Delay of left ventricular longitudinal expansion with diastolic dysfunction: impact on load dependence of e' and longitudinal strain rate

Is atrial fibrillation in HFpEF a distinct phenotype? Insights from multiparametric MRI and circulating biomarkers

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) frequently co-exist. There is a limited understanding on whether this coexistence is associated with distinct alterations in myocardial remodelling and mechanics. We aimed to determine if patients with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) represent a distinct phenotype.

METHODS

In this secondary analysis of adults with HFpEF (NCT03050593), participants were comprehensively phenotyped with stress cardiac MRI, echocardiography and plasma fibroinflammatory biomarkers, and were followed for the composite endpoint (HF hospitalisation or death) at a median of 8.5 years. Those with AF were compared to sinus rhythm (SR) and unsupervised cluster analysis was performed to explore possible phenotypes.

RESULTS

136 subjects were included (SR = 75, AF = 61). The AF group was older (76 ± 8 vs. 70 ± 10 years) with less diabetes (36% vs. 61%) compared to the SR group and had higher left atrial (LA) volumes (61 ± 30 vs. 39 ± 15 mL/m2, p < 0.001), lower LA ejection fraction (EF) (31 ± 15 vs. 51 ± 12%, p < 0.001), worse left ventricular (LV) systolic function (LVEF 63 ± 8 vs. 68 ± 8%, p = 0.002; global longitudinal strain 13.6 ± 2.9 vs. 14.7 ± 2.4%, p = 0.003) but higher LV peak early diastolic strain rates (0.73 ± 0.28 vs. 0.53 ± 0.17 1/s, p < 0.001). The AF group had higher levels of syndecan-1, matrix metalloproteinase-2, proBNP, angiopoietin-2 and pentraxin-3, but lower level of interleukin-8. No difference in clinical outcomes was observed between the groups. Three distinct clusters were identified with the poorest outcomes (Log-rank p = 0.029) in cluster 2 (hypertensive and fibroinflammatory) which had equal representation of SR and AF.

CONCLUSIONS

Presence of AF in HFpEF is associated with cardiac structural and functional changes together with altered expression of several fibro-inflammatory biomarkers. Distinct phenotypes exist in HFpEF which may have differing clinical outcomes.

A Wavelet Approach to the Estimation of Left Ventricular Early Filling Wave Propagation Velocity from Color M-Mode Echocardiograms

A new approach to calculating left ventricular (LV) early filling propagation velocity (VP) from color M-mode echocardiograms using wavelet analysis is described. Current methods for measuring VP do not account for the spatiotemporal variation in VP. They are confined by empirical assumptions and user inputs that hinder the accuracy of VP, limiting its clinical utility. We evaluated three methods for measuring LV early filling: conventional VP, the strength of propagation (VS) and wavelet propagation velocity (VW) determined from the most energetically significant wave (peak VW). Group A comprised 125 patients (n = 50 normal filling, n = 25 impaired relaxation, n = 25 pseudonormal filling and n = 25 restrictive filling), and group B comprised 69 patients (n = 32 normal, n = 15 dilated and n = 22 hypertrophic). Peak VW most accurately distinguished normal from diseased patients. For group A, the area under the receiver operating characteristic curve was 0.92 for peak VW versus 0.62 for VP, 0.63 for VS and 0.58 for intraventricular pressure difference. These correspond to a 50%-70% improvement in classification ability. Similar improvements were measured in group B. Peak VW may provide a more accurate evaluation of diastolic function than standard methods and enable better diagnostic classification of patients with diastolic dysfunction.

Development and Validation of a Phase-Filtered Moving Ensemble Correlation for Echocardiographic Particle Image Velocimetry

A new processing method for echocardiographic particle image velocimetry (EchoPIV) using moving ensemble (ME) correlation with dynamic phase correlation filtering was developed to improve velocity measurement accuracy for routine clinical evaluation of cardiac function. The proposed method was tested using computationally generated echocardiogram images. Error analysis indicated that ME EchoPIV yields a twofold improvement in bias and random error over the current standard correlation method (β_Pairwise = -0.15 vs. β_ME = -0.06; σ_Pairwise = 1.00 vs. σ_ME = 0.49). Subsequently a cohort of eight patients with impaired diastolic filling underwent similar evaluation. Comparison of patient EchoPIV velocity time series with corresponding color M-mode velocity time series revealed better agreement for ME EchoPIV compared with standard PIV processing (R_ME = 0.90 vs. R_Pairwise = 0.70). Further time series analysis was performed to measure filling propagation velocity and 1-D intraventricular pressure gradients. Comparison against CMM values indicated that both measurements are completely decorrelated for pairwise processing (R²_Vp = 0.15, R²_IVPD = 0.07), whereas ME processing correlates decently (R²_Vp = 0.69, R²_IVPD = 0.69). This new approach enables more robust processing of routine clinical scans and can increase the utility of EchoPIV for the assessment of left ventricular function.

Cardiac Imaging to Evaluate Left Ventricular Diastolic Function

Left ventricular diastolic dysfunction in clinical practice is generally diagnosed by imaging. Recognition of heart failure with preserved ejection fraction has increased interest in the detection and evaluation of this condition and prompted an improved understanding of the strengths and weaknesses of different imaging modalities for evaluating diastolic dysfunction. This review briefly provides the pathophysiological background for current clinical and experimental imaging parameters of diastolic dysfunction, discusses the merits of echocardiography relative to other imaging modalities in diagnosing and grading diastolic dysfunction, summarizes lessons from clinical trials that used parameters of diastolic function as an inclusion criterion or endpoint, and indicates current areas of research.

Presence and Implication of Temporal Nonuniformity of Early Diastolic Left Ventricular Wall Expansion in Patients With Heart Failure

BACKGROUND

Early-diastolic left ventricular (LV) longitudinal expansion is delayed with diastolic dysfunction. We hypothesized that, in patients with heart failure (HF), regardless of LV ejection fraction (EF), there is diastolic temporal nonuniformity with a delay of longitudinal relative to circumferential expansion.

METHODS AND RESULTS

Echocardiography was performed in 143 HF patients-50 with preserved EF (HFpEF) and 93 with reduced EF (HFrEF)-as well as 31 normal control subjects. The delay of early-diastolic mitral annular velocity from the mitral Doppler E (T_E-e') was measured as a parameter of the longitudinal expansion delay. The delay of the longitudinal early-diastolic global strain rate (SR_E) relative to circumferential SR_E (Delay_C-L) was calculated as a parameter of temporal nonuniformity. Intra-LV pressure difference (IVPD) was estimated with the use of color M-mode Doppler data as a parameter of LV diastolic suction. Although normal control subjects had symmetric LV expansion in early diastole, T_E-e' and Delay_C-L were significantly prolonged in HF regardless of EF (P < .01 vs control for all). Multivariate analysis revealed that Delay_C-L was the independent determinant of IVPD among the parameters of LV geometry and contraction (β = -0.21; P < .05).

CONCLUSION

An abnormal temporal nonuniformity of early-diastolic expansion is present in HF regardless of EF, which was associated with reduced LV suction.

Global longitudinal two-dimensional systolic strain is associated with hemodynamic alterations in arterial hypertension

Arterial hypertension can lead to the progressive deterioration of the left ventricular (LV) performance. The aim of this study was to estimate the relation of global longitudinal systolic strain (GLSS) with central and systemic hemodynamics assessed by applanation tonometry and impedance cardiography in 125 hypertensive patients. Those with more impaired GLSS characterized with 1/worse diastolic function (mitral inflow early phase (E) to mitral septal annulus early diastolic velocity (e') ratio, 8.0 vs. 7.0, P = .014); 2/lower LV performance (cardiac index, 3.14 vs. 3.64 l/min/m(2); P = .007), and 3/higher afterload (systemic vascular resistance index, 2506 vs. 2107 dyn s m(2)/cm(5); P = .008). No relevant differences in, that is, gender, age, blood pressure, LV mass index, left chambers dimensions, and central blood pressure characteristics were identified. The results revealed that impaired GLSS is related to LV diastolic dysfunction and altered hemodynamics which may be markers of early systolic LV dysfunction related to arterial hypertension.

Characterizing heart failure in the ventricular volume domain

Heart failure (HF) may be accompanied by considerable alterations of left ventricular (LV) volume, depending on the particular phenotype. Two major types of HF have been identified, although heterogeneity within each category may be considerable. All variants of HF show substantially elevated LV filling pressures, which tend to induce changes in LV size and shape. Yet, one type of HF is characterized by near-normal values for LV end-diastolic volume (EDV) and even a smaller end-systolic volume (ESV) than in matched groups of persons without cardiac disease. Furthermore, accumulating evidence indicates that, both in terms of shape and size, in men and women, the heart reacts differently to adaptive stimuli as well as to certain pharmacological interventions. Adjustments of ESV and EDV such as in HF patients are associated with (reverse) remodeling mechanisms. Therefore, it is logical to analyze HF subtypes in a graphical representation that relates ESV to EDV. Following this route, one may expect that the two major phenotypes of HF are identified as distinct entities localized in different areas of the LV volume domain. The precise coordinates of this position imply unique characteristics in terms of the actual operating point for LV volume regulation. Evidently, ejection fraction (EF; equal to 1 minus the ratio of ESV and EDV) carries little information within the LV volume representation. Thus far, classification of HF is based on information regarding EF combined with EDV. Our analysis shows that ESV in the two HF groups follows different patterns in dependency of EDV. This observation suggests that a superior HF classification system should primarily be founded on information embodied by ESV.

Altered spatial distribution of the diastolic left ventricular pressure difference in heart failure

BACKGROUND

The left ventricle fills in early diastole because of a progressive intraventricular pressure difference (IVPD) that extends from the left atrium to the left ventricular (LV). The aim of this study was to test the hypothesis that in patients with symptomatic heart failure (HF) regardless of LV ejection fraction (EF), an increase in left atrial (LA) pressure maintains early diastolic filling because of a preserved IVPD from the left atrium to the mid left ventricle, while the IVPD from the mid left ventricle to the apex is diminished because of reduced LV suction.

METHODS

One hundred fifty-one patients with HF (50 with HF with preserved EF [HFpEF; EF ≥ 50%] and 101 with HF with reduced EF [HFrEF; EF < 50%]) and 28 normal controls were prospectively enrolled. The IVPDs from the left atrium to the LV apex (total IVPD), the left atrium to the mid left ventricle (basilar IVPD), and the mid left ventricle to the apex (apical IVPD) were determined using color M-mode Doppler echocardiographic data to integrate the Euler equation. The propagation of early diastolic filling was also assessed by color M-mode Doppler.

RESULTS

The mean LV EF was 0.63 ± 0.07 in patients with HFpEF, 0.32 ± 0.09 in those with HFrEF, and 0.64 ± 0.06 in controls. Peak early diastolic transmitral flow velocities (E) were similar among the groups, and basilar IVPDs were maintained in the HFpEF and HFrEF groups (HFpEF, 1.59 ± 0.62 mm Hg; HFrEF, 1.49 ± 0.75 mm Hg; controls, 1.80 ± 0.61 mm Hg; P = NS, analysis of variance). However, apical IVPDs were decreased in both HF groups (HFpEF, 1.18 ± 0.56 mm Hg [P < .01 vs controls]; HFrEF, 0.87 ± 0.48 mm Hg [P < .01 vs controls]; controls, 1.65 ± 0.62 mm Hg), resulting in decreased total IVPDs in patients with HF (HFpEF, 2.55 ± 0.80 mm Hg [P < .01 vs controls]; HFrEF, 2.16 ± 0.80 mm Hg [P < .01 vs controls]; controls, 3.17 ± 0.91 mm Hg). E/e' ratios were increased in patients with HF, consistent with elevated LA pressure. In patients with HF, E was correlated with basilar IVPD but not with apical IVPD, whereas propagation of the filling was correlated with the apical IVPD but not with the basilar IVPD.

CONCLUSIONS

In patients with HFpEF and those with HFrEF, apical IVPDs were reduced while basilar IVPDs were maintained by elevated LA pressure, resulting in preserved E.