Human ventricular activation sequence and the simulation of the electrocardiographic QRS complex and its variability in healthy and intraventricular block conditions

Abstract

AimsTo investigate how variability in activation sequence and passive conduction properties translates into clinical variability in QRS biomarkers, and gain novel physiological knowledge on the information contained in the human QRS complex.Methods and resultsMultiscale bidomain simulations using a detailed heart-torso human anatomical model are performed to investigate the impact of activation sequence characteristics on clinical QRS biomarkers. Activation sequences are built and validated against experimentally-derived ex vivo and in vivo human activation data. R-peak amplitude exhibits the largest variability in terms of QRS morphology, due to its simultaneous modulation by activation sequence speed, myocardial intracellular and extracellular conductivities, and propagation through the human torso. QRS width, however, is regulated by endocardial activation speed and intracellular myocardial conductivities, whereas QR intervals are only affected by the endocardial activation profile. Variability in the apico-basal location of activation sites on the anterior and posterior left ventricular wall is associated with S-wave progression in limb and precordial leads, respectively, and occasional notched QRS complexes in precordial derivations. Variability in the number of early activation sites successfully reproduces pathological abnormalities of the human conduction system in the QRS complex.ConclusionVariability in activation sequence and passive conduction properties captures and explains a large part of the clinical variability observed in the human QRS complex. Our physiological insights allow for a deeper interpretation of human QRS biomarkers in terms of QRS morphology and location of early endocardial activation sites. This might be used to attain a better patient-specific knowledge of activation sequence from routine body-surface electrocardiograms.

Evaluation of Inverse Problem with Slow-Conducting Channel in Scar Area in a Post-Infarction Model

“…Specifically, the APD 90 was mainly used for the measurement of the APDs, which was measured as the time interval between the 90% of the voltage at the upstroke and at the down stroke of the APs. The tissue activation was mainly in accordance with the human ventricular activation sequence of Cardone-Noott et al [4], which the left ventricle (LV) endocardial surface was activated within 30ms and the transmural propagation accomplished in 35ms. As illustrated in the Tables 1-3, the model parameter values were modified to accommodate post-infarction condition for epicardial, endocardial and midmyocardial myocytes.…”

Computational techniques for ECG analysis and interpretation in light of their contribution to medical advances

“…Another work by Cardone-Noott et al [13] investigated the effect of changes in conductivities on the ECG morphology and how the variability in the activation sequence relates to changes in QRS biomarkers, by designing a 3D simulation pipeline with a human volumetric mesh and activation model based on the cellular O'Hara-Rudy model. Phenomenological approaches to modelling and simulation of electrical propagation have also been proposed using fast algorithms based on graph based theory [95,96].…”

“…Vigmond et al [100] for example showed the importance of superior vena cava and pulmonary vein openings in rotors by using a model of the atria built with two spheres containing holes as anatomical elements. However, despite being very useful because of their simplicity, Computational pipeline for ECG simulation from magnetic resonance images through 3D meshes and cellular electrophysiological models (left, from Zacur et al [87]) and the obtained simulation of the cardiac electrical activity (right, from Cardone-Noott et al [13]). Personalized cardiac magnetic resonance images (1) are segmented and preprocessed (2).…”

“…3D computer simulations are a powerful tool to address these issues. They allow personalized simulations of the ECG, allowing the interpretation of the ECG signals [13][14][15] as well as the generation of synthetic data for training and validation purposes.…”

A Two-Stage Purkinje Network for More Accurate ECG Representations

“…Since their invention, ECGs are still the most widely used non-invasive method to assess cardiac function and to investigate cardiac disorders (25). Despite the known natural variability to ventricular activation sequences across a healthy population, which translates to a variability observed in the QRS complexes of human ECGs, certain sites of early activation within the left and right ventricles have been identi ed in the literature, which de ne normal electrical excitation patterns (25). Thus, when interested in building an accurate multiscale cardiac model that accounts for electrophysiology within anatomically accurate cardiac domains, it becomes necessary to ensure that the resulting ECGs from the model match those clinical, both in health and in disease.…”