Left Ventricular Chamber Volume Research Articles

Mueller maneuver attenuates left atrial phasic volumes and myocardial strain in healthy younger adults.

The left atrium (LA) is a key, but incompletely understood, modulator of left ventricular (LV) filling. Inspiratory negative intrathoracic pressure swings alter cardiac loading conditions, which may impact LA function. We studied acute effects of static inspiratory efforts on LA chamber function, LA myocardial strain, and LV diastolic filling. We included healthy adults (10 males/9 females, 24 ± 4 yr) and used Mueller maneuvers to reduce intrathoracic pressure to -30 cmH2O for 15 s. Over six repeated trials, we used echocardiography to acquire LA- and LV-focused two-dimensional (2-D) images, and mitral Doppler inflow and annular tissue velocity spectra. Images were analyzed for LA and LV chamber volumes, tissue relaxation velocities, transmitral filling velocities, and speckle tracking-derived LA longitudinal strain. Repeated measures were made at baseline, early Mueller, late Mueller, then early release, and late release. In the late Mueller compared with baseline, LV stroke volume decreased by -10 ± 4 mL (P < 0.05) and then returned to baseline upon release; this occurred with a -11 ± 9 mL (P < 0.05) end-diastolic volume reduction. Early diastolic LV filling was attenuated, reflected by decreased tissue relaxation velocity (-2 ± 2 cm/s, P < 0.05), E-wave filling velocity (-13 ± 14 cm/s, P < 0.05), and LA passive emptying volume (-5 ± 5 mL, P < 0.05), each returning to baseline with release. LA maximal volume decreased (-5 ± 5 mL, P < 0.05) during the Mueller maneuver, but increased relative to baseline following release (+4 ± 5 mL, P < 0.05), whereas LA peak positive longitudinal strain decreased (-6 ± 6%, P < 0.05) and then returned to baseline. Attenuated LA and in turn, LV filling may contribute to acute stroke volume reductions experienced during forceful inspiratory efforts.NEW & NOTEWORTHY In healthy younger adults, the Mueller maneuver transiently reduces left atrial filling and passive emptying during the reservoir and conduit phases, respectively. Corresponding reductions are seen in left atrial reservoir and conduit phase longitudinal myocardial strain and strain rate. However, left atrial pump phase active function and mechanics are largely preserved compared with baseline. Rapid changes in LA chamber volumes and myocardial strain with recurrent forceful inspiratory efforts and relaxation may reflect acute LA stress.

Modification of a Transvalvular Microaxial Flow Pump for Instantaneous Determination of Native Cardiac Output and Volume

The current Impella CP pump used for mechanical circulatory support (MCS) in patients with cardiogenic shock (CS) cannot assess native cardiac output (CO) and left ventricular (LV) volumes. This data is valuable in facilitating device management and weaning. Admittance technology allows for accurate assessment of cardiac chamber volumes. This study tested the ability to engineer admittance electrodes onto an existing Impella CP pump to assess total and native CO in an instantaneous manner, as well as LV chamber volumes. Impella CP pumps were fitted with four admittance electrodes and placed in the LV of adult swine (n=9) subjected to three different hemodynamic conditions including Impella CP speed adjustments, administration of escalating doses of dobutamine, and microsphere injections into the left main artery to result in cardiac injury. CO by admittance electrodes was calculated from LV volumes and heart rate. In addition, CO was calculated in each instance via thermodilution, continuous CO (CCO) measurement, Fick's principle and aortic velocity-time integral (VTI) by echocardiography. Modified Impella CP pumps were placed in swine LV successfully. CO as determined by admittance electrodes was similar by trend with other methods of CO assessment, corrected for pump speed to calculate native CO, and calculated LV chamber volumes trended as expected in each experimental protocol. We report for the first time that an Impella CP pump can be fitted with admittance electrodes and used to determine total and native CO in various hemodynamic situations. Transvalvular mechanical circulatory support (MCS) devices such as the Impella CP do not have the ability to provide real-time information on native cardiac output (CO) and left ventricular (LV) volumes. This information is critical in device management and weaning in patients with cardiogenic shock (CS). We demonstrate for the first time, an Impella CP pump coupled with admittance electrodes are able to determine native CO, and left ventricle (LV) chamber volumes in multiple different hemodynamic situations such as Impella pump speed adjustments, escalating dobutamine administration, and cardiac injury from microsphere injection.

Sphingosine-1-phosphate levels are inversely associated with left ventricular and atrial chamber volume and cardiac mass in men

AimsSphingosine-1-phosphate (S1P) is a signaling lipid, which is involved in several cellular processes including cell growth, proliferation, migration and apoptosis. The associations of serum S1P levels with cardiac geometry and function are still not clear. We investigated the associations of S1P with cardiac structure and systolic function in a population-based sample.Methods and resultsWe performed cross-sectional analyses of 858 subjects (467 men; 54.4%), aged 22 to 81 years, from a sub-sample of the population-based Study of Health in Pomerania (SHIP-TREND-0). We analyzed the associations of serum S1P with structural and systolic function left ventricular (LV) and left atrial (LA) parameters as determined by magnetic resonance imaging (MRI) using sex-stratified multivariable-adjusted linear regression models. In men, MRI data showed that a 1 µmol/L lower S1P concentration was associated with an 18.1 mL (95% confidence interval [CI] 3.66–32.6; p = 0.014) larger LV end-diastolic volume (LVEDV), a 0.46 mm (95% CI 0.04–0.89; p = 0.034) greater LV wall thickness (LVWT) and a 16.3 g (95% CI 6.55–26.1; p = 0.001) higher LV mass (LVM). S1P was also associated with a 13.3 mL/beat (95% CI 4.49–22.1; p = 0.003) greater LV stroke volume (LVSV), an 18.7 cJ (95% CI 6.43–30.9; p = 0.003) greater LV stroke work (LVSW) and a 12.6 mL (95% CI 1.03–24.3; p = 0.033) larger LA end-diastolic volume (LAEDV). We did not find any significant associations in women.ConclusionsIn this population-based sample, lower levels of S1P were associated with higher LV wall thickness and mass, larger LV and LA chamber sizes and greater stroke volume and work of the LV in men, but not in women. Our results indicate that lower levels of S1P were associated with parameters related with cardiac geometry and systolic function in men, but not in women.Graphical abstract

Diets Containing Corn Oil, Coconut Oil and Cholesterol Alter Ventricular Hypertrophy, Dilatation and Function in Hearts of Rats Fed Copper-Deficient Diets

Cardiac hypertrophy and function were evaluated in rats fed diets containing deficient, marginal or adequate levels of copper. The fat concentration of the diets was either 10 g/100 g corn oil, 10 g/100 g coconut oil or 10 g/100 g coconut oil + 1 g/100 g added cholesterol. Left ventricular (LV) wall thickening of hearts in rats fed copper-deficient diets was characterized by greater (P < 0.05) LV free wall width, regardless of dietary fat type, and greater intraventricular septum width in the rats fed corn oil. Rats fed the copper-deficient diet with coconut oil + cholesterol had LV chamber volumes that were twofold larger than those of rats fed the copper-deficient diet with coconut oil or corn oil. Copper deficiency reduced LV chamber volume only in rats fed coconut oil + cholesterol. Cardiac LV end diastolic pressure in rats fed copper-deficient diets was twofold larger than in copper-adequate and copper-marginal groups fed corn oil or coconut oil. Hearts from rats fed the copper-deficient diet with corn oil compared with those from rats fed the copper-deficient diet with coconut oil + cholesterol had greater right ventricular (RV) and LV end diastolic pressures, LV pressures and LV and RV maximal rates of positive pressure development. Our data suggest that cardiac adaptations in rats fed copper-deficient diets are influenced by dietary fat type: 1) hearts of rats fed the copper-deficient diet with corn oil were concentrically hypertrophied, whereas cardiac contractility was maintained in the presence of high preload; 2) preload and contractility in hearts of coconut oil-fed rats was greater than cardiac response to cholesterol addition to the coconut oil diet; 3) hearts in copper-deficient rats fed coconut oil + cholesterol exhibited eccentric hypertrophy and ventricular dysfunction.

Prediction of response to cardiac resynchronization therapy using cardiac magnetic resonance imaging in non-ischemic dilated cardiomyopathy

Abstract Background Cardiac resynchronization therapy (CRT) is a well-established therapy for symptomatic heart failure with reduced ejection fraction, but the response is different for individuals. Although many modalities have been conducted to predict CRT response, cardiac magnetic resonance (CMR) to predict CRT response has still insufficient usefulness. Purpose We determine whether the parameters including late gadolinium enhancement (LGE) identified in CMR could act as predictors of CRT response. Methods We retrospectively investigated 124 patients with non-ischemic dilated cardiomyopathy who underwent CMR before CRT implantation between Jan 2010 and July 2021 in a single center. CRT response was defined as a decrease in left ventricular end-systolic volume (LVESV) &amp;gt;15% on echocardiography after at least 3 months after CRT implantation. Results Among the study population (mean age 65.7±11.2 years, mean EF 25±6.5%, 50% of female), 85 (69%) patients were defined as CRT responder. The CRT responders had more left bundle branch block (LBBB) compared with non-responders [79 (92.9%) vs. 23 (59.0%), p&amp;lt;0.001], but there was a no difference of QRS duration (158.7 vs 165.0ms, p=0.054) between two groups. CMR analysis showed that there were no significant differences in the left ventricular (LV) chamber volume and LV ejection fraction between CRT-responder and non-responder. However, the right ventricular (RV) chamber volume was smaller (RV end-diastolic volume index, 86.3 vs 103.5 ml/m2, p=0.039; RV end-systolic volume index, 49.3 vs 68.5 ml/m2, p=0.013) and the RV ejection fraction (RVEF) was higher (46.9 vs 37.6%, p=0.002) in CRT-responders compared with non-responders. The LGE on CMR was more shown in non-responders than in CRT-responders [33 (84.6%) vs 45 (52.9%), p&amp;lt;0.001]. In CMR parameters, RV dysfunction (RVEF &amp;lt;45%) [Odds ratio (OR), 0.21 (0.05–0.93), p=0.045] and LGE [OR, 0.21 (0.05–0.58), p=0.01] were significantly associated with poor CRT response. Conclusions The presence of LGE and RV dysfunction on CMR were associated with poor CRT response in patients with non-ischemic dilated cardiomyopathy. Further investigation with CMR for pre-CRT patients is needed to support these results. Funding Acknowledgement Type of funding sources: None.

Influence of ejection fraction on biomarker expression and response to spironolactone in people at risk of heart failure: findings from the HOMAGE trial.

Left ventricular ejection fraction (LVEF) can provide haemodynamic information and may influence the response to spironolactone and other heart failure (HF) therapies. We aimed to study patient characteristics and circulating protein associations with LVEF, and whether LVEF influenced the response to spironolactone. HOMAGE enrolled patients aged >60 years at high risk of developing HF with a LVEF ≥45%. Overall, 527 patients were randomized to either spironolactone or standard of care for ≈9months, and 276 circulating proteins were measured using Olink® technology. A total of 364 patients had available LVEF determined by the Simpson's biplane method. The respective LVEF tertiles were: tertile 1: <60% (n=122), tertile 2: 60%-65% (n=121), and tertile 3: >65% (n=121). Patients with a LVEF >65% had smaller left ventricular chamber size and volumes, and lower natriuretic peptide levels. Compared to patients with a LVEF <60%, those with LVEF >65% had higher levels of circulating c-c motif chemokine ligand-23 and interleukin-8, and lower levels of tissue plasminogen activator, brain natriuretic peptide (BNP), S100 calcium binding protein A12, and collagen type I alpha 1 chain (COL1A1). Spironolactone significantly reduced the circulating levels of BNP and COL1A1 without significant treatment-by-LVEF heterogeneity: BNP change β=-0.36 log2 and COL1A1 change β=-0.16 log2 (p < 0.0001 for both; interaction p > 0.1 for both). Spironolactone increased LVEF from baseline to month 9 by 1.1% (p=0.007). Patients with higher LVEF had higher circulating levels of chemokines and inflammatory markers and lower levels of stretch, injury, and fibrosis markers. Spironolactone reduced the circulating levels of natriuretic peptides and type 1 collagen, and increased LVEF.

Abstract 12119: Silencing of Notch Signaling Tempers the Occurrence of Arrhythmic Events in the Post-Infarcted Heart

Notch1 receptor signaling is active during cardiac development and is upregulated in the adult myocardium following ischemic damage. We previously documented that Notch1 signaling modulates the electrical activity of myocytes, but whether activation of the Notch receptor system contributes to the functional properties of the injured heart remains to be clarified. In the current study, we assessed the consequences of silencing of Notch1 signaling on electrical activity and arrhythmogenic behavior of the mouse heart, in physiological condition and following myocardial infarction (MI). For this purpose, mice with cardiac-restricted, inducible deletion of Notch1 gene (conditional knock-out, cKO) and corresponding control (Ctrl) mice were studied at baseline and up to one month after permanent coronary artery ligation. By echocardiography, left ventricular (LV) mass, chamber volume, and systolic function were comparable in both male and female naïve cKO and Ctrl mice. At ~2 and ~4 weeks after MI, chamber dilation occurred and ejection fraction was equally reduced in cKO and Ctrl animals. By electrocardiographic recordings in the conscious state over a period of 10 minutes, no arrhythmic events were observed in naïve Ctrl and cKO mice. In contrast, at one day after MI, a large fraction of Ctrl mice developed premature ventricular complexes (PVCs, 72%, n=18) and ventricular tachycardia (VT, 28%), but the fraction of cKO mice with PVCs was substantially reduced (31%, n=32) and VT was not observed. From 3-~30 days after MI, arrhythmic events occurred sporadically and no major differences were detected between the two groups of mice. Following euthanasia at 30 days after MI, infarcted hearts were perfused in a Langendorff system and monophasic action potential and pseudo-ECGs collected. Spontaneous VT were found in both Ctrl (18%, n=11) and cKO (7% n=14) hearts in sinus rhythm. Importantly, programmed electrical stimulation (S1-S2 protocol) induced PVCs and/or VT in 55% of Ctrl infarcted hearts (n=11), but only in 23% of cKO organs (n=13). Collectively, these findings support the possibility that Notch1 signaling modulates the electrical activity of the injured heart and its propensity to develop arrhythmias.

Abstract 12140: SCN1B Expression Modulates Sodium Influx in Cardiomyocytes and Diastolic Function in the Adult Heart

Voltage-gated sodium channels (VGSCs) are macromolecular complexes composed of a number of proteins regulating channel biophysical properties. VGSCs generate Na + current (I Na ) in myocytes and play fundamental roles in excitability and impulse conduction in the heart. Moreover, VGSCs condition mechanical properties of the myocardium, a process that appears to involve the late component of I Na . Variants in the gene SCN1B , encoding the VGSC β1 and β1B subunits, result in inherited neurological disorders and cardiac arrhythmias. But the precise contributions of β1/β1B subunits and VGSC integrity to the overall function of the adult heart remain to be clarified. For this purpose, adult mice with cardiac-restricted, inducible deletion of Scn1b (conditional knock-out, cKO) were studied. Myocytes from cKO mice had decreased levels of Scn1b transcripts (-85%) and increased densities of fast- (+20%) and slow-inactivating (+140%) components of I Na , with respect to cells from corresponding control (Ctrl) animals. By echocardiography, left ventricular (LV) mass, chamber volume, and systolic function were preserved in both male and female cKO mice, with respect to sex- and age-matched Ctrl animals. However, by transmitral flow Doppler echocardiography, cKO mice presented reduced velocity of the passive filling wave (-~20%), attenuated ratio of the passive-to-active filling velocity waves (-~20%), and prolonged isovolumic relaxation time (+~16%). Moreover, by pressure-volume (PV) loop assessment, cKO mice had steeper slope of the LV end diastolic PV relation and prolonged LV relaxation tau, suggesting impairment of diastolic function. Importantly, inhibition of late I Na with GS967 (0.5 mg/kg body weight) normalized left ventricular filling pattern and isovolumic relaxation time in cKO mice, but had no consequences in Ctrl animals. At the cellular level, cKO myocytes presented delayed kinetics of Ca 2+ transients decay and cell shortening with respect to Ctrl myocytes. These defects were partly corrected by inhibition of the late I Na . Collectively, these results document that VGSC β1/β1B subunits modulate electrical and mechanical function of the heart by regulating, at least in part, Na + influx in cardiomyocytes.

Surgical Treatment of Ischemic Dilative Cardiomyopathy by Ventricular Restoration

Patients with symptomatic post-ischemic dilative myocardiopathy of the left ventricle require, in selected cases, an operation to reshape and reduce the volume of the left ventricular chamber, in addition to surgical myocardial revascularization and mitral valve repair, with the aim of prolonging survival, improving the quality of life and minimizing the need for re-hospitalizations related to recurrent heart failure. This procedure is called surgical ventricular restoration (SVR), and is a useful tool for the treatment of heart failure patients as an alternative to heart transplant. This article provides an overview of surgical ventricular restoration for the treatment of dilative ischemic myocardiopathy. It illustrates several surgical options, describes the operative details, and discusses the correct indications for the procedure. Finally, an interesting protocol for one-step cell therapy during SVR is proposed, as an innovative treatment for heart failure patients.

P973 Predictive value of galectin-3 for cardiac remodelling in patients with acute heart failure

Abstract Background and objectives Heart failure is responsible for high mortality rates. Galectin-3 has been suggested as a potential heart failure development and progression mediator. This study aimed to show the relationship between galectin-3 and time evolution of left ventricular remodelling. Methods A total of 69 patients hospitalized with primary diagnosis of acute heart failure were enrolled and followed up for 6 months. For each, serum galectin-3 and echocardiographic parameters were measured at baseline and after 6 months. Results Mantel-Haenszel test showed highly significant association between pathological evolution of left ventricular end-diastolic diameter, left ventricular end-diastolic volume, relative wall thickness and increased or increasing galectin-3 levels over time (p &amp;lt; 0.001). High baseline galectin-3 levels (&amp;gt;16.5ng/ml) were associated with lower transmitral E peak velocity (68.59 ± 20.5; p = 0.021). Increased baseline galectin-3 levels (&amp;gt;16.5ng/ml) were associated with systolic dysfunction expressed by lower rates of dp/dt ratio (p = 0.018) and raised systolic pulmonary artery pressures (p = 0.046). There was a association between increased baseline galectin-3 levels and type I diastolic dysfunction (E/A &amp;lt; 1, p = 0.042) and this association tended to remain the same after 6 months. Conclusions Increased galectin-3 levels contribute to left ventricular evolutionary remodelling by its association with left ventricular chamber volume and diameter changes over time. Its levels also correlated with both systolic and diastolic dysfunction parameters.

How variable are the volumetric measurements from gated perfusion SPECT when a one-day stress-rest protocol is used?

BackgroundUsing myocardial perfusion scintigraphy (MPS), an increase in left ventricular (LV) volumes or a decrease in ejection fraction (EF) from rest to stress may be clinically important. The variation in these measures between the low-dose stress acquisition and high-dose rest acquisition in a one-day stress-rest protocol has not been established. We assessed the reproducibility of gated volumetric indices between stress and rest and the normal variation in ungated TID ratio for a one-day stress-rest 99mTc-tetrofosmin protocol. MethodsTwo thousand and one hundred and fifty eight (2158) 99mTc-tetrofosmin MPS patient studies were analyzed retrospectively. Studies were excluded for incomplete data, significant technical difficulties, or (for gated analysis but not for analysis of TID ratio) if the LV EF was > 75%. An analysis of gated data was undertaken to establish the reproducibility of ventricular volumes and EF between stress and rest scans. Ungated volume data were analyzed to determine the confidence limits of TID ratio according to ventricular volume. ResultsGated data were analyzed for 621 patients without inducible hypoperfusion. Mean EF at rest was slightly higher than after stress (62.4% ± 10.3% vs 61.2% ± 10.4%, P < 0.001), and the standard deviation of the difference was 5.2% (95% CI 4.9% to 5.5%). Ungated volumes were available for 992 non-ischaemic patients. The upper 95% CI for TID ratio was 1.23. This increased from 1.20 to 1.37 between the highest and lowest deciles of rest ungated volume. ConclusionUsing a one-day stress-rest 99mTc-tetrofosmin protocol, a fall in LV EF between rest and stress of > 11.6% or a TID ratio of > 1.23 is likely to be clinically reliable. The upper limit of normal for TID ratio needs to be increased for patients with small LV chamber volumes.

A Multicenter, Scan-Rescan, Human and Machine Learning CMR Study to Test Generalizability and Precision in Imaging Biomarker Analysis.

Automated analysis of cardiac structure and function using machine learning (ML) has great potential, but is currently hindered by poor generalizability. Comparison is traditionally against clinicians as a reference, ignoring inherent human inter- and intraobserver error, and ensuring that ML cannot demonstrate superiority. Measuring precision (scan:rescan reproducibility) addresses this. We compared precision of ML and humans using a multicenter, multi-disease, scan:rescan cardiovascular magnetic resonance data set. One hundred ten patients (5 disease categories, 5 institutions, 2 scanner manufacturers, and 2 field strengths) underwent scan:rescan cardiovascular magnetic resonance (96% within one week). After identification of the most precise human technique, left ventricular chamber volumes, mass, and ejection fraction were measured by an expert, a trained junior clinician, and a fully automated convolutional neural network trained on 599 independent multicenter disease cases. Scan:rescan coefficient of variation and 1000 bootstrapped 95% CIs were calculated and compared using mixed linear effects models. Clinicians can be confident in detecting a 9% change in left ventricular ejection fraction, with greater than half of coefficient of variation attributable to intraobserver variation. Expert, trained junior, and automated scan:rescan precision were similar (for left ventricular ejection fraction, coefficient of variation 6.1 [5.2%-7.1%], P=0.2581; 8.3 [5.6%-10.3%], P=0.3653; 8.8 [6.1%-11.1%], P=0.8620). Automated analysis was 186× faster than humans (0.07 versus 13 minutes). Automated ML analysis is faster with similar precision to the most precise human techniques, even when challenged with real-world scan:rescan data. Assessment of multicenter, multi-vendor, multi-field strength scan:rescan data (available at www.thevolumesresource.com) permits a generalizable assessment of ML precision and may facilitate direct translation of ML to clinical practice.

Natural History of Myocardial Injury and Chamber Remodeling in Acute Myocarditis.

Cardiovascular magnetic resonance (CMR) imaging is commonly used to diagnose acute myocarditis. However, the natural history of CMR-based tissue markers and their association with left ventricular recovery is poorly explored. We prospectively investigated the natural history of CMR-based myocardial injury and chamber remodeling over 12 months in patients with suspected acute myocarditis. One hundred patients with suspected acute myocarditis were enrolled. All underwent CMR evaluations at baseline and 12 months, inclusive of T2 and late gadolinium enhancement. Blinded quantitative analyses compared left ventricular chamber volumes, function, myocardial edema, and necrosis at each time point using predefined criteria. The predefined primary outcomes were improvement in left ventricular ejection fraction ≥10% and improvement in the indexed left ventricular end diastolic volume ≥10% at 12 months. The mean age was 39.9±14.5 years (82 male) with baseline left ventricular ejection fraction of 57.1±11.2%. A total of 72 patients (72%) showed late gadolinium enhancement at baseline with 57 (57%) having any T2 signal elevation. Left ventricular volumes and EF improved significantly at 12 months. Global late gadolinium enhancement extent dropped from 8.5±9.2% of left ventricular mass to 3.0±5.2% ( P=0.0001) with prevalence of any late gadolinium enhancement dropping to 48%. Reductions in global T2 signal ratio occurred at 12 months (1.85±0.3 to 1.56±0.2; P=0.0001) with prevalence of T2 ratio ≥2.0 dropping to 7%. Neither marker provided associations with the primary outcomes. In clinically suspected acute myocarditis, significant reductions in tissue injury markers occur during the first 12 months of convalescence. Neither the presence nor extent of the investigated CMR-based tissue injury markers were predictive of our pre-defined function or remodeling outcomes at 12 months in this referral population.

Open chest epicardial and transapical endocardial substrate ablation for ventricular tachycardia with left ventricular aneurysm in a porcine model.

Endo-epicardial radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) as a first-line strategy has been shown to improve outcomes. This study sought to evaluate the feasibility and validity of open-chest epicardial and transapical endocardial substrate ablation for VT with left ventricular aneurysm (LVA) applying to routine cardiac surgery. Porcine models of LVA with VT were developed and were divided into a study group (RFCA from the epicardium via direct-view and endocardium via transapical access) and a control group (endocardial RFCA via retrograde transaortic access). Substrate-based mapping and ablation targeting abnormal potentials were performed under thoracotomy. Outcomes, including procedural success and acute freedom from VT, were analysed. Twenty-four of 35 (68.57%) acute myocardial infarction (AMI) pigs developed LVA with VT in a 6-week survival period and were randomly divided into a study group (n=12) and a control group (n=12). All animals in the study group successfully underwent endocardial mapping and ablation by transapical access. The scar size of the endocardium and the left ventricular chamber volume were similar in the two groups. Acute freedom from VT in the study group was remarkably superior to that in the control group (88.33% vs. 58.33%, p=0.04). Combined, direct epicardial and transapical endocardial substrate mapping and ablation appeared to be feasible and effective for treating VT with LVA under thoracotomy.

The Accuracy of Left Ventricular and Left Atrial Volumetry Using 64-Slice Computed Tomography: In Vitro Validation Study With Human Cardiac Cadaveric Casts.

We aimed to validate the accuracy of imaging of left atrial and ventricular volumes using cardiac cadaveric silicone casts. Left atrial (n = 14) and ventricular (n = 15) casts were imaged using 64-slice computed tomography (CT). Water displacement (WD) of cardiac casts was used as the gold standard for volume measurements. Compared with WD, CT resulted in slightly higher left atrial and ventricular volumes (54 ± 25 vs 56 ± 26 mL [P = 0.003] and 57 ± 47 vs 66 ± 47 mL [P = 0.0001]). Variability between left atrial and ventricular volumes by CT and WD was low (coefficients of variation [CVs], 4% [intraclass correlation coefficient {ICC}, 0.99] and 12% [ICC, 0.97]). Intraobserver variability of CT was low for both the left atrium and the left ventricle (CVs, 1% [ICC, 1.00] and 4% [ICC, 1.00]). Cardiac CT is both accurate and reproducible in assessment of left ventricular and atrial chamber volumes.

The impact of menopausal hormone therapy (MHT) on cardiac structure and function: Insights from the UK Biobank imaging enhancement study.

BackgroundThe effect of menopausal hormone therapy (MHT)–previously known as hormone replacement therapy–on cardiovascular health remains unclear and controversial. This cross-sectional study examined the impact of MHT on left ventricular (LV) and left atrial (LA) structure and function, alterations in which are markers of subclinical cardiovascular disease, in a population-based cohort.MethodsPost-menopausal women who had never used MHT and those who had used MHT ≥3 years participating in the UK Biobank who had undergone cardiovascular magnetic resonance (CMR) imaging and free of known cardiovascular disease were included. Multivariable linear regression was performed to examine the relationship between cardiac parameters and MHT use ≥3 years. To explore whether MHT use on each of the cardiac outcomes differed by age, multivariable regression models were constructed with a cross-product of age and MHT fitted as an interaction term.ResultsOf 1604 post-menopausal women, 513 (32%) had used MHT ≥3 years. In the MHT cohort, median age at menopause was 50 (IQR: 45–52) and median duration of MHT was 8 years. In the non-MHT cohort, median age at menopause was 51 (IQR: 48–53). MHT use was associated with significantly lower LV end-diastolic volume (122.8 ml vs 119.8 ml, effect size = -2.4%, 95% CI: -4.2% to -0.5%; p = 0.013) and LA maximal volume (60.2 ml vs 57.5 ml, effect size = -4.5%, 95% CI: -7.8% to -1.0%; p = 0.012). There was no significant difference in LV mass. MHT use significantly modified the effect between age and CMR parameters; MHT users had greater decrements in LV end-diastolic volume, LV end-systolic volume and LA maximal volume with advancing age.ConclusionsMHT use was not associated with adverse, subclinical changes in cardiac structure and function. Indeed, significantly smaller LV and LA chamber volumes were observed which have been linked to favourable cardiovascular outcomes. These findings represent a novel approach to examining MHT’s effect on the cardiovascular system.

Estimating left ventricular volume with ROI-based convolutional neural network

The volume of the human left ventricular (LV) chamber is an important indicator for diagnosing heart disease. Although LV volume can be measured manually with cardiac magnetic resonance imaging (MRI), the process is difficult and time-consuming for experienced cardiologists. This paper presents an end-to-end segmentation-free method that estimates LV volume from MRI images directly. The method initially uses Fourier transform and a regression filter to calculate the region of interest that contains the LV chambers. Then convolutional neural networks are trained to estimate the end-diastolic volume (EDV) and end-systolic volume (ESV). The resulting models accurately estimate the EDV and ESV with a mean absolute error of 15.83 and 9.82 mL, respectively, and an ejection fraction with root mean square error of 5.56%. The comparison results show that the direct estimation methods possess attractive advantages over the previous segmentation-based estimation methods.

Cardiovascular response to prescribed detraining among recreational athletes.

Exercise-induced cardiac remodeling (EICR) and the attendant myocardial adaptations characteristic of the athlete's heart may regress during periods of exercise reduction or abstinence. The time course and mechanisms underlying this reverse remodeling, specifically the impact of concomitant plasma volume (PV) contraction on cardiac chamber size, remain incompletely understood. We therefore studied recreational runners ( n = 21, age 34 ± 7 yr; 48% male) who completed an 18-wk training program (~7 h/wk) culminating in the 2016 Boston Marathon after which total exercise exposure was confined to <2 h/wk (no single session >1 h) for 8 wk. Cardiac structure and function, exercise capacity, and PV were assessed at peak fitness (10-14 days before) and at 4 wk and 8 wk postmarathon. Mixed linear modeling adjusting for age, sex, V̇o2peak, and marathon finish time was used to compare data across time points. Physiological detraining was evidenced by serial reductions in treadmill performance. Two distinct phases of myocardial remodeling and hematological adaptation were observed. After 4 wk of detraining, there were significant reductions in PV (Δ -6.0%, P < 0.01), left ventricular (LV) wall thickness (Δ -8.1%, <0.05), LV mass (Δ -10.3%, P < 0.001), and right atrial area (Δ -8.2%, P < 0.001). After 8 wk of detraining, there was a significant reduction in right ventricle chamber size (end-diastolic area Δ = -8.0%, P < 0.05) without further concomitant reductions in PV or LV wall thickness. Abrupt reductions in exercise training stimulus result in a structure-specific time course of reverse cardiac remodeling that occurs largely independently of PV contraction. NEW & NOTEWORTHY Significant reverse cardiac remodeling, previously documented among competitive athletes, extends to recreational runners and occurs with a distinct time course. Initial reductions in plasma volume and left ventricular (LV) mass, driven by reductions in wall thickness, are followed by contraction of the right ventricle. Consistent with data from competitive athletes, LV chamber volumes appear less responsive to detraining and may be a more permanent adaptation to sport.

An abnormal TRPV4-related cytosolic Ca2 + rise in response to uniaxial stretch in induced pluripotent stem cells-derived cardiomyocytes from dilated cardiomyopathy patients

Dilated cardiomyopathy (DCM) is cardiac disease characterized by increased left ventricular chamber volume and decreased systolic function. DCM patient-specific human induced-pluripotent stem cells-derived cardiomyocytes (DCM-hiPSC-CMs) were generated. We found that uniaxial stretch elicited a cytosolic [Ca2+]i rise in hiPSC-CMs. Compared to control-hiPSC-CMs, DCM-hiPSC-CMs displayed a greater magnitude of [Ca2+]i responses to the cell stretch of 10–15% elongation in length. This stretch-induced [Ca2+]i rise was abolished by removal of extracellular Ca2+ and markedly attenuated by TRPV4 inhibitors HC-067047 and RN-1734. Application of nifedipine and tranilast also reduced the [Ca2+]i response but to a lesser degree. Moreover, the augmented [Ca2+]i was decreased by cytochalasin D treatment. Taken together, our study for the first time demonstrated an abnormal TRPV4-related mechanosensitive Ca2+ signaling in DCM-hiPSC-CMs.

Use of bio-informatics assessment schema (BIAS) to improve diagnosis and prognosis of myocardial perfusion data: results from the NHLBI-sponsored women's ischemia syndrome evaluation (WISE).

We introduce an algorithmic approach to optimize diagnostic and prognostic value of gated cardiac single photon emission computed tomography (SPECT) and magnetic resonance (MR) myocardial perfusion imaging (MPI) modalities in women with suspected myocardial ischemia. The novel approach: bio-informatics assessment schema (BIAS) forms a mathematical model utilizing MPI data and cardiac metrics generated by one modality to predict the MPI status of another modality. The model identifies cardiac features that either enhance or mask the image-based evidence of ischemia. For each patient, the BIAS model value is used to set an appropriate threshold for the detection of ischemia. Women (n=130), with symptoms and signs of suspected myocardial ischemia, underwent MPI assessment for regional perfusion defects using two different modalities: gated SPECT and MR. To determine perfusion status, MR data were evaluated qualitatively (MRIQL) and semi-quantitatively (MRISQ) while SPECT data were evaluated using conventional clinical criteria. Evaluators were masked to results of the alternate modality. These MPI status readings were designated "original". Two regression models designated "BIAS" models were generated to model MPI status obtained with one modality (e.g., MRI) compared with a second modality (e.g., SPECT), but importantly, the BIAS models did not include the primary Original MPI reading of the predicting modality. Instead, the BIAS models included auxiliary measurements like left ventricular chamber volumes and myocardial wall thickness. For each modality, the BIAS model was used to set a progressive threshold for interpretation of MPI status. Women were then followed for 38±14 months for the development of a first major adverse cardiovascular event [MACE: CV death, nonfatal myocardial infarction (MI) or hospitalization for heart failure]. Original and BIAS-augmented perfusion status were compared in their ability to detect coronary artery disease (CAD) and for prediction of MACE. Adverse events occurred in 14 (11%) women and CAD was present in 13 (10%). There was a positive correlation of maximum coronary artery stenosis and BIAS score for MRI and SPECT (P<0.001). Receiver operator characteristic (ROC) analysis was conducted and showed an increase in the area under the curve of the BIAS-augmented MPI interpretation of MACE vs. the original for MRISQ (0.78 vs. 0.54), MRIQL (0.78 vs. 0.64), SPECT (0.82 vs. 0.63) and the average of the three readings (0.80±0.02 vs. 0.60±0.05, P<0.05). Increasing values of the BIAS score generated by both MRI and SPECT corresponded to the increasing prevalence of CAD and MACE. The BIAS-augmented detection of ischemia better predicted MACE compared with the Original reading for the MPI data for both MRI and SPECT.