Apical 4-chamber View Research Articles

Relative interventricular septal brightness for subtype diagnosis of cardiac amyloidosis: pixel brightness analysis using echocardiographic images

Abstract Background In the subtypes of cardiac amyloidosis (CA), transthyretin-related (ATTR) CA has been reported to exhibit a higher prevalence of microcalcifications in the interventricular septum (IVS) compared to other subtypes. Whether microcalcifications in the IVS can stratify CA subtypes remains unclear. Methods A total of 442 patients with CA: 76 light chain/ amyloid A (AL/AA) type; 255 wild type ATTR (ATTRwt) and 48 variant ATTR (ATTRv) and 19 patients with endomyocardial biopsy-confirmed hypertensive heart disease (HHD) were subjected to echocardiographic pixel brightness quantification of the IVS using open-access image analysis software. The IVS Brightness Index (IVSBI) was defined as the ratio of the average pixel brightness in the IVS to that in the left ventricular (LV) wall opposite the IVS (see figure 1). Results The IVSBI from apical 4-chamber view was higher in both the ATTRwt group (median 1.40, IQR 1.22 to 1.67) and the ATTRv group (1.59, 1.32 to 2.00) compared to the HHD group (1.20, 1.02 to 1.37) and the AL/AA group (1.25, 1.11 to 1.46), respectively (P <0.001, see figure 2). In the 273 CA patients undergoing myocardial technetium-99m-pyrophosphate scintigraphy, patients with positive results (1.41, 1.24 to 1.70) exhibited a higher IVSBI compared to those with negative (1.19, 1.09 to 1.46) (P = 0.006). In Cox proportional hazards analysis, age, gender and LV ejection fraction adjusted hazard ratio for the all-cause death of IVSBI (0.5 increase) was 2.0 (95% CI 1.2 to 3.5, P = 0.012) among ATTRwt patients (n=157). Conclusions An IVSBI obtained from the apical 4-chamber view could prove valuable in differentiating ATTR subtypes in CA, potentially revealing subtle septal calcifications. A prognostic value may be derived from the elevation of IVSBI in ATTRwt patients.figure 1figure 2

Verification of intra- and inter-atrial conduction during Bachmann's bundle pacing using longitudinal bi-atrial strain

Abstract Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p<0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Normal reference values of left atrioventricular coupling index on two-dimensional echocardiography

Abstract Background From a physiological background, there is close relationship between left atrial (LA) and left ventricular (LV) expressed as coupling. The assessment of LA/LV coupling may reflect LV dysfunction and differentiate between normal and abnormal LV function. Aim of study The study is designed to sample normal subjects to provide the normal reference values of LA/LV coupling index (LACI) according to age and sex using 2-dimensional echocardiography (2DE). Methods 550 healthy subjects (51.9±17.8 years, 56% males) were included with good 2DE image quality enabled measurement of end-diastolic volumes of both LA and LV. LACI was defined as the ratio between LA to LV end-diastolic volumes. Results An off-line analysis of apical 4-chamber and 2-chamber views to obtain the 2DE measurements was performed within short time (1.5± 0.3 min). Measurement of LACI was obtained in all individuals. Subjects were divided into 3 age groups (G I: 18-40 years, G II: 41-65 years, and GIII: >65 years). As shown in table 1, the normal LACI values in the whole population was 0.17±0.08 with significantly higher in females (0.178±0.09) than males (0.15±0.06); P<0.02. The LACI values tends to be higher in females than males in the subdivided 3 age groups but not statistically significant. In both sexes, increasing age was associated with significant reduction of the mean LVEDV (P<0.0001), significant increase of the mean LAEDV (P= 0.004), and significant increase of LACI (P< 0.0001); especially considering the differences between the youngest and oldest age groups. Conclusions Measurement of LACI is feasible and easily obtainable using 2DE. Age and sex should be considered when defining normal reference values for LACI. The standardization of normal LACI values will help the future studies to assess the changes of these normal values in various cardiac abnormalities for prognostic risk stratification.

Serial changes in left atrial strain in symptomatic obstructive hypertrophic cardiomyopathy treated with mavacamten: insights from VALOR-HCM trial

Abstract Background In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM), the VALOR-HCM phase 3 randomized, double-blind, placebo-controlled clinical trial demonstrated that mavacamten, a cardiac myosin inhibitor, reduces the eligibility for septal reduction therapy with sustained improvement in left ventricular (LV) outflow tract gradients and symptoms. Mavacamten also resulted in favorable cardiac remodeling, including improvement in left atrial volume index (LAVI), LV diastolic function, and biomarkers (NT-proBNP and troponin T). However, the impact of mavacamten on LA function is not known. Objective We sought to assess serial changes in LA strain measures in patients enrolled in the VALOR-HCM trial. Methods VALOR-HCM included 112 symptomatic obstructive HCM patients (mean age 60 years, 51% male). Patients assigned to mavacamten at baseline (n=56) continued therapy for 56 weeks and those assigned to placebo crossed over to mavacamten (n=52) from week 16-56 (40-week exposure). Echocardiographic LA strain assessment was performed according to the current American and European guideline recommendations, using a vendor-neutral post processing software. For assessment of LA strain components (reservoir, conduit, and contraction), the non-foreshortened apical 4-chamber view was utilized. The zero reference was set at end-diastole. Results Serial changes in LAVI and all components of mean LA strain from baseline to week 56 are shown in the Figure. At baseline, LAVI and all mean LA strain values were worse than reported normal mean thresholds. There was a continued and significant improvement in all 3 LA strain values, from baseline to week 56, along with a significant reduction in LAVI. Improvement in LAVI was seen earlier than improvements in LA strain. There was a significant inverse correlation between change in mean LAVI and LA reservoir strain from baseline to week 56 (r= -0.42, p<0.001). Conclusions In the VALOR-HCM trial, average LAVI and baseline LA strain values were significantly worse than reported normal thresholds. Treatment with mavacamten resulted in an improvement in LAVI and LA strain values from baseline through week 56 suggesting a sustained favorable impact on cardiac remodeling. The advantageous cardiac remodeling associated with long-term treatment with mavacamten may in turn have a favorable impact on the observed high burden of atrial tachyarrhythmias in HCM.Serial changes in LA strain in VALOR-HCM

LA reservoir strain predicts elevated left atrial pressure in patients with Veno-Arterial (VA) extracorporeal membrane oxygenator (ECMO) support for cardiogenic shock

Abstract Background Veno-arterial (VA) extracorporeal membrane oxygenator (ECMO) is not a left ventricular (LV) support system as it increases aortic pressure and LV afterload due to retrograde blood flow in the aorta. This can lead to complications such as increased LV volume (LV distention), increased LV and left atrial (LA) pressures, and pulmonary edema. We sought to investigate the correlation between LA strain and invasive LA pressure (LAP) in patients with ECMO support for cardiogenic shock undergoing atrial septostomy with stenting. Methods and Results A total of 24 consecutive patients (52±20 years; 83% were male) undergoing atrial septostomy with stenting while being on ECMO support for cardiogenic shock for left heart decompression were analyzed. LAP was measured immediately after transeptal puncture and before deployment of interatrial septal stent. A comprehensive echocardiogram was performed in all patients prior to atrial septostomy. Median time difference between echocardiogram and LAP measurement was 3.5 (0.5-20) hours. LA strain analysis was performed using the TomTec Arena 2D-cardiac performance analysis (CPA) software. LA reservoir strain was measured at peak systole during the reservoir phase in a single apical 4-chamber view. Intraclass correlation coefficients between 2 different investigators were excellent (All> 0.95). Median LA reservoir strain and LAP were 3.2 (0.5-1) % and 23 (8-53) mmHg, respectively. LA reservoir strain significantly correlated with LAP (r=0.53, p=0.034). LA reservoir strain of < 1.5% can effectively predict markedly elevated LAP (LA> 30 mmHg) (OR =9.9, p =0.0016). Conclusions LA reservoir strain significantly correlated with invasive LAP. With the advent of strain imaging software, LA reservoir strain is a feasible, reproducible, noninvasive, and straightforward method to predict the need for left heart decompression and/or to guide optimal afterload management in patients with VA-ECMO for cardiogenic shock. Further a prospective simultaneous echocardiographic and invasive LAP study is needed.

Higher product of right ventricle to left ventricle diameter ratio and septal wall thickness is associated with increased risk of cardiovascular death in patients post TAVI

Abstract Background Right ventricular (RV) dilatation is a significant predictor for mortality in various cardiovascular diseases. Hypertrophy is common in patients undergoing transcatheter aortic valve implantation (TAVI). We tested the hypothesis that the product of right ventricle to left ventricle diameter (RV/LV) ratio and septal wall thickness (SWT) might be a determinant of cardiovascular death in TAVI patients. Methods This retrospective study enrolled 1123 patients undergoing TAVI in our department between 2009 and 2021 (mean age 81.4±5.6 year, male 51.2%). We assessed standard echocardiographic measures prior to the TAVI procedure. End-diastolic basal biventricular dimensions were measured from a standard apical 4-chamber view, and the ratio of RV dimension (RVD) to LV dimension (LVD) was calculated as the RV/LV ratio. We tested the prognostic performance of the product of RV/LV ratio and septal wall thickness (RV/LV ratio*SWT). The primary endpoint was cardiovascular (CV) death up to 2 years after TAVI. Results CV mortality was 11.8% (132/1123) at 2 years after TAVI. SWT was similar between the groups with and without CV death (11.9±1.9 vs. 11.6±1.8 mm, P=0.188). However, the RV/LV ratio (0.84±0.15 vs. 0.80±0.13, P=0.002) and RV/LV ratio*SWT (10.0±2.7 vs. 9.3±3.1 mm, P=0.005) were notably higher in the CV-death group compared to the no CV-death group. Higher RV/LV ratio*SWT remained independently associated with elevated 2-year CV mortality after TAVI (HR=1.09, 95% CI 1.01-1.17, P=0.024), while the RV/LV ratio was no longer significantly linked with CV mortality (HR=2.83, 95% CI 0.87-9.19, P=0.082) after adjusting for potential confounding factors including age, sex, and atrial fibrillation. RV/LV ratio*SWT >12.7 mm was associated with a twofold increased risk of 2-year CV mortality compared to patients with RV/LV ratio*SWT ≤12.7 mm (2-year mortality 14.4% vs. 6.0%, P<0.001; HR=2.04, 95% CI 1.25-3.32, P=0.004), regardless of age, sex, and atrial fibrillation. Conclusions Combined assessment of biventricular remodelling and left ventricular hypertrophy by calculating RV/LV ratio*SWT is of clinical importance for risk stratification of cardiovascular death among TAVI patients.

Diagnostic accuracy of artificial intelligence for identifying systolic and diastolic cardiac dysfunction in the emergency department

IntroductionCardiac point-of-care ultrasound (POCUS) can evaluate for systolic and diastolic dysfunction to inform care in the Emergency Department (ED). However, accurate assessment can be limited by user experience. Artificial intelligence (AI) has been proposed as a model to increase the accuracy of cardiac POCUS. However, there is limited evidence of the accuracy of AI in the clinical environment. The objective of this study was to determine the diagnostic accuracy of AI for identifying systolic and diastolic dysfunction compared with expert reviewers. MethodsThis was a prospective, observational study of adult ED patients aged ≥45 years with risk factors for systolic and diastolic dysfunction. Ultrasound fellowship-trained physicians used an ultrasound machine with existing AI software and obtained parasternal long axis, parasternal short axis, and apical 4-chamber views of the heart. Systolic dysfunction was defined as ejection fraction (EF) < 50 % in at least two views using visual assessment or E-point septal separation >10 mm. Diastolic dysfunction was defined as an E:A < 0.8, or ≥ 2 of the following: septal e' < 7 cm/s or lateral e' < 10 cm/s, E:e' > 14, or left atrial volume > 34 mL/m2. AI was subsequently used to measure EF, E, A, septal e', and lateral e' velocities. The gold standard was systolic or diastolic dysfunction as assessed by two independent physicians with discordance resolved via consensus. We performed descriptive statistics (mean ± standard deviation) and calculated the sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR-) of the AI in determining systolic and diastolic dysfunction with 95 % confidence interval (CI). Subgroup analyses were performed by body mass index (BMI). ResultsWe enrolled 220 patients, with 11 being excluded due to inadequate images, resulting in 209 patients being included in the study. Mean age was 60 ± 9 years, 51.7 % were women, and the mean BMI was 31 ± 8.1 mg/kg2. For assessing systolic dysfunction, AI was 85.7 % (95 %CI 57.2 % to 98.2 %) sensitive and 94.8 % (95 %CI 90.6 % to 97.5 %) specific with a LR+ of 16.4 (95 %CI 8.6 to 31.1) and LR- of 0.15 (95 % CI 0.04 to 0.54). For assessing diastolic dysfunction, AI was 91.9 % (95 %CI 85.6 % to 96.0 %) sensitive and 94.2 % (95 %CI 87.0 % to 98.1 %) specific with a LR+ of 15.8 (95 %CI 6.7 to 37.1) and a LR- of 0.09 (0.05 to 0.16). When analyzed by BMI, results were similar except for lower sensitivity in the BMI ≥ 30 vs BMI < 30 (100 % vs 80 %). ConclusionWhen compared with expert assessment, AI had high sensitivity and specificity for diagnosing both systolic and diastolic dysfunction.

Triphasic diastolic transmitral and intraventricular blood flows and their relationship with LV diastolic dysfunction according to echocardiography

An acceleration of blood flow in the diastasis phase with the formation of the so-called L-wave may be found in some patients. The transmitral blood flow is transformed into a triphasic in the presence of L-wave.Objective: to assess the frequency of L-wave presence and to evaluate the relationship between the presence of L-wave in Doppler imaging of left ventricular blood flow, transmitral blood flow at the level of the mitral valve leaflets, and modern criteria for assessing left ventricular diastolic function.Material and methods. The study included 105 patients (age 62.21 ± 11.97 (29–91) years, 61 men) with sinus rhythm. From a total of examined patients, 30 were conditionally healthy, 64 patients suffered from coronary heart disease, and 11 suffered from arterial hypertension. Pulsed-wave Doppler ultrasound of transmitral flow was performed in the apical 4-chamber view with the sample volume located at the level of the ends of the mitral valve leaflets, as well as at the level of the basal and middle segments of the left ventricle. The distinct positive wave on the spectrogram during the diastasis phase with a speed exceeding 20 cm/s was considered an additional L-wave, and such blood flow in diastole was considered triphasic.Results. Triphasic transmitral blood flow was found in 9 patients (8.5%), and triphasic intraventricular blood flow in another 30 patients (28.5%). Patients with triphasic transmitral blood flow were older, with a greater left atrial volume index, and LV diastolic dysfunction was more often detected compared to patients with triphasic intraventricular blood flow (66.7% compared to 23.3%, p = 0.042).Conclusion. Triphasic transmitral blood flow is revealing significantly less frequently than triphasic intraventricular blood flow (8.5% compared to 28.5%, p &lt; 0.001). Triphasic transmitral blood flow is more often observed in patients with left ventricular diastolic dysfunction.

Comparison of 6 handheld ultrasound devices by point-of-care ultrasound experts: a cross-sectional study

BackgroundPoint-of-care ultrasound (POCUS) has emerged as an essential bedside tool for clinicians, but lack of access to ultrasound equipment has been a top barrier to POCUS use. Recently, several handheld ultrasound devices (“handhelds”) have become available, and clinicians are seeking data to guide purchasing decisions. Few comparative studies of different handhelds have been done. We conducted a cross-sectional study comparing 6 handhelds readily available in the United States (Butterfly iQ + ™ by Butterfly Network Inc.; Clarius™ by Clarius Mobile Health; Kosmos™ by EchoNous; TE Air™ by Mindray; Vscan Air™ SL and CL by General Electric; and Lumify™ by Philips Healthcare). A multi-specialty group of physician POCUS experts (n = 35) acquired three standard ultrasound views (abdominal right upper quadrant, cardiac apical 4-chamber, and superficial neck and lung views) in random order on the same standardized patients and rated the image quality. Afterward, a final survey of the overall ease of use, image quality, and satisfaction of each handheld was completed.ResultsThirty-five POCUS experts specializing in internal medicine/hospital medicine, critical care, emergency medicine, and nephrology acquired and rated right upper quadrant, apical 4-chamber, and superficial neck and lung views with 6 different handhelds. For image quality, the highest-rated handhelds were Vscan Air™ for the right upper quadrant view, Mindray TE Air™ for the cardiac apical 4-chamber view, and Lumify™ for superficial views of the neck and lung. Overall satisfaction with image quality was highest with Vscan Air™, Lumify™, and Mindray, while overall satisfaction with ease of use was highest with Vscan Air™. The 5 most desirable characteristics of handhelds were image quality, ease of use, portability, probe size, and battery life. Ultimately, all 6 handhelds had notable advantages and disadvantages, with no single device having all desired qualities or features.ConclusionsThe overall satisfaction with image quality was rated highest with Vscan Air™, Lumify™, and Mindray TE Air™when acquiring right upper quadrant, apical 4-chamber, and superficial neck and lung views. No single handheld was perceived to be superior in image quality for all views. Vscan Air™ was rated highest for overall ease of use and was the most preferred handheld for purchase by POCUS experts.

Hypertension and Left Ventricular Strain in Pediatric Chronic Kidney Disease.

Left ventricular global longitudinal strain (LV GLS) on echocardiography is a sensitive yet clinically significant marker of myocardial dysfunction. Reduced LV GLS is prevalent in adults with chronic kidney disease and hypertension and is associated with adverse cardiovascular outcomes. It may be a biomarker of chronic kidney disease-associated myocardial dysfunction in children, but data are limited. Our objective was to describe LV GLS in the CKiD study (Chronic Kidney Disease in Children) and to examine the association between blood pressure (BP) and reduced LV GLS. A single apical 4-chamber view was used to estimate LV GLS. Our main analyses examined the association of clinic BP with the absolute value of LV GLS and LV GLS dichotomized at 16. Sensitivity analyses using 24-hour ambulatory BP monitoring data were also performed. Generalized estimating equations were used to account for within-person correlation and to estimate robust SEs for 95% CIs. Covariates in adjusted models included: age, sex, race, estimated glomerular filtration rate, urine protein, hemoglobin, left ventricular hypertrophy, and the use of renin-angiotensin system inhibitors. LV GLS was measured in 962 person-visits. A total of 77 assessments had an LV GLS <16. In adjusted models, both clinic systolic BP (odds ratio, 1.02 [95% CI, 1.01-1.03]) and diastolic BP (odds ratio, 1.02 [95% CI, 1.00-1.03]) percentiles were associated with LV GLS <16. Having awake or nighttime diastolic BP hypertension on ambulatory BP monitoring was significantly associated with a lower absolute value of LV GLS. Office systolic and diastolic hypertension was associated with diminished LV GLS. Only diastolic hypertension detected on ambulatory BP monitoring was associated with lower LV GLS.

Correlation between corrected carotid flow time and left ventricular outflow tract velocity-time integral using a novel technique.

Transthoracic echocardiography (TTE) is widely used for assessing patients in the intensive care unit, with cardiac output measurement being crucial for hemodynamic monitoring. This is achieved by measuring the velocity-time integral (VTI) of the left ventricular outflow tract (LVOT), which serves as a surrogate of stroke volume. However, conducting TTE in the critical care setting presents several challenges. Our primary objective was to investigate the relationship between carotid corrected flow time (cCFT) and LVOT VTI. Additionally, we aimed to determine the threshold cCFT value that reliably predicts a normal LVOT VTI. This proof-of-concept study involves a post-hoc analysis from a diagnostic accuracy investigation conducted in a medical-surgical intensive care unit. We included patients admitted to the ICU from December 2021 to January 2022. We used a phased array transducer to measure the cCFT at the left supraclavicular fossa and the LVOT VTI in an apical 5-chamber view. We included 22 patients. The Spearman coefficient between LVOT VTI and cCFT was 0.82 (p < 0.0001). The area under the ROC curve for cCFT to predict LVOT VTI equal to or greater than 17 cm was 0.871 (95% CI 0.660-0.974). A cCFT exceeding 283 ms predicted LVOT VTI equal to or greater than 17 cm with a sensitivity of 93.3% (95% CI 68.1% to 99.8%) and specificity of 85.7% (95% CI 42.1% to 99.6%). The cCFT, measured using a novel technique with a phased array transducer, shows a strong correlation with LVOT VTI. Additionally, cCFT predicts a normal LVOT VTI with good sensitivity and specificity in critically ill patients. Larger studies are warranted to validate these findings.

Effect of tafamidis on left atrial function of patients with transthyretin amyloid cardiomyopathy.

Transthyretin amyloid cardiomyopathy (ATTR-CM) is characterized by the functional and structural effects of amyloid infiltration, predominantly within the ventricles, causing biventricular wall thickening. Amyloid infiltration can be observed in the left atrium in ATTR-CM patients, but the association of left atrial (LA) myocardial function with cardiovascular events and of changes in LA myocardial function with tafamidis administration have not yet been clarified. Our aim was, therefore, to use speckle-tracking strain for investigating LA myocardial function in patients with ATTR-CM treated with tafamidis. We studied 55 patients with biopsy-proven ATTR-CM who had been treated with tafamidis (age: 76 ± 2years, male: 93%). For speckle-tracking analysis of LA myocardial function, the systolic LA strain (LA reservoir function) was defined for this study as LA myocardial function from the apical 4-chamber view. The primary endpoint was defined as a composite comprising cardiovascular death and/or heart failure hospitalization after tafamidis administration over a median follow-up period of 28 ± 4months. Patients with baseline LA strain < 8.6% (median value) experienced significantly more cardiovascular events than those without (log-rank P = 0.002). Moreover, LA strain in 26 patients worsened after tafamidis administration, and multivariate logistic regression analysis showed age, global longitudinal strain and relative apical longitudinal strain index were identified as independent determinants of deterioration of LA strain after tafamidis administration. In conclusion, baseline LA reservoir function is closely associated with cardiovascular events after tafamidis administration, and could be an additional parameter for the management of patients with ATTR-CM.

Echocardiographic image quality deteriorates with the severity of cardiogenic shock

BackgroundTransthoracic echocardiography (TTE) is the primary tool for assessing left ventricular (LV) function in cardiogenic shock (CS). However, inadequate image quality often hinders it. In this retrospective study, we investigated factors associated with LV image quality in patients admitted to the intensive care unit (ICU) with ischemic CS.ResultsTwo critical care physicians accredited in echocardiography independently reviewed the TTEs of 100 patients admitted to our tertiary cardiac ICU with ST-elevation myocardial infarction complicated by CS between October 2016 and September 2019. Endocardial border definition (EBD) was graded for each myocardial segment of the apical 4-chamber and 2-chamber views using a conventional scoring system (1 = good, 2 = suboptimal, 3 = poor, and 4 = not possible). The biplane EBD index (EBDi) was calculated by averaging all segments from both views. An average EBDi of both observers was correlated with clinical and echocardiographic parameters. The median age was 62 years [54, 73], and 78% were males. LV ejection fraction and cardiac index (CI) medians were 29% [20, 35] and 1.93 l/min/m2 [1.40, 2.51], respectively. The median biplane EBDi was nearly suboptimal (1.833 [1.542, 2.083]). There was no correlation between EBDi and age, sex, or body mass index. However, biplane EBDi demonstrated statistically significant correlations with PaO2 (r2 = 0.066, p = 0.01), mean arterial pressure (MAP, r2 = 0.055, p = 0.03), CI (r2 = 0.105, p < 0.01), tricuspid annulus systolic velocity (RV S’, r2 = 0.092, p = 0.01), and tricuspid regurge maximum velocity (TR Vmax, r2 = 0.067, p = 0.01). In a multivariate model, only CI correlated independently with EBDi (r2 = 0.105, p < 0.01). The biplane EBDi predicted CI (area under the curve (AUC) 0.70, p = 0.001) with good sensitivity (71%) and reasonable specificity (61%).ConclusionsThe study suggests that in patients admitted to the ICU with ischemic CS, LV image quality by TTE deteriorates with the severity of shock, as indicated by CI.

High-Throughput Deep Learning Detection of Mitral Regurgitation.

Diagnosis of mitral regurgitation (MR) requires careful evaluation by echocardiography with Doppler imaging. This study presents the development and validation of a fully automated deep learning pipeline for identifying apical 4-chamber view videos with color Doppler echocardiography and detecting clinically significant (moderate or severe) MR from transthoracic echocardiograms. A total of 58 614 transthoracic echocardiograms (2 587 538 videos) from Cedars-Sinai Medical Center were used to develop and test an automated pipeline to identify apical 4-chamber view videos with color Doppler across the mitral valve and then assess MR severity. The model was tested internally on a test set of 1800 studies (80 833 videos) from Cedars-Sinai Medical Center and externally evaluated in a geographically distinct cohort of 915 studies (46 890 videos) from Stanford Healthcare. In the held-out Cedars-Sinai Medical Center test set, the view classifier demonstrated an area under the curve (AUC) of 0.998 (0.998-0.999) and correctly identified 3452 of 3539 echocardiography videos as having color Doppler information across the mitral valve (sensitivity of 0.975 [0.968-0.982] and specificity of 0.999 [0.999-0.999] compared with manually curated videos). In the external test cohort from Stanford Healthcare, the view classifier correctly identified 1051 of 1055 manually curated videos with color Doppler information across the mitral valve (sensitivity of 0.996 [0.990-1.000] and specificity of 0.999 [0.999-0.999]). In the Cedars-Sinai Medical Center test cohort, MR moderate or greater in severity was detected with an AUC of 0.916 (0.899-0.932) and severe MR was detected with an AUC of 0.934 (0.913-0.953). In the Stanford Healthcare test cohort, the model detected MR moderate or greater in severity with an AUC of 0.951 (0.924-0.973) and severe MR with an AUC of 0.969 (0.946-0.987). In this study, a novel automated pipeline for identifying clinically significant MR from full transthoracic echocardiography studies demonstrated excellent performance across large numbers of studies and across multiple institutions. Such an approach has the potential for automated screening and surveillance of MR.

TTE apical 2-chamber view suggested mitral valve vegetation formation before treatment.

TTE apical 2-chamber view suggested mitral valve vegetation formation before treatment.

Deep Learning for Echo Analysis, Tracking, and Evaluation of Mitral Regurgitation (DELINEATE-MR).

Artificial intelligence, particularly deep learning (DL), has immense potential to improve the interpretation of transthoracic echocardiography (TTE). Mitral regurgitation (MR) is the most common valvular heart disease and presents unique challenges for DL, including the integration of multiple video-level assessments into a final study-level classification. A novel DL system was developed to intake complete TTEs, identify color MR Doppler videos, and determine MR severity on a 4-step ordinal scale (none/trace, mild, moderate, and severe) using the reading cardiologist as a reference standard. This DL system was tested in internal and external test sets with performance assessed by agreement with the reading cardiologist, weighted κ, and area under the receiver-operating characteristic curve for binary classification of both moderate or greater and severe MR. In addition to the primary 4-step model, a 6-step MR assessment model was studied with the addition of the intermediate MR classes of mild-moderate and moderate-severe with performance assessed by both exact agreement and ±1 step agreement with the clinical MR interpretation. A total of 61 689 TTEs were split into train (n=43 811), validation (n=8891), and internal test (n=8987) sets with an additional external test set of 8208 TTEs. The model had high performance in MR classification in internal (exact accuracy, 82%; κ=0.84; area under the receiver-operating characteristic curve, 0.98 for moderate or greater MR) and external test sets (exact accuracy, 79%; κ=0.80; area under the receiver-operating characteristic curve, 0.98 for moderate or greater MR). Most (63% internal and 66% external) misclassification disagreements were between none/trace and mild MR. MR classification accuracy was slightly higher using multiple TTE views (accuracy, 82%) than with only apical 4-chamber views (accuracy, 80%). In subset analyses, the model was accurate in the classification of both primary and secondary MR with slightly lower performance in cases of eccentric MR. In the analysis of the 6-step classification system, the exact accuracy was 80% and 76% with a ±1 step agreement of 99% and 98% in the internal and external test set, respectively. This end-to-end DL system can intake entire echocardiogram studies to accurately classify MR severity and may be useful in helping clinicians refine MR assessments.

Machine Learning and Deep Learning Methods for Fast and Accurate Assessment of Transthoracic Echocardiogram Image Quality.

High-quality echocardiogram images are the cornerstone of accurate and reliable measurements of the heart. Therefore, this study aimed to develop, validate and compare machine learning and deep learning algorithms for accurate and automated assessment of transthoracic echocardiogram image quality. In total, 4090 single-frame two-dimensional transthoracic echocardiogram images were used from apical 4-chamber, apical 2-chamber and parasternal long-axis views sampled from 3530 adult patients. The data were extracted from CAMUS and Unity Imaging open-source datasets. For every raw image, additional grayscale block histograms were developed. For block histogram datasets, six classic machine learning algorithms were tested. Moreover, convolutional neural networks based on the pre-trained EfficientNetB4 architecture were developed for raw image datasets. Classic machine learning algorithms predicted image quality with 0.74 to 0.92 accuracy (AUC 0.81 to 0.96), whereas convolutional neural networks achieved between 0.74 and 0.89 prediction accuracy (AUC 0.79 to 0.95). Both approaches are accurate methods of echocardiogram image quality assessment. Moreover, this study is a proof of concept of a novel method of training classic machine learning algorithms on block histograms calculated from raw images. Automated echocardiogram image quality assessment methods may provide additional relevant information to the echocardiographer in daily clinical practice and improve reliability in clinical decision making.

Echocardiogram by apical-subcostal protocol in prone position during invasive mechanical ventilation in cardiovascular intensive care unit

AimsTo evaluate the feasibility of a transthoracic echocardiogram using an apical-subcostal protocol in invasive mechanical ventilation (IMV) and prone position.MethodsProspective study of adults who required a prone position during IMV. A pillow was placed only under the left hemithorax in the prone position to elevate and ease the apical and subcostal windows. A critical care cardiologist (prone group) acquired and evaluated the images using the apical-subcostal protocol. Besides, we used ambulatory echocardiograms performed as a comparative group (supine group).Results86 patients were included, 43 in the prone and 43 in the supine. In the prone group, the indication to perform an echocardiogram was hemodynamic monitoring. All patients were ventilated with protective parameters, and the mean end-expiratory pressure was 10.6 cmH2O. The protocol was performed entirely in 42 of 43 patients in the prone group because one patient did not have any acoustic window. In the 43 patients in the prone group analyzed and compared to the supine group, global biventricular function was assessed in 97.7% (p = 1.0), severe heart valve disease in 88.4% (p = 0.055), ruled out of the presence of pulmonary hypertension in 76.7% (p = 0.80), pericardial effusion in 93% (p = 0.12), and volume status by inferior vena cava in 93% (p = 0.48). Comparing prone versus supine position, a statistical difference was found when evaluating the left ventricle apical 2-chamber view (65.1 versus 100%, p < 0.01) and its segmental function (53.4 versus 100%, p < 0.01).ConclusionThe echocardiogram using an apical-subcostal protocol is feasible in patients in the IMV and prone position.Graphical

An Innovative Apical-4-Chamber-long-axis Imaging Approach Precisely Tracks Progressive Deterioration of Mouse Ventricles, Atria, and Atrioventricular Valves

Transthoracic echocardiography stands as the primary non-invasive method for cardiac function evaluation in clinical settings. It’s widely used to assess chamber sizes, heart wall integrity, as well as the hemodynamic performance of the left ventricle (LV), right ventricle (RV), atria, and valves. However, applying comprehensive echocardiography assessments to mice has been challenging, primarily due to diffculties in obtaining on-axis apical 4-chamber views; most mouse studies have thus been restricted to evaluating the LV using short-axis M-mode assays. To overcome this limitation, we’ve recently developed a novel methodology to consistently obtain high-quality apical 4-chamber-long-axis (A4CLAX) view images of mouse heart. This advancement permits a range of clinically relevant functional assessments, including Long Axis Biplane (LAX-BP) assay, which has been shown to surpasses M-mode in estimating LV function. In this study, we delve into the breadth of comprehensive echocardiography assessments made possible for mice through the A4CLAX imaging approach. We performed a severe transverse aortic constriction (TAC) surgery on mice and monitored the pathological development in their hearts post-surgery. Alongside the expected hypertrophy, the LAX-BP assay revealed LV volumetric dilation as early as 1-week after TAC surgery Indicative of decompensated heart failure; however, m-mode was not able to pick up on this early dilation due to its lack of longitudinal assessment and inconsistent measurements of EDV and ESV. The apical 4 chamber view significantly improved the consistency and reliability of trans mitral and pulmonary vein doppler recordings and enabled us to reliably estimate the pressure relationships of the LV and Left Atrial (LA) pressure, which is consistent with the LAX-BP detected LV decompensation. Additionally, the high clarity of the 4 chamber images achieved improved visualization of both mitral and tricuspid valve leaflets. This allowed more precise characterization of valvular issues, including mitral regurgitation caused by LV dilatation, as well as identification of less common pathological occurrences like desynchronization of the tricuspid and mitral valve opening. A speckle tracking assay of the Right ventricle (RV) showed that a delayed contraction of the lateral apical RV wall caused the tricuspid valve to not open during the early filling phase, but rather at the atrial kick, leading to this valve desynchrony. This delayed contraction indicates a possible elevation of pulmonary pressure, as evidenced by pulmonary vein doppler indices and the analysis of pulmonary congestion. In conclusion, the innovative A4CLAX imaging technique revolutionizes murine heart analysis, bringing it in line with clinical echocardiography standards allowing for a whole heart analysis approach. It sensitively identifies subtle anomalies, providing a precise characterization of cardiac remodeling and disease progression in mouse hearts. This study has been supported by grants NIH-R01HL139006 and R21OD031965. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Pulmonary Transit Time Assessment by CEUS in Healthy Rabbits: Feasibility, and the Effects of UCAs Dilution Concentration.

To evaluate the inter-observer variability and the intra-observer repeatability of pulmonary transit time (PTT) measurement using contrast-enhanced ultrasound (CEUS) in healthy rabbits, and assess the effects of dilution concentration of ultrasound contrast agents (UCAs) on PTT. Thirteen healthy rabbits were selected, and five concentrations UCAs of 1:200, 1:100, 1:50, 1:10, and 1:1 were injected into the right ear vein. Five digital loops were obtained from the apical 4-chamber view. Four sonographers obtained PTT by plotting the TIC of right atrium (RA) and left atrium (LA) at two time points (T1 and T2). The frame counts of the first appearance of UCAs in RA and LA had excellent inter-observer agreement, with intra-class correlations (ICC) of 0.996, 0.988, respectively. The agreement of PTT among four observers was all good at five different concentrations, with an ICC of 0.758-0.873. The reproducibility of PTT obtained by four observers at T1 and T2 was performed well, with ICC of 0.888-0.961. The median inter-observer variability across 13 rabbits was 6.5% and the median variability within 14 days for 4 observers was 1.9%, 1.7%, 2.2%, 1.9%, respectively; The PTT of 13 healthy rabbits is 1.01 ± 0.18 second. The difference of PTT between five concentrations is statistically significant. The PTT obtained by a concentration of 1:200 and 1:100 were higher than that of 1:1, while there were no significantly differences in PTT of a concentration of 1:1, 1:10, and 1:50. PTT measured by CEUS in rabbits is feasible, with excellent inter-observer and intra-observer reliability and reproducibility, and dilution concentration of UCAs influences PTT results.