Midwall ejection fraction for assessing systolic performance of the hypertrophic left ventricle

The myocardial function index (MFI): An integrated measure of cardiac function in AL-cardiomyopathy

Background

Amyloid light chain (AL) amyloidosis is a systemic disease that can cause restrictive cardiomyopathy (AL-CM). Current imaging techniques are not sensitive to detect myocardial dysfunction in AL-CM. We sought to evaluate role of a novel marker of myocardial dysfunction (myocardial function index, MFI) obtained using changes in left ventricular (LV) blood pool and myocardial volume in diastole and systole.

Methods

Consecutive patients diagnosed with AL-CM who had underwent cardiac MRI between 2001-2017 were identified and compared to healthy individuals. Two independent operators used cardiac MRI to perform epicardial and endocardial tracings in systole and diastole to obtain myocardial volume in diastole (MVd) and myocardial volume in systole (MVs). Changes in myocardial volumes during the cardiac cycle were measured to calculate the MFI byM V d - M V s + S t r o k e v o l u m e MVd + L V e n d d i a s t o l i c v o l u m e . Multivariable analysis was performed to evaluate predictors of all-cause mortality and survival was evaluated using Kaplan Meier analysis.

Results

Patients with AL-CM (n = 129, 61 ± 10 years, 32 % women) were older and more likely to be men compared to the normal cohort (n = 101, 39 ± 15 years, 61 % women). MFI was lower in patients with AL-CM (19 % [15; 23] vs 38 % [35; 41], p < 0.001) and MFI < 30 % discriminated between AL-CM with 92 % sensitivity and 100 % specificity (AUC 0.98, p < 0.001). Higher MFI was independently associated with survival even after adjusting for conventional prognostic biomarkers of AL-CM (HR 0.02, 95 % CI 2.23 *104 - 0.24, p < 0.05). Two independent operators demonstrated high intra and inter-rater correlation in measurements used to calculate MFI.

Conclusion

MFI is a novel metric for assessing LV function. It is abnormal in patients with AL-CM and may play a role in risk stratification.

Diagnostic and prognostic value of an ejection fraction adjusted for myocardial remodeling

Introduction

Ejection fraction (EF) is widely used to evaluate heart function during heart failure (HF) due to its simplicity compared but it may misrepresent cardiac function during ventricular hypertrophy, especially in heart failure with preserved EF (HFpEF). To resolve this shortcoming, we evaluate a correction factor to EF, which is equivalent to computing EF at the mid-wall layer (without the need for mid-layer identification) rather than at the endocardial surface, and thus better complements other complex metrics.

Method

The retrospective cohort data was studied, consisting of 2,752 individuals (56.5% male, age 69.3 ± 16.4 years) admitted with a request of a troponin test and undergoing echocardiography as part of their clinical assessment across three centres. Cox-proportional regression models were constructed to compare the adjusted EF (EFa) to EF in evaluating risk of heart failure admissions.

Result

Comparing HFpEF patients to non-HF cases, there was no significant difference in EF (62.3 ± 7.6% vs. 64.2 ± 6.2%, p = 0.79), but there was a significant difference in EFa (56.6 ± 6.4% vs. 61.8 ± 9.9%, p = 0.0007). Both low EF and low EFa were associated with a high HF readmission risk. However, in the cohort with a normal EF (EF ≥ 50%), models using EFa were significantly more associative with HF readmissions within 3 years, where the leave one out cross validation ROC analysis showed a 18.6% reduction in errors, and Net Classification Index (NRI) analysis showed that risk increment classification of events increased by 12.2%, while risk decrement classification of non-events decreased by 16.6%.

Conclusion

EFa is associated with HF readmission in patients with a normal EF.

Effects of Hypertrophic and Dilated Cardiac Geometric Remodeling on Ejection Fraction

Background: Both heart failure (HF) with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) can present a wide variety of cardiac morphologies consequent to cardiac remodeling. We sought to study if geometric changes to the heart during such remodeling will adversely affect the ejection fraction (EF) parameter’s ability to serve as an indicator of heart function, and to identify the mechanism for it.

Methods and Results: A numerical model that simulated the conversion of myocardial strain to stroke volume was developed from two porcine animal models of heart failure. Hypertrophic wall thickening was found to elevate EF, while left ventricle (LV) dilation was found to depress EF when myocardial strain was kept constant, causing EF to inaccurately represent the overall strain function. This was caused by EF being calculated using the endocardial boundary rather than the mid-wall layer. Radial displacement of the endocardial boundary resulted in endocardial strain deviating from the overall LV strain, and this deviation varied with LV geometric changes. This suggested that using the epi- or endo-boundaries to calculate functional parameters was not effective, and explained why EF could be adversely affected by geometric changes. Further, when EF was modified by calculating it at the mid-wall layer instead of at the endocardium, this shortcoming was resolved, and the mid-wall EF could differentiate between healthy and HFpEF subjects in our animal models, while the traditional EF could not.

Conclusion: We presented the mechanism to explain why EF can no longer effectively indicate cardiac function during cardiac geometric changes relevant to HF remodeling, losing the ability to distinguish between hypertrophic diseased hearts from healthy hearts. Measuring EF at the mid-wall location rather than endocardium can avoid the shortcoming and better represent the cardiac strain function.

Safety assessment of HEA-enriched Cordyceps cicadae mycelia on the central nervous system (CNS), cardiovascular system, and respiratory system in ICR male mice

Cordyceps cicadae, an entomopathogenic fungus, is a source of traditional Chinese medicine in China. Due to the low yield of wild C. cicadae, artificial cultivation approaches will be needed to meet the increasing market demand. Using bioreactor culture can increase mass production and the abundance of the active component, N6-(2-hydroxyethyl)-adenosine (HEA). Here, we describe a safety assessment for a novel mycelium preparation method. Many studies have confirmed the safety of C. cicadae mycelia. However, the acute safety pharmacology of the C. cicadae enriched with the high HEA (3.90 mg/g) compound has not been evaluated. This study evaluated the central nervous system (CNS), cardiovascular system, and respiratory system in ICR male mice via oral gavage administration. For each requested item, two batches of eight mice tested on a vehicle (0.5% carboxymethyl cellulose, CMC) and C. cicadae mycelia (1,000 mg/kg) were performed. The heart rate at 60 min for the vehicle and C. cicadae mycelium treatment was 700.3 ± 55.4 and 603.0 ± 42.3 bpm, respectively (p = .4279). For echocardiographic analysis, the LV mass of the vehicle and drug treatment was 86.7 ± 6.4 and 80.2 ± 7.7, respectively (p = .0933). In the respiratory test, the tidal volume of the vehicle and drug treatments was 0.11 ± 0.01 and 0.14 ± 0.01 at 60 min, respectively (p = .4262). These results demonstrate that the oral administration of HEA-enriched C. cicadae mycelia is safe for the CNS, cardiovascular, and respiratory systems.

Inter-relationships between left ventricular mass, geometry and arterial stiffness

Objective

To investigate the inter-relationships between left ventricular mass (LVM), left ventricular (LV) geometry and arterial stiffness parameters (aortic pulse wave velocity [Ao-PWV] and heart rate-corrected augmentation index [c-AIx]) in patients with chronic heart failure (CHF).

Methods

This study was a secondary analysis of existing data that were collected from patients with CHF New York Heart Association class I–III with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). Transthoracic echocardiography was performed on all patients, along with measurement of arterial stiffness parameters (Ao-PWV and c-AIx) using sphygmocardiography.

Results

A total of 73 patients (58 males) with a mean ± SD age of 55.9 ± 11.6 years were enrolled in this study. Of these, 20 patients (27.4%) had systemic hypertension, 46 (63.0%) had type 2 diabetes mellitus. Ischaemic heart disease was the main aetiology of CHF (63 of 73 patients; 86.3%). In multiple linear regression, the left ventricular mass index (LVMI) was significantly associated with c-AIx (β = –1.59) and EF (β = –1.51). Comparison of Ao-PWV among the four LV geometric patterns revealed significant differences.

Conclusion

In this cohort of CHF patients, LVMI was predicted by c-AIx and EF. The corresponding values of Ao-PWV were parallel in different LV geometric patterns and confirmed their adverse prognostic values.

Assessment of left ventricular systolic and diastolic abnormalities in patients with hypertrophic cardiomyopathy using real-time three-dimensional echocardiography and two-dimensional speckle tracking imaging

Background

Conventional echocardiography is not sensitive enough to assess left ventricular (LV) dysfunction in hypertrophic cardiomyopathy (HCM) patients. This research attempts to find a new ultrasonic technology to better assess LV diastolic function, systolic function, and myocardial longitudinal and circumferential systolic strain of segments with different thicknesses in HCM patients.

Methods

This study included 50 patients with HCM and 40 healthy subjects as controls. The peak early and late mitral annulus diastolic velocities at six loci (E_a′ and A_a′, respectively) and the E_a′/A_a′ ratio were measured using real-time tri-plane echocardiography and quantitative tissue velocity imaging (RT-3PE-QTVI). The mean value of E_a′ at six loci (E_m′) was obtained for the calculation of E/E_m′ ratio. The LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV stroke volume (LVSV), and LV ejection fraction (LVEF) were measured using real-time three-dimensional echocardiography (RT-3DE). LV myocardial longitudinal peak systolic strain (LPSS) and circumferential peak systolic strain (CPSS) in the apical-middle-basal segments (LPSS_-api, LPSS_-mid, LPSS_-bas; CPSS_-api, CPSS_-mid, and CPSS_-bas, respectively) were obtained using a software for two-dimensional speckle tracking imaging (2D-STI). According to the different segmental thicknesses (STs) in each HCM patient, the values (LPSS and CPSS) of all the myocardial segments were categorized into three groups and the respective averages were computed.

Results

The E_a′, A_a′, and, E_a′/A_a’ ratio in HCM patients were lower than those in the controls (all p < 0.001), while the E/E_m′ ratio in HCM patients was higher than that in the controls (p < 0.001). The LVEDV, LVSV, and LVEF were significantly lower in HCM patients than in controls (all p < 0.001). In HCM patients, the LPSS_-api, LPSS_-mid, LPSS_-bas, CPSS_-api, CPSS_-mid, and CPSS_-bas and the LPSS and CPSS of LV segments with different thicknesses were all significantly reduced (all p < 0.001).

Conclusions

In HCM patients, myocardial dysfunction was widespread not only in the obviously hypertrophic segments but also in the non-hypertrophic segments; the LV systolic and diastolic functions were damaged, even with a normal LVEF. LV diastolic dysfunction, systolic dysfunction, and myocardial deformation impairment in HCM patients can be sensitively revealed by RT-3PE-QTVI, RT-3DE, and 2D-STI.

Chronic Endurance Exercise Impairs Cardiac Structure and Function in Middle-Aged Mice with Impaired Nrf2 Signaling

Nuclear factor erythroid 2 related factor 2 (Nrf2) signaling maintains the redox homeostasis and its activation is shown to suppress cardiac maladaptation. Earlier we reported that acute endurance exercise (2 days) evoked antioxidant cytoprotection in young WT animals but not in aged WT animals. However, the effect of repeated endurance exercise during biologic aging (WT) characterized by an inherent deterioration in Nrf2 signaling and pathological aging (pronounced oxidative susceptibility-Nrf2 absence) in the myocardium remains elusive. Thus, the purpose of our study was to determine the effect of chronic endurance exercise-induced cardiac adaptation in aged mice with and without Nrf2. Age-matched WT and Nrf2-null mice (Nrf2-/-) (>22 months) were subjected to 6 weeks chronic endurance exercise (25 meter/min, 12% grade). The myocardial redox status was assessed by expression of antioxidant defense genes and proteins along with immunochemical detection of DMPO-radical adduct, GSH-NEM, and total ubiquitination. Cardiac functions were assessed by echocardiography and electrocardiogram. At sedentary state, loss of Nrf2 resulted in significant downregulation of antioxidant gene expression (Nqo1, Ho1, Gclm, Cat, and Gst-α) with decreased GSH-NEM immuno-fluorescence signals. While Nrf2-/- mice subjected to CEE showed an either similar or more pronounced reduction in the transcript levels of Gclc, Nqo1, Gsr, and Gst-α in relation to WT littermates. In addition, the hearts of Nrf2-/- on CEE showed a substantial reduction in specific antioxidant proteins, G6PD and CAT along with decreased GSH, a pronounced increase in DMPO-adduct and the total ubiquitination levels. Further, CEE resulted in a significant upregulation of hypertrophy genes (Anf, Bnf, and β-Mhc) (p < 0.05) in the Nrf2-/- hearts in relation to WT mice. Moreover, the aged Nrf2-/- mice exhibited a higher degree of cardiac remodeling in association with a significant decrease in fractional shortening, pronounced ST segment, and J wave elevation upon CEE compared to age-matched WT littermates. In conclusion, our findings indicate that while the aged WT and Nrf2 knockout animals both exhibit hypertrophy after CEE, the older Nrf2 knockouts showed ventricular remodeling coupled with profound cardiac functional abnormalities and diastolic dysfunction.

Recommendations on the Use of Echocardiography in Adult Hypertension: A Report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Advanced Parameters of Cardiac Mechanics in Children with CKD: The 4C Study

BACKGROUND AND OBJECTIVES

Newer parameters of cardiac mechanics provide additional insights on cardiac dysfunction in adult patients with CKD. The aim of this study was to identify prevalence of subclinical abnormalities in cardiac function through the analysis of novel indices of cardiac mechanics in a large population of children with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 2009 and 2011, the prospective observational Cardiovascular Comorbidity in Children with CKD Study enrolled patients with CKD ages 6-17 years old with eGFR=10-45 ml/min per 1.73 m(2) in 14 European countries. Cardiac morphology and function were assessed through echocardiography. The analysis presented encompasses global radial, longitudinal, and circumferential strains as well as time to peak analysis. Data were compared with 61 healthy children with comparable age and sex.

RESULTS

Data on 272 patients with CKD with complete echocardiographic assessment are reported (age =12.8±3.5 years old; 65% boys). Patients with CKD showed mildly higher office BP values and higher prevalence of left ventricular hypertrophy, but no differences were observed among groups in left ventricular ejection fraction. Strain analysis showed significantly lower global radial strain (29.6%±13.3% versus 35.5%±8.9%) and circumferential strain components (-21.8%±4.8% versus -28.2%±5.0%; both P<0.05) in patients with CKD without significant differences observed in longitudinal strain (-15.9%±3.4% versus -16.2%±3.7%). Lower values of global radial strain were associated with lower circumferential endocardial-to-epicardial gradient (r=0.51; P<0.01). This association remained significant after adjusting for BP, eGFR, and presence of left ventricular hypertrophy. Eventually, patients with CKD also showed higher delay in time to peak cardiac contraction (58±28 versus 37±18 milliseconds; P<0.05).

CONCLUSIONS

A significant proportion of children with CKD show impaired systolic mechanics. Impaired systolic function is characterized by lower radial strain, transmural circumferential gradient, and mild cardiac dyssynchrony. This study suggests that analysis of cardiac strain is feasible in a large multicenter study in children with CKD and provides additional information on cardiac pathophysiology of this high-risk population.