Helical structure of the ventricular myocardium. A narrative review of cardiac mechanics.

To date, the ventricular myocardial band is the anatomical-functional model that best explains cardiac mechanics during systolic-diastolic phenomena in the cardiac cycle. The implications of the model fundamentally affect the anatomical interpretation of the ventricular myocardium, giving meaning to the direction that muscle fibers take, turning them into an object of study with potential clinical, imaging, and surgical applications. Re-interpreting the anatomy of the ventricular muscle justifies changes in the physiological interpretation, from its functional focus as a fiber unraveling the mechanical phenomena carried out during systole and diastole. We identify the functioning of the heart from the electrical and hemodynamic point of view, but it is necessary to delve into the mechanics that originate the hemodynamic changes observed flowmetrically, and that manifested during the pathology. In this review, the mechanical phenomena that the myocardium performs in each phase of the cardiac cycle are broken down in detail, emphasizing the physical displacements that each of the muscle segments presents, as well as a vision of their alteration and in which pathologies they are mainly identified. Visually, an anatomical correlation to the echocardiogram is provided, pointing out the direction of the segmental myocardial displacement by the strain velocity vector technique.

Acute Abdomen and Appendicitis in 1010 Pediatric Patients With COVID-19 or MIS-C: A Multinational Experience from Latin America.

BACKGROUND: To date, there are only sporadic reports of acute abdomen and appendicitis in children with coronavirus disease 2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C). METHODS: Children 17 years of age or younger assessed in 5 Latin American countries with a diagnosis of microbiologically confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and children fulfilling MIS-C definition were included. For children with acute abdomen, we investigate main radiologic patterns, surgical treatment and intraoperative findings, outcomes. FINDINGS: One-thousand ten children were enrolled. Forty-two children (4.2%) had a clinical diagnosis of acute abdomen. Four (9.5%) were diagnosed with MIS-C and did not undergo surgery. The remaining 38 children (3.8%) underwent abdominal surgery due to suspected appendicitis, 34 of them (89.7%) had an intraoperative diagnosis of acute appendicitis (AA), while 4 of them had nonsurgical findings. Eight children died (0.8%), none of them being diagnosed with appendicitis. Children with AA were significantly older than those without (P < 0.0001). Children with complicated appendicitis had more frequently fever (85.7% vs. 60%), intestinal distension on the abdominal radiograph (7.1% vs. none), leukocytosis (85.7% vs. 40%) and high levels of C-reactive protein (35.7% vs. 5%), although differences were not statistically significant. CONCLUSIONS: Our study showed that children may present with acute abdomen during COVID-19 or MIS-C, which is not always associated with intraoperative findings of appendicitis, particularly in case of MIS-C. Further studies are needed to better characterize children with acute abdomen during COVID-19 or MIS-C, to avoid delay in diagnosis of surgical conditions and at the same time, minimize unnecessary surgical approaches.

High rates of antibiotic prescriptions in children with COVID-19 or multisystem inflammatory syndrome: A multinational experience in 990 cases from Latin America.

AIM: This study aims to assess rates of antibiotic prescriptions and its determinants in in children with COVID-19 or Multisystem Inflammatory Syndrome (MIS-C). METHODS: Children <18 years-old assessed in five Latin Americas countries with a diagnosis of COVID-19 or MIS-C were enrolled. Antibiotic prescriptions and factors associated with their use were assessed. RESULTS: A total of 990 children were included: 921 (93%) with COVID-19, 69 (7.0%) with MIS-C. The prevalence of antibiotic use was 24.5% (n = 243). MIS-C with (OR = 45.48) or without (OR = 10.35) cardiac involvement, provision of intensive care (OR = 9.60), need for hospital care (OR = 6.87), pneumonia and/or ARDS detected through chest X-rays (OR = 4.40), administration of systemic corticosteroids (OR = 4.39), oxygen support, mechanical ventilation or CPAP (OR = 2.21), pyrexia (OR = 1.84), and female sex (OR = 1.50) were independently associated with increased use of antibiotics. There was significant variation in antibiotic use across the hospitals. CONCLUSION: Our study showed a high rate of antibiotic prescriptions in children with COVID-19, in particular in those with severe disease or MIS-C. Prospective studies are needed to provide better evidence on the recognition and management of bacterial infections in COVID-19 children.

COVID-19 and Multisystem Inflammatory Syndrome in Latin American Children: A Multinational Study.

BACKGROUND: To date, there are no comprehensive data on pediatric COVID-19 from Latin America. This study aims to assess COVID-19 and Multisystem Inflammatory Syndrome (MIS-C) in Latin American children, to appropriately plan and allocate resources to face the pandemic on a local and international level. METHODS: Ambispective multicenter cohort study from 5 Latin American countries. Children 18 years of age or younger with microbiologically confirmed SARS-CoV-2 infection or fulfilling MIS-C definition were included. FINDINGS: Four hundred nine children were included, with a median age of 3.0 years (interquartile range 0.6-9.0). Of these, 95 (23.2%) were diagnosed with MIS-C. One hundred ninety-one (46.7%) children were admitted to hospital and 52 (12.7%) required admission to a pediatric intensive care unit. Ninety-two (22.5%) patients required oxygen support: 8 (2%) were started on continuous positive airway pressure and 29 (7%) on mechanical ventilation. Thirty-five (8.5%) patients required inotropic support. The following factors were associated with pediatric intensive care unit admission: preexisting medical condition (P < 0.0001), immunodeficiency (P = 0.01), lower respiratory tract infection (P < 0.0001), gastrointestinal symptoms (P = 0.006), radiologic changes suggestive of pneumonia and acute respiratory distress syndrome (P < 0.0001) and low socioeconomic conditions (P = 0.009). CONCLUSIONS: This study shows a generally more severe form of COVID-19 and a high number of MIS-C in Latin American children, compared with studies from China, Europe and North America, and support current evidence of a more severe disease in Latin/Hispanic children or in people of lower socioeconomic level. The findings highlight an urgent need for more data on COVID-19 in Latin America.

Routine use of Point-of-Care lung ultrasound during the COVID-19 pandemic / Uso rutinario del ultrasonido pulmonar en el punto de atención durante la pandemia por COVID-19

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Correlación anatómica de la estructura helicoidal del miocardio ventricular mediante ecocardiografía / Anatomical correlation of the helical structure of the ventricular myocardium through echocardiography

INTRODUCCIÓN Y OBJETIVOS: La estructura helicoidal del miocardio ventricular ofrece una comprensión simple de la anatomía cardiaca bajo un argumento fisiológico demostrado en estudios experimentales y de imagen cardiaca que da sentido a la contracción electromecánica durante el ciclo cardiaco. Se ha estandarizado descriptivamente la técnica de preparación y disección del miocardio propuesta empíricamente por Torrent-Guasp mediante digitodisección para correlacionar anatómica y topográficamente la banda helicoidal con proyecciones ecocardiográficas de eje largo, eje corto y de 4 cámaras. MÉTODOS: Se disecaron 42 corazones -20 bovinos, 20 porcinos y 2 humanos- para estandarizar la técnica de disección del miocardio; después se identificaron con colores los diferentes segmentos para correlacionar las piezas anatómicas con las proyecciones ecocardiográficas. RESULTADOS: La pérdida del 38% de la masa estandariza la disección, y resulta eficiente para realizar la disección del miocardio. No se encontró diferencia morfológica en la banda de los corazones estudiados. En las proyecciones ecocardiográficas se pueden identificar los 4 segmentos miocárdicos. CONCLUSIONES: La estandarización de la técnica es útil para disecar cualquier tipo de corazón. El ecocardiograma es útil para valorar los diferentes segmentos en que se divide el miocardio. Se necesitan más estudios que generen otras aplicaciones prácticas de este conocimiento a la ecocardiografía y otros campos

INTRODUCTION AND OBJECTIVES: The helical structure of the ventricular myocardium provides a simple view of cardiac anatomy, based on physiological evidence that has been broadly demonstrated in experimental and imaging studies, and helps to explain the electromechanical contraction of the myocardium during the cardiac cycle. The aim of this study was to standardize and provide a detailed description of the technique for preparing and manually dissecting the myocardium proposed empirically by Torrent-Guasp. A further aim was to anatomically and topographically correlate the helical band with echocardiographic long-axis, short-axis, and 4-chamber projections. METHODS: We dissected 42 hearts-20 bovine, 20 porcine and 2 human hearts-to standardize the myocardial dissection technique. Subsequently, the distinct segments were color coded to correlate the anatomical specimens with echocardiographic projections. RESULTS: Loss of 38% of the myocardial mass after boiling was sufficient to standardize myocardial dissection and allowed an efficient technique. No morphological differences were found between the bands of the hearts studied. The 4 myocardial segments could be identified in the echocardiographic projections. CONCLUSIONS: Standardization of the technique is useful to dissect any type of heart. Echocardiography is useful to assess the distinct segments that compose the myocardium. More research is needed to generate practical applications of this knowledge to echocardiography and other fields

Arquitectura de la pared ventricular. Respuesta / Ventricular mural architecture. Response

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Anatomical Correlation of the Helical Structure of the Ventricular Myocardium Through Echocardiography.

INTRODUCTION AND OBJECTIVES: The helical structure of the ventricular myocardium provides a simple view of cardiac anatomy, based on physiological evidence that has been broadly demonstrated in experimental and imaging studies, and helps to explain the electromechanical contraction of the myocardium during the cardiac cycle. The aim of this study was to standardize and provide a detailed description of the technique for preparing and manually dissecting the myocardium proposed empirically by Torrent-Guasp. A further aim was to anatomically and topographically correlate the helical band with echocardiographic long-axis, short-axis, and 4-chamber projections. METHODS: We dissected 42 hearts-20 bovine, 20 porcine and 2 human hearts-to standardize the myocardial dissection technique. Subsequently, the distinct segments were color coded to correlate the anatomical specimens with echocardiographic projections. RESULTS: Loss of 38% of the myocardial mass after boiling was sufficient to standardize myocardial dissection and allowed an efficient technique. No morphological differences were found between the bands of the hearts studied. The 4 myocardial segments could be identified in the echocardiographic projections. CONCLUSIONS: Standardization of the technique is useful to dissect any type of heart. Echocardiography is useful to assess the distinct segments that compose the myocardium. More research is needed to generate practical applications of this knowledge to echocardiography and other fields.

Myocardial Rupture in Acute Myocardial Infarction: Mechanistic Explanation Based on the Ventricular Myocardial Band Hypothesis.

BACKGROUND: Torrent-Guasp explains the structure of the ventricular myocardium by means of a helical muscular band. Our primary purpose was to demonstrate the utility of echocardiography in human and porcine hearts in identifying the segments of the myocardial band. The second purpose was to evaluate the relation of the topographic distribution of the myocardial band with some post-myocardial infarction ruptures. METHODS: Five porcine and one human heart without cardiopathy were dissected and the ventricular myocardial segments were color-coded for illustration and reconstruction purposes. These segments were then correlated to the conventional echocardiographic images. Afterwards in three cases with post-myocardial infarction rupture, a correlation of the topographic location of the rupture with the distribution of the ventricular band was made. RESULTS: The human ventricular band does not show any differences from the porcine band, which confirms the similarities of the four segments; these segments could be identified by echocardiography. In three cases with myocardial rupture, a correlation of the intra-myocardial dissection with the distribution of the ventricular band was observed. CONCLUSIONS: Echocardiography is helpful in identifying the myocardial band segments as well as the correlation with the topographic distribution of some myocardial post-infarction ruptures.