Left atrial enlargement is associated with pulmonary vascular disease in heart failure with preserved ejection fraction

AIMS

Elevated left atrial (LA) pressure is a pathophysiologic hallmark of heart failure with preserved ejection fraction (HFpEF). Chronically elevated LA pressure leads to LA enlargement, which may impair LA function and increase pulmonary pressures. We sought to evaluate the relationship between LA volume and pulmonary arterial haemodynamics in patients with HFpEF.

METHODS AND RESULTS

Data from 85 patients (aged 69 ± 8 years) who underwent exercise right heart catheterization and echocardiography were retrospectively analysed. All had symptoms of heart failure, left ventricular ejection fraction ≥50% and haemodynamic features of HFpEF. Patients were divided into LA volume index-based tertiles (≤34 ml/m2 , >34 to ≤45 ml/m2 , >45 ml/m2 ). A subgroup analysis was performed in patients with recorded LA global reservoir strain (n = 60), with reduced strain defined as ≤24%. Age, sex, body surface area and left ventricular ejection fraction were similar between volume groups. LA volume was associated with blunted increases in cardiac output with exercise (padjusted  <0.001), higher resting mean pulmonary artery pressure (padjusted  = 0.003), with similar wedge pressure (padjusted  = 1). Pulmonary vascular resistance (PVR) increased with increasing LA volume (padjusted  <0.001). Larger LA volumes featured reduced LA strain (padjusted  <0.001), with reduced strain associated with reduced PVR-compliance time (0.34 [0.28-0.40] vs. 0.38 [0.33-0.43], p = 0.03).

CONCLUSION

Increasing LA volume may be associated with more advanced pulmonary vascular disease in HFpEF, featuring higher PVR and pulmonary pressures. Reduced LA function, worse at increasing LA volumes, is associated with a disrupted PVR-compliance relationship, further augmenting impaired pulmonary haemodynamics.

Impaired myocardial reserve underlies reduced exercise capacity and heart rate recovery in preterm-born young adults

Aims 

We tested the hypothesis that the known reduction in myocardial functional reserve in preterm-born young adults is an independent predictor of exercise capacity (peak VO₂) and heart rate recovery (HRR).

Methods and results 

We recruited 101 normotensive young adults (n = 47 born preterm; 32.8 ± 3.2 weeks’ gestation and n = 54 term-born controls). Peak VO₂ was determined by cardiopulmonary exercise testing (CPET), and lung function assessed using spirometry. Percentage predicted values were then calculated. HRR was defined as the decrease from peak HR to 1 min (HRR₁) and 2 min of recovery (HRR₂). Four-chamber echocardiography views were acquired at rest and exercise at 40% and 60% of CPET peak power. Change in left ventricular ejection fraction from rest to each work intensity was calculated (EFΔ40% and EFΔ60%) to estimate myocardial functional reserve. Peak VO₂ and per cent of predicted peak VO₂ were lower in preterm-born young adults compared with controls (33.6 ± 8.6 vs. 40.1 ± 9.0 mL/kg/min, P = 0.003 and 94% ± 20% vs. 108% ± 25%, P = 0.001). HRR₁ was similar between groups. HRR₂ decreased less in preterm-born young adults compared with controls (−36 ± 13 vs. −43 ± 11 b.p.m., P = 0.039). In young adults born preterm, but not in controls, EFΔ40% and EFΔ60% correlated with per cent of predicted peak VO₂ (r² = 0.430, P = 0.015 and r² = 0.345, P = 0.021). Similarly, EFΔ60% correlated with HRR₁ and HRR₂ only in those born preterm (r² = 0.611, P = 0.002 and r² = 0.663, P = 0.001).

Conclusions 

Impaired myocardial functional reserve underlies reductions in peak VO₂ and HRR in young adults born moderately preterm. Peak VO₂ and HRR may aid risk stratification and treatment monitoring in this population.

Left atrial strain predicts cardiovascular response to exercise in young adults with suboptimal blood pressure

AIMS

To investigate the left ventricular response to exercise in young adults with hypertension, and identify whether this response can be predicted from changes in left atrial function at rest.

METHODS

A total of 127 adults aged 18-40 years who completed clinical blood pressure assessment and echocardiography phenotyping at rest and during cardiopulmonary exercise testing, were included. Measurements were compared between participants with suboptimal blood pressure ≥120/80mm Hg (n = 68) and optimal blood pressure <120/80mm Hg (n = 59). Left ventricular systolic function during exercise was obtained from an apical four chamber view, while resting left atrial function was assessed from apical four and two chamber views.

RESULTS

Participants with suboptimal blood pressure had higher left ventricular mass (p = 0.031) and reduced mitral E velocity (p = 0.02) at rest but no other cardiac differences. During exercise, their rise in left ventricular ejection fraction was reduced (p = 0.001) and they had higher left ventricular end diastolic and systolic volumes (p = 0.001 and p = 0.001, respectively). Resting cardiac size predicted left ventricular volumes during exercise but only left atrial booster pump function predicted the left ventricular ejection fraction response ( β = .29, p = 0.011). This association persisted after adjustment for age, sex, body mass index, and mean arterial pressure.

CONCLUSION

Young adults with suboptimal blood pressure have a reduced left ventricular systolic response to exercise, which can be predicted by their left atrial booster pump function at rest. Echocardiographic measures of left atrial function may provide an early marker of functionally relevant, subclinical, cardiac remodelling in young adults with hypertension.

Changes in the Preterm Heart From Birth to Young Adulthood: A Meta-analysis

CONTEXT

Preterm birth is associated with incident heart failure in children and young adults.

OBJECTIVE

To determine the effect size of preterm birth on cardiac remodeling from birth to young adulthood.

DATA SOURCES

Data sources include Medline, Embase, Scopus, Cochrane databases, and clinical trial registries (inception to March 25, 2020).

STUDY SELECTION

Studies in which cardiac phenotype was compared between preterm individuals born at <37 weeks' gestation and age-matched term controls were included.

DATA EXTRACTION

Random-effects models were used to calculate weighted mean differences with corresponding 95% confidence intervals.

RESULTS

Thirty-two observational studies were included (preterm = 1471; term = 1665). All measures of left ventricular (LV) and right ventricular (RV) systolic function were lower in preterm neonates, including LV ejection fraction (P = .01). Preterm LV ejection fraction was similar from infancy, although LV stroke volume index was lower in young adulthood. Preterm LV peak early diastolic tissue velocity was lower throughout development, although preterm diastolic function worsened with higher estimated filling pressures from infancy. RV longitudinal strain was lower in preterm-born individuals of all ages, proportional to the degree of prematurity (R ² = 0.64; P = .002). Preterm-born individuals had persistently smaller LV internal dimensions, lower indexed LV end-diastolic volume in young adulthood, and an increase in indexed LV mass, compared with controls, of 0.71 g/m² per year from childhood (P = .007).

LIMITATIONS

The influence of preterm-related complications on cardiac phenotype could not be fully explored.

CONCLUSIONS

Preterm-born individuals have morphologic and functional cardiac impairments across developmental stages. These changes may make the preterm heart more vulnerable to secondary insults, potentially underlying their increased risk of early heart failure.

P374 Prediction of an adverse cardiovascular response to physical exercise from resting echocardiography imaging in young adults with suboptimal blood pressure

Funding Acknowledgements

British Heart Foundation (BHF) grants (PG/13/58/30397)

Background

Young adults with mildly elevated blood pressure are less likely to engage with physical activity. This may be because early hypertension alters myocardial response to moderate exercise, leading to greater perceived exertion and lower levels of enjoyment. As atrial and ventricular function are closely coupled we investigated whether subclinical atrial changes at rest may identify this myocardial response.

Purpose

To identify whether subclinical changes in left atrial function at rest predict response to exercise by performing left atrial deep-phenotyping in a cohort of young adults with a range of blood pressures.

Methods

Seventy-one full-term born young adults (25.25 ± 5.13 years) were enrolled in the Young Adult Cardiovascular Health sTudy (YACHT) to undergo baseline clinical and cardiovascular phenotyping including detailed blood pressure measurement. Cardiopulmonary exercise testing combined with echocardiography imaging was performed to assess the myocardial response to physical exercise at 40%, 60% and 80% of peak exercise load for all participants. Left ventricular ejection fraction and global longitudinal strain were measured from an apical four chamber view at each exercise load, and resting left atrial phasic function was assessed by conventional and speckle tracking echocardiography from apical four and two chamber views (figure 1).

Results

In this young cohort with a range of blood pressure (120.9 ± 12.96/70.85 ± 9.78 mmHg), resting left atrial reservoir and conduit function, but not left atrial structural measures, showed good correlation with left ventricular ejection fraction and global longitudinal strain during 40%, 60% and 80% of peak exercise. The association between resting left atrial conduit with left ventricular deformation at 60% of peak exercise intensity remained significant when adjusted for age, sex and mean arterial pressure (P = 0.007).

Conclusion

Left atrial phasic function at rest predicts left ventricular responses to physical exercise in this cohort of young adults, which may relate to early subclinical left atrial remodelling in early hypertension. These findings require validation in other cohorts and investigation of whether this exercise limitation can be overcome in young hypertensives.

Abstract P374 Figure 1

P2608Impact of sub-clinical systolic dysfunction on exercise hemodynamics in HFpEF: time to integrate diastolic and systolic indices

Background

A potential role for subclinical systolic impairment as a contributor to the pathophysiology and outcomes of heart failure with preserved ejection fraction (HFpEF) has been proposed recently. However, the precise relationship of indices of systolic dysfunction with exercise hemodynamics in HFpEF is not known. In this study, we characterize the relationship between left ventricular mechanical function assessed by strain imaging with the key hemodynamic features of HFpEF at rest and during exercise.

Methods

Simultaneous echocardiography and exercise right heart catheterization was performed in 90 subjects (68 HFpEF, 22 control) referred for assessment of dyspnea. HFpEF was defined as left ventricular ejection fraction (LVEF) ≥50% with a pulmonary capillary wedge pressure (PCWP) ≥15mmHg at rest and/or ≥25mmHg at maximal exertion. Measures of left ventricular strain were taken using speckle tracking and analyzed together with natriuretic peptides and rest and exercise hemodynamics.

Results

At rest, HFpEF patients had impaired GLS compared to NCD subjects (−18.4±2.5 vs −21.2±3.5%, p≤0.001. Ejection fraction was similar (62±6 vs 61±6%, p=0.81). With worsening global longitudinal strain, patients with HFpEF displayed a worse cardiac index at both rest and exercise (p<0.001 for both), but similar filling pressure (p=0.85). The tertile with the worst strain had the highest level of natriuretic peptide. The association of strain with peak cardiac index was independent of LVEF, BNP, age, LAVI, LVMI, and systolic blood pressure.

Conclusions

Despite a preserved ejection fraction, a proportion of patients with HFpEF display impaired GLS, which correlates with a worse cardiac output. Impaired GLS was not associated with higher filling pressures at rest or exercise.

Acknowledgement/Funding

National Heart Foundation of Australia

Impaired left atrial strain predicts abnormal exercise haemodynamics in heart failure with preserved ejection fraction

BACKGROUND

Elevated left atrial (LA) pressure, particularly during exercise, is associated with symptomatic status and survival in patients with heart failure with preserved ejection fraction (HFpEF). We aimed to characterize the contribution of abnormal LA mechanical properties to exercise haemodynamics in HFpEF.

METHODS AND RESULTS

Simultaneous echocardiography and right heart catheterization were performed in 71 subjects with left ventricular ejection fraction ≥ 50% referred for assessment of exertional dyspnoea. According to haemodynamic evaluation, 49 patients were diagnosed with HFpEF [pulmonary capillary wedge pressure (PCWP) ≥ 15 mmHg at rest and/or ≥ 25 mmHg at maximal exertion] and 22 as non-cardiac dyspnoea. Apical two- and four-chamber views were used for blinded two-dimensional LA speckle tracking analysis. HFpEF was characterized by impaired LA reservoir (24.3 ± 9.6 vs. 36.7 ± 8.4%, P < 0.001) and pump strain (-11.5 ± 3.2 vs. -17.0 ± 3.4%, P < 0.001); and increased stiffness (0.8 ± 0.7 vs. 0.2 ± 0.1 mmHg/%, P < 0.001). Reservoir and pump strain correlated with exercise PCWP (r = -0.64 and r = 0.72, P < 0.001), and remained independent predictors after adjusting for left ventricular mass index, LA volume index, mean E/e' and systolic blood pressure (B = -0.66 and B = 1.41, respectively, P < 0.001). LA stiffness was strongly related to B-type natriuretic peptide levels (r = 0.73, P < 0.001; B = 173.0, P < 0.001). Reservoir strain at cut-off of ≤ 33% predicted invasively verified HFpEF diagnosis with 88% sensitivity and 77% specificity, providing a net reclassification improvement of 12% in comparison to the 2016 European Society of Cardiology criteria for non-invasive diagnosis of HFpEF.

CONCLUSIONS

Impaired LA reservoir and pump function and increased stiffness are associated with abnormal exercise haemodynamics in HFpEF. These markers provide significant HFpEF diagnostic utility in elderly ambulatory patients with dyspnoea.

Physiological Stress Elicits Impaired Left Ventricular Function in Preterm-Born Adults

BACKGROUND

Experimental and clinical studies show that prematurity leads to altered left ventricular (LV) structure and function with preserved resting LV ejection fraction (EF). Large-scale epidemiological data now links prematurity to increased early heart failure risk.

OBJECTIVES

The authors performed echocardiographic imaging at prescribed exercise intensities to determine whether preterm-born adults have impaired LV functional response to physical exercise.

METHODS

We recruited 101 normotensive young adults born preterm (n = 47; mean gestational age 32.8 ± 3.2 weeks) and term (n = 54) for detailed cardiovascular phenotyping. Full clinical resting and exercise stress echocardiograms were performed, with apical 4-chamber views collected while exercising at 40%, 60%, and 80% of peak exercise capacity, determined by maximal cardiopulmonary exercise testing.

RESULTS

Preterm-born individuals had greater LV mass (p = 0.015) with lower peak systolic longitudinal strain (p = 0.038) and similar EF to term-born control subjects at rest (p = 0.62). However, by 60% exercise intensity, EF was 6.7% lower in preterm subjects (71.9 ± 8.7% vs 78.6 ± 5.4%; p = 0.004) and further declined to 7.3% below the term-born group at 80% exercise intensity (69.8 ± 6.4% vs 77.1 ± 6.3%; p = 0.004). Submaximal cardiac output reserve was 56% lower in preterm-born subjects versus term-born control subjects at 40% of peak exercise capacity (729 ± 1,162 ml/min/m2 vs. 1,669 ± 937 ml/min/m2; p = 0.021). LV length and resting peak systolic longitudinal strain predicted EF increase from rest to 60% exercise intensity in the preterm group (r = 0.68, p = 0.009 and r = 0.56, p = 0.031, respectively).

CONCLUSIONS

Preterm-born young adults had impaired LV response to physiological stress when subjected to physical exercise, which suggested a reduced myocardial functional reserve that might help explain their increased risk of early heart failure. (Young Adult Cardiovascular Health sTudy [YACHT]; NCT02103231).

Antifungal susceptibilities, varieties, and electrophoretic karyotypes of clinical isolates of Cryptococcus neoformans from Brazil, Chile, and Venezuela

One hundred clinical isolates of Cryptococcus neoformans from human immunodeficiency virus (HIV)-infected and non-HIV-infected patients from Brazil, Chile, and Venezuela were separated according to varieties and tested for antifungal susceptibility. A high susceptibility to antifungal agents was observed among all the isolates. The electrophoretic karyotyping of 51 strains revealed good discrimination among Cryptococcus neoformans var. neoformans strains.