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.

Cardiopulmonary Imaging Utilization and Findings among Hospitalized COVID-19 Patients in Latin America: (From "RIMAC: Registry IMAging Cardiopulmonary among Hospitalized COVID-19 Patients in LATAM").

Objectives: Describe the use and findings of cardiopulmonary imaging-chest X-ray (cX-ray), echocardiography (cEcho), chest CT (cCT), lung ultrasound (LUS), and/or cardiac magnetic resonance imaging (cMRI)-in COVID-19 hospitalizations in Latin America (LATAM). Background: There is a lack of information on the images used and their findings during the SARS-CoV-2 pandemic in LATAM. Methods: Multicenter, prospective, observational study of COVID-19 inpatients, conducted from March to December 2020, from 12 high-complexity centers, in nine LATAM countries. Adults (>18 years) with at least one imaging modality performed, followed from admission until discharge and/or in-hospital death, were included. Results: We studied 1,435 hospitalized patients (64% males) with a median age of 58 years classified into three regions: Mexico (Mx), 262; Central America and Caribbean (CAC), 428; and South America (SAm), 745. More frequent comorbidities were overweight/obesity, hypertension, and diabetes. During hospitalization, 58% were admitted to the ICU. The in-hospital mortality was 28%, and it was highest in Mx (37%).The most frequent images performed were cCT (61%), mostly in Mx and SAm, and cX-ray (46%), significant in CAC. The cEcho was carried out in 18%, similarly among regions, and LUS was carried out in 7%, with a higher frequently in Mx. Abnormal findings on the cX-ray were peripheral or basal infiltrates, and in cCT abnormal findings were the ground glass infiltrates, more commonly in Mx. In LUS, interstitial syndrome was the most abnormal finding, predominantly in Mx and CAC.Renal failure was the most prevalent complication (20%), predominant in Mx and SAm. Heart failure developed in 13%, predominant in Mx and CAC. Lung thromboembolism was higher in Mx while myocardial infarction was in CAC.Logistic regression showed associations of abnormal imaging findings and their severity, with comorbidities, complications, and evolution. Conclusions: The use and findings of cardiopulmonary imaging in LATAM varied between regions and had a great impact on diagnosis and prognosis.