Biplane Method Research Articles

Reduced stroke volume by resting 2-dimensional echocardiography negatively affects survival in patients with abnormal ejection fraction

Abstract Background Abnormal (<50%) ejection fraction (EF) is a cornerstone of risk stratification and therapy, but also an imperfect proxy of left ventricular (LV) cardiac pump function, better assessed with stroke volume (SV). Aim To assess the value of SV in stratifying risk of patients with abnormal EF. Methods In a prospective, observational, multicenter study, we recruited 746 patients (age 66± 11 years, 536 males, 72%, 359 with previous myocardial infarction, 48%) with chronic coronary syndromes (CCS) and EF <50% referred for resting transthoracic echocardiography with technically successful 2-dimensional volumetric echocardiography in 17 accredited laboratories. We quantitatively assessed LV end-diastolic volume (EDV) and end-systolic volume (ESV) by Simpson’s biplane method. EF (EDV-ESV/EDV) and SV (EDV-ESV) were calculated from LV volumes. The outcome end-point was all-cause death. Results EF was 39±9%, SV 48±20 ml. There were 100 all-cause deaths during a median follow-up of 796 days (interquartile range 420-1286 days). Receiver-operating curve analysis identified SV≤31.4 ml/b as the best cut-off for predicting mortality. At multivariable analysis, after adjustment for age and prior myocardial infarction, EF <40% and SV ≤31.4 ml/b were significantly associated with decreased survival (HR 2.09, 95%, confidence intervals 1.09-4.01, p=0.024). The annual mortality was lowest (3.19%) in the group with mildly reduced (40-49%) EF and normal (>31.4 ml) SV, and highest (8.30%) in patients with both reduced EF and abnormal SV: see figure. Conclusion Patients with CCS and abnormal EF are a prognostically heterogeneous group, and the mortality rate is almost 3-times worse in patients with reduced EF and abnormal SV compared to patients with mildly reduced EF and normal SV. A simple resting volumetric two-dimensional echocardiography can offer an efficient risk stratification, beyond EF, with no extra imaging or analysis time.Figure

Combined activation of complement and coagulation is associated with myocardial injury in ST-elevation myocardial infarction

Abstract Introduction Experimental data indicates that the complement system and the coagulation cascade can activate each other. The magnitude of this interaction in acute myocardial infarction is not known. We aimed to investigate a possible association between complement activation and coagulation activation in patients with acute ST-elevation myocardial infarction (STEMI), as well as how they relate to myocardial injury estimated by troponin T (TnT) and myocardial function assessed by echocardiography. Purpose To increase the understanding of the interaction between complement activation and coagulation activation in STEMI, and the clinical relevance to myocardial injury. Methods Blood samples were drawn after percutaneous coronary intervention (PCI) in 864 patients with STEMI. Myocardial function was measured as left ventricular ejection fraction (LVEF), estimated by visual approximation or Simpson biplane method within 3 months. Complement activation was assessed by ELISA of circulating levels of the terminal complement complex (TCC). Activation of coagulation was assessed by ELISA of prothrombin fragment 1+2 (F1+2) and D-dimer, and endogenous thrombin potential (ETP), analyzed by calibrated automated thrombogram assay. Results TCC was weakly correlated to F1+2 (r=0.086, p=0.012), D-dimer (r=0.176, p<0.001) and ETP (r=0.144, p<0.001). In univariate linear regression analysis, this association persisted for D-dimer and ETP. When adjusting for associated covariables, the association only persisted for ETP (Table 1). Patients with above-median TCC and D-dimer had significantly higher peak TnT (Figure 1). In logistic regression, having combined above-median TCC and D-dimer was predictive of an LVEF ≤40% (Table 2). Conclusion In this large STEMI cohort, complement activation by TCC was weakly associated with coagulation activation. Combined high levels of TCC and D-dimer were linked to higher peak TnT and lower LVEF, possibly reflecting greater myocardial injury. The interaction between complement and coagulation activation might be relevant for clinical outcomes in STEMI patients and warrants further investigation.

Discrimination of Left Atrial Strain Patterns in Hypertensive Heart Disease and Hypertrophic Cardiomyopathy: a Cardiac Magnetic Resonance Feature.

To assess left atrial (LA) strain parameters using cardiovascular magnetic resonance imaging feature tracking (cardiac MRI-FT) for differentiating hypertensive heart disease (HHD) from hypertrophic cardiomyopathy (HCM), which are two left ventricular hypertrophic diseases that could present with similar morphologies in early stage but differ in clinical symptoms and treatment strategies. 45 patients with HHD, 85 patients with HCM (non-obstructive hypertrophiccardiomyopathy [HNCM, n = 45] and obstructive hypertrophic cardiomyopathy [HOCM, n = 40]) and 30 healthy controls (HC) were retrospectively included. LA volumes, strain, and strain rate were determined by manually contouring on the two- and four-chamber views of the CMR-FT module using CVI 42 software. LA volume parameters including LA maximum, precontraction, and minimum volume index, and total, passive, and active emptying fractions were obtained using the biplane methods. The LA strain parameters, including total strain (εs), passive strain (εe), active strain (εa), peak positive strain rate (SRs), early peak negative strain rate (SRe), and late peak negative strain rate (SRa), were obtained from the LA strain curve. The LA strain and LA strain rate were impaired in both HHD group and HCM group, and they were the most severely impaired in the HOCM group. εs (AUC = 0.691, P = 0.006; the best cutoff value, 25.1%), εa (AUC = 0.654, P = 0.027; the best cutoff value, 10.5%), SRs (AUC = 0.710, P = 0.003; the best cutoff value, 0.81 1/s) and SRa (AUC = 0.667, P = 0.016; the best cutoff value, -1.30 1/s) showed significant differences in the identification between HHD and HNCM. All LA strain parameters were different in the identification between HHD and HOCM (all P < 0.05).LA strain parameters can be helpful for differentiating HHD from HCM, providing valuable insights for diagnosis.

Longitudinal strain correlates with 6-minute walk distance whereas ejection fraction and diastolic parameters do not

BackgroundImpaired functional capacity is a common symptom in patients with heart failure. Standard measures of left ventricular (LV) function, such as ejection fraction (EF) and LV diastolic parameters, do not correlate with measures of functional capacity. The aim of this study is to determine if measures of global and regional LV strain better correlate with 6-minute walk distance than does EF or measures of LV diastolic function.Methods120 patients referred to a cardiology clinic for evaluation of known or suspected heart failure were approached for enrollment. Of those 120 patients, 58 had an echocardiogram within 3 months of enrollment with images adequate for regional and global strain assessment, had no contra-indication to exercise testing, and had no previously documented non-cardiac explanation for dyspnea on exertion. In those 58 patients, 6-minute walk distance was measured, LV EF was determined with Simpson’s biplane method, and global and regional longitudinal strain were measured with TomTec Image Arena 4.5.1 software.ResultsLV EF had no correlation with 6-minute walk distance (r = 0.22, p = 0.09) even when controlling for age, gender, and BMI (p = 0.07). No measures of LV diastolic function (including E velocity, Deceleration Time, e’ annular velocities, or E/e’) had a correlation with 6-minute walk distance. Multiple measures of global and regional LV longitudinal systolic function had a correlation with 6-minute walk distance. Longitudinal strain of the basal LV segments had the strongest correlation with 6-minute walk distance (r= -0.36, p = 0.005), and correlation persisted after controlling for age, gender, BMI, and systolic blood pressure (p = 0.004).ConclusionsLongitudinal strain correlates with a measure of functional capacity, but LVEF and traditional measures of LV diastolic dysfunction do not. Measures of longitudinal strain, especially in basal LV segments, will likely be an important marker of clinically relevant LV function.Graphical

Correlation of Global Longitudinal Strain with Functional Status of Patients with Left Ventricular Systolic Dysfunction: Does Gender Difference Exist?

Objectives: Two-dimensional (2D) echocardiographic (echo) assessment of the left ventricular ejection fraction (LVEF) by Simpson’s biplane method is routinely used in clinical practice for patient management. The measurement of global longitudinal strain (GLS) using speckle tracking echocardiography is a new method for assessing left ventricular (LV) systolic function with several advantages. There are very few observations regarding the correlation of 2D GLS with the functional status of patients with the LV systolic dysfunction (LVSD). Therefore, we aimed to evaluate the superiority of GLS over Simpson’s method of LVEF in predicting the functional status of the patients with moderate-to-severe LVSD (ejection fraction &lt;40%) and to find out if any difference exists between male and female patients. Materials and Methods: Fifty patients aged 18–80 years satisfying the inclusion and exclusion criteria were studied over a period of 2 months. Simpson’s method was used to calculate 2D LVEF. 2D GLS was assessed using an automated function imaging technique. The Minnesota living with heart failure questionnaire was used to assess the functional status of patients. Results: Correlation of functional status of patients was better with 2D GLS than 2D LVEF, although both were found to be statistically significant and no statistically significant difference was found in observations between both genders. Conclusion: The correlation of functional status of patients with moderate-to-severe LVSD was better with 2D GLS than 2D LVEF. Further studies are needed to identify the gender differences in 2D GLS correlation with the functional status of patients with LVSD.

Multimodal echocardiography for assessing whether left ventricular geometry affects right atrial phasic function in patients with obstructive sleep apnea syndrome: A cross-sectional observational study.

Recent studies have shown that right atrial (RA) function are important predictors of cardiovascular morbidity and mortality. However, the study data about RA phasic function in obstructive sleep apnea syndrome (OSAS) patients are scarce, especially based on the left ventricular geometry. So, we aimed to assess the influence of left ventricular geometry on RA phasic function in OSAS patients via a multimodal echocardiographic approach. Total of 235 OSAS patients were enrolled in this cross-section study and underwent complete clinical, polysomnography, and echocardiography examinations. The OSAS patients were divided into four groups based on left ventricular mass index (LVMI) and relative wall thickness (RWT): normal geometry (NG), concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH). RA phasic function was evaluated via multimodal echocardiography approach (two-dimensional echocardiography biplane method [2DE]; two-dimensional speckle-tracking echocardiography [2D-STE]; and three-dimensional echocardiography [3DE]). The multiple linear regression analysis was used to determine the relationship between left ventricular geometry and RA phasic function. The RA volume and indices increased from NG to CR to EH to CH. RA total emptying fraction and RA strain during systole decreased from NG to CR to EH to CH. RA passive emptying fraction and RA strain during early diastole similarly decreased. RA active emptying fraction and RA strain during late diastole also gradually increased similarly. In analyses that adjusted for gender, age, body mass index, systolic blood pressure, apnea-hypopnea index, LVMI, systolic pulmonary artery pressure, and right ventricular free wall thickness, CH was associated with RA reservoir and conduit function via 2DE area-length method, whereas CH and EH were associated with RA reservoir and conduit function via 2D-STE and 3DE method. Further, CH was associated with RA booster pump function via 2DE area-length method, 2D-STE, and 3DE method. The RA volumes and phasic function varied with left ventricular geometry via multimodal echocardiography approach. CH had the apparent negative effect on RA phasic function.

Left ventricular systolic dysfunction predicts clinical prognosis in patients with acute ischemic stroke after intravenous thrombolysis.

Although intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis is the most effective early treatment for acute ischemic stroke (AIS), outcomes vary greatly among patients. Left ventricular systolic dysfunction (LVSD) is prone to distant organ ischemia and may be a predictor for poor prognosis in AIS patients undergoing intravenous thrombolysis (IVT). Our aim was to investigate the predictivity of LVSD diagnosis (as measured by left ventricular ejection fraction (LVEF)) on 90-day clinical outcomes in AIS patients undergoing thrombolysis. The current prospective cohort study continuously enrolled 273 AIS patients from the National Stroke Prevention and Treatment Engineering Management Special Database who underwent IVT and completed echocardiography within 24 h of admission between 2021 and 2023. LVSD was examined by evaluation of the echocardiographic LVEF values using Simpson's biplane method of discs in line with international guidelines, and defined as a LVEF value < 50%. Multivariable ordinal logistic regression model was performed to analyze the association between LVEF and functional outcome at 3 months. Restricted cubic spline (RCS) was used to examine the shape of the dose-response association between reduced LVEF and poor functional outcomes. Subgroup analysis was also employed to further verify the reliability and practicability of the results. Baseline data analysis showed LVSD patients had more comorbidities including on multivariate analyses, LVSD (OR 2.78, 95% CI 1.23 to 6.24, P=0.014), pre-existing diabetes mellitus (OR 2.08, 95% CI 1.11 to 3.90, P=0.023) and NIHSS on arrival (OR 1.31, 95% CI 1.21 to 1.49, P<0.001) were independent predictors of poor functional outcomes (mRS ≥ 3) at 3 months. Multivariable-adjusted spline regression indicated a linear dose-response association between LVEF after IVT and poor functional outcomes (p for linearity < 0.001), with the optimal cutoff values of LVEF being 0.48. Our finding indicated that AIS patients with LVSD after IVT had poorer outcomes, suggesting the need to monitor and optimize LVEF in stroke management.

COMPARISON OF LEFT VENTRICULAR VOLUMES AND EJECTION FRACTION VALUES BETWEEN ECHOCARDIOGRAPHY AND CARDIAC MAGNETIC RESONANCE: A PILOT STUDY

Objective: Although transthoracic echocardiography (TTE) is the most commonly used technique to evaluate left ventricular (LV) parameters, cardiac magnetic resonance (CMR) is considered to provide more accurate measurements. The aim of this study was to compare LV end-diastolic volume (LVEDV), end-systolic volume (LVESV) and ejection fraction (LVEF) assessed by TTE with those parameters obtained by CMR. Design and method: The study included 100 patients who underwent both TTE and CMR between 2021 and 2023. Echocardiographic images were analysed retrospectively by three independent investigators (R1, R2, R3). The following parameters were obtained using Simpson's biplane method: LVEDV, LVESV and LVEF. The echocardiographic values assessed by each investigator were then compared with reference values obtained by CMR. Statistical analyses were performed using repeated measures ANOVA with post hoc pairwise t-tests with Bonferroni correction. Results: The mean age of the study population was 47±18 years, 64% were male, and the median time between TTE and CMR was 27 days. The most common indication for CMR was evaluation of suspected cardiomyopathy (42%), followed by suspected acute myocarditis (16%). The repeated measures ANOVA test showed that there was a significant difference between measurements (R1/R2/R3/CMR) of LVEDV (R1=132.47 ml, R2=132.38 ml, R3=122.69 ml, CMR=183.72 ml, p=0.002) and LVESV (R1=59.27 ml, R2=65.7 ml, R3=60.97 ml, CMR=80.23 ml, p=0.002). Post hoc analysis showed that the differences were only due to the discrepancy between each echocardiographer and magnetic resonance imaging. There was no significant difference in LVEF between measurements (R1=44.44%, R2=47.56%, R3=46.96%, CMR=48.5%, p=0.243). Conclusions: Our study shows that echocardiographic values of LV volumes and EF have low interobserver variability. TTE tends to underestimate LV volumes compared to CMR, but LVEF is similar with both techniques.

Validation of Left Atrial Volume Correction for Single Plane Method on Four-Chamber Cine Cardiac MRI.

Left atrial (LA) assessment is an important marker of adverse cardiovascular outcomes. Cardiovascular magnetic resonance (CMR) accurately quantifies LA volume and function based on biplane long-axis imaging. We aimed to validate single-plane-derived LA indices against the biplane method to simplify the post-processing of cine CMR. In this study, 100 patients from Leeds Teaching Hospitals were used as the derivation cohort. Bias correction for the single plane method was applied and subsequently validated in 79 subjects. There were significant differences between the biplane and single plane mean LA maximum and minimum volumes and LA ejection fraction (EF) (all p < 0.01). After correcting for biases in the validation cohort, significant correlations in all LA indices were observed (0.89 to 0.98). The area under the curve (AUC) for the single plane to predict biplane cutoffs of LA maximum volume ≥ 112 mL was 0.97, LA minimum volume ≥ 44 mL was 0.99, LA stroke volume (SV) ≤ 21 mL was 1, and LA EF ≤ 46% was 1, (all p < 0.001). LA volumetric and functional assessment by the single plane method has a systematic bias compared to the biplane method. After bias correction, single plane LA volume and function are comparable to the biplane method.

Assessing left atrial size and pump function in ischemic stroke patients: Is cardiac MRI superior to transthoracic echocardiography?

ObjectivesCurrent guidelines recommend transthoracic echocardiography (TTE) following an ischemic stroke as the primary technique to identify cardiac abnormalities associated with an increased risk of cerebral embolism. It is unclear whether cardiac magnetic resonance imaging (cMRI), a technique shown to provide increased imaging resolution, may also enhance the cardiac assessment of ischemic stroke patients. We compared cMRI with TTE in the evaluation of Left Atrial (LA) size and pump function in a cohort of 44 patients with ischemic stroke. Materials and methodsThe biplane method was utilized to acquire LA diameters as well as area measurements in both TTE and cMRI. We calculated LA volume (LAV), LAV index (LAVI), LA Global Longitudinal Strain (GLS) and LA pump function. Results were compared using paired two sample for means t-test. Lin's concordance correlation coefficient (CCC) and Bland-Altman methods quantified the agreement of measurements obtained by TTE and cMRI. ResultsLAVI measurements by cMRI were significantly larger (34.97 v. 28.81; p = 0.001) than by TTE. The concordance correlation demonstrated only a weak agreement between LA size measured by cMRI and TTE (ρc = 0.397; p= 0.001, 95% CI 0.16 - 0.59), and the Bland-Altman plot demonstrated that LAVI measured by cMRI averaged 6.3 ml/m2 larger magnitude than those obtained by TTE. ConclusionsUsing TTE alone leads to an underestimation of LA abnormalities important in the evaluation of ischemic stroke patients. Nearly one in every five ischemic stroke patients evaluated based on the current guidelines may have a missed potential source of cardiac embolism.

Association of Ejection Fraction with Reperfusion Parameters Before and After Primary Percutaneous Coronary Intervention

Background: Resolution of ST-segment (STR) and thrombolysis in myocardial infarction (TIMI) and frame count (TFC) are useful parameters to evaluate the reperfusion status following primary percutaneous coronary intervention (PPCI) in ST-elevation myocardial infarction (STEMI) patients. Objectives: Here, the association of ejection fraction (EF), as a parameter of systolic function, with TFC and STR was assessed in patients with STEMI who underwent PPCI. Methods: Ejection fraction was evaluated by transthoracic echocardiography using Simpson’s biplane method before PPCI in the first 24 hours after the admission of STEMI patients. Also, STR and TFC were assessed in all patients after PPCI. Then, the association of EF with STR and TFC was examined before and after the operation. Results: STEMI patients with STR less or greater than 50% were comparable in terms of clinical and demographic characteristics and laboratory indices. Our results showed a weak inverse correlation between EF before PPCI and TFC (r = -0.2336, P = 0.0002). However, there was a strong inverse correlation between EF after PPCI and TFC (P &lt; 0.0001, r = -0.3137). The results of correlation analysis showed that the mean EF (pre- and post-PPCI) was significantly higher in patients with STR of ≥50% compared to those with STR &lt; 50%. Conclusions: The results of this study showed that EF after PPCI, as an echocardiographic indicator, could reflect the status of cardiac and microvascular perfusion. We also found that cardiac status on ECG could better reflect EF.

Myocardial Work for Dynamic Monitoring of Myocardial Injury in Neonatal Asphyxia.

To assess the value of parameters of myocardial work for dynamic monitoring of myocardial injury after neonatal asphyxia. Fifty-three neonates with asphyxia admitted within 24h after delivery were divided into a mild asphyxia group (n = 40) and severe asphyxia group (n = 13). Echocardiography was performed within 24h post-birth, within 72h post-birth (48h after first echo), and during recovery. The left ventricular ejection fraction on M-mode echocardiography and by Simpson's biplane method (LVEF and Bi-EF, respectively), stroke volume (SV), cardiac output (CO), cardiac index (CI), global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), and other parameters were measured. Echocardiographic indicators were compared between groups and over time. GWI was significantly increased at 72h in the mild asphyxia group (P < 0.05) but showed no significant change over time in the severe asphyxia group (P > 0.05). While GCW increased significantly over time in both groups (P < 0.05), it increased earlier in the mild asphyxia group. Time and grouping factors had independent effects on GWI and GCW (P > 0.05). The characteristics of differences in GWI and GCW between the two groups were different from those for LVEF, Bi-EF, SV, CO, CI, and GLS and their change characteristics with improvement from treatment. GWI and GCW changed significantly during recovery from neonatal asphyxia, and their change characteristics differed between mild and severe asphyxia cases. Myocardial work parameters can be used as valuable supplements to traditional indicators of left ventricular function to dynamically monitor the recovery from myocardial injury after neonatal asphyxia.

Abstract 14461: Impact of Intermittent vs Persistent Left Ventricle Outflow Tract Obstruction on Left Atrial Strain and Diastolic Function in a Young Hypertrophic Cardiomyopathy Cohort

Background: Adolescents and young adults with hypertrophic cardiomyopathy (HCM) and persistent left ventricular outflow tract obstruction (LVOTO) have larger left atrial volume (LAV) and abnormal diastolic function and left atrial (LA) strain compared to those without resting LVOTO. It is unknown whether intermittent LVOTO with exercise results in smaller LAV and improved diastolic function and LA strain indices compared to persistent LVOTO. Methods: All HCM patients with echo and exercise stress echocardiography (ESE) from 2014-2022 at a single center were enrolled. The cohort was divided into 3 ESE hemodynamics groups: 1) No LVOTO (all gradients &lt; 30 mmHg, n=48); 2) Intermittent LVOTO (no rest gradient, exercise ≥30 mmHg, n=41); 3) Persistent LVOTO (rest/exercise ≥30mm Hg, n=29). LAV (biplane method), LAV Z scores, LV lateral e’, lateral e’ Z scores, LA reservoir (LASr), conduit (LAScd), and contractile (LASct) strain (TOMTEC Arena AutoSTRAIN) were analyzed. For each parameter, mean values were compared across groups using one-way analysis of variance. The Bonferroni method was used to compare Group 2 to 1 and 3. Results: 118 patients (31% F, median age 17 yrs, range 7-39) formed the cohort. Mean LAV was 64.9, 65.1, and 79.5 ml in Groups 1, 2, and 3 respectively. Differences in group means were found for LAV Z score, lateral e’, lateral e’ Z score, LASr, and LAScd (all p≤0.01). In Group 2 vs 3, LAV Z score was significantly lower (0.46 v 1.89) and LV lateral e’, lateral e’ Z score, and LAScd were significantly higher (lateral e’: 13.1 v 9.0 cm/s; lateral e’ Z score: -2.0 v -3.4; LAScd: 26.0 v 21.1%) (Fig 1). LASr did not differ significantly in Group 2 vs 3. No significant differences were found in Group 2 vs 1. Conclusion: In one of the largest young HCM cohorts, intermittent obstruction was associated with smaller LAV, better diastolic indices, and higher LA conduit strain versus persistent obstruction. Longer follow-up is needed to assess change as those with intermittent LVOTO age.

Abstract 17637: Lacking MicroRNA-1’s Biophysical Action Causes Heart Failure Revealed by a Newly Developed Biplane Echocardiography of Mouse Heart

MicroRNA-1 (miR1) is the most abundant microRNA in the heart and plays a key role in maintaining cardiac homeostasis through a well-known RNAi mechanism. Recently, we found a novel biophysical function of miR1 to physically bind to and modulate cardiac ion channels. A human single nucleotide polymorphism-hSNP14A/G (rs776480338) of miR1, in which the 14th nucleotide “A” is mutated to “G”, specifically abolishes the biophysical modulation while maintaining the RNAi. However, the physiological significance of microRNA’s biophysical action remains unknown. To study this, we created a single-nucleotide 14A/G mutation on miR1-1 and miR1-2 genes by using CRISPR/Cas9 and developed 14G-mutated homozygous (14G-Homo, miR1-1 14G/G:miR1-2 14G/G) transgenic mice. In addition, we also developed a new echocardiography methodology that can consistently record clear 4-chamber views of mouse hearts, allowing integration of 4-chamber and long axis views for the clinically recommended Biplane Simpson’s assessment of left ventricular (LV) function. Validation via Cardiac Magnetic Resonance (CMR) revealed that the Biplane method is more accurate than M-mode analysis for precise assessments of mouse LV functional parameters. These findings were highlighted in practice by monitoring both Wild Type (WT) and 14G-Homo mice at 2, 3, and 4 months of age, in which M-mode consistently overestimated LV parameters. Moreover, the clarity of the 4 chamber images enables many cardiac analyses that were previously not feasible for the mouse heart, such as the mitral valve color doppler that revealed turbulent blood flow into the LV of 14G-Homo mice. With the 4-chamber view methodology, we also studied the right ventricular (RV) function by assessing fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE) and found that cardiac functional deterioration of 14G-Homo mice most likely originated in the LV, followed by RV deteriorations and development of heart failure. In conclusion, our study demonstrated that the biophysical action of miR1 is essential to cardiac homeostasis. Additionally, our new imaging methodology enables more clinically comparable analyses which significantly improve translational implications of mouse cardiac research.

Abstract 16427: Despite Machine Learning Models, QRS Duration Remains the Superior ECG Criterion for Predicting Left Ventricular Dilation in Patients With Left Bundle Branch Block

Introduction: The utility of ECG to diagnose left ventricular (LV) dilation in patients with left bundle branch block (LBBB) is not known. We sought to compare the diagnostic yield of ECG using (i) QRS duration, (ii) published LVH criteria, and (iii) machine learning (ML) models to detect increased left ventricular end diastolic volume indexed (LVEDVi) in the setting of LBBB. Hypothesis: ML is superior to QRS duration and LVH criteria to detect increased LVEDVi among LBBB. Methods: 12-lead ECGs were processed to reconstruct orthogonal X, Y, Z leads using Kors’s matrix and obtain root-mean-squared (3D) ECG. R wave, S wave and overall amplitudes, voltage-time-integrals (VTIs), and other ECG features were extracted from all ECG leads. ML algorithms [logistic regression (LR), support vector classifier (SVC), decision trees (DT), random forest (RF), gradient boosted machine (GBM) and boosted trees (BT)] were trained to predict increased LVEDVi (women &gt;61 mL/m 2 , men &gt;74 mL/m 2 ) from ECG features on a training set of 2668 ECGs with typical LBBB and echocardiogram within 45 days before or after ECG. LVEDV was measured using ASE biplane method of discs. We obtained ROC AUCs for prediction of increased LVEDVi by (i) QRS duration, (ii) published LVH criteria, and (iii) ML models in a separate validation set of adults with typical LBBB. Results: Among the validation set of 413 adults (53% women, age 73±12 yr) with LBBB, QRS duration alone had a higher AUC (women 0.668, men 0.699) for diagnosing increased LVMi compared to standard LVH criteria (Table). The best ML model (RF with overall AUC 0.694) did not substantially outperform QRS duration alone. Conclusions: In patients with LBBB, QRS duration ≥150 in women and ≥160 in men is a superior predictor of LV dilation than traditional ECG-based LVH criteria, with no additional value added by ML methods.

Speckle tracking echocardiography-derived left ventricular global longitudinal strain in ex-thalassaemics.

Long term survivors of haematopoietic stem cell transplantation (HSCT) for β-thalassemia major are designated "ex-thalassaemics". Whether ex-thalassaemics continue to harbour residual myocardial dysfunction and thereby stand the risk of heart failure-related morbidity and mortality is unknown. The aim of this study was to assess the prevalence and predictors of subclinical left ventricular (LV) dysfunction in an apparently normal ex-thalassaemic population. We conducted a single centre cross-sectional study among 62 ex-thalassaemic patients, who had undergone HSCT for β-thalassaemia major at our centre. The primary outcome variable was LV systolic dysfunction, as assessed by 1) LV global longitudinal strain (GLS) derived by 2D speckle tracking echocardiography and 2) LV ejection fraction (EF) derived by 2D Simpsons Biplane method. Among the 62 patients included in the study, 7 [11.3%] were found to have LV systolic dysfunction, all of which were subclinical. Of these, 4 [6.5%] had abnormal GLS and LVEF, 2 [3.2%] had abnormal GLS with normal LVEF, and 1 [1.6%] had abnormal LVEF with low normal mean GLS. There were no statistically significant predictors of LV dysfunction in this cohort. There was a high prevalence of subclinical myocardial dysfunction in the ex-thalassaemic population reiterating the need for close follow up of these patients. 2D Speckle tracking echocardiography-derived LV global longitudinal strain is an effective tool in detecting subclinical myocardial dysfunction in this cohort.

The Recovery of Left Ventricular Function in Cases of Primary Angioplasty for Acute Myocardial Infarction

Background: This study is to investigate the recovery in left ventricular ejection fraction in the first 3 months after acute myocardial infarction treated with primary angioplasty. Left ventricular function (LVF) is the main predictor of long term prognosis in cases of survival after acute myocardial infarction. Study aims to investigate successful improvement in left ventricular ejection fraction after primary angioplasty.&#x0D; Methodology: A cross sectional study was conducted at Chaudhary Pervaiz Ellahi Institute of Cardiology, Multan from 1stSeptember 2019 to 30thSeptember 2020. Left ventricular ejection fraction was evaluated in 100 patients treated with primary angioplasty. Primary angioplasty is a very 1st treatment to re-open the locked artery after acute myocardial infarction. Ejection fraction was measured with Echocardiography Simpson’s biplane method at 3rd day and 3 months after angioplasty. Collected data was analyzed by using SPSS version 23. Chi square test was applied to see association among variables.&#x0D; Results: One hundred patients were included this study. The mean age and BMI of the patients was 59.45±6.01 years and 24.76±8.02 kg/m2, respectively. Male 70 (70%) and female 30 (30%) ratio was 7:3. LVEF at 3rd month was observed in ≤40% in 223 (23.0%) patients and &gt;40% in 77 (77%) patients. Male patients were greater in number that’s why LVEF is also observed in greater in male gender (p&lt;0.001). Increase in age also have no impact on procedure success (p&gt;0.050).&#x0D; Conclusion: Results of this study reveal that primary angioplasty is successful treatment plan in patients with acute myocardial infarction. A significant recovery of left ventricular function during 3 months after primary angioplasty in acute Myocardial infarction (MI) patients was observed.

Evaluation of Wearable Acoustic Sensors and Machine Learning Algorithms for Automated Measurement of Left Ventricular Ejection Fraction

Left ventricular ejection fraction (EF) is a predictor of mortality and guides clinical decisions. Although transthoracic echocardiography (TTE) is commonly used for measuring EF, it has limitations, such as subjectivity and requires expert personnel. Advancements in biosensor technology and artificial intelligence are allowing systems capable of determining left ventricular function and providing automated measurement of EF. In this study, we tested new wearable automated real-time biosensors (Cardiac Performance System [CPS]) that compute EF using waveform machine learning on cardiac acoustic signals. The primary aim was to compare the accuracy of CPS EF with TTE EF. Adult patients presenting to cardiology, presurgical, and diagnostic radiology clinical settings in an academic center were enrolled. TTE examination was performed by a sonographer, followed immediately by a 3-minute recording of acoustic signals from CPS biosensors placed on the chest by nonexpert personnel. TTE EF was calculated offline using the Simpson biplane method. A total of 81 patients (aged 19 to 88years, 27 women, 20% to 80% EF) were included. Deming regression and Bland-Altman analysis were performed to assess the accuracy of CPS EF against TTE EF. Both Deming regression (slope 0.9981; intercept 0.03415%) and Bland-Altman analysis (bias -0.0247%; limits of agreement [-11.65, 11.60]%) demonstrated equivalency between CPS EF and TTE EF. The receiver operating characteristic for measuring sensitivity and specificity of CPS in identifying subjects with abnormal EF showed an area under the curve value of 0.974 for identifying EF <35% and 0.916 for detecting EF <50% CPS EF intraoperator and interoperator assessments demonstrated low variability. In conclusion, this technology measuring cardiac function from noninvasive biosensors and machine learning on acoustic signals provides an accurate EF measurement that is automated, real-time, and acquired rapidly by personnel with minimal training.

THE ASSOCIATION OF HYPERTENSION AND OBESITY: WHAT IMPACT ON THE LONGITUDINAL SYSTOLIC FUNCTION OF THE LEFT VENTRICLE

Objective: Hypertension and obesity are well known each result in heart failure with preserved ejection fraction. Indeed, there is ample evidence that the accumulation of adipose tissue in obese subjects negatively affects the left atrial and ventricular structure, as well as diastolic and systolic function. Predisposing factors for heart failure with preserved LVEF are advanced age, hypertension, diabetes, dyslipidemia and obesity. The development of the 2D strain has made it possible to make an early diagnosis of ventricular dysfunction in patients with cardiovascular risk factors. Design and method: This work consists of performing in a series of 128 hypertensive patients divided into two subgroups: 58 obese patients and 70 patients with normal BMI. A complete cardiographic echo study was performed in both subgroups, including LVEF by Simpson biplane method, calculation of indexed left ventricular mass and parietal relative thickness, analysis of diastolic function and finally study of longitudinal LV deformation by speckle tracking technique. Results: We note in this work that dyslipidemia and diabetes were significantly more prevalent in the HTA+obesity arm. The average blood pressure figures were slightly higher in the HTA+obesity arm. LVH was clearly predominant in the HTA+obesity arm with a more consequent decrease in the longitudinal contraction index. In obese hypertensive patients, LVH was most often concentric (53.4%). An increase in filling pressures was found in 11 obese hypertensive patients compared to only 4 non-obese hypertensive patients (p = 0.0001), with a good correlation with the decrease in GLS. These results suggest that increased BMI is closely associated with atrioventricular interaction in patients with hypertension, with a perfect correlation with impairment of longitudinal systolic function and diastolic function compared to the control group. Conclusions: Although the pathophysiological mechanism behind obesity is disputed, several possible explanations have been proposed: obesity has been considered a state of chronic volume overload, increased blood volume, neurohormonal activation, thus increasing oxidative stress. Therefore, obesity is associated with mild ventricular dilation (eccentric remodeling). However, this finding is in contrast to other studies that associate obesity with a concentric rather than eccentric remodeling of the LV.

The Role of Myocardial Strain Imaging in the Pre- and Post-Operative Assessment of Patients with Single Ventricle.

The term "single ventricle" refers to a wide range of cardiac structural and functional abnormalities which cause the morphologically right or left ventricle to be hypoplastic or functionally inadequate. Patients with single-ventricle physiology have followed a series of palliative surgeries, resulting in the dominant ventricle supporting only the systemic circulation and the systemic venous return draining directly to the pulmonary arteries. Such patients present a progressive decline in myocardial performance, and their management is associated with high morbidity, mortality and resource usage. At each management step, imaging is critical in eligibility assessment, pre-procedural planning and prompt detection of myocardial dysfunction. However, the complex and asymmetric geometry of the dominant ventricle and its segmental wall motion abnormalities make the echocardiographic evaluation of myocardial performance in these patients rather challenging. Consequently, conventional 2-dimensional echo functional parameters, such as ejection fraction by Simpson's biplane method or shortening fraction by M-mode, is complex and often not feasible to apply. On the other hand, speckle-tracking echocardiography is angle and geometry independent and has better reproducibility. As such, it constitutes an appealing method for assessing myocardial function in patients with single-ventricle hearts. Therefore, this review aims to investigate the role of myocardial strain imaging by speckle-tracking echocardiography in the pre-and post-operative assessment of patients with single-ventricle hearts.