Radiographic Left Atrial Size Measurement of Dogs in Different Mitral Valve Disease Stages with Four Different Methods

The left atrial size increases (LAS) in patients with mitral valve disease (MVD) as the disease progresses. The vertebral left atrial size (VLAS), the modified-vertebral left atrial size (M-VLAS), and the radiographic left atrial dimension (RLAD) are methods reported to assess LAS on dogs' radiographs. All these methods transform the LAS into vertebral units. The thoracic inlet (TI) has been used as a reliable reference point to measure the cardiac silhouette of dogs with MVD in different stages. The objective of this study was to assess the clinical utility of measuring a dog LAS on right thoracic X-rays using the TI as a reference and determine whether it could differentiate dogs in different MVD stages. LAS was divided by the TI to obtain the thoracic inlet left atrial score (TILAS). This was a retrospective observational study including 135 apparently healthy dogs performed to assess their LAS with four different methods: VLAS, M-VLAS, RLAD, and TILAS. Thirty-six dogs from the general population were selected and compared to 100 dogs in different MVD stages. The TILAS was significantly different between the control dogs and MVD dogs, increasing with the disease stage: control dogs 0.51 ± 0.08, B1 0.57 ± 0.14, B2 0.75 ± 0.13, and C 0.84 ± 0.18. VLAS, M-VLAS, and RLAD also increased as the disease progressed, as shown in previous studies. The TILAS accuracy to distinguish MVD dogs with cardiac enlargement was comparable to VLAS, M-VLAS, and RLAD (AUC 0.91 vs. 0.93, 0.90, and 0.94 respectively). A TILAS > 0.8 can identify dogs with cardiac enlargement secondary to MVD.

Left atrial area index provides the best prediction of atrial fibrillation in ischemic stroke patients: results from the LAETITIA observational study

Background and aims

Left atrial (LA) enlargement has been repeatedly shown to be associated with the diagnosis of atrial fibrillation (AF). In clinical practice, several parameters are available to determine LA enlargement: LA diameter index (LADI), LA area index (LAAI), or LA volume index (LAVI). We investigated the predictive power of these individual LA parameters for AF in patients with acute ischemic stroke or transient ischemic attack (TIA).

Methods

LAETITIA is a retrospective observational study that reflects the clinical reality of acute stroke care in Germany. Consecutive patient cases with acute ischemic cerebrovascular event (CVE) in 2019 and 2020 were identified from the Mannheim stroke database. Predictive power of each LA parameter was determined by the area under the curve (AUC) of receiver operating characteristic curves. A cutoff value was determined. A multiple logistic regression analysis was performed to confirm the strongest LA parameter as an independent predictor of AF in patients with acute ischemic CVE.

Results

A total of 1,910 patient cases were included. In all, 82.0% of patients had suffered a stroke and 18.0% had a TIA. Patients presented with a distinct cardiovascular risk profile (reflected by a CHA2DS2-VASc score ≥2 prior to hospital admission in 85.3% of patients) and were moderately affected on admission [median NIHSS score 3 (1; 8)]. In total, 19.5% of patients had pre-existing AF, and 8.0% were newly diagnosed with AF. LAAI had the greatest AUC of 0.748, LADI of 0.706, and LAVI of 0.719 (each p < 0.001 vs. diagonal line; AUC-LAAI vs. AUC-LADI p = 0.030, AUC-LAAI vs. AUC-LAVI p = 0.004). LAAI, increasing NIHSS score on admission, and systolic heart failure were identified as independent predictors of AF in patients with acute ischemic CVE. To achieve a clinically relevant specificity of 70%, a cutoff value of ≥10.3 cm2/m2 was determined for LAAI (sensitivity of 69.8%).

Conclusion

LAAI revealed the best prediction of AF in patients with acute ischemic CVE and was confirmed as an independent risk factor. An LAAI cutoff value of 10.3 cm2/m2 could serve as an inclusion criterion for intensified AF screening in patients with embolic stroke of undetermined source in subsequent studies.

Validation of a focused echocardiographic training program in first opinion practice

BACKGROUND

The EPIC study defines criteria, including echocardiographic assessments of left atrial to aortic ratio (LA: Ao) and left ventricular internal diameter in diastole normalized for body weight (LVIDdN), for dogs with preclinical myxomatous mitral valve disease (MMVD) likely to benefit from pimobendan therapy. Access to echocardiography by a cardiologist is not universally available.

HYPOTHESIS/OBJECTIVES

Completion of a focused echocardiographic training program would result in accurate identification of dogs fulfilling the EPIC criteria by primary care veterinarians (PC).

PARTICIPANTS

Six PCs with no previous echocardiographic experience.

METHODS

Prospective diagnostic test accuracy study. After training, each PC evaluated ≤10 dogs that they believed to have preclinical MMVD. The evaluation was repeated by 1 of 3 cardiology diplomates, blinded to the PC's findings. Agreement between clinical assessments and echocardiographic measurements was assessed.

RESULTS

Fifty-seven dogs were evaluated by PCs; 1 dog was withdrawn because of congestive heart failure. The median time between PC and cardiologist evaluation was 0 days (range, 0-8). One incorrect diagnosis of MMVD was made by a PC (this dog had dilated cardiomyopathy [DCM]); preclinical MMVD was confirmed by the cardiologist in 55 dogs. No difference in LA: Ao (P = .96; CV = 6.9%) was detected between PCs and cardiologists. LVIDdN (1.69 cm/kg^0.294 (1.26-2.21) vs 1.73 cm/kg^0.294 (1.32-2.73); P = .001; CV = 6.5%), was significantly lower when measured by PCs vs cardiologists. PCs and cardiologists agreed regarding assessment of EPIC criteria in 49/56 dogs (Alpha = .761, 95% confidence interval 0.697-0.922).

CONCLUSIONS AND CLINICAL IMPORTANCE

The program effectively trained PCs to accurately assess EPIC criteria in dogs with preclinical MMVD.

Left atrial size predicts long-term outcome after balloon mitral valvuloplasty

BACKGROUND

The treatment of choice for severe rheumatic mitral stenosis is balloon mitral valvuloplasty (BMV). Numerous predictors of immediate and long-term procedural success have been described. The aims of this study were to describe our experience with BMV over the last decade and to evaluate predictors of long-term event-free survival.

METHODS

Medical records were retrospectively analyzed of patients who underwent BMV between 2009 and 2021. The primary outcome was a composite endpoint of all-cause mortality, mitral valve replacement (MVR), and repeat BMV. Long-term event-free survival was estimated using Kaplan-Meier curves. Logistic regression was used to create a multivariate model to assess pre-procedural predictors of the primary outcome.

RESULTS

A total of 96 patients underwent BMV during the study period. The primary outcome occurred in 36 patients during 12-year follow-up: one (1%) patient underwent re-BMV, 28 (29%) underwent MVR, and eight (8%) died. Overall, event-free survival was 62% at 12 years. On multivariate analysis, pre-procedural left atrial volume index (LAVI) > 80 mL/m2 had a significant independent influence on event-free survival, as did previous mitral valve procedure and systolic pulmonary arterial pressure above 50 mmHg.

CONCLUSIONS

Despite being a relatively low-volume center, excellent short and long-term results were demonstrated, with event-free survival rates consistent with previous studies from high-volume centers. LAVI independently predicted long-term event-free survival.

The Role of the Left Atrium: From Multimodality Imaging to Clinical Practice: A Review

In recent years, new interest is growing in the left atrium (LA). LA functional analysis and measurement have an essential role in cardiac function evaluation. Left atrial size and function are key elements during the noninvasive analysis of diastolic function in several heart diseases. The LA represents a “neuroendocrine organ” with high sensitivity to the nervous, endocrine, and immune systems. New insights highlight the importance of left atrial structural, contractile, and/or electrophysiological changes, introducing the concept of “atrial cardiomyopathy”, which is closely linked to underlying heart disease, arrhythmias, and conditions such as aging. The diagnostic algorithm for atrial cardiomyopathy should follow a stepwise approach, combining risk factors, clinical characteristics, and imaging. Constant advances in imaging techniques offer superb opportunities for a comprehensive evaluation of LA function, underlying specific mechanisms, and patterns of progression. In this literature review, we aim to suggest a practical, stepwise algorithm with integrative multimodality imaging and a clinical approach for LA geometry and functional analysis. This integrates diastolic flow analysis with LA remodelling by the application of traditional and new diagnostic imaging techniques in several clinical settings such as heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), and mitral regurgitation (MR).

Left Atrial Diameter in the Prediction of Thromboembolic Event and Death in Atrial Fibrillation

Background: This study aimed to determine the predictive value of left atrial diameter (LAD), and the incremental prognostic value of LAD in combination with CHA2DS2-VASc score for predicting thromboembolic event and all-cause death in patients with non-valvular atrial fibrillation (AF). Methods: This is a prospective study from 27 hospitals during 2014−2017. LADi is LAD data indexed by body surface area, and LADi in the 4th quartile (LADi Q4) was considered high. Results: A total of 2251 patients (mean age 67.4 years, 58.6% male) were enrolled. Mean follow-up duration was 32.3 months. Rates of thromboembolic events and all-cause death were significantly higher in LADi Q4 patients than in LADi Q1−3 patients (2.89 vs. 1.11 per 100 person-years, p < 0.001, and 7.52 vs. 3.13 per 100 person-years, p < 0.001, respectively). LADi Q4 is an independent predictor of thromboembolic events and all-cause death with an adjusted hazard ratio and 95% confidence interval of 1.94 (1.24−3.05) and 1.81 (1.38−2.37), respectively. LADi has incremental prognostic value on top of the CHA2DS2-VASc score with the increase in global chi-square for thromboembolism (p = 0.005) and all-cause death (p < 0.001). Conclusions: LADi is an independent predictor of thromboembolic event and has incremental prognostic value in combination with CHA2DS2-VASc score in AF patients.

Biatrial volume ratio predicts low voltage areas in atrial fibrillation

BACKGROUND

Left atrial volume (LAV) and low voltage areas (LVAs) are acknowledged markers for worse rhythm outcome after ablation of atrial fibrillation (AF). Some studies reported the importance of increased right atrial volume (RAV) as a predictor for arrhythmia recurrences in AF patients.

OBJECTIVE

To investigate association between the LAV/RAV ratio and LVAs presence.

METHODS

Patients undergoing first AF ablation were included. LVAs were assessed peri-procedurally using high-density 3D maps and defined as <0.5 mV. All patients underwent pre-procedural cardiovascular magnetic resonance imaging. LAV (biplane) and RAV (monoplane 4-chamber) were assessed prior to ablation, and the LAV/RAV ratio was calculated.

RESULTS

The study population included 189 patients (age mean 63 ± 10 years, 33% women, 57% persistent AF, 22% LVAs). There were 149 (79%) patients with LAV > RAV. In univariable analysis LAV > RAV was associated with LVAs (OR 6.803, 95%CI 1.395-26.514, p = .016). The association remained robust in multivariable model after adjustment for persistent AF, CHA₂ DS₂ -VASc score, and heart rate (OR 5.981, 95%CI 1.256-28.484, p = .025). Using receiver operator curve analysis, LAV > RAV (AUC 0.668, 95%CI 0.585-0.751, p = .001) was significant predictor for LVAs. In multivariable analysis, after adjustment for age, persistent AF, and renal function, RAV≥LAV was threefold higher in males (OR 3.040, 95%CI 1.050-8.802, p = .04).

CONCLUSIONS

LAV > RAV is useful for the prediction of electro-anatomical substrate in AF. LAV > RAV was associated with LVAs presence, while male sex remained associated with RAV≥LAV and less LVAs.

Correlation Between CHA2DS2-VASc Score and Left Atrial Size in Patients With Atrial Fibrillation: A More Than 15-Year Prospective Follow-Up Study

Background: Left atrial (LA) size represents atrial fibrillation (AF) burden and has been shown to be a predictor for AF stroke. The CHA₂DS₂-VASc score is also a well-established predictor of AF stroke. It is unknown to cardiologists whether these two risk scores are correlated, whether both are independent prognostic predictors and complimentary to each other, or whether one of them is a major determinant of stroke risk for AF patients.

Method: A total of 708 patients from the National Taiwan University Atrial Fibrillation Registry were longitudinally followed up for more than 15 years. Left atrial size was measured by M mode of echocardiography. Adverse thromboembolic endpoints during follow-up were defined as ischemic stroke or transient ischemic attack.

Results: The mean age was 72.1 ± 12.9 years, with 53% men. Both LA size and CHA₂DS₂-VASc score were associated with the risk of stroke in univariate analyses. There was a weak but significant positive correlation between LA size and CHA₂DS₂-VASc score (r = 0.17, P < 0.0001). Patients with higher CHA₂DS₂-VASc scores had a higher mean LA size (P < 0.01 for trend). When combining LA size and CHA₂DS₂-VASc score in the multivariable Cox model, only CHA₂DS₂-VASc score remained statistically significant [HR 1.39 (1.20–1.63); P < 0.001].

Conclusion: LA size is not an independent predictor of AF stroke, and calculation of CHA₂DS₂-VASc score may be an alternative to measurement of echocardiographic LA size when evaluating the risk of stroke for AF patients.

Effects of body mass index and gender on left atrial size in Chinese hypertensive patients

BACKGROUND

Left atrial enlargement (LAE) is a common cardiac structural change in patients with hypertension, and obesity could further promote LAE. However, little is known about the effect of overweight on left atrial size, and if there is a gender difference of the effect. The aim of this study was to analyze the effects of different body mass index (BMI) grades (normal weight, overweight, and obesity) on left atrial size in both male and female patients with hypertension.

METHODS

A total of 710 patients with hypertension were divided into 3 study groups: normal weight group (BMI < 24 g/m², n = 302), overweight group (24 kg/m² ≤ BMI < 28 kg², n = 318), and obesity group (BMI ≥28 kg/m², n = 90). The clinical data, echocardiographic indexes and left atrial size were obtained from all the subjects. Pearson correlation analysis was used to analyze the correlation between clinical variables and left atrial diameter (LAD)/left atrial diameter index (LADI), and stepwise regression evaluation was used to study the relevant factors affecting LAD/LADI among all patients, male and female patients for possible gender difference.

RESULTS

The significant difference in LADI was noted in the three study groups with obesity group of 23.96 ± 2.90 mm/m, overweight group of 22.50 ± 3.02 mm/m and normal weight group of 21.08 ± 2.80 mm/m, respectively (P < . 05). After adjusting for age and gender, there was still significant difference in LADI among the three groups (P < . 05). The correlation between BMI and LADI was higher than that between systolic blood pressure (SBP) and diastolic blood pressure (DBP) (r = 0.348 vs 0.092 and -0.068, respectively, P < .05). After adjusting for other influencing factors, there was still a significant correlation between BMI and LADI (β = 0.326, P < .001), but no correlation was found between SBP and DBP (P > .05). For each additional unit of BMI, LAD increased by 0.034 mm and LADI increased by 0.305 mm/m. Multiple linear regression analysis showed that BMI, left ventricular mass index (LVMI), age and female gender were independently correlated with LADI (P < .05). And BMI was the most significant influencing factor of LADI in male patients (β = 0.350, P < .001), followed by LVMI (β = 0.343, P < .001). While in female patients, LVMI was the most significant (β = 0.353, P < .001), followed by BMI (β = 0.302, P < .001).

CONCLUSION

Overweight and obesity were significantly associated with LAE in hypertensive patients, with obesity more significant than overweight. While BMI had the greatest correlation with LAE in male, LVMI was the most important determinant of LAE in female. Therefore, in addition to weight loss, more attention should be paid to early inhibition of left ventricular remodeling in female with hypertension.

Left atrial size and risk of recurrent ischemic stroke in cardiogenic cerebral embolism

BACKGROUND

Left atrial enlargement (LAE) was reported to be associated with ischemic stroke and its recurrence. Limited data are available on the relationship of LAE and cardiogenic cerebral embolism (CCE). Our aim is to access the association of left atrial size and the recurrence of ischemic stroke in CCE.

METHODS

We prospectively included 303 CCE patients who underwent transthoracic echocardiography (TTE). Left atrial size was estimated with left atrial diameter (LAD), diameter/height (LAD/H), and left atrial diameter/body surface area (LAD/BSA). The endpoint was one-year recurrent ischemic stroke. Cox proportional hazard models were performed to access the association between left atrial size and recurrent ischemic stroke.

RESULTS

During follow-up, 27 patients suffered recurrent ischemic stroke. In multivariate COX regression models adjusted for confounders including age, gender, hypertension, diabetes, and history of stroke or transient ischemic attack (TIA), platelet count, fasting blood glucose (FBG), antithrombotic drugs at discharge, stroke volume, and cardiac output, LAD, LAD/H, and LAD/BSA all were independent risk factors of recurrent ischemic stroke [LAD: HR 1.065, 95% CI (1.006-1.128), p = .029; LAD/H: HR 1.157, 95% CI (1.066-1.255), p < .001; LAD/BSA: HR 1.128, 95% CI (1.059-1.202), p < .001]. Receiver-operator characteristic curves showed that LAD/BSA had better predicting effect. The area under the curve (AUC) was 0.543 [95%CI (0.444-0.642), p = .461) for LAD, 0.626 [95%CI (0.530-0.723), p = .03] for LAD/H, and 0.655 [95%CI (0.558-0.752), p = .008] for LAD/BSA.

CONCLUSION

LAE is an independent risk factor for one-year recurrence of ischemic stroke in patients with CCE.

Effect of expiratory phase for radiographic detection of left heart enlargement in dogs with mitral regurgitation

Radiography is a standard diagnostic test for characterizing left heart enlargement in dogs however limited information is available on the effects of respiratory phases. This prospective and retrospective method comparison study investigated the respiratory effect on the size and shape of the left heart in dogs to determine the usefulness of expiratory radiographs to detect enlargements in the left atrium (LA) and left ventricle (LV). Thoracic radiographs taken at full inspiration and expiration were evaluated in 20 normal beagles and 100 dogs diagnosed with mitral regurgitation (MR). Vertebral heart score (VHS), vertebral left atrial size, elevation of the carina, and dorsal bulging of LA on lateral view and lateral bulging of the left auricular appendage and LV on ventrodorsal view were assessed. In normal dogs, there were no significant differences in the evaluative factors between inspiration and expiration. In dogs with MR, VHS did not change according to respiration. However, bulging of the LA, left auricular appendage, and LV had sharp margin during expiration compared with inspiration. The expiratory radiographic finding of LA bulging had a higher correlation with the LA to aorta ratio compared with LA bulging in the inspiratory radiography. Using a LA to aorta echocardiographic ratio greater than 1.5 as the gold standard, the radiographic sensitivity for LA enlargement was higher during expiration than inspiration. These findings of our study indicated that expiratory radiography can be helpful to support the detection of left heart enlargement, although it can overestimate LA enlargement in dogs with MR.

Left Atrial Enlargement and the Risk of Stroke: A Meta-Analysis of Prospective Cohort Studies

Background: The association between left atrial size and the risk of stroke has not been fully understood. We performed a meta-analysis of prospective cohort studies to determine whether left atrial enlargement (LAE) is associated with an increased risk of stroke.

Methods: We searched PubMed, EMBASE, Web of Science, and the Cochrane Library through May 2019. Prospective cohort studies were included if they reported hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of stroke with respect to LAE. All meta-analyses were performed using a random-effects model.

Results: Six studies involving 66,007 participants and 3,549 stroke events were included. Compared with patients without LAE, those with LAE had an increased risk of stroke (adjusted HR 1.68, 95% CI 1.36–2.07). There was also a graded association with stroke relating to LAE (adjusted HR for mild LAE 1.50, 95% CI 0.98–2.28; moderate LAE 1.40, 95% CI 1.12–1.75; and severe LAE 1.59, 95% CI 1.33–1.90). Furthermore, for each increase of 1 cm in left atrial diameter, the odds of stroke were increased by 24% (adjusted HR 1.24, 95% CI 1.03–1.50).

Conclusions: Our meta-analysis demonstrated that LAE is associated with an increased and graded risk of stroke.

Compromised left atrial function and increased size predict raised cavity pressure: a systematic review and meta-analysis

AIM

This meta-analysis assesses left atrial (LA) cavity and myocardial function measurements that predict pulmonary capillary wedge pressure (PCWP).

METHODS

PubMed-MEDLINE, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry were searched up to December 2018 for studies on the relationship of LA diameter, LA indexed volume (LAVI max, LAVI min), peak atrial longitudinal (PALS), peak atrial contraction (PACS) strain and total emptying fraction (LAEF) with PCWP. Eighteen studies with 1343 patients were included. Summary sensitivity and specificity (with 95% CI) for evaluation of diagnostic accuracy and the best cut-off values for different LA indices in predicting raised PCWP were estimated using summary receiver operating characteristic analysis.

RESULTS

The pooled analysis showed association between PCWP and LA diameter: Cohen's d = 0·87, LAVI max: d = 0·92 and LAVI min: d = 1·0 (P<0·001 for all). A stronger correlation was found between PCWP and PALS: d = 1·26, and PACS: d = 1·62, total EF d = 1·22 (P<0·0001 for all). PALS ≤19% had a summary sensitivity of 80% (65-90) and summary specificity of 77% (52-92), positive likelihood ratio (LR+) 3·74, negative likelihood ratio (LR-) <0·25 and DOR > 15·1 whereas LAVI ≥34 ml m^-2 had summary sensitivity of 75% (55-89) and summary specificity 77% (57-90), with LR+ >3, LR- 0·32 and DOR >10·1.

CONCLUSIONS

Compromised LA myocardial function and increased size predict raised cavity pressure. These results should assist in optimum follow-up of patients with fluctuating LA pressure.

Left atrial ejection force predicts the outcome after catheter ablation for paroxysmal atrial fibrillation

INTRODUCTION

Left atrium (LA) systolic dysfunction is observed in the early stages of atrial fibrillation (AF) prior to LA anatomical change. We investigated whether LA systolic dysfunction predicts recurrent AF after catheter ablation (CA) in patients with paroxysmal AF.

METHODS AND RESULTS

We studied 106 patients who underwent CA for paroxysmal AF. LA systolic function was assessed with the LA emptying volume = Maximum LA volume (LAV_max ) - Minimum LA volume (LAV_min ), LA emptying fraction = [(LAV_max - LAV_min )/LAV_max ] × 100, and LA ejection force calculated with Manning's method [LA ejection force = (0.5 × ρ × mitral valve area × A² )], where ρ is the blood density and A is the late-diastolic mitral inflow velocity. Recurrent AF was detected in 35/106 (33%) during 14.6 ± 9.1 months. Univariate analysis revealed reduced LA ejection force, decreased LA emptying fraction, larger LA diameter, and elevated brain natriuretic peptide as significant variables. On multivariate analysis, reduced LA ejection force and larger LA diameter were independently associated with recurrent AF. Moreover, patients with reduced LA ejection force and larger LA diameter had a higher risk of recurrent AF than preserved LA ejection force (log-rank P = 0.0004).

CONCLUSIONS

Reduced LA ejection force and larger LA diameter were associated with poor outcome after CA for paroxysmal AF, and could be a new index to predict recurrent AF.

Left atrial size and risk of recurrent ischemic stroke in a Chinese population

BACKGROUND

Although a number of studies have reported the role of an increased left atrial (LA) size on stroke, limited data are collected about the relationship between LA enlargement and recurrent ischemic stroke in the Chinese population. Our aim was to assess the association of LA size with the risk of stroke recurrence, particularly with recurrent cardioembolic or cryptogenic stroke in ischemic stroke patients.

METHODS

The study recruited 313 consecutive patients with acute first-ever ischemic stroke. Echocardiographic LA diameter was measured and indexed by height and body surface area separately. The endpoint was recurrent ischemic stroke. Cox proportional hazard models were used to examine the association of LA size with total recurrent ischemic stroke and recurrent cardioembolic or cryptogenic stroke while adjusting for baseline demographics characteristics, clinical factors, echocardiographic left ventricular ejection fraction, and medication.

RESULTS

Over a median follow-up period of 1.63 years, 47 recurrent ischemic strokes (21 were cardioembolic or cryptogenic) occurred. In a multivariate model adjusted for potential confounders, compared with the bottom tertiles of LA diameter indexed to height (LA diameter/H), the top tertile of LA diameter/H was significantly associated with the total recurrent ischemic stroke (adjusted HR 3.610, 95% CI 1.870-6.967, p < .001) and the composite of recurrent cardioembolic or cryptogenic stroke (adjusted HR 5.673, 95% CI 1.780-18.084, p = .003). Results were similar when LA diameter indexed to body surface area (LA diameter/BSA) was involved in the analysis.

CONCLUSION

LA size is an independent predictor of total recurrent ischemic stroke and the composite of recurrent cardioembolic or cryptogenic stroke.

Echocardiographic sizing of the left atrium of the transplanted heart

BACKGROUND

The left atrium (LA) in the transplanted heart (TH) is a surgically created chamber from variable portions of donor and recipient LA. The American Society of Echocardiography (ASE) recommends measuring LA size in native hearts using biplane LA volume index (LAVI) as a more accurate measurement than LA anterior-posterior diameter (LA-APD). We hypothesized that LA-APD underestimates LA size when compared with LAVI in the TH.

METHODS

Patients with a TH from 1/05 to 1/10 who had a transthoracic echocardiogram within 24 months of transplant were studied. Patients were excluded if they had an ejection fraction <50%, left ventricular hypertrophy, >mild aortic or mitral regurgitation, or poor image quality. Echocardiograms were analyzed for LA-APD and LAVI. LA size was classified as normal, mild, moderate, or severely enlarged based on age and sex specific cutoffs per the ASE.

RESULTS

Of 297 patients evaluated, 160 met inclusion criteria. Mean age was 57 ± 13 years and 79% were males. Mean LA-APD and LAVI were 4.3 ± 0.6 cm and 36 ± 14 mL/m(2), respectively. LAVI correlated with LA-APD (r = 0.43, R(2) = 0.18, P < 0.0001). By LA-APD measurement, 20 (13%) LA were classified as having moderate or severe LA enlargement versus 80 (50%) by LAVI, P = 0.001. LA size was underclassified by ≥ 2 classes in 44 (28%) by LA-APD versus LAVI.

CONCLUSIONS

In the setting of cardiac transplant, the LA size classified by LA-APD is commonly less than that classified by LAVI.

Clinical implications of left atrial enlargement: a review

Echocardiographically determined left atrial (LA) size has been shown to be a significant predictor of cardiovascular (CV) outcomes. We review the physiology and echocardiographic assessment of LA size and functions and describe the pathophysiologic determinants and clinical implications of LA enlargement. However, despite strong evidence, standardized LA size assessment and generalized applicability of its clinical implications to patient care have yet to be determined. Nevertheless, current findings suggest that echocardiographically determined LA size may become an important clinical risk identifier in preclinical CV disease and should be assessed as a part of routine comprehensive echocardiographic evaluation.