorded. Both left atrial (minimal and maximal) volumes increased but increase in the minimal volume was more pronounced, and the ejection fraction diminished. Left atrial expansion index decreased and the fraction of left ventricular inflow volume resulting from atrial contraction increased. Two patients displayed abnormal left ventricular diastolic function. During epinephrine infusion, E/A and e' decreased, and isovolumetric relaxation time increased.

CONCLUSIONS

In this group of young adults without structural heart disease, epinephrine infusion was safe, did not produce any complications, and induced a small but significant decrease in left atrial function and left ventricular diastolic function.

The influence of white-coat hypertension on left atrial phasic function

We aimed to investigate the association between white-coat hypertension (WCH) and left atrial (LA) phasic function assessed by the volumetric and speckle tracking method. This cross-sectional study included 52 normotensive individuals, 49 subjects with WCH and 56 untreated hypertensive patients who underwent a 24-h ambulatory BP monitoring and complete two-dimensional echocardiographic examination (2DE). WCH was diagnosed if clinic blood pressure (BP) was elevated and 24-h BP was normal. We obtained that maximum, minimum LA and pre-A LAV volumes and volume indexes gradually and significantly increased from the normotensive subjects, throughout the white-coat hypertensive individuals to the hypertensive patients. Passive LA emptying fraction (EF), representing the LA conduit function, gradually reduced from normotensive to hypertensive subjects. Active LA EF and the parameter of the LA booster pump function increased in the same direction. Similar results were obtained by 2DE strain analysis. The LA stiffness index gradually increased from normotensive controls, throughout white-coat hypertensive subjects to hypertensive patients. Clinic systolic BP was associated with LA passive EF (β= -0.283, p = 0.001), LA active EF (β = 0.342, p < 0.001), LA total longitudinal strain (β= -0.356, p < 0.001), LA positive longitudinal strain (β= -0.264, p = 0.009) and LA stiffness index (β = 0.398, p < 0.001) without regard to age, BMI, left ventricular structure and diastolic function in the whole study population. In the conclusion, WCH significantly impacts LA phasic function and stiffness. Clinic systolic BP was associated with functional and mechanical LA remodeling in the whole study population.

Prognostic Relevance of Left Atrial Dysfunction in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Left atrial (LA) size is an established marker of risk for adverse outcomes in heart failure with preserved ejection fraction (HFpEF). However, the independent prognostic importance of LA function in HFpEF is not known.

METHODS AND RESULTS

We assessed LA function measured by speckle-tracking echocardiography in 357 patients with HFpEF enrolled in the Treatment Of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial who were in sinus rhythm at the time of echocardiography. Lower peak LA strain, indicating LA dysfunction, was associated with older age, higher prevalence of atrial fibrillation and left ventricular (LV) hypertrophy, worse LV and right ventricular systolic function, and worse LV diastolic function. At a mean follow-up of 31 months (interquartile range, 18-43months), 91 patients (25.5%) experienced the primary composite end point of cardiovascular death, HF hospitalization, and aborted sudden death. Lower peak LA strain was associated with a higher risk of the composite end point (hazard ratio, 0.96 per unit of reduction in strain; 95% confidence interval, 0.94-0.99; P=0.009) and of HF hospitalization alone (hazard ratio, 0.95 per unit of reduction in strain; 95% confidence interval, 0.92-0.98; P=0.003). The association of LA strain with incident HF hospitalization remained significant after adjustment for clinical confounders, but not after further adjustment for LV global longitudinal strain and the E/E' ratio, parameters of LV systolic and diastolic function, respectively.

CONCLUSIONS

LA dysfunction in HFpEF is associated with a higher risk of HF hospitalization independent of potential clinical confounders, but not independent of LV strain and filling pressure. Impairment in LV systolic and diastolic function largely explains the association between impaired LA function and higher risk of HF hospitalization in HFpEF.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00094302.

Left Atrial Volumes and Function by Three-Dimensional Echocardiography

Background—

Our study sought to (1) identify reference values for left atrial (LA) volumes and phasic function indices by 3-dimensional echocardiography (3DE) and compare them with those measured by 2-dimensional echocardiography (2DE) and (2) analyze their relationship with age, sex, body size, and left ventricular function. Accuracy and reproducibility of 3DE and 2DE have been also tested to evaluate the robustness of our data.

Methods and Results—

We obtained maximal, minimal, and preA LA volumes by 3DE and 2DE in 276 healthy volunteers (18–79 years; 57% women). Limits of normality for LA volumes and total LA emptying fraction were larger with 3DE than with 2DE (maximal LA volume: 43 versus 35 mL/m 2 ; preA LA volume: 31 versus 25 mL/m 2 ; minimal LA volume: 18 versus 14 mL/m 2 ; 53 versus 48%, respectively; P <0.001). 3DE LA volumes indexed by body surface area were similar in men and women and increased with age. On multivariable analysis, age, weight, and left ventricular systolic and diastolic function indices resulted as correlates of LA 3DE indices. LA volumes were tightly correlated with cardiac magnetic resonance measurements, yet more underestimated by 2DE versus 3DE (bias±SD: −17±16 versus −7±15 mL, respectively). Among all LA parameters, maximal LA volume and total emptying fraction were the most reproducible, including at test-retest and at expert versus trainee comparisons.

Conclusions—

This study provides reference values for LA 3DE volumes and function from a relatively large cohort of healthy subjects with a wide age range. Our data may help clinicians to identify LA remodeling and dysfunction.

Left Atrial Structure and Function Across the Spectrum of Cardiovascular Risk in the Elderly: The Atherosclerosis Risk in Communities Study

BACKGROUND

Although left atrial (LA) enlargement is a recognized risk factor for adverse cardiovascular outcomes, emerging evidence supports the importance of LA function. We examined LA emptying fraction (LAEF) across the spectrum of cardiovascular disease burden in a large cohort of elderly adults living in the community.

METHODS AND RESULTS

We studied 1142 participants in the Atherosclerosis Risk in Communities (ARIC) study who were in sinus rhythm, free of valvular disease, and had acceptable quality 3-dimensional echocardiograms (mean age, 76±5 years; 59% women). We determined the cross-sectional correlates of LAEF and compared LAEF among elderly adults without cardiovascular disease or cardiovascular risk factors (n=201), those with hypertension (n=734), and those with overt heart failure (HF; n=207). In multivariable analysis, lower LAEF was associated with higher LA volumes and worse left ventricular systolic and diastolic functions. Elderly participants free of cardiovascular disease or risk factors had smaller LA volumes than those with hypertension (LA volume max/ body surface area 30.2±6.6 versus 33.0±9.0 mL/m(2); P=0.001), but similar LAEF (55.2±10.3% versus 53.8±11.5%, respectively; P=0.357). Participants with HF had higher LA volume (39.8±13.3 mL/m(2)) and worse LAEF (47.6±14.6%) than participants with hypertension or participants free of cardiovascular disease or risk factors (all P<0.001).

CONCLUSIONS

In a community-based cohort, LA function was impaired in participants with prevalent HF, but there were no significant differences in LA function between participants with hypertension and those with free of cardiovascular disease or risk factors, despite greater LA size in the former.

Evaluation of single right atrial volume and function with magnetic resonance imaging in children with hypoplastic left heart

BACKGROUND

Standardized methods to evaluate atrial properties in single ventricles are lacking.

OBJECTIVE

To determine the feasibility of quantifying right atrial volumes and function in hypoplastic left heart using MRI.

MATERIALS AND METHODS

We studied 15 infants with hypoplastic left heart prior to Glenn surgery (mean age 4.2 months [standard deviation 0.3]) who underwent cardiac MRI with evaluation of atrial volumes and emptying fraction using monoplane two-chamber, monoplane four-chamber, and biplane methods, all of which were compared to the atrial short-axial oblique stack method. We compared atrial end-diastolic volume, end-systolic volume and emptying fraction among these methods. We analyzed reproducibility of the methods using Bland‒Altman plots.

RESULTS

Both four-chamber and biplane methods showed high correlations for atrial end-diastolic volume (r = 0.7 and r = 0.8, respectively; P < 0.01) and end-systolic volume (r = 0.8 and r = 0.9, respectively; P < 0.01) with small mean differences (-0.2 ± 2.9 standard deviation [SD] ml and -0.8 ± 1.6 ml, respectively, for atrial end-diastolic volume and -0.8 ± 1.5 ml and -0.9 ± 0.9 ml, respectively, for atrial end-systolic volume). The short-axial oblique method was the most reproducible, followed by the four-chamber method.

CONCLUSION

MRI assessment of atrial volume and function is feasible in hypoplastic left heart and might provide further insight into single-ventricle mechanics.

Prognostic value of left atrial function in systemic light-chain amyloidosis: a cardiac magnetic resonance study

BACKGROUND

Cardiac involvement in systemic light-chain amyloidosis (AL) imparts an adverse impact on outcome. The left atrium (LA), by virtue of its anatomical location and muscular wall, is commonly affected by the amyloid process. Although LA infiltration by amyloid fibrils leads to a reduction in its pump function, the infiltration of the left ventricular (LV) myocardium results in diastolic dysfunction with subsequent increase in filling pressures and LA enlargement. Even though left atrial volume (LAV) is an independent prognostic marker in many cardiomyopathies, its value in amyloid heart disease remains to be determined. In addition, few data are available as to the prognostic value of LA function in systemic AL. Using cardiac magnetic resonance (CMR), the current study aims to assess the prognostic significance of the maximal LAV and total LA emptying fraction (LAEF) in patients with AL.

METHODS AND RESULTS

Fifty-four consecutive patients (age 66 ± 10 years, 59% males) with confirmed systemic AL and mean LV ejection fraction of 60 ± 12% underwent CMR. As compared with patients with no or minimal cardiac involvement (Mayo Clinic [MC] stage I), those at moderate and high risk (MC stages II and III) had significantly larger indexed maximal LAV (36 ± 15 vs. 46 ± 13 vs. 52 ± 19 mL/m(2), P = 0.03) and indexed minimal LAV (20 ± 6 vs. 34 ± 11 vs. 44 ± 17 mL/m(2), P < 0.001), lower LAEF (42 ± 9 vs. 26 ± 13 vs. 16 ± 9%, P < 0.0001) but similar LVEF. Furthermore, myocardial late gadolinium enhancement (LGE) was more frequent and significantly associated with lower LAEF. LAEF was also significantly lower in symptomatic (NHYA ≥ II, 22 ± 14%) as compared with asymptomatic patients (NYHA class I, 33 ± 13%, P = 0.006). Two-year survival rate was lower in patients with LAEF ≤ 16% as compared with those with LAEF > 16% (37 ± 11 vs. 94 ± 4%, P = 0.001). In multivariate analysis, lower LAEF remained independently associated with a higher risk of 2-year mortality (HR = 1.08 per 1% decrease, 95% CI: 1.02-1.15, P = 0.003).

CONCLUSION

In patients with systemic AL, LAEF as assessed by CMR is associated with NYHA functional class, MC stage, myocardial LGE and 2-year mortality.

Echocardiographic measurement of left atrial volume: Does the method matter?

BACKGROUND

Four two-dimensional echocardiographic methods (cube, ellipsoid, Simpson's and area-length) can be used to assess left atrial volume (LAV).

AIMS

To compare absolute LAV measurements and evaluate agreement regarding the semiquantitative assessment of degree of left atrial (LA) enlargement, between methods.

METHODS

We prospectively measured LAV in 51 healthy volunteers using the four methods, and defined thresholds for moderate (mean+2 standard deviations [SDs]) and severe (mean+4 SDs) LA enlargement for each method. In 372 patients referred for echocardiography, we compared absolute LAV measurements and agreement between methods.

RESULTS

LAV was significantly different between methods in the healthy volunteer group (11 ± 4, 17 ± 3, 26 ± 6 and 28 ± 7 mL/m(2), respectively; P<0.0001), resulting in different thresholds for moderate and severe LA enlargement. LAV was also significantly different in the 372 patients (30 ± 20, 47 ± 27, 61 ± 34 and 65 ± 36 mL/m(2), respectively; P<0.0001). Agreement regarding degree of LA enlargement (none, moderate, severe), using the area-length method as reference, was modest with the cube method (kappa=0.41), correct with the ellipsoid method (kappa=0.60) and excellent with Simpson's method (kappa=0.83).

CONCLUSION

The choice of the method had a major effect on assessment of degree of LA enlargement. Our results suggest that the cube and ellipsoid methods, which significantly underestimated LAV and provided modest agreement, should be disregarded. In contrast, Simpson's method and the area-length method were slightly different, but showed close agreement, and should be preferred, using dedicated thresholds (50 and 56 mL/m(2) respectively).

Association of left atrial function with incident atypical atrial flutter after atrial fibrillation ablation

BACKGROUND

Symptomatic left atrial (LA) flutter (LAFL) is common after atrial fibrillation (AF) ablation.

OBJECTIVE

The purpose of this study was to examine the association of baseline LA function with incident LAFL after AF ablation.

METHODS

The source cohort included 216 patients with cardiac magnetic resonance (CMR) before initial AF ablation between 2010 and 2013. Patients who underwent cryoballoon or laser ablation, patients with AF during CMR, and those with suboptimal CMR, or missing follow-up data were excluded. Baseline LA volume and function were assessed by feature-tracking CMR analysis.

RESULTS

The final cohort included 119 patients (mean age 58.9 ± 11 years; 76.5% men; 70.6% patients with paroxysmal AF). During a median follow-up of 421 days (interquartile range 235-751 days), 22 patients (18.5%) had incident LAFL. Baseline LA volume was similar between the 2 groups. In contrast, baseline reservoir, conduit, and contractile function of the LA were significantly impaired in patients with incident LAFL. Baseline global peak longitudinal atrial strain (PLAS) <22.65% predicted incident LAFL with 86% sensitivity and 68% specificity (C statistic 0.76). In a multivariable model adjusting for age, heart failure, and LA volume, PLAS (hazard ratio 0.9 per % increase in PLAS; P = .003) and LA linear lesions (hazard ratio 2.94; P = .020) were independently associated with incident LAFL. The coexistence of PLAS <22.65% and linear lesions was associated with 9-fold increased hazard of incident LAFL.

CONCLUSION

Baseline LA function and linear lesions were independently associated with incident LAFL after AF ablation. Linear lesions should be limited to selected cases, especially in patients with impaired LA function.

The influence of left ventricular geometry on left atrial phasic function in hypertensive patients

OBJECTIVE

We aimed to investigate left atrial (LA) phasic function in hypertensive patients with different geometric patterns using two-dimensional (2DE) and three-dimensional (3DE) echocardiography.

METHODS

This cross-sectional study included 213 hypertensive subjects who underwent a complete 2DE and 3DE examination. The new updated criteria for left ventricular (LV) geometry, which consider LV mass index, LV end-diastolic diameter and relative wall thickness, were applied. According to this classification, the subjects were divided into six groups: normal geometry, concentric remodeling, eccentric non-dilated left ventricular hypertrophy (LVH), concentric LVH, dilated LVH and concentric-dilated LVH.

RESULTS

2DE and 3DE LA volumes gradually increased from normal LV geometry to concentric and concentric-dilated LVH. LA reservoir and conduit functions, estimated by 2DE and 3DE LA total and passive emptying fractions, were decreased in subjects with concentric and concentric-dilated LVH. LA booster pump function was increased in patients with concentric, dilated and concentric-dilated LVH compared to subjects with normal LV geometry. The same results regarding LA phasic function were provided by 2DE strain analysis. Concentric, dilated and non-concentric dilated LVH were associated with LA enlargement independently of main demographic and clinical features.

CONCLUSION

LV geometric patterns significantly influence LA phasic function. Concentric and dilated LVH patterns have the most prominent negative effect on LA enlargement assessed by both 2DE and 3DE.

Assessment of left sided filling dynamics in diastolic dysfunction using cardiac computed tomography

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) often accompanies coronary artery disease but is difficult to assess since it involves a complex interaction between LV filling and left atrial (LA) emptying.

OBJECTIVE

To characterize simultaneous changes in LA and LV volumes using cardiac computed tomography (CT) in a group of patients with various grades of DD based on echocardiography.

METHODS

We identified 35 patients with DD by echocardiography, who had also undergone cardiac CT, and 35 age-matched normal controls. LV and LA volumes were measured every 10% of the RR interval, using semi-automatic software. From these, - systolic, early-diastolic and late-diastolic volume changes were calculated, and additional parameters of diastolic filling derived. Conduit volume was defined as the difference between the LV and LA early-diastolic volume change.

RESULTS

Patients with DD had significantly larger LV mass, and LA volumes, reduced early emptying volumes and increased conduit volume as percent of early LV filling (All p<0.001). LA function, manifesting as total emptying fraction (LATEF), decreased proportionately with worsening grades of DD (p<0.001). LA contractile function was maintained until advanced grade-3 DD. By receiver operating characteristic analysis, LATEF had an AUC of 0.88 to separate between normals and DD. At a threshold of <42.5%, LATEF has 97% sensitivity and 69% specificity to detect DD.

CONCLUSIONS

DD is characterized by reduced LA function and an alteration in the relative contributions of the atrial emptying and conduit volume components of early LV filling. In patients undergoing cardiac CT, it is possible to identify the presence and severity of DD.

Normal left-atrial structure and function despite concentric left-ventricular remodelling in a cohort of patients with Anderson-Fabry disease

AIMS

Anderson-Fabry Disease (AFD) is an important cause of cardiomyopathy characterized by concentric left-ventricular hypertrophy (LVH). We evaluated the extent of left-atrial (LA) structural and functional remodelling in this group of patients given that LA remodelling is a marker of adverse outcomes in the presence of LVH.

METHODS AND RESULTS

Clinical profiles were obtained and cardiac MRI was performed in cohorts of patients with AFD (n = 31), healthy controls (n = 23), and a positive control cohort with known concentric remodelling and LVH (CR/H, n = 21). Of patients with AFD, 58% were on enzyme-replacement therapy (ERT), 84% were on renin-angiotensin system antagonism, and 65% were on statins. Despite a similar increase in LV mass index in the AFD when compared with the CR/H cohort, mean LA volumes for the AFD group were similar to those seen in the healthy control group. Following from this, we observed that the percentage contribution to LV stroke volume due to elastic/passive and active LA emptying was similar in the AFD and healthy control groups, while passive emptying was significantly lower in the CR/H group. The consequences of LVH in the AFD cohort were manifested in atrioventricular uncoupling, whereby the extent of elastic/passive and active LA emptying was not a function of the extent of longitudinal movement of the mitral annular plane, as it was in healthy control subjects.

CONCLUSION

Left-atrial structure and function were relatively normal in our cohort of patients with AFD, who were also judiciously treated with a contemporary strategy that includes renin-angiotensin system antagonism, statins, and ERT.

Biomarkers of cardiomyocyte injury and stress identify left atrial and left ventricular remodelling and dysfunction: A population-based study

BACKGROUND/OBJECTIVES

The validation of effective screening tools for the identification of patients with subclinical myocardial remodelling is a major clinical need. Thus, we explored the associations of circulating biomarkers of cardiomyocyte injury and stress with subclinical cardiac remodelling and dysfunction, and with biomarkers reflecting collagen turnover.

METHODS

We randomly recruited 727 subjects from a general population (51.2% women; mean age 51.3 years). Measurements included echocardiographic left atrial (LA) and left ventricular (LV) structure and function, quantification of high sensitivity cardiac Troponin T (hs-cTnT), NT-proBNP, and biomarkers of collagen types I and III turnover.

RESULTS

In unadjusted and adjusted analyses, the prevalence of LA enlargement (LAE), LV hypertrophy (LVH) and LV diastolic dysfunction (LVDD) increased with higher hs-cTnT (P ≤ 0.031). NT-proBNP was independently associated with LVDD (P=0.009). Both biomarkers combined yielded significant integrated discrimination and net reclassification improvements (P ≤ 0.014 and P ≤ 0.009, respectively) for LAE, LVH and LVDD, over the conventional risk factors, and were independently and positively associated with biomarkers of collagen type I turnover. In a sensitivity analysis, after excluding participants with previous cardiac diseases, our findings remained consistent.

CONCLUSIONS

Our population-based study suggested that subclinical LV and LA remodelling were associated with hs-cTnT, and that, in combination with NT-proBNP, hs-cTnT showed incremental diagnostic utility over the conventional risk factors. Both biomarkers were associated with biomarkers of collagen type I turnover. Thus, biomarkers of cardiomyocyte microinjury and hemodynamic stress may stimulate fibrosis-related mechanisms and facilitate the diagnosis of subclinical LA and LV remodelling and dysfunction in the general population.