Sudden Cardiac Death Survival Prediction from Restitution Dispersion Analysis

Increase in the dispersion of action potential duration restitution (APDR) has been associated with sudden cardiac death (SCD). A marker, Δα, was proposed to quantify APDR dispersion from the electrocardiogram (ECG). 609 ECG recordings were analysed. The marker Δα stratified patients according to their risk of suffering from SCD

High arrhythmic risk in antero-septal acute myocardial ischemia is explained by increased transmural reentry occurrence

Acute myocardial ischemia is a precursor of sudden arrhythmic death. Variability in its manifestation hampers understanding of arrhythmia mechanisms and challenges risk stratification. Our aim is to unravel the mechanisms underlying how size, transmural extent and location of ischemia determine arrhythmia vulnerability and ecG alterations. High performance computing simulations using a human torso/biventricular biophysically-detailed model were conducted to quantify the impact of varying ischemic region properties, including location (LAD/LcX occlusion), transmural/subendocardial ischemia, size, and normal/slow myocardial propagation. ecG biomarkers and vulnerability window for reentry were computed in over 400 simulations for 18 cases evaluated. Two distinct mechanisms explained larger vulnerability to reentry in transmural versus subendocardial ischemia. Macro-reentry around the ischemic region was the primary mechanism increasing arrhythmic risk in transmural versus subendocardial ischemia, for both LAD and LcX occlusion. transmural micro-reentry at the ischemic border zone explained arrhythmic vulnerability in subendocardial ischemia, especially in LAD occlusion, as reentries were favoured by the ischemic region intersecting the septo-apical region. St elevation reflected ischemic extent in transmural ischemia for LCX and LAD occlusion but not in subendocardial ischemia (associated with mild St depression). the technology and results presented can inform safety and efficacy evaluation of anti-arrhythmic therapy in acute myocardial ischemia

MRI-Based Computational Torso/Biventricular Multiscale Models to Investigate the Impact of Anatomical Variability on the ECG QRS Complex

Aims:Patient-to-patient anatomical differences are an important source of variability in the electrocardiogram, and they may compromise the identification of pathological electrophysiological abnormalities. This study aims at quantifying the contribution of variability in ventricular and torso anatomies to differences in QRS complexes of the 12-lead ECG using computer simulations. Methods:A computational pipeline is presented that enables computer simulations using human torso/biventricular anatomically based electrophysiological models from clinically standard magnetic resonance imaging (MRI). The ventricular model includes membrane kinetics represented by the biophysically detailed O’Hara Rudy model modified for tissue heterogeneity and includes fiber orientation based on the Streeter rule. A population of 265 torso/biventricular models was generated by combining ventricular and torso anatomies obtained from clinically standard MRIs, augmented with a statistical shape model of the body. 12-lead ECGs were simulated on the 265 human torso/biventricular electrophysiology models, and QRS morphology,duration and amplitude were quantified in each ECG lead for each of the human torso-biventricular models. Results:QRS morphologies in limb leads are mainly determined by ventricular anatomy,while in the precordial leads, and especially V1 to V4, they are determined by heart position within the torso. Differences in ventricular orientation within the torso can explain morphological variability from monophasic to biphasic QRS complexes. QRS duration ismainly influenced by myocardial volume, while it is hardly affected by the torso anatomyor position. An average increase of 0.12±0.05 ms in QRS duration is obtained for eachcm3of myocardial volume across all the leads while it hardly changed due to changes in torso volume. Conclusion:Computer simulations using populations of human torso/biventricular models based on clinical MRI enable quantification of anatomical causes of variability in the QRS complex of the 12-lead ECG. The human models presented also pave theway toward their use as testbeds in silico clinical trial

ECG-Based Unsupervised Clustering in Coronary Artery Disease Associates with Ventricular Arrhythmia

Coronary Artery Disease (CAD) is a leading cause of life-threatening ventricular arrhythmias (LTVAs). This study aimed to identify distinct clusters of CAD individuals based on QRS morphology using a 3-nearest neighbors clustering algorithm. Cluster 1, characterized by the lowest QRS amplitudes and widest QRS complexes, was strongly associated with LTVA risk

Análisis frecuencial del complejo QRS del electrocardiograma para la caracterización de la estimulación con marcapasos

Se propone el análisis de bajas frecuencias del complejo QRS para caracterizar los efectos en la activación ventricular tras la estimulación con marcapasos en pacientes bradicárdicos. Los resultados obtenidos podrían aplicarse para mejorar la identificación de zonas de estimulación que conduzcan a una activación ventricular más fisiológica

Changes in QRS and T-wave Loops Subsequent to an Increase in Left Ventricle Globularity as in Intrauterine Growth Restriction: a Simulation Study

[EN] Cardiovascular remodeling induced by intrauterine growth restriction manifests in adulthood by more globular ventricles, as evidenced by in vivo measurements. The angle between the dominant vectors of the QRS and T-wave loops has been reported to be significantly altered as a result of the induced remodeling. To investigate whether the more globular ventricular shape was a major factor contributing to such alteration, we performed electrophysiological simulations in a human biventricular model for control and in a model obtained by deforming the control one to represent a more spherical left ventricle (SLV). Transmural ventricular heterogeneities and a Purkinje network were included. 12-lead ECGs were calculated, from which spatial QRS and T-wave angles were computed. The angle between the T-wave and the XZ-plane was found to increase in the SLV model, showing a variation similar to that reported in in vivo studies. However, the angle between the dominant vectors of the QRS and T-wave loops projected onto the XY-plane was lower for control, contrary to clinical observations in IUGR adults. Other clinical results could not be reproduced in our simulations either. Our findings suggest that a more globular left ventricular shape leads to changes in the angles of QRS and T-wave loops, but further research is needed to fully understand these changes and the underlying mechanismsI would like to acknowledge support by Fundaci ' on Carolina, Universidad de Zaragoza and Universidad Polit ' ecnica Salesiana through its doctoral scholar-ship. This work was supported by projects ERC-StG 638284 (ERC), PID2019-105674RB-I00 and PID2019104881RB-I00 (MICINN) and LMP124-18 and reference group T39-20R (Arag ' on Government cofunded by FEDER 2014-2020 "Building Europe from Aragon"). Computations were performed using ICTS NANBIOSIS (HPC unit at U. Zaragoza). N. Ortigosa acknowledges support from Generalitat Valenciana under grant Prometeo/2017/102 and Spanish MINECO under grant MTM2016-76647-PBueno-Palomeque, FL.; Mountris, KA.; Mincholé, A.; Ortigosa, N.; Bailón, R.; Pueyo, E.; Laguna, P. (2020). Changes in QRS and T-wave Loops Subsequent to an Increase in Left Ventricle Globularity as in Intrauterine Growth Restriction: a Simulation Study. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.438S1

Estimación de la dispersión espacial de la restitución en pacientes isquémicos a partir del electrocardiograma: ventajas del uso de varias derivaciones

En este proyecto se estima, siguiendo el método de un trabajo anterior, la dispersión de la restitución en tejidos ventriculares a partir del electrocardiograma, en pacientes isquémicos y no isquémicos (pero con otras enfermedades) y se comparan los resultados obtenidos con los de pacientes sanos obtenidos en el trabajo mencionado anteriormente. Además, se comparan dos técnicas diferentes de delineado (extracción de marcas del electrocardiograma para el análisis posterior): singlelead, donde se emplea información de una única derivación, y multilead, donde se emplea información de varias derivaciones

Inflammatory response in mixed viral-bacterial community-acquired pneumonia

BACKGROUND: The role of mixed pneumonia (virus+bacteria) in community-acquired pneumonia (CAP) has been described in recent years. However, it is not known whether the systemic inflammatory profile is different compared to monomicrobial CAP. We wanted to investigate this profile of mixed viral-bacterial infection and to compare it to monomicrobial bacterial or viral CAP. METHODS: We measured baseline serum procalcitonin (PCT), C reactive protein (CRP), and white blood cell (WBC) count in 171 patients with CAP with definite etiology admitted to a tertiary hospital: 59 (34.5%) bacterial, 66 (39.%) viral and 46 (27%) mixed (viral-bacterial). RESULTS: Serum PCT levels were higher in mixed and bacterial CAP compared to viral CAP. CRP levels were higher in mixed CAP compared to the other groups. CRP was independently associated with mixed CAP. CRP levels below 26 mg/dL were indicative of an etiology other than mixed in 83% of cases, but the positive predictive value was 45%. PCT levels over 2.10 ng/mL had a positive predictive value for bacterial-involved CAP versus viral CAP of 78%, but the negative predictive value was 48%. CONCLUSIONS: Mixed CAP has a different inflammatory pattern compared to bacterial or viral CAP. High CRP levels may be useful for clinicians to suspect mixed CAP

Comparación de los efectos de la estimulación cardíaca convencional y la estimulación de rama izquierda sobre la despolarización y repolarización ventricular en el ECG

La estimulación de rama izquierda (ERI) ha surgido como alternativa a la convencional (EVD) en pacientes con marcapasos. Hemos comprobado que ERI lleva a mayor sincronía en la activación ventricular (complejo QRS más estrecho y menor área) y reducción en la dispersión de la repolarización (menor intervalo Tpe) que EVD

Variación del ángulo entre QRS y onda T del ECG en función del índice de esfericidad ventricular en sujetos con crecimiento intrauterino retardado: un estudio computacional

Pacientes con crecimiento intrauterino retardado (CIR) presentan variaciones anatómicas y electrofisiológicas en el corazón y su relación todavía no se conoce. Este estudio investiga mediante simulación computacional el impacto del aumento del índice de esfericidad ventricular y se valida con el cambio en los vectores de la despolarización y repolarización, en una cohorte de pacientes y sujetos control