Study of the Myocardial Contraction and Relaxation Velocities through Doppler Tissue Imaging Echocardiography: A New Alternative in the Assessment of the Segmental Ventricular Function

Silva, Carlos Eduardo Suaide; Ferreira, Luiz Darcy Cortez; Peixoto, Luciana Braz; Monaco, Claudia; Gil, Manuel Adán; Ortiz, Jayme Pinto

doi:10.1590/s0066-782x2002000200009

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…At that time the heart is not fully relaxed, and mechanical systole is not complete. We therefore suggest that the EMw is a more appropriate [and now feasible, using Doppler echocardiography (Silva et al ., 2002)] way to measure electrical‐mechanical disturbances.…”

Section: Limitations Of the Studymentioning

confidence: 99%

The Electro‐Mechanical window: a risk marker for Torsade de Pointes in a canine model of drug induced arrhythmias

Linde

Deuren

Somers

et al. 2010

British J Pharmacology

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In cardiovascular pharmacology, electrical and mechanical events can be distinguished, and the phrase 'electro-mechanical window' (EMw) describes the temporal difference between these events. We studied whether changes in EMw have potential predictive value for the occurrence of arrhythmias in fentanyl/etomidate-anaesthetized beagle (FEAB) dogs. EXPERIMENTAL APPROACHThe EMw was calculated as differences between the QT interval and QLVPend in FEAB dogs during atrial pacing, treatment with isoprenaline or atropine, body temperature changes and induction of Torsade de Pointes (TdP) in an LQT1 model. KEY RESULTSThe electrical systole (QT interval) was shorter than the duration of the mechanical event (QLVPend), providing a positive EMw. Atrial pacing, atropine or body temperature changes had no major effects on EMw, despite large changes in QT duration. However, b-adrenoceptor stimulation (with isoprenaline) decreased the EMw (from 90 to 5 ms) and in combination with HMR1556, a blocker of the slowly activating potassium current (IKs), induced a large negative EMw (-109 ms) and TdP. Prevention of TdP by atenolol or verapamil was associated with a less negative EMw (-23 to -16 ms). Mexiletine, a poorly effective long QT treatment, did not affect the EMw or prevent TdP induction. CONCLUSIONS AND IMPLICATIONSThe EMw is a marker, other than QT prolongation, of TdP risk in the FEAB model. Therefore, we suggest examining the EMw as a risk marker in cardiovascular safety studies and as a potential biomarker to improve clinical management of long QT syndrome patients, especially in patients with borderline QT prolongation. LINKED ARTICLE

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Section: Limitations Of the Studymentioning

confidence: 99%

The Electro‐Mechanical window: a risk marker for Torsade de Pointes in a canine model of drug induced arrhythmias

Linde

Deuren

Somers

et al. 2010

British J Pharmacology

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“…The myocardial wall has been divided into 12 segments (Silva et al 2002) that are composed of three layers (base, medium and apex). Each layer is separated in 4 components corresponding to the septal, lateral, anterior and inferior walls (Fig.…”

Section: Model Descriptionmentioning

confidence: 99%

A Tissue-Level Electromechanical Model of the Left Ventricle: Application to the Analysis of Intraventricular Pressure

et al. 2009

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The ventricular pressure profile is characteristic of the cardiac contraction progress and is useful to evaluate the cardiac performance. In this contribution, a tissue-level electromechanical model of the left ventricle is proposed, to assist the interpretation of left ventricular pressure waveforms. The left ventricle has been modeled as an ellipsoid composed of twelve mechano-hydraulic sub-systems. The asynchronous contraction of these twelve myocardial segments has been represented in order to reproduce a realistic pressure profiles. To take into account the different energy domains involved, the tissue-level scale and to facilitate the building of a modular model, multiple formalisms have been used: Bond Graph formalism for the mechano-hydraulic aspects and cellular automata for the electrical activation. An experimental protocol has been defined to acquire ventricular pressure signals from three pigs, with different afterload conditions. Evolutionary Algorithms have been used to identify the model parameters in order to minimize the error between experimental and simulated ventricular pressure signals. Simulation results show that the model is able to reproduce experimental ventricular pressure. In addition, electro-mechanical activation times have been determined in the identification process. For example, the maximum electrical activation time is reached, respectively, 96.5, 139.3 and 131.5 ms for the first, second, and third pigs. These preliminary results are encouraging for the application of the model on non-invasive data like ECG, arterial pressure or myocardial strain.

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“…The myocardial wall has been divided into 12 segments (Silva et al 2002) that are composed of three layers (base, medium and apex).…”

Section: Model Descriptionmentioning

confidence: 99%

A tissue-level electromechanical model of the left ventricle: Application to the analysis of intraventricular pressure

Rolle

Hernández

Richard

et al. 2007

2007 Computers in Cardiology

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Abstract:The ventricular pressure profile is characteristic of the cardiac contraction progress and is useful to evaluate the cardiac performance. In this contribution, a tissue-level electromechanical model of the left ventricle is proposed, to assist the interpretation of left ventricular pressure waveforms.The left ventricle has been modeled as an ellipsoid composed of twelve mechano-hydraulic subsystems. The asynchronous contraction of these twelve myocardial segments has been represented in order to reproduce a realistic pressure profiles. To take into account the different energy

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Study of the Myocardial Contraction and Relaxation Velocities through Doppler Tissue Imaging Echocardiography: A New Alternative in the Assessment of the Segmental Ventricular Function

Cited by 11 publications

References 11 publications

The Electro‐Mechanical window: a risk marker for Torsade de Pointes in a canine model of drug induced arrhythmias

The Electro‐Mechanical window: a risk marker for Torsade de Pointes in a canine model of drug induced arrhythmias

A Tissue-Level Electromechanical Model of the Left Ventricle: Application to the Analysis of Intraventricular Pressure

A tissue-level electromechanical model of the left ventricle: Application to the analysis of intraventricular pressure

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