Avaliação Cardiodinâmica Não Invasiva por Cardiografia de Impedância durante o Teste de Caminhada de Seis Minutos em Pacientes com Insuficiência Cardíaca / Non-Invasive Assessment of Cardiodynamics by Impedance Cardiography during the Six-Minute Walk Test in Patients with Heart Failure

Resumo Fundamento O Teste de Caminhada de seis Minutos (TC6M) é comumente usado para avaliar pacientes com insuficiência cardíaca. No entanto, vários fatores clínicos podem influenciar a distância percorrida pelos pacientes no teste. A cardiografia de impedância (CI) na avaliação morfológica é uma ferramenta útil para avaliar a hemodinâmica cardíaca de maneira não invasiva. Objetivo Este estudo teve como objetivo comparar as respostas de aceleração e desaceleração do Débito Cardíaco (DC), da Frequência Cardíaca (FC), e do Volume Sistólico (VS) ao TC6M de indivíduos com insuficiência cardíaca e fração de ejeção reduzida (ICFEr) com as de controles sadios. Métodos Este é um estudo transversal observacional. O DC, a FC, o VS e o Índice Cardíaco (IC) foram avaliados antes, durante e após o TC6M por CI. O nível de significância adotado na análise estatística foi 5%. Resultados Foram incluídos 27 participantes (13 com ICFEr e 14 controles sadios). A aceleração do DC e da FC foi significativamente diferente entre os grupos (p<0,01 e p=0,039, respectivamente). Encontramos diferenças significativas no VS, no DC e no IC entre os grupos (p<0,01). A regressão linear mostrou uma contribuição deficiente do VS à mudança no DC no grupo com ICFEr (22,9% versus 57,4%). Conclusão O principal resultado deste estudo foi o fato de que indivíduos com ICFEr apresentaram valores mais baixos de aceleração do DC e da FC durante o teste de exercício submáximo em comparação a controles sadios. Isso pode indicar um desequilíbrio na resposta autonômica ao exercício nessa condição.

Abstract Background The six-minute walk test (6MWT) is commonly used to evaluate heart failure (HF) patients. However, several clinical factors can influence the distance walked in the test. Signal-morphology impedance cardiography (SM-ICG) is a useful tool to noninvasively assess hemodynamics. Objective This study aimed to compare cardiac output (CO), heart rate (HR), and stroke volume (SV) acceleration and deceleration responses to 6MWT in individuals with HF and reduced ejection fraction (HFrEF) and healthy controls. Methods This is a cross-sectional observational study. CO, HR, SV and cardiac index (CI) were evaluated before, during, and after the 6MWT assessed by SM-ICG. The level of significance adopted in the statistical analysis was 5%. Results Twenty-seven participants were included (13 HFrEF and 14 healthy controls). CO and HR acceleration significantly differed between groups (p<0.01; p=0.039, respectively). We found significant differences in SV, CO and CI between groups (p<0.01). Linear regression showed an impaired SV contribution to CO change in HFrEF group (22.9% versus 57.4%). Conclusion The main finding of the study was that individuals with HFrEF showed lower CO and HR acceleration values during the submaximal exercise test compared to healthy controls. This may indicate an imbalance in the autonomic response to exercise in this condition.

Desarrollo de un modelo por inteligencia artificial con hemodinamia no invasiva para predecir preeclampsia en embarazos de alto riesgo / Artificial Intelligence Modeling with Non-Invasive Hemodynamics to Predict Preeclampsia in High-Risk Pregnancy

RESUMEN Introducción: la preeclampsia (PE) es la principal causa de morbimortalidad materno-fetal en nuestro país. Alteraciones hemodinámicas precoces durante el embarazo podrían predecir la evolución a PE. El machine learning (ML) permite el hallazgo de patrones ocultos que podrían detectar precozmente el desarrollo de PE. Objetivos: desarrollar un árbol de clasificación con variables de hemodinamia no invasiva para predecir precozmente desarrollo de PE. Material y métodos: estudio observacional prospectivo con embarazadas de alto riesgo (n=1155) derivadas del servicio de Obstetricia desde enero 2016 a octubre 2022 para el muestreo de entrenamiento por ML con árbol de clasificación j48. Se seleccionaron 112 embarazadas entre semanas 10 a 16, sin tratamiento farmacológico y que completaron el seguimiento con el término de su embarazo con evento final combinado (PE): preeclampsia, eclampsia y síndrome HELLP. Se evaluaron simultáneamente con cardiografía de impedancia y velocidad de onda del pulso y con monitoreo ambulatorio de presión arterial de 24 hs (MAPA). Resultados: presentaron PE 17 pacientes (15,18%). Se generó un árbol de clasificación predictivo con las siguientes variables: índice de complacencia arterial (ICA), índice cardíaco (IC), índice de trabajo sistólico (ITS), cociente de tiempos eyectivos (CTE), índice de Heather (IH). Se clasificaron correctamente el 93,75%; coeficiente Kappa 0,70, valor predictivo positivo (VPP) 0,94 y negativo (VPN) 0,35. Precisión 0,94, área bajo la curva ROC 0,93. Conclusión: las variables ICA, IC, ITS, CTE e IH predijeron en nuestra muestra el desarrollo de PE con excelente discriminación y precisión, de forma precoz, no invasiva, segura y con bajo costo.

ABSTRACT Background: Preeclampsia (PE) is the main cause of maternal-fetal morbidity and mortality in our country. Early hemodynamic changes during pregnancy could predict progression to PE. Machine learning (ML) enables the discovery of hidden patterns that could early detect PE development. Objectives: The aim of this study was to build a classification tree with non-invasive hemodynamic variables for the early prediction of PE occurrence. Results: Seventeen patients (15.18%) presented PE. A predictive classification tree was generated with arterial compliance index (ACI), cardiac index (CI), cardiac work index (CWI), ejective time ratio (ETR), and Heather index (HI). A total of 93.75% patients were correctly classified (Kappa 0.70, positive predictive value 0.94 and negative predictive value 0.35; accuracy 0.94, and area under the ROC curve 0.93). Conclusion: ACI, CI, CWI, ETR and HI variables predicted the early development of PE in our sample with excellent discrimination and accuracy, non-invasively, safely and at low cost.

Comparative Study of Cardiac Output Measurement by Regional Impedance Cardiography and Thermodilution Method in Patients Undergoing off Pump Coronary Artery Bypass Graft Surgery

Background:An ideal CO monitor should be noninvasive, cost effective, reproducible, reliable during various physiological states. Limited literature is available regarding the noninvasive CO monitoring in open chest surgeries. Aim: The aim of this study was to compare the CO measurement by Regional Impedance Cardiography (RIC) and Thermodilution (TD) method in patients undergoing off pump coronary artery bypass graft surgery (OPCAB). Settings and Design: We conducted a prospective observational comparative study of CO measurement by the noninvasive RIC method using the NICaSHemodynamicNavigator systemand the gold standardTDmethod using pulmonary artery catheterin patients undergoingOPCAB.Atotal of 150 data pair from the two CO monitoring techniques were taken from 15 patients between 40-70 years at various predefined time intervals of the surgery. Patients and Methods: We have tried to find out the accuracy, precision and cost effectiveness of the newer RIC technique. Mean CO, bias and precision were compared for each pair i.e.TD-CO and RIC-CO as recommended by Bland and Altman.The Sensitivity and specificity of cutoff value to predict change in TD-CO was used to create a Receiver operating characteristic or ROC curve. Results: Mean TD-CO values were around 4.52 ± 1.09 L/min, while mean RIC- CO values were around 4.77± 1.84 L/min. The difference in CO change was found to be statistically not significant (p value 0.667). The bias was small (-0.25). The Bland Altman plot revealed a mean difference of -0.25 litres.The RIC method had a sensitivity of 55.56 % and specificity of 33.33 % in predicting 15% change in CO of TD method and the total diagnostic accuracy was 46.67%. Conclusion: A fair correlation was found between the two techniques. The RIC method may be considered as a promising noninvasive, potentially low cost alternative to the TD technique of hemodynamic measurement.

Exosomal miR-152-5p and miR-3681-5p function as potential biomarkers for ST-segment elevation myocardial infarction

Abstract Background: The strain parameters of Real-Time Three-Dimensional Spot Tracking Echocardiography (RT3D-STE) are GLS, GAS, GRS, and GCS, while each index can significantly diagnose Acute Myocardial Infarction (AMI) patients, but none of them can distinguish between NSTEMI and STEMI. MicroRNAs (miRNAs) play essential roles in Acute Myocardial Infarction (AMI), but little is known about the value of exosome miRNA combined with RealTime Three-Dimensional Spot Tracking Echocardiography (RT3D-STE) between ST-segment Elevation Myocardial Infarction (STEMI) and Non-ST-segment Elevation Myocardial Infarction (NSTEMI). Aim: To estimate the exosomal miRNAs related to strain parameters of RT3D-STE as biomarkers for early detection of STEMI and NSTEMI. Methods: The present study collected plasma samples from thirty-four (34) patients with AMI (including STEMI and NSTEMI) and employed high-throughput sequence technology and real-time quantitative polymerase chain reaction (RT-qPCR) to identify the differentially expressed miRNAs. The Pearson correlation coefficient is used to measure the strength of a linear association between differentially expressed miRNAs and strain parameters of RT3D-STE. Results: Twenty-eight (28) differentially expressed exosomal miRNAs were universally identified between STEMI, NSTEM, and normal groups. Among them, there are 10 miRNAs (miR-152-5p, miR-3681-5p, miR-193a-5p, miR-193b-5p miR-345-5p, miR-125a-5p, miR-365a-3p, miR-4520-2-3p, hsa-miR-193b-3p and hsa-miR-5579-5p) with a Pearson correlation greater than 0.6 with RT3D-STE strain parameters. Especially, miR-152-5p and miR-3681-5p showed the most significant correlation with RT3D-STE strain parameters. Target genes of these 10 miRNAs are analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment, and they were found to be mainly involved in the cellular metabolism processes and HIF-1 signaling pathway. RT-qPCR verified the significant differential expression of miR-152-5p and miR-3681-5p between STEMI and NSTEM groups. Conclusion: RT3D-STE and exosome miRNAs can be used as a hierarchical diagnostic system in AMI. If the RT3D-STE is abnormal, the exosome miRNAs can be detected again to obtain more detailed and accurate diagnostic results between STEMI and NSTEM groups. Exosomal miR-152-5p and miR-3681-5p may serve as potential biomarkers for ST-segment elevation myocardial infarction. HIGHLIGHTS RT3D-STE and exosome miRNAs can be used as a hierarchical diagnostic system in AMI. Exosomal miR-152-5p and miR-3681-5p function as potential biomarkers for ST-segment elevation myocardial infarction.

Peer teaching, a didactic strategy for learning basic electrocardiography / La enseñanza por pares, una estrategia didáctica para el aprendizaje de la electrocardiografía básica

Abstract Teaching electrocardiography is a very important area in undergraduate student training. A constant concern of professors is for physicians in training to acquire competence in reading and interpreting electrocardiograms (EKGs). This study describes and explores how the didactic strat egy of peer teaching improves learning processes for second-year medical students. Evidence was found that peer teaching fosters significant learning of cardiac physiology and electrocardiograms, in particular, because it allows students to acquire abilities and skills in EKG reading, and improves the understanding and interpretation of this test. In addition, it promotes horizontal peer relationships which facilitate the development of autonomy, self-learning and teamwork. (Acta Med Colomb 2021; 46. DOI:https://doi.org/10.36104/amc.2021.1971).

Resumen La enseñanza de la electrocardiografía es un área de gran importancia en la formación de los estudiantes de pregrado, para los docentes es una preocupación constante que los médicos en for mación adquieran las competencias para la lectura e interpretación del electrocardiograma (ECG). El presente estudio describe e indaga sobre cómo la estrategia didáctica de la enseñanza por pares mejora los procesos de aprendizaje de los estudiantes de segundo año de formación médica. Se halló evidencia de que la enseñanza por pares favorece el aprendizaje significativo de la fisiología cardiaca y del electrocardiograma, en particular, porque permite la adquisición de habilidades y destrezas a los estudiantes en la lectura del ECG y mejora la comprensión e interpretación de dicho examen; además, propicia relaciones horizontales entre pares que facilitan el desarrollo de la autonomía, el autoaprendizaje y el trabajo en equipo. (Acta Med Colomb 2021; 46. DOI:doi.org/10.36104/amc.2021.1971).

La preeclampsia es precedida por alteración de la función cardiovascular / Preeclampsia is Preceded by Cardiovascular Function Abnormalities

RESUMEN Introducción: La preeclampsia (PE) se acompaña de cambios en la función cardiovascular (FCV). Sin embargo, es desconocido si los cambios preceden y persisten a la manifestación clínica de PE. Objetivos: Evaluar las diferencias en la FCV, en la semana 22 de gestación (22sg) y un año posterior al parto (1app) en las pacientes que evolucionaron a la PE vs. a la normotensión (N). También, la asociación entre la FCV en 22sg y la evolución a PE. Material y métodos: Estudio prospectivo, que incluyó 260 primíparas normotensas. Se midió en la semana 22sg y a 1app: laboratorio de rutina, proteinuria de 24horas, presión arterial (PA). Por cardiografía por impedancia: índice cardíaco (IC) y de resistencia vascular sistémica (IRVS), velocidad de onda de pulso (VOP). Se formaron 3 grupos según la evolución a: PE, G1, HTA gestacional (HG) G2, y N, G3. Los resultados se presentan como media ± DS, ANOVA y test post hoc, p < 0,05. Resultados: 12 pacientes evolucionaron a PE, 18 a HG y 220 a N. El G1 presentó en los dos tiempos de medición, valores inferiores de IC y superiores de PA, IRP y VOP comparados al G3. El G2 presentó valores intermedios entre el G1 y el G3. La VOP y el IRP en la 22sg de gestación resultaron predictores de PE. Conclusiones: Las pacientes que evolucionaron a PE presentaron en fase temprana del embarazo diferente FCV respecto a las normotensas. El diagnóstico temprano de estos cambios contribuiría a predecir la PE y prevenir sus complicaciones.

ABSTRACT Background: Preeclampsia (PE) is associated with changes in cardiovascular function (CVF), but whether these changes precede and persist in the clinical phase of the disease is still unknown. Objectives: The aim of this study was to evaluate the differences in CVF during 22 weeks of gestation and one year after delivery in patients who developed PE vs. those with normotension (N). The association between CVF on 22 weeks of gestation and the development of PE was also analyzed. Methods: We conducted a prospective study including 260 normotensive primiparous women. Routine laboratory tests, 24-hour urine protein and blood pressure (BP) were measured on 22 weeks and one year after delivery. Cardiac index (CI) systemic vascular resistance index (SVRI) and pulse wave velocity (PWV) were measured by impedance cardiography. The population was divided into three groups according to the outcome during pregnancy: PE: G1, gestational hypertension (GH): G2 and normotension: G3. The results are presented as mean ± SD, ANOVA and post hoc test, p < 0.05. Results: Twelve patients evolved to PE, 18 to GH and 220 remained with N. In G1, CI was lower and BP, SVRI and PWV were higher than in G3 on 22 weeks and one year after delivery. In G2, values were always intermediate between G1 and G3. PWV and SVRI measured on 22 weeks resulted predictors of PE. Conclusions: Patients who developed PE had different CVF in the early stage of pregnancy than those with normotension. The early diagnosis of those changes could predict PE and thus contribute to prevent its complications.

Correlation between Echo-Doppler Study and Impedance Cardiography in Acute Myocardial Infarction

Introduction: Acute Myocardial Infarction(AMI) is quitecommon and despite lack of adequate infrastructure it isa compulsion for doctors in India to treat patients of AMIeven in the rural hospitals due to lack of transportation andcommunication facilities on round the clock basis. In ruralsetup usually ECG and Troponin biomarker kits are available.Aim and objective of the present study was to validateimpedance cardiography derived haemodynamic parametersagainst echo-doppler study.Material and methods: 200 patients of AMI were subjectedto impedance cardiography and echodoppler study.Results: Echocardiographic Mean±S.D values of LVEDV,LVESV , LVEF, IVCT, IVRT, LVET, Total Diastolic Time,Total Systolic Time & MPI were as follows 80.78±25.554,40.62±13.062, 41.18±15.669, 46.13±8.5, 50±8.907,65.93±12.103, 334.11±38.668, 482.97±83.164, 318.4±32.715& 0.4311±0.0732 respectively. Similarly impedancecardiographic Mean±S.D. values of LVEDV, LVESV , LVEF,IVCT, IVRT, LVET, Total Diastolic Time, Total Systolic Timeand MPI are as follows: 102.813±26.006, 53.048±14.773,39.646±18.095, 40.4786±10.820, 56.953±13.69,67.153±20.0375, 327.2035±23.91123, 449.4202±91.3202,349.8660±56.011 and 0.4106±0.08682 respectively.Conclusion: There was strong positive correlation among allthe haemodynamic parameters of echocardiography and ICGand the P values were significant in all the parameters studied(<0.001). It can be used for haemodynamic assessment ofpatients in rural setup where the facility of echo-doppler studyor invasive haemodynamic monitoring is not available.

Clinical study of 2D Echo cardiography findings in stroke- ischemic patients

Background: The Echocardiography is the mainstay investigation tool used in stroke patients. Stroke has acquired third place as leading cause of death with ischemic stroke being very common among all the types of the stroke.Objective of the study was to evaluate 2D Echo cardiography findings in the stroke (ischemic) patients.Methods: Hospital based cross sectional study was carried out among the confirmed 50 patients of ischemic stroke. Routine investigations has been done to all the patients included in the study, specific investigations like 2D echo and CT brain (Plain), Doppler study of carotids and fasting lipid profile has been done.Results: Majority of the study subjects belonged to the age group of 60-69 years i.e. 36% followed by the age group of 50-59 years. The most common risk factor for this ischemic stroke found out in the present study was hypertension in 66% of the cases. The prevalence of ischemic stroke was 70% in the males and 30% in the females. Out of 50 cases, 43 cases i.e. 86% were having abnormal lipid profile. Bilateral carotid atherosclerosis (64%) is more common than the unilateral carotid atherosclerosis (36%) on color Doppler study. Mitral annular calcification was the most common finding in 2D ECHO study in 52% of the cases.Conclusions: Males are more affected than females. Hypertension and smoking are two major and predominant risk factors for stroke. Elderly age group is commonly affected. Bilateral carotid atherosclerosis is common finding on color Doppler study and Mitral annular calcification the most common finding in 2D ECHO study.

Correlation between Three Methods of Blood Pressure Measurement (Impedance Cardiography, Sphygmomanometry, and Invasive Methods)

Aims and Objectives: The aims of the study were to find out the correlation between three methods of blood pressure (BP) measurement with impedance cardiography (ICG) device, conventional non-invasive sphygmomanometer, and cath lab-based invasive arterial pressure (AP) study. Patients Materials and Methods: Patients who had definite indications for coronary angiography (CAG) or coronary intervention due to cardiac reasons were selected for the measurement of BP by three methods, namely, by transducer-based invasive central aortic pressure study, by ICG, and by conventional sphygmomanometry. One hundred patients of acute myocardial infarction having chest pain, ST elevation in two or more contiguous leads of electrocardiogram (ECG), biomarker positivity, and echocardiographic evidence of regional wall motion abnormality were selected. Transfemoral or radial access of the ascending aorta allowed the measurement of central aortic pressure during invasive procedure. CAG was done in the cath lab having “Siemens™ Axiom Artis Zee (floor)” equipment. The subjects who were unwilling to participate, who were moribund, critically ill subjects, and patients with concomitant heart failure, arrhythmia, and valvular lesions were excluded from the study. GE™ Vivid 7 Dimension machine was used for ECG-gated echo-Doppler studies. ICG-derived BP values (systolic BP [SBP], diastolic BP [DBP], mean AP [MAP], and pulse pressure) were recorded for comparison with similar pressure data obtained from two other methods. Results and Analysis: Analysis of results show a comparison of data on SBP, DBP, and MAP measured by three methods by sphygmomanometry, invasive, and ICG methods. The analysis also shows the values of correlation coefficients – all of which are significantly positive correlations. ICG has been found to have positive correlation with both sphygmomanometric and invasive methods of BP measurement. It also shows a graphical presentation of the correlation between SBP, DBP, and MAP measured by three methods by sphygmomanometry, invasive, and ICG methods. Conclusion: There is a significant correlation between three methods of BP measurement with ICG device, conventional noninvasive sphygmomanometer-based method, and cath lab-based invasive AP study

Correlation between Coronary Angiography and Impedance Cardiography

Aims and Objectives: The aims of the study were to find out the correlation between coronary angiographic findings and hemodynamic parameters derived from impedance cardiography (ICG) and echo-Doppler study. Patients, Materials and Methods: A total of 200 patients of acute myocardial infarction having chest pain, ST elevation in two or more contiguous leads of electrocardiogram (ECG), biomarker positivity, echocardiographic evidence of regional wall motion abnormality (RWMA), and coronary angiographic evidence of coronary lesions were recruited. Subjects unwilling to participate, moribund, critically ill subjects, and patients with concomitant heart failure, arrhythmia, and valvular lesions were excluded from the study. GE™ Vivid 7 Dimension machine was used for ECG-gated echo-Doppler studies. The left ventricular ejection fraction (LVEF), stroke volume (SV), RWMA, diastolic function, etc., were observed. ICG measured LVEDV, LVESV, LVEF, and other parameters particularly amplitudes of the different waves. Coronary angiography (CAG) was done in the Cath Lab having “Siemens™ Axiom Artis Zee (floor)” equipment. Results and Analysis: Results-analysis revealed there is negative correlation (Pearson’s correlation coefficient, r = −0.8) between augmentation pressure and coronary angiographic stenosis percentage and P value is also significant (P = 0.034). Pulse pressure (PP) also is positively correlated (r = −0.78) with coronary angiographic stenosis percentage and P value is also significant (P = 0.027). There is a negative correlation (r = −0.259) between augmentation index (AIx) and coronary angiographic lesions and that is statistically significant (P = 0.03). Conclusion: There is a positive correlation between ICG -derived hemodynamic parameters and the percentage stenosis of coronary arteries. Rise of augmentation pressure and PP in the ICG waveform is associated with coronary artery disease severity. AIx is negatively correlated with severity of coronary arterial stenosis

Test-Retest Reliability of Non-Invasive Cardiac Output Measurement during Exercise in Healthy Volunteers in Daily Clinical Routine / Confiabilidade Teste-Reteste de Medição Não-Invasiva de Débito Cardíaco durante Exercício em Voluntários Saudáveis sob Condições Clínicas de Rotina

Abstract Background: Thoracic bioreactance (TB), a noninvasive method for the measurement of cardiac output (CO), shows good test-retest reliability in healthy adults examined under research and resting conditions. Objective: In this study, we evaluate the test-retest reliability of CO and cardiac power (CPO) output assessment during exercise assessed by TB in healthy adults under routine clinical conditions. Methods: 25 test persons performed a symptom-limited graded cycling test in an outpatient office on two different days separated by one week. Cardiorespiratory (power output, VO2peak) and hemodynamic parameters (heart rate, stroke volume, CO, mean arterial pressure, CPO) were measured at rest and continuously under exercise using a spiroergometric system and bioreactance cardiograph (NICOM, Cheetah Medical). Results: After 8 participants were excluded due to measurement errors (outliers), there was no systematic bias in all parameters under all conditions (effect size: 0.2-0.6). We found that all noninvasively measured CO showed acceptable test-retest-reliability (intraclass correlation coefficient: 0.59-0.98; typical error: 0.3-1.8). Moreover, peak CPO showed better reliability (intraclass correlation coefficient: 0.80-0.85; effect size: 0.9-1.1) then the TB CO, thanks only to the superior reliability of MAP (intraclass correlation coefficient: 0.59-0.98; effect size: 0.3-1.8). Conclusion: Our findings preclude the clinical use of TB in healthy subject population when outliers are not identified.

Resumo Fundamento: A biorreatância torácica (BT), um método não invasivo destinado à medição do débito cardíaco (DC), mostra boa confiabilidade teste-reteste em adultos saudáveis examinados em condições de pesquisa e repouso. Objetivo: No presente estudo, avaliamos a confiabilidade teste-reteste da avaliação do DC e trabalho cardíaco (TC) durante exercício, avaliado por BT em adultos saudáveis sob condições clínicas de rotina. Métodos: 25 indivíduos realizaram teste ergométrico gradual sintoma-limitante em ambiente ambulatorial em dois dias diferentes, com intervalo de uma semana. Parâmetros cardiorrespiratórios (trabalho cardíaco, VO2máx) e hemodinâmicos (frequência cardíaca, volume sistólico, DC, pressão arterial média, TC) foram medidos em repouso e continuamente sob exercício utilizando sistema espiroergométrico e cardiógrafo de biorreatância (NICOM, Cheetah Medical). Resultados: Após 8 participantes terem sido excluídos devido a erros de medição (outliers), não houve viés sistemático em nenhum dos parâmetros em todas as condições (tamanho do efeito: 0,2-0,6). Observamos que todos os débitos cardíacos medidos de forma não invasiva apresentaram níveis aceitáveis de confiabilidade teste-reteste (coeficiente de correlação intraclasse: 0,59-0,98; erro típico: 0,3-1,8). Além disso, TC máximo apresentou melhor confiabilidade (coeficiente de correlação intraclasse: 0,80-0,85; tamanho do efeito: 0,9-1,1), seguido do DC pela BT, graças apenas à confiabilidade superior da PAM (coeficiente de correlação intraclasse: 0,59-0,98; tamanho do efeito: 0,3-1,8). Conclusão: Nossos achados impedem o uso clínico da BT em indivíduos saudáveis quando outliers não forem identificados.

A Study Of Left Atrial Area And Volume On Echocardiography Among Atrial Fibrillation Cases With Various Aetiology

Background: Atrial fibrillation (AF) is the most common arrhythmia. It is associated with significant morbidity and mortality. The size and volume of left atrium is an important development of atrial fibrillation which land up subjects into various complications so present study was carried out to study echocardiography findings (size and volume) among AF Cases with various underlying aetiology. Material and methods: A cross-sectional observational study was conducted for duration of 2 years to measure left atrial size and volume by echocardiography in patients of atrial fibrillation in various diseases. Aproforma was designed to collect the desired information from the patients. The preformed structured proforma consisted of recording of investigations was used as data collection tool. All efforts were made to diagnose the aetiology of atrial fibrillation. Results: A total of 50 cases of AF were studied with mean age of study participants 53.68±12.74 yrs (range 25-80yrs) and F: M-1.3:1. Major risk factors found were RHD (44%) Hypertension (28%) IHD (24%) and DM (14%).Mean LAvolume and size on echo measurement was 78.16ml and 2 28.88cm .There was significant dilatation of LAamong RHD with p<0.05 among major risk factors found in study.

Impedance cardiography in the evaluation of patients with arterial hypertension / Impedância cardiografica na avaliação de pacientes com hipertensão arterial

Arterial hypertension is responsible for high morbidity and mortality. Despite increasing awareness of the consequences of uncontrolled hypertension and the publication of several recommendations and guidelines, blood pressure control rates are suboptimal, and approximately half of the patients do not reach the targets. Defined as an increase in blood pressure, hypertension is characterized by hemodynamic abnormalities in cardiac output, systemic vascular resistance, or arterial compliance. Therefore, the approach to arterial hypertension can be improved by the knowledge of the hemodynamics underlying the blood pressure increase. Impedance Cardiography has emerged as a new strategy to customize therapy and monitor patients aiming to improve blood pressure control according to the hemodynamic profile, rather than a blind intensive care approach. This is a review of impedance cardiography evidence, its benefits, actual and future applications in the approach and management of arterial hypertension

Accuracy and Efficacy of Impedance Cardiography as a Non-Invasive Cardiac Function Monitor

PURPOSE: The most common method of monitoring cardiac output (CO) is thermodilution using pulmonary artery catheter (PAC), but this method is associated with complications. Impedance cardiography (ICG) is a non-invasive CO monitoring technique. This study compared the accuracy and efficacy of ICG as a non-invasive cardiac function monitoring technique to those of thermodilution and arterial pressure contour. MATERIALS AND METHODS: Sixteen patients undergoing liver transplantation were included. Cardiac index (CI) was measured by thermodilution using PAC, arterial waveform analysis, and ICG simultaneously in each patient. Statistical analysis was performed using intraclass correlation coefficient (ICC) and Bland-Altman analysis to assess the degree of agreement. RESULTS: The difference by thermodilution and ICG was 1.13 L/min/m², and the limits of agreement were −0.93 and 3.20 L/min/m². The difference by thermodilution and arterial pressure contour was 0.62 L/min/m², and the limits of agreement were −1.43 and 2.67 L/min/m². The difference by arterial pressure contour and ICG was 0.50 L/min/m², and the limits of agreement were −1.32 and 2.32 L/min/m². All three percentage errors exceeded the 30% limit of acceptance. Substantial agreement was observed between CI of thermodilution with PAC and ICG at preanhepatic and anhepatic phases, as well as between CI of thermodilution and arterial waveform analysis at preanhepatic phase. Others showed moderate agreement. CONCLUSION: Although neither method was clinically equivalent to thermodilution, ICG showed more substantial correlation with thermodilution method than with arterial waveform analysis. As a non-invasive cardiac function monitor, ICG would likely require further studies in other settings.

Ultrasound cardiography examinations detect victims' long-term realized and potential consequences after major disasters: a case-control study

BACKGROUND@#An increase in cardiovascular diseases has been reported following major disasters. Previous work has shown that ultrasonographic findings from ultrasound cardiography examination (UCG) increased until the 44th month after the tsunami caused by the Great East Japan Earthquake. The present study conducted UCG among victims in the tsunami disaster area and investigated the frequency of disaster-related cardiovascular diseases and changes over time until the 55th month after the disaster.@*METHODS@#The subjects were residents of temporary housing complexes and neighboring housing in Watari-gun, Miyagi Prefecture, Japan. There were 207 subjects in the 18th month, 125 in the 30th month, 121 in the 44th month, and 106 in the 55th month after the disaster. Data were collected through UCG and self-report questionnaire.@*RESULTS@#Significant changes were observed among subjects with clinical findings from the UCG, which increased over the study period-from 42.0 to 60.8, 72.7, and 73.6% beginning in the 18th month after the disaster (p < 0.0001).@*CONCLUSIONS@#It is possible that the UCG can become a useful examination to visualize the potential impact of a major disaster on the cardiac function of victims. Victims with clinical findings continued increasing not only during the acute phase after a disaster but also in the long term. We therefore need to keep this in mind, and note that it is important to establish a support system to control cardiovascular diseases from the early stage of disaster.@*TRIAL REGISTRATION@#UMIN; ID000029802. R000034050 . 2 November 2017.

The value of electro-mechanical activation time ratio in predicting the major adverse events in hospitalized patients / 中华急诊医学杂志

Objective To evaluate the value of adjusted electro-mechanical activation time ratio (EMAT％) in predicting the major adverse events occurred in hospitalized patients with cardiovascular diseases.Methods A cohort of 453 patients aged ＞ 18 years with cardiovascular diseases were consecutively enrolled from January 1st 2016 to August 1st 2016.The data of EMAT％ were documented three times in the first 24 hours after admission,and at the same time,B type natriuretic peptide,left ventricle ejection fraction and troponin I were recorded.The exclusion criteria were valvular heart diseases,congenital heart diseases,the pregnant and perinatal women,and the patients with untreated cancer.The major adverse events were defined to be cardiogenic death,onset of acute heart failure,cardiogenic shock,myocardial infarction,ventricular tachycardia/fibrillation,and heart arrest.There were 25 patients suffering from major adverse events and 428 patients without any form of adverse events.Multivariate logistic regression analysis was used to determine the association between adjusted electro-mechanical activation time ratio (EMAT％) and major adverse events.The predictive value was established by receiver operating characteristic curve.Results From this trial,elevated EMAT％ was proved to be the independent riskfactor (EMAT％ OR =1.444,95％ CI:1.201-1.736,P ＜ O.05) for the occurrence of major adverse events in patients with cardiovascular diseases admitted in hospital,and BNP ＞ 200 pg/mL was independent risk factor too.The area under the curve of EMAT％ was 0.887 (95％ CI:0.812-0.962,P ＜ 0.05),Youden index 0.653,the sensibility of predicting the end point of major adverse events was 0.840 when the optimal cutoff point was set at EMAT％ ＞ 11.5 ％ and the specificity was 0.813.Conclusion The elevated EMAT％ is found to be the independent risk factor for predicting the onset of major adverse events in patients with cardiovascular diseases admitted in hospital,and it can be used to identify the critical patients.

The value of magnetic resonance imaging and ultrasonic cardiography in women with high altitude pulmonary arterial hypertension / 中华医学超声杂志（电子版）

Objective To assess the diagnostic value of 3.0T magnetic resonance imaging (MRI) and ultrasonic cardiography in women with high altitude pulmonary arterial hypertension (PAH). Methods Seventy-six women with high altitude PAH treated at our hospital were divided into either an MRI group (group A) or an ultrasonic cardiography group (group B), with 38 cases in each group. Fifty healthy women from high altitude areas were enrolled as a control group (group C). Group A underwent MRI examination alone, Group B underwent ultrasonic cardiography examination alone, and Group C underwent concomitant MRI and ultrasonic cardiography examinations. Diagnosis accuracy and diagnostic results were compared among different groups. Results Compared with group B, diagnosis accuracy significantly rose in group A (P < 0.05). MRI showed that except right ventricular end diastolic transverse diameter,left atrial diameter, aortic diameter, and right ventricular end systolic transverse diameter, other indexes differed significantly between groups A and C (P < 0.05). Ultrasonic cardiography showed that the SPAP of group B was (44.5 ± 8.6) mmHg. Right ventricular outflow tract, pulmonary artery, right ventricular inner diameter, right atrial inner diameter, right ventricle anterior wall, interventricular septal thickness, right ventricular Tei index, and right ventricular ejection fraction differed significantly between groups B and C (P<0.05), although there was no significant difference in LVEF or LV-Tei between the two groups (P>0.05). Conclusion Both MRI and ultrasonic cardiography can diagnoses high altitude PAH in women effectively. MRI can accurately evaluate the heart structure and function in women with high altitude PAH, representing a more efficient diagnostic method.

Dynamic Characteristic Mechanism of Atrial Septal Defect Using Real-Time Three-Dimensional Echocardiography and Evaluation of Right Ventricular Functions / 华中科技大学学报（医学）（英德文版）

The dynamic characteristics of the area of the atrial septal defect (ASD) were evaluated using the technique of real-time three-dimensional echocardiography (RT 3DE),the potential factors re sponsible for the dynamic characteristics of the area of ASD were observed,and the overall and local volume and functions of the patients with ASD were measured,RT 3DE was performed on the 27 normal controls and 28 patients with ASD.Based on the three-dimensional data workstations,the area of ASD was measured at P wave vertex,R wave vertex,T wave starting point,and T wave terminal point and in the T-P section.The right atrial volume in the same time phase of the cardiac cycle and the motion displacement distance of the tricuspid annulus in the corresponding period were measured.The measured value of the area of ASD was analyzed.The changes in the right atrial volume and the motion displacement distance of the tricuspid annulus in the normal control group and the ASD group were compared.The right ventricular ejection fractions in the normal control group and the ASD group were compared using the RT 3DE long-axis eight-plane (LA 8-plane) method.Real-time three-dimensional volume imaging was performed in the normal control group and ASD group (n=30).The right ventricular inflow tract,outflow tract,cardiac apex muscular trabecula dilatation,end-systolic volume,overall dilatation,end-systolic volume,and appropriate local and overall ejection fractions in both two groups were measured with the four-dimensional right ventricular quantitative analysis method (4D RVQ) and compared.The overall right ventricular volume and the ejection fraction measured by the LA 8-plane method and 4D RVQ were subjected to a related analysis.Dynamic changes occurred to the area of ASD in the cardiac cycle.The rules for dynamic changes in the area of ASD and the rules for changes in the right atrial volume in the cardiac cycle were consistent.The maximum value of the changes in the right atrial volume occurred in the end-systolic period when the peak of the curve appeared.The minimum value of the changes occurred in the end-systolic period and was located at the lowest point of the volume variation curve.The area variation curve for ASD and the motion variation curve for the tricuspid annulus in the cardiac cycle were the same.The displacement of the tricuspid annulus exhibited directionality.The measured values of the area of ASD at P wave vertex,R wave vertex,T wave starting point,T wave terminal point and in the T-P section were properly correlated with the right atrial volume (P＜0.001).The area of ASD and the motion displacement distance of the tricuspid annulus were negatively correlated (P＜0.05).The right atrial volumes in the ASD group in the cardiac cycle in various time phases increased significantly as compared with those in the normal control group (P=0.0001).The motion displacement distance of the tricuspid annulus decreased significantly in the ASD group as compared with that in the normal control group (P=0.043).The right ventricular ejection fraction in the ASD group was lower than that in the normal control group (P=0.032).The ejection fraction of the cardiac apex trabecula of the ASD patients was significantly lower than the ejection fractions of the right ventricular outflow tract and inflow tract and overall ejection fraction.The difference was statistically significant (P=0.005).The right ventricular local and overall dilatation and end-systolic volumes in the ASD group increased significantly as compared with those in the normal control group (P=0.031).The aRVEF and the overall ejection fraction decreased in the ASD group as compared with those in the normal control group (P=0.0005).The dynamic changes in the area of ASD and the motion curves for the right atrial volume and tricuspid annulus have the same dynamic characteristics.RT 3DE can be used to accurately evaluate the local and overall volume and functions of the right ventricle.The local and overall volume loads of the right ventricle in the ASD patients increase significantly as compared with those of the normal people.The right ventricular cardiac apex and the overall systolic function decrease.

Evaluation of volume overload in critical patients by monitoring change of cardiac output under bed head raising combined with passive leg raising / 中华危重病急救医学

Objective To investigate whether the change of cardiac output (CO) with bed head raising (BHR) combined with passive leg raising (PLR) can be used to assess volume overload in critical patients.Methods A prospective observational diagnostic trial was designed. The patients who underwent fluid resuscitation 6 hours or more, and admitted to intensive care unit (ICU) of Meizhou People's Hospital in Guangdong Province from January to December in 2016 were enrolled. Volume overload were identified with the criteria including the increasing of pulmonary rales, the higher levels of N-terminal brain natriuretic peptide (NT-proBNP) and new pulmonary exudates in chest radiograph. CO and heart rate (HR) were monitored with impedance cardiography at supine position and BHR by 30°(BHR30), 60° (BHR60), and PLR in all patients. The changes of CO (?CO30,?CO60,?COPLR) and HR (?HR30,?HR60,?HRPLR) were calculated at different positions. The receiver operating characteristic curve (ROC) was used to evaluate the predictive values of?CO30,?CO60 and combination of?CO60 and?COPLR on volume overload.Results A total of 62 patients were enrolled in this study, with 44 males and 18 females, age of (58.9±15.9) years, a body mass index of (22.7±2.4) kg/m2, and an acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score of 18.7±4.4. The CO of 32 patients with volume overload was significantly increased at BHR30 or BHR60 compared with supine position [?CO30 was (14.5±11.5)%,?CO60 was (26.9±17.5)%, bothP 0.05). There was no consistent change of CO at BHR30 or BHR60 compared with supine position in 30 patients without volume overload,?CO30 was (-3.4±9.1)% (P 0.05), while CO was significantly increased after PLR,?COPLR was (12.4±11.3)% (P < 0.01). There was no significant change of HR after BHR and PLR in patients with volume overload and non volume overload. ROC curve showed that when the cut-off value of ΔCO30≥3.3%, the area under ROC curve (AUC) was 0.903±0.039, the sensitivity was 90.6%, the specificity was 80.0%, and the accuracy was 85.5% for predicting volume overload; when the cut-off value of ΔCO60≥5.6%, the AUC was 0.911±0.036, the sensitivity was 96.9%, the specificity was 73.3%, and the accuracy was 85.5% for predicting volume overload. If volume overload was assessed by the increase of ΔCO60 combining with the decrease of ΔCOPLR, the AUC was 0.928±0.034, the optimal cut-off value for the new combined predictive indicator in predicting volume overload was -0.008, and the sensitivity, specificity, accuracy was 96.9%, 83.3%, 90.3%, respectively, and its evaluation effect is better than the use of ΔCO30 or ΔCO60 alone.Conclusion The change of CO with BHR combined with PLR can be used to accurately evaluate volume overload in patient with critically illness.