Left Atrial Index Is a Predictor of Exercise Capacity in Patients with Hypertrophic Cardiomyopathy

Pressure-Strain Loops, a Novel Non-invasive Approach for Assessment of Children with Cardiomyopathy

Non-invasive myocardial work (MW) by left ventricular (LV) pressure-strain loops (PSL) is a novel method for assessing myocardial function while adjusting for afterload, yet pediatric data remain lacking. The aims of this study were to investigate the different patterns of LV PSL and non-invasive MW in pediatric patients with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and their association with exercise tolerance. We included 110 pediatric subjects (mean age, 13 ± 4 years, 35 DCM, 40 HCM, and 35 healthy controls). Standard and speckle-tracking echocardiography were performed. LV PSLs were generated, and global work index (GWI), MW efficiency (GWE), constructive work (GCW), and wasted work (GWW) were compared between groups. Regression analysis was used to assess the influence of ventricular function, dimensions, wall thickness, and wall stress on MW and to predict the association between MW and VO2 max as a surrogate of exercise capacity. Patients with DCM had significantly lower GWI compared to controls (GWI 479.6 ± 263.0 vs 1610.1 ± 211.0, P < 0.005). GWE was significantly reduced in DCM (79.3 ± 7.9 vs 95.2 ± 1.3, P < 0.005) due to significantly reduced GCW and increased GWW. HCM patients had significant reduction in GWI and GWE from normal (1237.7 ± 449.1 vs 1610.1 ± 211.0, P = 0.001 and 89.6 ± 4.9 vs 95.2 ± 1.3, P < 0.005, respectively), although less severe than with DCM. In a multivariate regression analysis, GWE had the highest association with VO2 max in both cohorts (DCM: β = 0.68, P = 0.001, HCM: β = 0.71, P = 0.007). Non-invasively assessed myocardial work and LV PSLs provide novel insights into the mechanisms of dysfunction in pediatric patients with cardiomyopathy with good prediction of clinical status and thus hold promise to further explore myocardial mechanistic with clinical relevance in different disease entities.

Cardiopulmonary Exercise Test in Patients with Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with chronic diseases frequently adapt their lifestyles to their functional limitations. Functional capacity in Hypertrophic Cardiomyopathy (HCM) can be assessed by stress testing. We aim to review and analyze the available data from the literature on the value of Cardiopulmonary Exercise Test (CPET) in HCM. Objective measurements from CPET are used for evaluation of patient response to traditional and new developing therapeutic measurements.

METHODS

A systematic review of the literature was conducted in PubMed, Web of Science and Cochrane in Mar-20. The original search yielded 2628 results. One hundred and two full texts were read after the first screening, of which, 69 were included for qualitative synthesis. Relevant variables to be included in the review were set and 17 were selected, including comorbidities, body mass index (BMI), cardiac-related symptoms, echocardiographic variables, medications and outcomes.

RESULTS

Study sample consisted of 69 research articles, including 11,672 patients (48 ± 14 years old, 65.9%/34.1% men/women). Treadmill was the most common instrument employed (n = 37 studies), followed by upright cycle-ergometer (n = 16 studies). Mean maximal oxygen consumption (VO2max) was 22.3 ± 3.8 mL·kg^-1·min^-1. The highest average values were observed in supine and upright cycle-ergometer (25.3 ± 6.5 and 24.8 ± 9.1 mL·kg^-1·min^-1; respectively). Oxygen consumption in the anaerobic threshold (ATVO2) was reported in 18 publications. Left ventricular outflow tract gradient (LVOT) > 30 mmHg was present at baseline in 31.4% of cases. It increased to 49% during exercise. Proportion of abnormal blood pressure response (ABPRE) was higher in severe (>20 mm) vs. mild hypertrophy groups (17.9% vs. 13.6%, p < 0.001). Mean VO2max was not significantly different between severe vs. milder hypertrophy, or for obstructive vs. non-obstructive groups. Occurrence of arrhythmias during functional assessment was higher among younger adults (5.42% vs. 1.69% in older adults, p < 0.001). Twenty-three publications (9145 patients) evaluated the prognostic value of exercise capacity. There were 8.5% total deaths, 6.7% cardiovascular deaths, 3.0% sudden cardiac deaths (SCD), 1.2% heart failure death, 0.6% resuscitated cardiac arrests, 1.1% transplants, 2.6% implantable cardioverter defibrillator (ICD) therapies and 1.2 strokes (mean follow-up: 3.81 ± 2.77 years). VO2max, ATVO2, METs, % of age-gender predicted VO2max, % of age-gender predicted METs, ABPRE and ventricular arrhythmias were significantly associated with major outcomes individually. Mean VO2max was reduced in patients who reached the combined cardiovascular death outcome compared to those who survived (-6.20 mL·kg^-1·min^-1; CI 95%: -7.95, -4.46; p < 0.01).

CONCLUSIONS

CPET is a valuable tool and can safely perform for assessment of physical functional capacity in patients with HCM. VO2max is the most common performance measurement evaluated in functional studies, showing higher values in those based on cycle-ergometer compared to treadmill. Subgroup analysis shows that exercise intolerance seems to be more related to age, medication and comorbidities than HCM phenotype itself. Lower VO2max is consistently seen in HCM patients at major cardiovascular risk.

Left Atrial Strain and Function in Pediatric Hypertrophic Cardiomyopathy

BACKGROUND

Left atrial (LA) strain and dysfunction are early markers of diastolic dysfunction, associated with poor exercise capacity in adults with hypertrophic cardiomyopathy (HCM). Literature on assessment of LA mechanics in pediatric HCM is lacking. The aim of this study was to assess LA strain and LA function in pediatric patients who have HCM with (phenotype positive [P+]) and without (genotype positive, phenotype negative [G+P-]) ventricular hypertrophy and evaluate their correlation with exercise stress test parameters.

METHODS

Seventy-eight children (3-25 years of age) with HCM (P+, n = 46; G+P-, n = 32) and 20 healthy control subjects were retrospectively studied. LA conduit function, reservoir function, and pump function were computed using phasic LA volumetric analysis. LA reservoir strain (LASr) and LA contractile strain were measured using speckle-tracking echocardiography. Exercise test findings within 12 months of echocardiography were recorded.

RESULTS

LA conduit function (36% vs 48%, P < .001) and LA reservoir function (137% vs 180%, P < .001) were lower in P+ than in G+P- patients. LA contractile function did not differ between the groups (31% vs 32%, P = .87). Compared with patients with G+P- HCM, those with P+HCM had lower four-chamber LASr (29% vs 41%, P < .001), two-chamber LASr (30% vs 41%, P < .001), average LASr (29% vs 42%, P < .001), and LA contractile strain (9% vs 12%, P = .016). In the cohort of patients with HCM who underwent stress testing (n = 35), LA conduit function weakly correlated with aerobic capacity (r = 0.42, P = .019).

CONCLUSIONS

Children with P+HCM have reduced LA function, measurable by both volumetric and strain analysis. Altered LA mechanics are associated with poor exercise capacity. This study lays the foundation for the evaluation of novel LA parameters in pediatric HCM and warrants larger longitudinal studies to assess its clinical significance.

Left atrial remodeling postseptal myectomy for severe obstructive hypertrophic cardiomyopathy: Analysis by two-dimensional speckle-tracking echocardiography

BACKGROUND

Septal myectomy relieves left ventricular outflow obstruction (LVOTO) and is associated with excellent long-term outcomes. LVOTO is associated with diastolic dysfunction and increased left atrial (LA) size. We sought to investigate the changes in LA volumes and function postmyectomy and the association between these changes with clinical outcomes postmyectomy.

METHODS

Sixty-six hypertrophic cardiomyopathy patients undergoing myectomy were retrospectively studied. Preprocedural and 6- to 18-month postmyectomy follow-up transthoracic echocardiographic images were obtained. LA volumes and strain were assessed by two-dimensional speckle-tracking echocardiography.

RESULTS

Left atrial volumes, that is, indexed maximal, minimal, and pre-A volumes reduced postmyectomy, yet remained increased compared to controls (105.6 ± 34.5 mL vs 84.9 ± 26.7 mL, 45.2 ± 25.7 mL vs 35.4 ± 22.6 mL, 70.1 ± 31.4 mL vs 35.4 ± 22.6 mL, respectively, P < 0.05). The total emptying index did not improve postmyectomy and remained lower than controls (58.6 ± 12.4 vs 59.9 ± 12.8, P = NS) whereas atrial contraction improved, yet did not normalize (active emptying index 36.1 ± 14.9 vs 41.1 ± 16.2, P < 0.05). The conduit volume remained reduced postmyectomy (18.6 ± 13.3 mL vs 16.6 ± 15.1 mL, P = NS). LA strain also did not improve postmyectomy (26.8 ± 7.3 vs 28.5 ± 8.8, P = NS). A multivariable logistic regression identified preprocedural E/e' ratio and indexed maximal LA volume, as independent predictors for LA volume reduction ≥20% postmyectomy. During a mean follow-up of 4.9 ± 2.3 years postmyectomy, 24.2% of the patients developed atrial fibrillation and <5% of patients were severely symptomatic. We found no associations between LA volumes/function and atrial fibrillation or symptoms postmyectomy.

CONCLUSION

Postmyectomy LA volumes decreased, and the contractile function improved. There was no association between LA volumes/function and clinical outcomes postmyectomy. Notably, the LA remained enlarged (though to a lesser degree) with reduced strain and emptying fraction, suggesting possible atrial myopathy.

Predictors of Exercise Capacity in Patients with Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy (HOCM) patients exhibit compromised peak exercise capacity (VO₂peak). Importantly, severely reduced VO₂peak is directly related to increased morbidity and mortality in these patients. Therefore, we sought to determine clinical predictors of VO₂peak in HOCM patients. HOCM patients who performed symptom-limited cardiopulmonary exercise testing between 1995 and 2016 were included for analysis. Peak VO₂ was reported as absolute peak VO₂, indexed to body weight and analyzed as quartiles, with quartile 1 representing the lowest VO₂peak. Step-wise regression models using demographic features and clinical and physiologic characteristics were created to determine predictors of HOCM patients with the lowest VO₂peak. We included 1177 HOCM patients (age: 53 ± 14 years; BMI: 24 ± 12 kg/m²) with a VO₂peak of 18.0 ± 5.6 mL/kg/min. Significant univariate predictors of the lowest VO₂peak included age, female sex, New York Health Association (NYHA) class, BMI, left atrial volume index, E/e’, E/A, hemoglobin, N-terminal pro b-type natriuretic peptide (NT-proBNP), and a history of diabetes, hypertension, stroke, atrial fibrillation, or coronary artery disease. Independent predictors of the lowest VO₂peak included age (OR, CI: 1.03, 1.02–1.06; p < 0.0001), women (4.66, 2.94–7.47; p = 0.001), a history of diabetes (2.05, 1.17–3.60; p = 0.01), BMI (0.94, 0.92–0.96; p < 0.0001), left atrial volume index (1.07, 1.05–1.21; p = 0.04), E/e’ (1.05, 1.01–1.08; p = 0.004), hemoglobin (0.76, 0.65–0.88; p = 0.0004), and NT-proBNP (1.72, 1.42–2.11; p < 0.0001). These findings demonstrate that demographic factors (i.e., age and sex), comorbidities (e.g., diabetes and obesity), echocardiography indices, and biomarkers (e.g., hemoglobin and NT-proBNP) are predictive of severely compromised VO₂peak in HOCM patients.

Effect of Body Mass Index on Exercise Capacity in Patients With Hypertrophic Cardiomyopathy

The objective of this study was to evaluate the relation between body mass index (BMI), exercise capacity, and symptoms in patients with hypertrophic cardiomyopathy (HC) and to utilize results of cardiopulmonary exercise tests (CPX) and transthoracic echocardiograms to understand the mechanism(s) of reduced exercise capacity across body mass index groups. Over a 6-year period, 510 consecutive patients with HC seen at a tertiary referral center underwent (CPX) and a transthoracic echocardiogram. Increasing BMI was associated with decreased exercise capacity as assessed by peak VO₂ (ml/kg/min). However, the prevalence of cardiac impairment did not vary by BMI group. In conclusion, these findings suggest that in some patients with hypertrophic cardiomyopathy, cardiac impairment is not the primary cause of exercise limitation and weight loss may result in improved exercise capacity.

Effects of septal myectomy on left ventricular diastolic function and left atrial volume in patients with hypertrophic cardiomyopathy

Ventricular septal myectomy in patients with obstructive hypertrophic cardiomyopathy (HC) has been shown to reduce left ventricular (LV) outflow tract (LVOT) gradient and improve symptoms, although little data exist regarding changes in left atrial (LA) volume and LV diastolic function after myectomy. We investigated changes in LA size and LV diastolic function in patients with HC after septal myectomy from 2004 to 2011. We studied 25 patients (age 49.2 ± 13.1 years, 48% women) followed for a mean of 527 days after surgery who had serial echocardiography at baseline and at most recent follow-up, at least 6 months after myectomy. In addition to myectomy, 3 patients (12%) underwent Maze surgery and 13 (52%) underwent mitral valve surgery, of whom 5 had a mitral valve replacement or mitral annuloplasty. Patients with mitral valve replacement or mitral annuloplasty were excluded from LV diastolic function analysis. LA volume index decreased (from 47.2 ± 17.6 to 35.9 ± 17.0 ml/m(2), p = 0.001) and LV diastolic function improved with an increase in lateral e' velocity (from 7.3 ± 2.9 to 9.8 ± 3.1 cm/sec, p = 0.01) and a decrease in E/e' (from 14.8 ± 6.3 to 11.7 ± 5.5, p = 0.051). Ventricular septal thickness and LVOT gradient decreased, and symptoms of dyspnea and heart failure improved, with reduction in the New York Heart Association functional class III/IV symptoms from 21 (84%) to 1 (4%). In conclusion, relief of LVOT obstruction in HC by septal myectomy results in improved LV diastolic function and reduction in LA volume with improved symptoms.

Comparison of clinical presentation, left ventricular morphology, hemodynamics, and exercise tolerance in obese versus nonobese patients with hypertrophic cardiomyopathy

Obesity is independently associated with left ventricular (LV) hypertrophy and thus may be an important modifier of the hypertrophic cardiomyopathy (HC) phenotype. We examined if obesity modifies the clinical presentation, LV morphology, outflow hemodynamics, and exercise tolerance in HC. In this cross-sectional study, 88 obese (body mass index [BMI] ≥30 kg/m(2)) and 154 nonobese (BMI <30 kg/m(2)) patients from the Johns Hopkins HC clinic were compared with respect to a variety of clinical and LV echocardiographic measurements. Obese patients (36.4%) were more likely to report exertional dyspnea (p = 0.04) and chest pain (p = 0.002) and had greater prevalence of hypertension (p = 0.008). LV posterior wall thickness (p = 0.01) but not the septal wall (p ≥0.21) was significantly greater in obese patients, resulting in an increased LV mass index (p = 0.003). No significant differences in LV systolic and diastolic functions were observed, but obesity was associated with higher LV stroke volume (p = 0.03), inducible LV outflow tract gradients (p = 0.045), and chance of developing LV outflow tract obstruction during stress (p = 0.035). In multivariate analysis, BMI was associated with increased posterior (but not septal) wall thickness (β = 0.15, p = 0.02) and LV mass index (β = 0.18, p = 0.005), particularly in those with hypertension. Obesity was also associated with reduced exercise time and functional capacity, and BMI independently correlated with reduced exercise tolerance. In conclusion, obesity is associated with larger LV mass, worse symptoms, lower exercise tolerance, and labile obstructive hemodynamics in HC. The association with increased outflow tract gradients has particular importance as contribution of obesity to the pressure gradients may influence clinical decisions in labile obstructive HC.

Systolic function reserve using two-dimensional strain imaging in hypertrophic cardiomyopathy: comparison with essential hypertension

BACKGROUND

Although patients with hypertrophic cardiomyopathy (HCM) have normal ejection fractions at rest, the investigators hypothesized that these patients have differentially abnormal systolic function reserves, limiting their exercise capacity compared with patients with hypertension (HTN).

METHODS

Forty patients with HCM (mean age, 39.1 ± 12 years), 20 patients with HTN with LVH, and 33 healthy individuals underwent resting and peak exercise echocardiography using two-dimensional strain imaging. Peak longitudinal systolic strain (εsys) and strain rate were measured in apical views. Circumferential εsys and left ventricular (LV) twist were analyzed from short-axis views. LV systolic dyssynchrony was measured from regional longitudinal strain curves as the standard deviation of time to peak strain (time from the beginning of the Q wave on electrocardiography to peak εsys) between 12 segments. The differences between resting and peak exercise values were analyzed, and functional reserve was calculated as the difference divided by the resting value.

RESULTS

In patients with HCM, resting values for longitudinal εsys, systolic strain rate, early diastolic strain rate, and atrial diastolic strain rate were significantly lower, while circumferential εsys and twist were higher, compared with patients with HTN and controls (P < .0001). Functional systolic reserve increased during exercise in controls (17 ± 6%), increased to a lesser extent in patients with HTN (10 ± 16%), and was markedly attenuated in patients with HCM (-23 ± 28%) (P < .001). At peak exercise, even with augmented circumferential εsys and twist in patients with HCM (P < .01) compared with those with HTN, both remained lower than in controls (P < .001). LV dyssynchrony was amplified during exercise in patients with HCM compared with those with HTN (P < .001). Within the entire population, exercise capacity was clearly correlated with systolic functional reserve. However when taken separately, it was mainly related to resting LV dyssynchrony and diastolic function in patients with HCM, whereas it was linked to age and LV wall thickness in those with HTN.

CONCLUSIONS

Patients with HCM have significantly limited systolic function reserve and more dynamic dyssynchrony with exercise compared with those with HTN. Two-dimensional strain imaging during stress may provide a new and reliable method to identify patients at higher cardiovascular risk.

Diastolic function is associated with quality of life and exercise capacity in stable heart failure patients with reduced ejection fraction

Exercise capacity and quality of life (QOL) are important outcome predictors in patients with systolic heart failure (HF), independent of left ventricular (LV) ejection fraction (LVEF). LV diastolic function has been shown to be a better predictor of aerobic exercise capacity in patients with systolic dysfunction and a New York Heart Association (NYHA) classification ≥II. We hypothesized that the currently used index of diastolic function E/e' is associated with exercise capacity and QOL, even in optimally treated HF patients with reduced LVEF. This prospective study included 44 consecutive patients aged 55±11 years (27 men and 17 women), with LVEF<0.50 and NYHA functional class I-III, receiving optimal pharmacological treatment and in a stable clinical condition, as shown by the absence of dyspnea exacerbation for at least 3 months. All patients had conventional transthoracic echocardiography and answered the Minnesota Living with HF Questionnaire, followed by the 6-min walk test (6MWT). In a multivariable model with 6MWT as the dependent variable, age and E/e' explained 27% of the walked distance in 6MWT (P=0.002; multivariate regression analysis). No association was found between walk distance and LVEF or mitral annulus systolic velocity. Only normalized left atrium volume, a sensitive index of diastolic function, was associated with decreased QOL. Despite the small number of patients included, this study offers evidence that diastolic function is associated with physical capacity and QOL and should be considered along with ejection fraction in patients with compensated systolic HF.

Left atrial enlargement and reduced physical function during aging

Diastolic dysfunction, often seen with increasing age, is associated with reduced exercise capacity and increased mortality. Mortality rates in older individuals are linked to the development of disability, which may be preceded by functional limitations. The goal of this study was to identify which echocardiographic measures of diastolic function correlate with physical function in older subjects. A total of 36 men and women from the Louisiana Healthy Aging Study, age 62-101 yr, received a complete echocardiographic exam and performed the 10-item continuous-scale physical-functional performance test (CS-PFP-10). After adjustment for age and gender, left atrial volume index (ρ = -0.59; p = .0005) correlated with the total CS-PFP-10 score. Increased left atrial volume index may be a marker of impaired performance of activities of daily living in older individuals.

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a fascinating disease of marked heterogeneity. Hypertrophic cardiomyopathy was originally characterized by massive myocardial hypertrophy in the absence of known etiology, a dynamic left ventricular outflow obstruction, and increased risk of sudden death. It is now well accepted that multiple mutations in genes encoding for the cardiac sarcomere are responsible for the disease. Complex morphologic and pathophysiologic differences, disparate natural history studies, and novel treatment strategies underscore the challenge to the practicing cardiologist when faced with the management of the hypertrophic cardiomyopathy patient.

Relationship between baseline resting diastolic function and exercise capacity in patients with hypertrophic cardiomyopathy undergoing treadmill stress echocardiography: a cohort study

OBJECTIVE

Diastolic dysfunction (DD) is often incriminated in the symptomatology of patients with hypertrophic cardiomyopathy (HCM), but with limited supporting data. This study sought to assess the relationship between baseline diastolic function and exercise capacity in patients with HCM.

DESIGN

Retrospective study.

SETTING

Tertiary referral centre from Cleveland, Ohio, USA.

PARTICIPANTS

695 consecutive patients with a diagnosis of HCM who underwent exercise stress echocardiography between 1996 and 2011.

PRIMARY AND SECONDARY OUTCOME MEASURES

Diastolic function was reassessed from the resting echocardiograms by two blinded board-certified cardiologists. Maximal metabolic equivalents (MET) were extracted from the records. Multivariate regression analysis was performed to determine independent predictors of METs achieved.

RESULTS

Of 695 patients, 130 were excluded because of inability to assess diastolic function. There was no significant difference in maximal METs achieved between those excluded and included in the analysis (p=0.80). There were 495 remaining patients with a mean age (SD) of 50 (15) years, and 32% women among whom 102 (21%) had normal diastolic function, 243 (49%) stage 1 DD; 131 (26%) stage 2 DD and 19 (4%) stage 3 DD. Patients with advanced DD had lower maximal METs achieved compared with those with normal diastolic function (OR 3.18(1.96 to 5.14) for stage 1 versus normal, and 3.21(1.89 to 5.43) for stage ≥2 versus normal, p<0.0001 for both). After adjustment for demographics, comorbidities, echocardiographic parameters and haemodynamics, baseline DD was not an independent predictor of maximal METs achieved.

CONCLUSIONS

Although baseline DD is common in patients with HCM, it does not predict maximal METs achieved beyond traditional risk factors.

Restrictive physiology is associated with poor outcomes in children with hypertrophic cardiomyopathy

Pediatric patients with hypertrophic cardiomyopathy (HCM) and restrictive physiology (RP) with poor outcomes have been identified, but data on their course are limited. Our goal was to delineate the clinical features and course of children with HCM and RP. An institutional review of 119 patients identified between 1985 and 2010 with the diagnosis of HCM was performed. The diagnosis of RP was based on >1 echocardiogram along with at least one of the following: left atrial enlargement without evidence of left ventricle dilation, E/E' ratio ≥ 10, and E/A ratio ≥ 3. Outcomes analysis was performed using Cox or Poisson regression when appropriate. RP was present in 50 (42%) patients. In patients without RP, 10-year freedom-from-death or aborted sudden cardiac death (aSCD), and death or heart transplant (HT), were 93.6 and 98.5%, respectively. In patients with RP, 10-year freedom-from-death or aSCD, and death or HT, were 59.0 and 71.2%, respectively. RP conferred a 3.5-fold increase in incidence rate of hospitalization (P = 0.01), a 3.8-fold increase in hazard of death or aSCD (P = 0.02), and a 5.7-fold increase in hazard of death or HT (P = 0.04). Assessment for RP is of paramount importance in children with HCM because those without RP have a good prognosis, and those with RP account for the majority of poor outcomes.

Left atrial remodelling in hypertrophic cardiomyopathy: relation with exercise capacity and biochemical markers of tissue strain and remodelling

BACKGROUND

Left atrial remodelling, assessed as left atrial volume (LAV), has been proposed as a good marker of left ventricular diastolic dysfunction. The aim of this study was to analyse the influence of LAV on exercise performance in hypertrophic cardiomyopathy (HCM), and in a subset of subjects, assess the relation of LAV and exercise performance to four biomarkers of disease pathophysiology: matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) (as indices of tissue remodelling), N-terminal portion of pro B-type natriuretic peptide (NT-pro-BNP) (associated with ventricular dysfunction) and C-reactive protein (CRP, an index of inflammation).

METHODS

We studied 75 consecutive HCM patients (aged 46 +/- 14 years, 56 men) where LAV was calculated assuming the ellipsoid model with two orthogonal planes. LAV was indexed to body surface area. Exercise capacity was evaluated by treadmill exercise test (symptom limited) and assessed with metabolic equivalent units (MET). Basal NT-pro-BNP and CRP levels were measured in 70 patients, whereas MMP-2 and TIMP-1 in 43 patients.

RESULTS

Enlarged LAV was observed in those patients with previous atrial fibrillation (p = 0.016). Mean LAV was greater in patients with impaired functional New York Heart Association (NYHA) class (p < 0.001). LAV correlated with age (Spearman, r: 0.28), higher maximal left ventricular wall thickness (r: 0.32) and raised E/A ratio (r: 0.37) (all p < 0.01). LAV was significantly correlated with NT-pro-BNP values (r: 0.34; p = 0.04), MMP-2 (r: 0.32; p = 0.034), CRP (r: 0.33; p = 0.005) and correlated inversely with MET units (r: -0.39; p < 0.01). In multivariate analysis, MET units were only associated with NT-pro-BNP (p = 0.002) and LAV (p = 0.010).

CONCLUSIONS

Enlarged LAV is associated with impaired functional NYHA class and inversely with treadmill exercise capacity. Enlarged LAV is also associated with NT-pro-BNP, MMP-2 and CRP, perhaps as markers of disease severity and tissue remodelling. Age, LAV and NT-pro-BNP are independent predictors of exercise performance.

Significance of left atrial volume in patients < 20 years of age with hypertrophic cardiomyopathy

Left atrial (LA) enlargement is an indicator of chronic elevation in left ventricular (LV) end-diastolic pressure as well as diastolic dysfunction. There is a lack of data on the significance of LA volume in the pediatric population. The objective of this study was to elucidate the relation between LA volume and diastolic dysfunction, clinical symptoms, and exercise capacity in young patients with hypertrophic cardiomyopathy. All patients aged <20 years with obstructive hypertrophic cardiomyopathy who underwent evaluation at the Mayo Clinic from 2002 to 2006 were retrospectively identified. Reviews of the LA volume index and other traditional diastolic Doppler echocardiographic parameters, as well as clinical data, were performed. A total of 88 patients (66 male) were studied. The median age at evaluation was 14 years. The mean LA volume index was 39 +/- 19 ml/m(2). Additional echocardiographic parameters included a mean LV outflow gradient of 55 +/- 51 mm Hg, a mean E/E' ratio of 14.0 +/- 7.6, and a mean maximal septal wall thickness of 23 +/- 9 mm. On univariate linear regression analysis, LA volume index had an excellent correlation with diastolic dysfunction grade (p <0.001, r(2) = 0.6), LV outflow tract gradient, mitral E/E', and the degree of mitral regurgitation. LA volume index was also positively associated with symptom score (p = 0.005) and maximal oxygen consumption on exercise test (n = 22; p = 0.01). On multivariate analysis, LA volume index was related to diastolic dysfunction grade (p <0.001) and mean mitral regurgitation grade (p = 0.05). In conclusion, this study demonstrates the potential clinical importance of LA volume index in pediatric hypertrophic cardiomyopathy as a marker of the severity of underlying diastolic dysfunction, symptom score, and decreased exercise capacity. LA volume index has significant diagnostic and prognostic value in these patients.

Increased left atrial volume index: potent biomarker for first-ever ischemic stroke

OBJECTIVE

To establish the incidence and correlation of increased left atrial volume index (LAVI) in patients with first-ever ischemic stroke.

PARTICIPANTS AND METHODS

Using our institution's epidemiological database, we defined a cohort of 432 patients (cases) who underwent transthoracic echocardiography within 60 days of first ischemic stroke between January 1, 1985, and December 31, 1994. Left atrial volume was measured with the biplane area-length method, indexed to body surface area (LAVI, expressed as mL/m(2)). The control group consisted of 416 community residents who underwent transthoracic echocardiography as participants in a stroke risk factor study. Increased LAVI was defined as 28 mL/m(2) or higher. Survival in patients was compared with expected survival among white Minnesotans and was further modeled as a function of age, sex, LAVI, and clinical risk factors.

RESULTS

Among the included 306 patients, 230 (75%) had increased LAVI (mean+/-SD, 49+/-21 mL/m(2)). Patients with increased LAVI were older than those with normal LAVI (mean+/-SD age, 76+/-11 vs 71+/-13 years; P=.003) and had more cardiovascular risk factors (mean+/-SD number, 1.8+/-0.07 vs 1.3+/-0.89; P<.001). Mean LAVI was higher in cases than in age- and sex-matched controls (P<.001). At 5-year follow-up, cases showed excess mortality compared with age-matched controls (P=.001). After variables were adjusted for age, sex, and clinical risk factors, LAVI was independently associated with mortality.

CONCLUSION

A useful index for prediction of adverse cardiovascular events, LAVI might also predict first ischemic stroke and subsequent mortality.

Usefulness of left atrial volume index to predict heart failure hospitalization and mortality in ambulatory patients with coronary heart disease and comparison to left ventricular ejection fraction (from the Heart and Soul Study)

The predictive value of left atrial (LA) dilatation in ambulatory adults with coronary artery disease is not known. It was hypothesized that echocardiographic LA volume index (LAVI) predicts heart failure (HF) hospitalization and mortality with similar statistical power as left ventricular ejection fraction (LVEF) in ambulatory adults with coronary artery disease. We measured LAVI in 935 adults without atrial fibrillation, atrial flutter, or significant mitral valve disease in the Heart and Soul Study. LAVI was calculated using the biplane method of disks. Outcomes included HF hospitalization and mortality. Logistic regression odds ratios (ORs) were calculated and adjusted for age, demographics, medical history, left ventricular mass, diastolic function, and LVEF. Mean LAVI was 32 +/- 11 ml/m2, and mean LVEF was 62 +/- 10%. Sixty-six patients (7%) had LAVI >50 ml/m2. There were 108 HF hospitalizations and 180 deaths at 4.3 years of follow-up. C statistics calculated as the area under the receiver-operator characteristic curve were the same (0.60) for LAVI and LVEF in predicting mortality. The unadjusted OR for HF hospitalization was 4.4 for LAVI >50 ml/m2 and 5.3 for LVEF <45% (p <0.001). In those with normal LVEF, the ORs for LAVI >50 ml/m2 were 5.2 for HF hospitalization (p <0.0001) and 2.5 for mortality (p = 0.006). After multivariate adjustment, LAVI >50 ml/m2 was predictive of HF hospitalization (OR 2.4, p = 0.02), and LAVI >40 ml/m2 was predictive of mortality (OR 1.9, p = 0.005). In conclusion, LAVI had similar predictability as LVEF for HF hospitalization and mortality in ambulatory adults with coronary artery disease.

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

OBJECTIVES

The purpose of this study was to evaluate the role of diastolic dysfunction as measured by left atrial (LA) size in patients undergoing stress echocardiography (SE).

BACKGROUND

Left atrial size is a surrogate marker of diastolic function. However, its prognostic value in patients referred for SE is not well defined.

METHODS

We evaluated 2,705 patients (60 +/- 13 years, 47% men) undergoing SE (56% dobutamine). Patients with significant mitral valve disease (mitral stenosis or > or = moderate mitral regurgitation) were excluded. Enlarged LA was defined as a LA size indexed to body surface area > or =2.4 cm/m2. Follow-up (mean 2.7 +/- 1.0 years) for nonfatal myocardial infarction or cardiac death (n = 122) was obtained.

RESULTS

A dilated LA was able to further risk-stratify both the normal and abnormal SE groups. In the presence of a dilated LA, an abnormal SE portends a worse prognosis compared with patients with normal LA size. Cox proportional modeling showed that a dilated LA added incremental value over traditional risk factors, stress electrocardiographic, rest echocardiographic, and SE variables for the prediction of hard events (global chi-square increased from 90.4 to 113.1 to 176.1 to 184.4 to 190.5; p < 0.05 all groups). Left atrial size was a significant predictor of events independent of left ventricular systolic dysfunction and ischemia (relative risk = 1.84, 95% confidence interval 1.19 to 2.85; p = 0.006).

CONCLUSIONS

In patients referred for stress echocardiography, LA size provides independent and incremental value over standard risk factors including left ventricular systolic dysfunction and ischemia. Left atrial size is a powerful prognosticator and should be routinely used in the prognostic interpretation of stress echocardiography.