caritro

NUMERICAL MODELLING OF THE ELECTRICAL ACTIVITY OF THE HEART FOR THE STUDY OF THE VENTRICULAR DYSSYNCHRONY

Goal of the research

The main goal of the research is the aggregation of the advanced expertises in the clinical, numerical and image-reconstruction environments provided by the units, aiming at improving the knowledge of the ventricular dissincrony and at proposing new indices for its detection.

Units involved in the research

1. The Divisions of Cardiology and Radiology, Ospedale S. Maria del Carmine, Rovereto (TN), Italy. They will be involved in the acquisition of biomedical data and in the clinical and diagnostic support;
2. The laboratory MOX at Dipartimento di Matematica, Politecnico di Milano, Italy. It will be involved in the image reconstruction and in the numerical modelization.

People involved

PI OF THE PROJECT: Domenico Catanzariti, MD, Divisione di Cardiologia, Ospedale S. Maria del Carmine, Rovereto (TN) (former PI Giuseppe Vergara, MD)
LEADER PROJECT AT MOX: Alfio Quarteroni, MOX, Politecnico di Milano
PRINCIPAL COORDINATOR: Christian Vergara, Universita’ di Bergamo
PhD STUDENT: Simone Palamara, MOX, Politecnico di Milano
OTHER COLLABORATORS: Elena Faggiano, Fabio Nobile, MOX, Politecnico di Milano
OTHER CLINICIANS: Maurizio Centonze, MD, Divisione di Radiologia della APSS, TRENTO;
Cesarino Pangrazzi, Divisione di Cardiologia, Ospedale S. Maria del Carmine, Rovereto (TN)

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THE CLINICAL PROBLEM

The cardiac insufficiency (CI) represents the main cause of hospitalization after the age of 65 years, and the related mortality is very high.
There is nowadays a big interest in this pathology in order to find efficient therapies. In particular, a great attention has been done to the ventricular dissincrony (VD) as a possible cause of CI. With this respect, in the last years the cardiac resynchronization therapy (CRT) became a possible therapy.
This is based on the simultaneous stimulation of both the ventricles through an implantable electrical device (IED).
With the aim at diagnosing VD in a patient with CI, the principal indicator used in the clinical pratice of all the world is the QRS length in the electrocardiogram (ECG), which is easily computable non-invasively.
However, in the 30% of the cases this indicator is not trustworthy and therefore it is necessary to introduce alternative indices. The mathematical and numerical modelling could be an effective tool in the study of VD and then in finding new indices for its diagnosis.
Video : CRT
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Results

The Purkinje fibers

The Purkinje fibers (PF) provide a rapid and coordinate activation of the ventricular myocardium.
PF are electrically connected to the ventricular muscle only at certain insertion sites, called Purkinje muscle junctions (PMJ).
From these sites the depolarization wave enters the heart muscle, allowing the ventricular excitation and contraction.

Clinical data

We acquired MRI images and electrical mapps of the left ventricle by means of the EnSite NavX system.
The mapping is obtained by inserting catheters inside the left ventricular chamber of the patient and measuring a local ECG at each acquired point.

Generation of a patient-specific Purkinje network

Since the electrical activation of the ventricle depends strongly on the PF network, it is necessary to model its presence in order to obtain a realistic activation model.
Thus, in our study we implemented an algorithm for the explicit generation of a patient-specific PF network driven by the clinical measurements.
In Fig. 2 the generation of the Purkinje fibers and the numerical simulation of a healthy activation are shown.

Coupling with the muscle activation

We also study the numerical coupling of the electrical problems in the network and in the muscle. To do this we considered the Eikonal problem or the Monodomain problem in both subproblems, and we investigate suitable strategies to solve the coupled problem both in the healthy and in patological conditions

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Fig1. – The Purkinje fibers in canine ventricle.
animation
Fig2. – Generation of the Purkinje fibers and simulation of an healthy activation.

 

PUBLICATIONS

 

  • Vergara C., Palamara S., Catanzariti D., Pangrazzi C., Nobile F., Centonze M., Faggiano E., Maines M., Quarteroni A., Vergara G., Patient-specific generation of the Purkinje network driven by clinical measurements of a normal propagation. Medical & Biological Engineering & Computing, 52(10), pp. 813–826, 2014. pdf
  • S. Palamara, C. Vergara, D. Catanzariti, E. Faggiano, M. Centonze, C. Pangrazzi, M. Maines, A. Quarteroni,Computational generation of the Purkinje network driven by clinical measurements: The case of pathological propagations. Int. J. Num. Meth. Biomed. Eng., DOI: 10.1002/cnm.2689. pdf
  • Palamara S., Vergara C., Faggiano E., Nobile F., An effective algorithm for the generation of patient-specific Purkinje networks in computational electrocardiology J. Comp. Phys., 283, pp. 495–517, 2015. pdf

    CONFERENCES

    • S. Palamara, Numerical study of the electrical activity of the left ventricle based on in vivo measurements. Poster presentation at “Cardiac imaging and modelling: Principles, Methods and Clinical Relevance”, Oxford, UK, 2-6 July, 2012
    • S. Palamara, “Patient-specific computational generation of Purkinje fibers network driven by clinical measurements”. Oral presentation at Workshop “CIMAB & GASVA on Theoretical Approaches and Related Mathematical Methods in Biology, Medicine and Environment”, Universita’ di Milano, April 4-6, 2013
    • S. Palamara, “Patient-specific computational generation of Purkinje network driven by clinical measurements”. Oral presentation at V international Symposium on “Modelling of Physiological Flows”, Chia Laguna, Italy, June 11-14, 2013
    • S. Palamara, “An effective algorithm for the generation of patient-spefic Purkinje networks in computational electrocardiology”. Oral presentation at Workshop “1st International Workshop on Latest Advances in Cardiac Modeling” (LACM 2013)”, Technische Universitat, Munchen (Germany), July 10-11, 2013
    • S.Palamara, “An effective algorithm for the generation of patient-spefic Purkinje networks in computational electrocardiology”. Invited presentation at the 3rd International Conference on “Computational & Mathematical Biomedical Engineering”, within the minisymposium “Multiphysics & Multiscale Models for Simulating Total Heart Function”, City University of Hong Kong, Hong Kong, December 16-18, 2013
    • S.Palamara, “Generation of patient-specific Purkinje networks driven by clinical measurements: normal and abnormal electrical activations in the left ventricle”. Invited presentation at the “First Joint International Meeting RSME-SCM-SEMA-SIMAI-UMI” , within the minisymposium “Mathematical and numerical modeling of the cardiac electro-mechanical coupling”, Facultad de Ciencia y Tecnologia, Leioa, Bilbao, 28 June – 4 July, 2014
    • S.Palamara, “Patient-specific model of the electrical activity in the heart: generation of Purkinje networks driven by clinical measurements”. Invited presentation at the Conference “Simai 2014”, within the mini symposium “Numerical methods for coupled problems”, Taormina, Italy , July 7-10, 2014