Echocardiography in Cardiovascular Public Health: The Feigenbaum Lecture 2008

Echocardiographic measures of the left heart and cerebrospinal fluid biomarkers of Alzheimer's disease pathology in cognitively intact adults: The CABLE study

INTRODUCTION

This study delineated the interrelationships between subclinical alterations in the left heart, cerebrospinal fluid (CSF), Alzheimer's disease (AD) biomarkers, and cognition.

METHODS

Multiple linear regressions were conducted in 1244 cognitively normal participants (mean age = 65.5; 43% female) who underwent echocardiography (left atrial [LA] and left ventricular [LV] morphologic or functional parameters) and CSF AD biomarkers measurements. Mediating effects of AD pathologies were examined. Differences in cardiac parameters across ATN categories were tested using analysis of variance (ANOVA) and logistic regressions.

RESULTS

LA or LV enlargement (characterized by increased diameters and volumes) and LV hypertrophy (increased interventricular septal or posterior wall thickness and ventricular mass) were associated with higher CSF phosphorylated (p)-tau and total (t)-tau levels, and poorer cognition. Tau pathologies mediated the heart-cognition relationships. Cardiac parameters were higher in stage 2 and suspected non-Alzheimer's pathology groups than controls.

DISCUSSION

These findings suggested close associations of subclinical cardiac changes with tau pathologies and cognition.

HIGHLIGHTS

Various subclinical alterations in the left heart related to poorer cognition. Subclinical cardiac changes related to tau pathologies in cognitively normal adults. Tau pathologies mediated the heart-cognition relationships. Subclinical cardiac changes related to the AD continuum, especially to stage 2. The accumulation of cardiac alterations magnified their damage to the brain.

Role of open access echocardiography in detection of cardiac structural and functional abnormalities

PURPOSE

To evaluate the prevalence and incidence of significant structural heart disease in targeted patients with cardiac symptoms referred by general practitioners (GPs) using open access echocardiography, without prior clinical evaluation by a cardiologist.

DESIGN

Data were derived from 488 subjects who underwent transthoracic echocardiography between January and April 2018. Patients were referred directly by GPs in East Berkshire, South England, through an online platform. Echocardiography was performed within 4-6 weeks of referral and all reports were assessed by a consultant cardiologist with expedited follow-up facilitated pro re nata. Results were analysed to determine the frequency of detection of structural abnormalities, particularly of the left ventricle and cardiac valves.

RESULTS

Echocardiography was prospectively performed in consecutive subjects (50% male, mean (±SD) age 68.5±22 years; 50% female; mean (±SD) 64.6 (±19.1)). At least one abnormality likely to change management was found in 133 (27.3%) of all open access echocardiograms. Clinical heart failure with left ventricular systolic dysfunction (LVSD) and diastolic dysfunction was confirmed in 46 (9%) and 69 (14%), respectively. Of the 46 patients with LVSD, 33 were new diagnoses. Significant cardiac valve disease was found in 42 (8.6%) patients. 12 of these had known valvular disease or previous valvular surgery, and 30 were new diagnoses.

CONCLUSION

Major structural and functional cardiac abnormalities are common in late middle-aged patients who present to GPs with cardiac symptoms and signs. Reported, unrestricted open access echocardiography enables early detection of significant cardiac pathology and timely intervention may improve cardiovascular outcomes.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Simultaneous Analysis of 2D Echo Views for Left Atrial Segmentation and Disease Detection

We propose a joint information approach for automatic analysis of 2D echocardiography (echo) data. The approach combines a priori images, their segmentations and patient diagnostic information within a unified framework to determine various clinical parameters, such as cardiac chamber volumes, and cardiac disease labels. The main idea behind the approach is to employ joint Independent Component Analysis of both echo image intensity information and corresponding segmentation labels to generate models that jointly describe the image and label space of echo patients on multiple apical views, instead of independently. These models are then both used for segmentation and volume estimation of cardiac chambers such as the left atrium and for detecting pathological abnormalities such as mitral regurgitation. We validate the approach on a large cohort of echoes obtained from 6,993 studies. We report performance of the proposed approach in estimation of the left-atrium volume and detection of mitral-regurgitation severity. A correlation coefficient of 0.87 was achieved for volume estimation of the left atrium when compared to the clinical report. Moreover, we classified patients that suffer from moderate or severe mitral regurgitation with an average accuracy of 82%.

Three-Dimensional Echocardiographic Assessment of Left Heart Chamber Size and Function with Fully Automated Quantification Software in Patients with Atrial Fibrillation

BACKGROUND

Echocardiographic determination of left heart chamber volumetric parameters by using manual tracings during multiple beats is tedious in atrial fibrillation (AF). The aim of this study was to determine the usefulness of fully automated left chamber quantification software with single-beat three-dimensional transthoracic echocardiographic data sets in patients with AF.

METHODS

Single-beat full-volume three-dimensional transthoracic echocardiographic data sets were prospectively acquired during consecutive multiple cardiac beats (≥10 beats) in 88 patients with AF. In protocol 1, left ventricular volumes, left ventricular ejection fraction, and maximal left atrial volume were validated using automated quantification against the manual tracing method in identical beats in 10 patients. In protocol 2, automated quantification-derived averaged values from multiple beats were compared with the corresponding values obtained from the indexed beat in all patients.

RESULTS

Excellent correlations of left chamber parameters between automated quantification and the manual method were observed (r = 0.88-0.98) in protocol 1. The time required for the analysis with the automated quantification method (5 min) was significantly less compared with the manual method (27 min) (P < .0001). In protocol 2, there were excellent linear correlations between the averaged left chamber parameters and the corresponding values obtained from the indexed beat (r = 0.94-0.99), and test-retest variability of left chamber parameters was low (3.5%-4.8%).

CONCLUSIONS

Three-dimensional transthoracic echocardiography with fully automated quantification software is a rapid and reliable way to measure averaged values of left heart chamber parameters during multiple consecutive beats. Thus, it is a potential new approach for left chamber quantification in patients with AF in daily routine practice.

Registry report of structural and functional cardiac abnormalities diagnosed by echocardiography in an asymptomatic population

BACKGROUND

The epidemiology of heart disease is changing, with rheumatic heart disease becoming less common but degenerative valve disorders, heart failure and atrial fibrillation (AF) increasing.

OBJECTIVE

We sought to determine the prevalence of structural cardiac abnormalities in the apparently symptom-free adult population within our prospective echocardiography (echo) registry.

METHODS

Our echo registry comprised echo studies and associated demographic and clinical data obtained prospectively from 362 consecutive asymptomatic subjects aged 50-74 years and without known heart disease referred between 2011 and 2012 from general practices in the South East of England.

RESULTS

221 echo abnormalities were detected in 178 (49%) subjects (46% men; mean (±SD) age 63.9±9.2 years; 98% Caucasian). A major abnormality was detected in seven subjects: four had a large secundum atrial septal defect, one had critical aortic stenosis, one severe mitral regurgitation and one features of hypertrophic cardiomyopathy. Twelve subjects had left ventricular systolic dysfunction with an ejection fraction (EF) <50% (of whom 10 had EF <40%). Four subjects had AF. Minor echo abnormalities were evident in the remaining 171 (47%) subjects. Abnormalities were commoner in patients with cardiovascular risk factors or a history of cardiac disease than in those without (53% vs 38%). In multivariate analyses stratified by gender, for women, increased age (F=33.3, p<0.001) and systolic blood pressure (F=9.2, p=0.003) were associated with abnormal echo findings; for men, increased age (F=12.0, p<0.001) and lower cholesterol (F=4.2, p=0.042) predicted an increase in abnormal findings on echo.

CONCLUSIONS

Unrecognised cardiac abnormalities are very common in middle-aged men and women with no overt symptoms. Echo offers the potential to identify the need for early intervention and treatment to improve cardiovascular outcomes.

Relationship between cognitive impairment and echocardiographic parameters: a review

With >24 million people affected worldwide, dementia is one of the main public health challenges modern medicine has to face. The path leading to dementia is often long, with a wide spectrum of clinical presentations, and preceded by a long preclinical phase. Previous studies have demonstrated that clinical strokes and covert vascular lesions of the brain contribute to the risk for developing dementia. Although it is not yet known whether preventing such lesions reduces the risk for dementia, it is likely that starting preventive measures early in the course of the disease may be beneficial. Echocardiography is a widely available, relatively inexpensive, noninvasive imaging modality whereby morphologically or hemodynamically derived parameters may be integrated easily into a risk assessment model for dementia. The aim of this review is to analyze the information that has accumulated over the past two decades on the prognostic value of echocardiographic factors in cognitive impairment. The associations between cognitive impairment and echocardiographic parameters, including left ventricular systolic and diastolic indices, left atrial morphologic parameters, cardiac output, left ventricular mass, and aortic root diameter, have previously been reported. In the light of these studies, it appears that echocardiography may help further improve currently used risk assessment models by allowing detection of subclinical cardiac abnormalities associated with future cognitive impairment. However, many limitations, including methodologic heterogeneity and the observational designs of these studies, restrict the scope of these results. Further prospective studies are required before integrating echocardiography into a preventive strategy.

Evaluation of atrial electromechanic delay and left atrial mechanical functions in the patients with secundum type atrial septal defect

AIM

The aim of our study was to evaluate atrial electromechanical delay (AEMD) and left atrial mechanical functions (LAMF) in the patients with secundum-type atrial septal defect (ASD).

METHOD

We included 72 patients with secundum type ASD in the study group and 35 gender and age-matched healthy volunteers for the control group. Maximal, minimal, and presystolic LA volumes were measured by modified Simpson method and indexed to the body surface area (BSA). Inter-AEMD, right and left intra-AEMD were measured from the lateral and septal mitral annulus and tricuspid annulus using tissue Doppler imaging (TDI).

RESULTS

The age, gender, systolic and diastolic blood pressure, heart rate (HR), BSA, and body mass index (BMI) parameters were not significantly different between the groups. Left atrial active and total emptying fractions and conduit volumes were significantly lower in the patients with ASD compared with the control group (P = 0.006, P = 0.001, and P = 0.032, respectively). Total emptying volume was increased in patients with ASD (P = 0.021). Passive emptying volume and fraction and active emptying volumes were not different significantly between the groups (P > 0.05). The left intraatrial, right intraatrial, and inter-AEMDs were significantly longer in the ASD group (P = 0.032, P = 0.013, and P = 0.003, respectively).

CONCLUSION

The left atrial reservoir and contractile pump functions are reduced; the left intraatrial, right intraatrial, and inter-AEMDs are increased in the patients with ASD.

Effect of percutaneous transvenous mitral commissurotomy on left atrial appendage function: an immediate and 6-month follow-up transesophageal Doppler study

BACKGROUND

The left atrial appendage (LAA) is a common site of thrombus formation and is the source of systemic thromboembolism in patients with rheumatic mitral stenosis. LAA contractile dysfunction is a common finding in these patients. The aim of this study was to assess immediate and 6-month follow-up LAA function by transesophageal Doppler echocardiography in patients who underwent percutaneous transvenous mitral commissurotomy (PTMC).

METHODS

Forty-seven consecutive patients with symptomatic critical mitral stenosis who underwent PTMC were enrolled. All had underwent transthoracic and transesophageal echocardiography before, 24 hours after, and 6 months after PTMC. Pulse Doppler velocities of the LAA were measured, including peak early diastolic (E wave), peak late diastolic (A wave), and peak systolic (S wave). The corresponding tissue Doppler velocities of the LAA, including peak early diastolic (E(LAA)), peak late diastolic (A(LAA)), and peak systolic (S(LAA)), were also measured. LAA ejection fraction was measured using the modified Simpson's method.

RESULTS

The mean age of the 47 enrolled patients was 31.7 ± 10.26 years. Thirty-eight patients were in sinus rhythm, and the remaining nine were in atrial fibrillation. PTMC was successful in all patients. The pulse Doppler velocities of the LAA at baseline, after PTMC, and at 6-month follow-up were as follows: for the E wave, 15.29 ± 2.26, 17.02 ± 2.25, and 17.97 ± 2.55 cm/sec, respectively (P < .001); for the A wave 22.45 ± 4.11, 24.19 ± 4.21, and 25.99 ± 4.51 cm/sec, respectively (P < .001); and for the S wave, 28.52 ± 4.37, 31.45 ± 5.37, and 33.06 ± 4.99 cm/sec, respectively (P < .001). The corresponding tissue Doppler velocities of LAA were as follows: for E(LAA), 4.65 ± 0.91, 5.28 ± 0.85, and 5.80 ± 0.84 cm/sec, respectively (P < .001); for A(LAA), 6.67 ± 1.12, 7.33 ± 1.17, and 7.88 ± 1.22 cm/sec, respectively (P < .001); and for S(LAA), 4.67 ± 1.12, 5.52 ± 1.18, 6.07 ± 1.11 cm/sec, respectively (P < .001). There was a nonsignificant increase in LAA ejection fraction (48.97 ± 8.14% vs 52.3 ± 13.76% vs 52.11 ± 16.3%, respectively, P = .052). On subgroup analysis between patients in sinus rhythm and those with atrial fibrillation, there was no significant difference for LAA ejection fraction and pulse and tissue Doppler velocities. Very good intraclass correlation of the LAA parameters was also observed for the reproducibility of the data.

CONCLUSIONS

The present study shows contractile dysfunction of the LAA in patients with critical mitral stenosis, which significantly improved after PTMC, and a further improvement was observed at 6-month follow-up. Favorable 6-month improvements in LAA parameters suggest continuous structural remodeling of the LAA after PTMC, which is clinically attributed to the absence of thromboembolism. Although there was an improvement in LAA function, it was far below the normal range, suggesting a need for continuous long-term monitoring and management of thromboembolism in these patients.