The overall objective of proposed work is to develop and evaluate improved methods for providing robust estimates of spatial distributions of cardiac electrophysiologic properties from extracellular potential fields. The rationale for the studies is the need for sensitive techniques to better characterize cardiac behavior from direct (invasive) and indirect (non-invasive) measurements, particularly important for assessing diseased myocardium where signals have low amplitude and are often fractionated. Specific objectives include: 1) development and evaluation of a new technique, multi-reference histograms (MRHs), for providing estimates of local, myocardial activation and recovery times, 2) assessment of utility of MRHs for delineating electrically active from passive (non-depolarizing) tissue and for detecting multiple, close but uncoupled activation fronts, 3) characterization of 2 and 3 dimensional, macro-level myocardial anisotropy and inhomogeneity by electrical and statistical means, 4) development and evaluation of methods using non-linear time alignment, spatial correlation and electrocardiographic deflection areas to quantitatively compare subtle differences and detect small changes in cardiac behavior, both locally and globally, 5) assessment of the extent to which measurement uncertainty, data dimensionality and sampling completeness affect information transfer from the heart to the body surface, and 6) application of inverse techniques to the problem of localizing early ventricular depolarization from epicardial and cavitary potential distributions. Objectives will be met through theoretical and experimental studies. Significance of the proposed work lies in the likelihodd that improved methods for characterizing cardiac electrophysiology at the macro level will lead to improvement in distinguishing normal and abnormal cardiac electrical activity, reduction of uncertainty in the interpretation of cardiac electrical signals, and improved assessment of cardiac events from body surface potentials. Health relatedness of the work lies in the need for sensitive, non-invasive methods to detect and characterize cardiac diseases and conditions early in and during their evolution.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL042388-03
Application #
3360570
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Project Start
1989-04-01
Project End
1994-03-31
Budget Start
1991-04-01
Budget End
1992-03-31
Support Year
3
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of Utah
Department
Type
Schools of Medicine
DUNS #
City
Salt Lake City
State
UT
Country
United States
Zip Code
84112
Fuller, M S; Sandor, G; Punske, B et al. (2000) Estimates of repolarization dispersion from electrocardiographic measurements. Circulation 102:685-91
Abildskov, J A; Lux, R L (2000) Simulated torsade de pointes--the role of conduction defects and mechanism of QRS rotation. J Electrocardiol 33:55-64
Lux, R L; Fuller, M S; MacLeod, R S et al. (1999) Noninvasive indices of repolarization and its dispersion. J Electrocardiol 32 Suppl:153-7
Ni, Q; MacLeod, R S; Lux, R L (1999) Three-dimensional activation mapping in ventricular muscle: interpolation and approximation of activation times. Ann Biomed Eng 27:617-26
Lux, R L; Fuller, M S; MacLeod, R S et al. (1998) QT interval dispersion: dispersion of ventricular repolarization or dispersion of QT interval? J Electrocardiol 30 Suppl:176-80
Abildskov, J A; Lux, R L (1997) Effects of heart rate on vulnerability to fibrillation in a computer model. J Electrocardiol 30:307-13
Abildskov, J A; Lux, R L (1997) Mechanisms in adrenergic dependent onset of torsades de pointes. Pacing Clin Electrophysiol 20:88-94
Green, L S; Fuller, M P; Lux, R L (1997) Three-dimensional distribution of ST-T wave alternans during acute ischemia. J Cardiovasc Electrophysiol 8:1413-9
Abildskov, J A; Lux, R L (1996) Effects of premature responses on vulnerability to fibrillation in a computer model. J Electrocardiol 29:213-21
Green, L S; Lux, R L; Ershler, P R et al. (1994) Resolution of pace mapping stimulus site separation using body surface potentials. Circulation 90:462-8

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