Atrioventricular Coupling Research Articles

Left atrial function in diabetes: does it help?

Left atrial (LA) structural, functional and mechanical changes have important role in development of diabetic cardiomyopathy and it was discovered that LA remodeling has important prognostic role in the patients with diabetes (DM). Previously the focus of echocardiographic studies in DM population was on the left ventricular structure and function, but the atrioventricular coupling was proved to be one of the main predictors of cardiovascular morbidity and mortality in DM patients. Each phase of LA cycle has determinant role in the atrioventricular coupling and therefore the accurate assessment of LA phasic function gained importance over last decade. The failure of any of the three LA phasic functions (reservoir, conduit or contractile) leads potentially to LA dilatation, left ventricular diastolic dysfunction, atrial fibrillation and ultimately development of heart failure with preserved (or even reduced) ejection fraction. Even though LA phasic function has not been extensively studied in DM population, it is reasonable to hypothesize that LA dysfunction is very frequent in these patients, considering the high prevalence of atrial fibrillation and heart failure in these individuals. In research and clinical purposes two techniques have been used for determination of LA phasic function: volumetric and strain. Although these methods fundamentally differ, with their own advantages and limitations, they also provide comparable results that can direct our therapeutic approach in DM patients. Namely, not only that LA function represents an independent predictor of cardiovascular outcome in DM patients, but also it has been also associated with parameters of glycemic control. This review summarized the current knowledge regarding LA phasic function in DM patients.

Changes in left and right ventricular longitudinal function after pulmonary valve replacement in patients with Tetralogy of Fallot.

Timing and indication for pulmonary valve replacement (PVR) in patients with repaired Tetralogy of Fallot (rToF) and pulmonary regurgitation (PR) are uncertain. To improve understanding of pumping mechanics, we investigated atrioventricular coupling before and after surgical PVR. Cardiovascular magnetic resonance was performed in patients (n = 12) with rToF and PR > 35% before and after PVR and in healthy controls (n = 15). Atrioventricular plane displacement (AVPD), global longitudinal peak systolic strain (GLS), atrial and ventricular volumes, and caval blood flows were analyzed. Right ventricular (RV) AVPD and RV free wall GLS were lower in patients before PVR compared with controls (P < 0.0001; P < 0.01) and decreased after PVR (P < 0.0001 for both). Left ventricular AVPD was lower in patients before PVR compared with controls (P < 0.05) and decreased after PVR (P < 0.01). Left ventricular GLS did not differ between patients and controls (P > 0.05). Right atrial reservoir volume and RV stroke volume generated by AVPD correlated in controls (r = 0.93; P < 0.0001) and patients before PVR (r = 0.88; P < 0.001) but not after PVR. In conclusion, there is a clear atrioventricular coupling in patients before PVR that is lost after PVR, possibly because of loss of pericardial integrity. Impaired atrioventricular coupling complicates assessment of ventricular function after surgery using measurements of longitudinal function. Changes in atrioventricular coupling seen in patients with rToF may be energetically unfavorable, and long-term effects of surgery on atrioventricular coupling is therefore of interest. Also, AVPD and GLS cannot be used interchangeably to assess longitudinal function in rToF.NEW & NOTEWORTHY There is a clear atrioventricular coupling in patients with Tetralogy of Fallot (ToF) and pulmonary regurgitation before surgical pulmonary valve replacement (PVR) that is lost after operation, possibly because of loss of pericardial integrity. The impaired atrioventricular coupling complicates assessment of ventricular function after surgery when using measurements of longitudinal function. Left ventricular atrioventricular plane displacement (AVPD) found differences between patients and controls and changes after PVR that longitudinal strain could not detect. This indicates that AVPD and strain cannot be used interchangeably to assess longitudinal function in repaired ToF.

P4380Echocardiographically determined myocardial work An emerging bioassay for clinical studies Results from the STAAB cohort study

Abstract Introduction A novel echocardiographic method to non-invasively determine myocardial work based on speckle-tracking derived longitudinal strain and blood pressure has recently been validated and offers new opportunities to study the mechanistic associations. Heart failure patients with prolonged electrical conduction (ie, left bundle branch block) exhibit reduced myocardial global work efficiency (GWE) due to an increase in global wasted work (GWW), which could be improved by biventricular pacing. We here investigated the association of ETI and myocardial work in a non-diseased population. Methods The Characteristics and Course of Heart Failure STAges A/B and Determinants of Progression (STAAB) cohort study carefully characterized a representative sample of the population of a medium-sized town in Germany, aged 30–79 years and free from heart failure. Off-line analysis of the standardized, quality-controlled transthoracic echocardiograms regarding myocardial work yields the following parameters: global constructive work (GCW): work performed during shortening in systole and adding negative work during lengthening in isovolumic relaxation; global wasted work (GWW): negative work performed during lengthening in systole adding work performed during shortening in isovolumic relaxation; and global work efficiency (GWE): GCW/(GCW+GWW). Results We performed myocardial work analysis in 935 individuals from the sample of the first planned STAAB interim analysis who were in sinus rhythm, had preserved left ventricular ejection fraction and were free from significant valvular disease (51% female, 53±12 years). In linear regression including age, sex, heart rate, and ETI, we found increasing heart rate (64±10 bpm), QRS width (95±12 ms), QT interval (414±28 ms), and PQ interval (164±28 ms) associated with lower GWE (−0.11, −0.02, −0.03, and −0.001, respectively; all p&lt;0.05) and higher GWW (+2.64, +0.29, +0.79, +0.16 mmHg%, respectively; all p&lt;0.05). Conclusion In subjects free of overt cardiac disease, GWE strongly associated with ETI. Prolonged atrio-ventricular and intra-ventricular coupling and repolarization was associated with an increase in wasted work, while constructive work was not affected. These findings not only suggest a positive effect on myocardial energetics by reducing the heart rate, but also advocate the concept of myocardial work as a bioassay that is responsive to subtle changes. Myocardial work holds promise to be further studied in diseased patient groups. Acknowledgement/Funding German Ministry of Research and Education within the Comprehensive Heart Failure Centre Würzburg (BMBF 01EO1004 and 01EO1504)

Atrioventricular mechanical coupling and major adverse cardiac events in female patients following acute ST elevation myocardial infarction

Sex-specific outcome data following myocardial infarction (MI) are inconclusive with some evidence suggesting association of female sex and increased major adverse cardiac events (MACE). Since mechanistic principles remain elusive, we aimed to quantify the underlying phenotype using cardiovascular magnetic resonance (CMR) quantitative deformation imaging and tissue characterisation. In total, 795 ST-elevation MI patients underwent post-interventional CMR imaging. Feature-tracking (CMR-FT) was performed in a blinded core-laboratory. Left ventricular function was quantified using ejection fraction (LVEF) and global longitudinal/circumferential/radial strains (GLS/GCS/GRS). Left atrial function was assessed by reservoir (εs), conduit (εe) and booster-pump strains (εa). Tissue characterisation included infarct size, microvascular obstruction and area at risk. Primary endpoint was the occurrence of MACE within 1 year. Female sex was associated with increased MACE (HR 1.96, 95% CI 1.13-3.42, p = 0.017) but not independently of baseline confounders (p = 0.526) with women being older, more often diabetic and hypertensive (p < 0.001) and of higher Killip-class (p = 0.010). Tissue characterisation was similar between sexes. Women showed impaired atrial (εs p = 0.011, εe p < 0.001) but increased systolic ventricular mechanics (GLS p = 0.001, LVEF p = 0.048). While atrial and ventricular function predicted MACE in men only LV GLS and GCS were associated with MACE in women irrespective of confounders (GLS p = 0.036, GCS p = 0.04). In men ventricular systolic contractility is impaired and volume assessments precisely stratify elevated risks. In contrast, women experience reduced atrial but increased ventricular systolic strain. This may reflect ventricular diastolic failure with systolic compensation, which is independently associated with MACE adding incremental value to sex-specific prognosis evaluation.

The importance of integrated left atrial evaluation: From hypertension to heart failure with preserved ejection fraction.

Functional analysis and measurement of left atrium are an integral part of cardiac evaluation, and they represent a key element during non-invasive analysis of diastolic function in patients with hypertension (HT) and/or heart failure with preserved ejection fraction (HFpEF). However, diastolic dysfunction remains quite elusive regarding classification, and atrial size and function are two key factors for left ventricular (LV) filling evaluation. Chronic left atrial (LA) remodelling is the final step of chronic intra-cavitary pressure overload, and it accompanies increased neurohormonal, proarrhythmic and prothrombotic activities. In this systematic review, we aim to purpose a multi-modality approach for LA geometry and function analysis, which integrates diastolic flow with LA characteristics and remodelling through application of both traditional and new diagnostic tools. The most important studies published in the literature on LA size, function and diastolic dysfunction in patients with HFpEF, HT and/or atrial fibrillation (AF) are considered and discussed. In HFpEF and HT, pulsed and tissue Doppler assessments are useful tools to estimate LV filling pressure, atrio-ventricular coupling and LV relaxation but they need to be enriched with LA evaluation in terms of morphology and function. An integrated evaluation should be also applied to patients with a high arrhythmic risk, in whom eccentric LA remodelling and higher LA stiffness are associated with a greater AF risk. Evaluation of LA size, volume, function and structure are mandatory in the management of patients with HT, HFpEF and AF. A multi-modality approach could provide additional information, identifying subjects with more severe LA remodelling. Left atrium assessment deserves an accurate study inside the cardiac imaging approach and optimised measurement with established cut-offs need to be better recognised through multicenter studies.

Atrioventricular dromotropathy: evidence for a distinctive entity in heart failure with prolonged PR interval?

Heart failure (HF) is often accompanied by atrioventricular (AV) conduction disturbance, represented by prolongation of the PR interval on the electrocardiogram. Studies suggest that PR prolongation exists in at least 10% of HF patients, and it seems more prevalent in the presence of prolonged QRS duration. A prolonged PR interval may result in elevated left ventricular (LV) end-diastolic pressure, diastolic mitral regurgitation, and reduced LV pump function. This seems especially the case in patients with heart disease, in whom it is associated with an increased risk for atrial fibrillation, advanced AV heart block, HF, and death. These findings point towards the importance of proper AV coupling in HF patients. A few studies, strongly differing in design, suggest that restoration of AV coupling in patients with PR prolongation by pacing improves cardiac function and clinical outcomes. These observations argue for AV-dromotropathy as a potential target for pacing therapy, but other studies show inconsistent results. Given its potential clinical implications, restoration of AV coupling by pacing warrants further investigation. Additional possible future research goals include assessing different techniques to measure compromised AV coupling, determine the best site(s) of ventricular pacing, and assess a potential influence of diastolic mitral regurgitation in the efficacy of such therapy.

Characterization of rate and regularity of ventricular response during atrial tachyarrhythmias. Insight on atrial and nodal determinants

Objective: Ventricular rate and regularity affect hemodynamic stability and are targets of rate control therapy in patients with atrial flutter (AFL) and atrial fibrillation (AF). Nevertheless, the characteristics and determinants of ventricular response during these atrial arrhythmias are poorly understood. This work aims to investigate the effects of changes in atrial activity and atrioventricular (AV) conduction patterns on ventricular response in patients with atrial tachyarrhythmias by a combined quantitative analysis of atrial and ventricular time series. Approach: Time series were determined in patients during 24 episodes of AFL and 13 episodes of AF. Ventricular response was characterized in terms of mean ventricular interval, time-domain variability parameters, and entropy-based irregularity measures (quadratic entropy rate, QSE, and coefficient of sample entropy, COSEn). Atrial activity was characterized in terms of mean atrial rate and variability. AV conduction was analyzed by AV synchrogram method, quantifying the stability of AV coupling and the average AV conduction ratio. The dependence of ventricular features on atrial/AV determinants was investigated by correlation analysis. Main results: The analysis showed ventricular response to display a wide spectrum of variability and irregularity features at changing atrial and AV properties. The ventricular interval was significantly correlated with the AV conduction ratio (Spearman correlation coefficient ρ = −0.76, p < 0.005), while it did not correlate with atrial rate. The variability and irregularity of ventricular response were influenced by both atrial and AV parameters. QSE and COSEn significantly increased at shorter atrial cycle lengths (ρ = −0.67 and −0.71, p < 0.005), at higher atrial variability (ρ = 0.80 and 0.77, p < 0.005), at reduced AV coupling (ρ = −0.91, p < 0.005) and at smaller AV conduction ratios (ρ = −0.65 and −0.52, p < 0.005). Significance: The identification of the determinants of ventricular rate and regularity may have significant implications in the development of efficacious rate control strategies in patients with atrial tachyarrhythmias.

Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction

Left atrial (LA) compliance and contractility influence left ventricular stroke volume. We hypothesized that diminished LA compliance and contractile function occur early during the development of heart failure with preserved ejection fraction (HFpEF) and impair overall cardiac performance. Cardiac magnetic resonance imaging, echocardiography, left ventricular and LA pressure-volume studies, and tissue analyses were performed in a model of early HFpEF (elderly dogs, renal wrap-induced hypertension, exogenous aldosterone; n=9) and young control dogs (sham surgery; n=13). Early HFpEF was associated with LA enlargement, cardiomyocyte hypertrophy, and enhanced LA contractile function (median active emptying fraction 16% [95% confidence interval, 13-24]% versus 12 [10-14]%, P=0.008; end-systolic pressure-volume relationship slope 2.4 [1.9-3.2]mm Hg/mL HFpEF versus 1.5 [1.2-2.2]mm Hg/mL controls, P=0.01). However, atrioventricular coupling was impaired and the curvilinear LA end-reservoir pressure-volume relationship was shifted upward/leftward in HFpEF (LA stiffness constant [βLA] 0.16 [0.11-0.18]mm Hg/mL versus 0.06 [0.04-0.10]mm Hg/mL controls; P=0.002), indicating reduced LA compliance. Impaired atrioventricular coupling and lower LA compliance correlated with lower left ventricular stroke volume. Total fibrosis and titin isoform composition were similar between groups; however, titin was hyperphosphorylated in HFpEF and correlated with βLA. LA microvascular reactivity was diminished in HFpEF versus controls. LA microvascular density tended to be lower in HFpEF and inversely correlated with βLA. In early-stage hypertensive HFpEF, LA cardiomyocyte hypertrophy, titin hyperphosphorylation, and microvascular dysfunction occur in association with increased systolic and diastolic LA chamber stiffness, impaired atrioventricular coupling, and decreased left ventricular stroke volume. These data indicate that maladaptive LA remodeling occurs early during HFpEF development, supporting a concept of global myocardial remodeling.

Hypertensive patients with left ventricular hypertrophy have global left atrial dysfunction and impaired atrio-ventricular coupling.

The aim of this study was to comprehensively investigate left atrial (LA) reservoir, conduit, and booster pump functions, as well as their predictors in patients with primary systemic arterial hypertension (HTN) and left ventricular (LV) hypertrophy. Thirty patients with HTN and LV hypertrophy, but no history of atrial arrhythmia or heart failure, were compared with 29 normotensive controls. Speckle-tracking echocardiography of the LA wall was used to measure systolic and diastolic strains and strain rates. Early diastolic velocity of transmitral flow/early diastolic mitral annular motion velocity (E/E')/peak systolic LA strain (S-LAs) was used as an index of LA stiffness. HTN patients had higher LV mass index, impaired LV diastolic function, and higher LA volume index than controls. LA reservoir, conduit, and booster pump functions were significantly lower and LA stiffness was greater. Multiple regression analysis indicated that increased LV mass and LV filling pressures as well as reduced LV strain or E' were predictors for reduced atrial function. HTN patients showed a significant impairment of the three components of LA function. These changes were correlated with LV hypertrophy and dysfunction, and presumably related to LA fibrotic changes, underlining the importance of LA-LV coupling. The prognostic value of these new speckle-tracking echocardiography-based LA strain indices needs to be evaluated by future studies.

Changes in Mitral Annular Ascent with Worsening Echocardiographic Parameters of Left Ventricular Diastolic Function.

Background. While the mitral annular plane systolic excursion (MAPSE) has been suggested as a surrogate measurement of left ventricular ejection fraction, less is known about the relative value of mitral annular ascent (MAa). Methods. Our database was queried for complete transthoracic echocardiograms performed for any clinical indication. Baseline echocardiographic measurements were compared to determine any correlation between MAa and traditional Echo-Doppler echocardiographic measures to characterize left ventricular diastolic dysfunction (LVDD). Results. Patients with normal LV diastolic function were younger (41 ± 13 years) than patients with LVDD (stage 1: 61 ± 13 years; stage 2: 57 ± 14 years; and stage 3: 66 ± 17 years; p = 0.156). LV ejection fraction decreased in patients with stage 2 LVDD (63 ± 17%) and was further reduced in patients with stage 3 LVDD (28 ± 21; p = 0.003). Discussion. While a vigorous MAa excursion was seen in patients with stage 1 LVDD, MAa significantly decreased in stage 2 and stage 3 LVDD patients. Our results highlight the importance of atrioventricular coupling, as MAa motion seems to reflect changes in left atrial pressure. Additional studies are now required to better examine atrioventricular interactions and electromechanical coupling that might improve our assessment of LV diastolic function.

Abstract 14660: Effect of PR Interval on Mortality Reduction With Cardiac Resynchronization Therapy - A Secondary Analysis of the COMPANION Trial

Introduction: Prolonged PR intervals may impair atrioventricular mechanical coupling and adversely affect cardiac performance. We hypothesize that patients with advanced systolic heart failure, wide QRS complexes, and prolonged PR intervals will have improved survival from cardiac resynchronization therapy with defibrillator (CRT-D) regardless of whether left bundle branch block (LBBB) or non-LBBB is present. Methods: Patients enrolled in the optimal pharmacologic therapy (OPT) and CRT-D arms of the COMPANION trial were included in a multivariable Cox model of all-cause mortality as a function of presence of LBBB and value of PR interval at baseline. Hazard ratios representing the mortality reduction for CRT-D versus OPT were estimated together with pointwise 95% confidence intervals (CIs). Results: A total of 308 OPT and 595 CRT-D patients were included in the analysis. In both the LBBB (n=648) and non-LBBB (n=255) subgroups, the mortality reduction associated with CRT-D compared to OPT was greater with increasingly prolonged baseline PR interval (Figure 1, p=0.02 for each subgroup). Hazard ratios for CRT-D versus OPT (with 95% CIs) for PR intervals of 200ms and 250ms were 0.51 [0.35,0.74] and 0.30 [0.18,0.50] respectively for the LBBB subgroup, and 0.86 [0.50,1.5] and 0.39 [0.18,0.86] respectively for the non-LBBB subgroup. For non-LBBB patients with PR interval ≤200ms, there was no evidence of mortality benefit with CRT-D (p=0.60). Conclusions: In patients with advanced systolic heart failure, wide QRS complexes, and prolonged PR intervals, restoration of atrioventricular mechanical coupling with CRT-D may improve survival in both LBBB and non-LBBB recipients. In patients with non-LBBB, a benefit from CRT-D may occur in patients with prolonged PR intervals. Figure 1: Risk for all-cause mortality by hazard ratios stratified according to PR interval quartiles.

197 Left Atrial Remodelling and Atrioventricular Coupling in a Canine Model of Early Heart Failure with Preserved Ejection Fraction

Background Left atrial (LA) compliance and contractility are key determinants of left ventricular (LV) stroke volume. LA remodelling and dysfunction in heart failure with preserved ejection fraction (HFpEF) are considered to be late presenting features, secondary to hypertension-induced LV diastolic dysfunction and chronic LA pressure overload. However, a recent unifying hypothesis has stipulated that systemic and coronary microvascular inflammation drive HFpEF pathophysiology. Considering this paradigm, we hypothesised that diminished LA compliance and contractile function occur early during HFpEF development and further impair cardiac performance. Methods Cardiac magnetic resonance imaging, echocardiography, invasive LV and LA pressure volume (PV) analysis and tissue analysis were performed in an experimental model of early-stage HFpEF (elderly dogs with renal wrap induced hypertension and exogenous aldosterone; n = 9) and young control dogs (sham surgery; n = 13). Results Early HFpEF was associated with LA enlargement, LA myocyte hypertrophy, and enhanced LA contractile function (LA active emptying fraction 18 ± 6 vs 12 ± 2%, p = 0.03; LA end-systolic PV relationship slope: 2.7 ± 0.9 HFpEF vs 1.5 ± 0.6 mmHg/mL controls, p = 0.01). However left atrioventricular systolic coupling was impaired (ratio of LV to LA end-systolic PV relationship slope 1.3 ± 0.4 HFpEF vs 0.8 ± 0.4 Controls, p 2 , p = 0.07) and inversely correlated with LA s (r=-0.66, p = 0.006). Titin isoform composition (N2BA/N2B ratio) was similar between groups, but titin hyperphosphorylation was seen in HFpEF LA and LV tissue. LA titin hyperphosphorylation correlated with LA s (r = 0.54, p = 0.03). LA microvascular reactivity was also diminished in HFpEF versus controls. Conclusions Maladaptive LA remodelling is present in early-stage experimental HFpEF and compromises overall cardiac performance. Reduced LA compliance in HFpEF may relate to contributions from LA ischaemia and titin-based cardiomyocyte stiffening. Thus, pathophysiological mechanisms involved in the development of HFpEF directly affect both atrial and ventricular myocardium.

Dynamics of AV coupling during human atrial fibrillation: role of atrial rate.

The causal relationship between atrial and ventricular activities during human atrial fibrillation (AF) is poorly understood. This study analyzed the effects of an increase in atrial rate on the link between atrial and ventricular activities during AF. Atrial and ventricular time series were determined in 14 patients during the spontaneous acceleration of the atrial rhythm at AF onset. The dynamic relationship between atrial and ventricular activities was quantified in terms of atrioventricular (AV) coupling by AV synchrogram analysis. The technique identified n:m coupling patterns (n atrial beats in m ventricular cycles), quantifying their percentage, maximal length, and conduction ratio (= m/n). Simulations with a difference-equation AV model were performed to correlate the observed dynamics to specific atrial/nodal properties. The atrial rate increase significantly affected AV coupling and ventricular response during AF. The shortening of atrial intervals from 185 ± 32 to 165 ± 24 ms (P < 0.001) determined transitions toward AV patterns with progressively decreasing m/n ratios (from conduction ratio = 0.34 ± 0.09 to 0.29 ± 0.08, P < 0.01), lower occurrence (from percentage of coupled beats = 27.1 ± 8.0 to 21.8 ± 6.9%, P < 0.05), and higher instability (from maximal length = 3.9 ± 1.5 to 2.8 ± 0.7 s, P < 0.01). Advanced levels of AV block and coupling instability at higher atrial rates were associated with increased ventricular interval variability (from 123 ± 52 to 133 ± 55 ms, P < 0.05). AV pattern transitions and coupling instability in patients were predicted, assuming the filtering of high-rate irregular atrial beats by the slow recovery of nodal excitability. These results support the role of atrial rate in determining AV coupling and ventricular response and may have implications for rate control in AF.

Atrio-ventricular coupling in patients with transposition of the great arteries after atrial switch by Magnetic Resonance Imaging

Background Diastolic function has been little explored in d-transposition of the great arteries palliated by atrial switch (d-TGA). However, early detection of diastolic dysfunction could be of major clinical interest and could explain clinical status in this population. We aimed: 1/ to characterize diastolic function in d-TGA after atrial switch from velocity encoded cardiac magnetic resonance (CMR) data and 2/ to study associations between diastolic function indices and objective measurements of clinical status evaluated by exercise test. Methods Forty five patients (11 females; mean age 32±4 years) with atrially switched d-TGA and 45 healthy subjects matched for age and sex were prospectively included. CMR examination was performed in both groups, and cardio-pulmonary exercise test was performed within 24 hours in patients. CMR tricuspid, mitral inflow and systemic ventricular outflow tract velocities and flow-rates were analyzed using custom software to estimate diastolic parameters (figure). Pulmonary vein baffle, atrial areas and right atrial strain as [(maximal atrial area - minimal atrial area) / maximal atrial area] were also measured. Results CMR diastolic parameters were significantly different in d-TGA patients as compared to controls. In d-TGA patients, parameters of systemic right ventricular (RV) relaxation were markedly impaired compared to left ventricle of controls, as reflected by a significant increase in deceleration and isovolumic relaxation times (p<0.01). Early trans-tricuspid peak filling-rate (Ef) and RV filling duration were negatively correlated with systemic RV remodeling index (Mass/volume) (r=-0.38 and -0.45, respectively, p<0.01). Systemic RV stroke volume and Ef were significantly associated with baffle size (r=0.35 and r=0.33, p≤0.02, respectively). While peak VO2 was not related to systemic RV volumes, RVEF and to RV Mass, it was significantly associated with systemic ventricle filling indices, such as Ef/filling volume, A wave, filling volume. In multivariate analysis, a significant association was found between RA strain and exercise peak oxygen uptake (r=0.42, p<0.01) in d-TGA patients, while systemic RV ejection fraction was not correlated with exercise performances. Such associations were independent of age, gender and body mass index. Conclusions In d-TGA after atrial switch, systemic RV exposed to systolic dysfunction can be also characterized by an early impairment of diastolic function. Systemic RV diastolic dysfunction is characterized by abnormal RV relaxation that limits cardiac output augmentation. Funding

Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.

The rapid technological developments of the past decade and the changes in echocardiographic practice brought about by these developments have resulted in the need for updated recommendations to the previously published guidelines for cardiac chamber quantification, which was the goal of the joint writing group assembled by the American Society of Echocardiography and the European Association of Cardiovascular Imaging. This document provides updated normal values for all four cardiac chambers, including three-dimensional echocardiography and myocardial deformation, when possible, on the basis of considerably larger numbers of normal subjects, compiled from multiple databases. In addition, this document attempts to eliminate several minor discrepancies that existed between previously published guidelines.

Spatial heterogeneity of four-dimensional relative pressure fields in the human left ventricle.

To assess the spatial heterogeneity of the four-dimensional (4D) relative pressure fields in the healthy human left ventricle (LV) and provide reference data for normal LV relative pressure. Twelve healthy subjects underwent a cardiac MRI examination where 4D flow and morphological data were acquired. The latter data were segmented and used to define the borders of the LV for computation of relative pressure fields using the pressure Poisson equation. The LV lumen was divided into 17 pie-shaped segments. In the normal left ventricle, the relative pressure in the apical segments was significantly higher relative to the basal segments (P < 0.0005) along both the anteroseptal and inferolateral sides after the peaks of early (E-wave) and late (A-wave) diastolic filling. The basal anteroseptal segment showed significantly lower median pressure than the opposite basal inferolateral segment during both E-wave (P < 0.0005) and A-wave (P = 0.0024). Relative pressure in the left ventricle is heterogeneous. During diastole, the main pressure differences in the LV occur along the basal-apical axis. However, pressure differences were also found in the short axis direction and may reflect important aspects of atrioventricular coupling. Additionally, this study provides reference data on LV pressure dynamics for a group of healthy subjects.

Abstract 17241: Impaired Left Atrioventricular Coupling Compromises Cardiac Performance in Heart Failure With Preserved Ejection Fraction

Background: In heart failure with preserved ejection fraction (HFpEF), left ventricular (LV) systolic elastance (Ees) increases in tandem with increases in arterial elastance (Ea), which maintains ejection fraction but limits systolic reserve and precipitates volume sensitivity. The left atrium (LA) lies in series with the LV and contributes to LV stroke volume. We hypothesized that HFpEF is associated with increased LA systolic elastance (E LA ) and deranged atrioventricular (AV) coupling which may additionally compromise cardiac performance. Methods: HFpEF was modeled by experimental hypertension (bilateral renal wrap + DOCA) in elderly dogs (n=9). LA and LV structure, function (echo, MRI) and invasively assessed pressure-volume relationships (PVR, open-chest; pericardiotomy; admittance catheter) were compared to sham-operated young dogs (control; n=13). Results: As compared to controls, HFpEF dogs displayed concentric remodeling, with increased diastolic stiffness, Ea and Ees (p&lt;0.05 for all) and reduced Ea/Ees (p=0.03). LA maximum volume (28±3 vs 23±3mL, p=0.007), LA stroke volume (4±1 vs2±1mL, p=0.006), LA active emptying fraction (18±6 vs 12±2%, p=0.03) and LA ejection rate (51±14 vs 30±16mL/s) were higher in HFpEF versus controls, suggesting increased LA stroke work and inotropy. At matched heart rate and LA pressure, E LA was steeper in HFpEF than control (2.7±0.9 vs 1.5±0.6mmHg/mL, p=0.01) and positively correlated with Ees (r=0.6, p=0.005) and Ea (r=0.66, p=0.002). However AV mismatch occurred as increases in E LA were not proportionate to increases in Ees (Ees/E LA 1.3±0.4 HFpEF vs 0.8±0.4 control, p&lt;0.05). On linear regression, worse AV coupling (i.e. higher Ees/E LA ) was associated with lower LV stroke volume ( Figure ). Conclusion: In experimental HFpEF, despite enhanced LA contractility, AV coupling was deranged. Worse AV coupling may further contribute to reserve dysfunction, LA pressure rise, and susceptibility to pulmonary edema in HFpEF.

Assessment of inter-atrial, inter-ventricular, and atrio-ventricular interactions in tetralogy of Fallot patients after surgical correction. Insights from two-dimensional speckle tracking and three-dimensional echocardiography.

We aimed to assess biatrial size and function, interactions on atrial and ventricular levels, and atrio-ventricular coupling in patients after tetralogy of Fallot repair. A total of 34 patients with a mean age of 20.9±9 years, and 35 healthy controls, underwent two-dimensional speckle tracking echocardiography for ventricular and atrial strain measurements and real-time three-dimensional echocardiography to assess ventricular and atrial volumes. When compared with controls, tetralogy of Fallot patients had significantly reduced right atrial peak atrial longitudinal strain (p<0.01), right atrial peak atrial contraction strain (p<0.01), right atrial ejection fraction (p<0.01), left atrial peak atrial longitudinal strain (p<0.01), left atrial peak atrial contraction strain (p<0.05), and left atrial ejection fraction (p<0.01). In the tetralogy of Fallot group, left ventricular ejection fraction was negatively related to the right ventricular end-systolic volume normalised to body surface area (r=-0.62, p<0.01). An association was found in patients between the right atrial peak longitudinal strain and mean right ventricular strain (r=0.64, p<0.01). In patients, the left atrial peak longitudinal strain correlated negatively with right atrial end-diastolic volume normalised to body surface area (r=-0.67, p<0.01), whereas the left atrial ejection fraction correlated weakly with left ventricular ejection fraction (r=0.41, p<0.05). In asymptomatic tetralogy of Fallot patients, biatrial dysfunction exists and can be quantified via two-dimensional speckle tracking echocardiography as well as real-time three-dimensional echocardiography. Different forms of interactions on atrial and ventricular levels are evident among such cohorts.

Alterations in Left Atrial Structure, Phasic Function and Atrioventricular Coupling Impact Cardiac Performance in Heart Failure with Preserved Ejection Fraction

Alterations in Left Atrial Structure, Phasic Function and Atrioventricular Coupling Impact Cardiac Performance in Heart Failure with Preserved Ejection Fraction

COMBINED ATRIOVENTRICULAR LONGITUDINAL STRAIN RATE DURING ISOVOLUMIC CONTRACTION PREDICTS PULMONARY CAPILLARY WEDGE PRESSURE IN PATIENTS WITH SYSTOLIC DYSFUNCTION

BACKGROUND Reportedly, mitral annular velocities derived by tissue Doppler imaging (TDI)-during isovolumic contraction (IVV) can predict pulmonary capillary wedge pressure (PCWP) in heart failure patients with depressed ejection fraction (EF). We investigated the use of color TDI-derived left atrial (LA) and left ventricular (LV) longitudinal strain rate (SR) during isovolumic contraction (IC) to predict the invasively measured PCWP. METHODS AND RESULTS Forty patients referred with symptoms of heart failure were prospectively studied [age: 56±8 years, 12 (30%) females, and mean LVEF: 51±14%]. PCWP was measured invasively immediately after echocardiography. Mitral annular IVV was measured for all patients and SR during the IC and ejection were measured for the LV (LVSR-IC, LVSR-Ej) as well as the LA (LASR-IC, and LASR-Ej). Atrioventricular SR during IC and Ej (AVSR-IC, AVSR-Ej) was calculated as the sum of the LV and LA values. Patients were classified and compared based on their EF into 19 (49%) with EF≥55%, and 21 (51%) with EF<55%. No significant differences were noted for age, sex, risk factors, and medications between both patients with EF≥55% and EF<55%. Compared to EF≥55%, patients with EF<55% had lower IVV (4.63±1.2 vs. 7.01±1.9 cm/s, P<0.001), LVSR-Ej (1±0.3 vs. 1.2±0.2, P=0.03), LASR-IC (1.3±0.6 vs. 1.9±1, P=0.03), LASR-Ej (1.5±0.5 vs. 2.6±1.3 s-1, P=0.001), AVSR-IC (2±0.8 vs. 2.7±1.06 s-1, P=0.023), and AVSR-Ej (2.5±0.6 vs. 3.9±1.1 s-1, <0.001). LVSR-IC, LVSR-Ej, LASR-IC, AVSR-IC, and IVV correlated with PCWP in only in EF<55%, with the strongest correlation noted for AVSR-IC (r=-0.72, <0.001). Other correlates with PCWP in EF<55% were E/e' and left atrial volume (r=0.47, 0.7, P=0.04, 0.001; respectively). Multivariate regression revealed that in patients with EF<55% AVSR-IC was the only independent predictor of PCWP. Finally, IVV correlated with LVSR-IC and LASR-IC and this correlation became strongest with AVSR-IC (r=0.77, 0.001). CONCLUSION The combined LV and LA longitudinal SR during IC as represented by AVSR-IC showed a strong correlation with PCWP in patients with depressed EF. The correlation between mitral annular IVV and PCWP in those patients can be a product of this combination and may a function of atrioventricular mechanical coupling.