Imaging Dispersion of Myocardial Repolarization, II

Ghanem, Raja N.; Burnes, John E.; Waldo, Albert L.; Rudy, Yoram

doi:10.1161/hc3601.094277

Cited by 73 publications

(30 citation statements)

References 30 publications

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“…A gradient of ARIs from RV to LV and from LV apex to base was imaged. Similar gradients were measured in canine hearts (14,19). The normal canine heart (14) was found to have an average ARI of 200 ms (vs. 235 ms for human hearts in this study).…”

Section: Discussionsupporting

confidence: 79%

“…The ability to image and determine cardiac repolarization is important, because repolarization abnormalities and large dispersions are underlying causes of many arrhythmias (14,19). Normal ventricular repolarization was characterized by T wave electrograms, potential maps, recovery-time isochrones, and ARI maps.…”

Section: Discussionmentioning

confidence: 99%

“…Electrocardiographic imaging (ECGI) (9) is a noninvasive cardiac electrical imaging modality that can image epicardial potentials, electrograms, and isochrones (activation sequences) using electrocardiographic measurements from many body surface locations together with heart-torso geometry obtained from computed tomography (CT). This imaging technique was extensively validated previously in normal and abnormal canine hearts (10)(11)(12)(13)(14). In a recent technical report (9), we introduced the methodology of ECGI application in humans, using single examples of ventricular and atrial activation in a normal subject and in patients with right bundle branch block, ventricular pacing, and atrial flutter.…”

mentioning

confidence: 99%

“…4B (all times are from QRS onset). The corresponding activation recovery interval (ARI) (14) map is shown in Fig. 4C.…”

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confidence: 99%

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Activation and repolarization of the normal human heart under complete physiological conditions

Ramanathan

Jia

Ghanem

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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226

166

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Knowledge of normal human cardiac excitation stems from isolated heart or intraoperative mapping studies under nonphysiological conditions. Here, we use a noninvasive imaging modality (electrocardiographic imaging) to study normal activation and repolarization in intact unanesthetized healthy adults under complete physiological conditions. Epicardial potentials, electrograms, and isochrones were noninvasively reconstructed. The normal electrophysiological sequence during activation and repolarization was imaged in seven healthy subjects (four males and three females). Electrocardiographic imaging depicted salient features of normal ventricular activation, including timing and location of the earliest right ventricular (RV) epicardial breakthrough in the anterior paraseptal region, subsequent RV and left ventricular (LV) breakthroughs, apex-to-base activation of posterior LV, and late activation of LV base or RV outflow tract. The repolarization sequence was unaffected by the activation sequence, supporting the hypothesis that in normal hearts, local action potential duration (APD) determines local repolarization time. Mean activation recovery interval (ARI), reflecting local APD, was in the typical human APD range (235 ms). Mean LV apex-to-base ARI dispersion was 42 ms. Average LV ARI exceeded RV ARI by 32 ms. Atrial images showed activation spreading from the sinus node to the rest of the atria, ending at the left atrial appendage. This study provides previously undescribed characterization of human cardiac activation and repolarization under normal physiological conditions. A common sequence of activation was identified, with interindividual differences in specific patterns. The repolarization sequence was determined by local repolarization properties rather than by the activation sequence, and significant dispersion of repolarization was observed between RV and LV and from apex to base.noninvasive electrocardiographic imaging ͉ normal cardiac activation and repolarization ͉ normal sinus rhythm U nderstanding normal cardiac excitation provides a necessary baseline for understanding abnormal cardiac electrical activity and rhythm disorders of the heart, a major cause of death and disability. So far, knowledge of normal human cardiac excitation has been obtained mostly through extrapolation from animal studies, including canine (1, 2) and chimpanzee (3). In addition, human data have been obtained from intraoperative epicardial mapping (4-7) and isolated human hearts (8). Extrapolation of animal studies to humans is limited by interspecies differences in anatomy and electrophysiology. Also, the animal and human studies were conducted under nonphysiological conditions (e.g., anesthesia effects and heart exposure during intraoperative mapping; effects of isolation and absence of neural inputs, mechanical loading, and normal perfusion in isolated heart studies). Until now, it has not been possible to study cardiac excitation in intact healthy subjects under normal physiological conditions because of the unavailabili...

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

“…4B (all times are from QRS onset). The corresponding activation recovery interval (ARI) (14) map is shown in Fig. 4C.…”

mentioning

confidence: 99%

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Activation and repolarization of the normal human heart under complete physiological conditions

Ramanathan

Jia

Ghanem

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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226

166

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“…[4][5][6] It was also shown to image cardiac repolarization and its spatial dispersion. 16 Recently, ECGI was also applied in human subjects, demonstrating its ability to image normal activation and repolarization, locate initiation sites during right and left ventricular pacing, image the conduction abnormality associated with right bundle branch block (RBBB) and image the right-atrial reentry circuit during typical atrial flutter. 21 The procedure of ECGI involves solving Laplace's equation in the source-free volume conductor between the torso and epicardial surfaces.…”

Section: Introductionmentioning

confidence: 99%

Accuracy of Quadratic Versus Linear Interpolation in Noninvasive Electrocardiographic Imaging (ECGI)

Ghosh

Rudy

2005

Ann Biomed Eng

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Electrocardiographic Imaging (ECGI) is a cardiac functional imaging modality, noninvasively reconstructing epicardial potentials, electrograms and isochrones (activation maps) from multichannel body surface potential recordings. The procedure involves solving Laplace's equation in the source-free volume conductor between torso and epicardial surfaces, using Boundary Element Method (BEM). Previously, linear interpolation (LI) on three-noded triangular surface elements was used in the BEM formulation. Here, we use quadratic interpolation (QI) for potentials over six-noded linear triangles. The performance of LI and QI in ECGI is evaluated through direct comparison with measured data from an isolated canine heart suspended in a human-torso-shaped electrolyte tank. QI enhances the accuracy and resolution of ECGI reconstructions for two different inverse methods, Tikhonov regularization and Generalized Minimal Residual (GMRes) method, with the QI-GMRes combination providing the highest accuracy and resolution. QI reduces the average relative error (RE) between reconstructed and measured epicardial potentials by 25%. It preserves the amplitude (average RE reduced by 48%) and morphology of electrograms better (average correlation coefficient for QI ~ 0.97, LI ~ 0.92). We also applied QI to ECGI reconstructions in human subjects during cardiac pacing, where QI locates ventricular pacing sites with higher accuracy (≤10 mm) than LI (≤18 mm).

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ST Segment Mapping in Ventricular Tachycardia

Şahiner

Oto

2012

Cardiac Mapping

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Imaging Dispersion of Myocardial Repolarization, II

Cited by 73 publications

References 30 publications

Activation and repolarization of the normal human heart under complete physiological conditions

Activation and repolarization of the normal human heart under complete physiological conditions

Accuracy of Quadratic Versus Linear Interpolation in Noninvasive Electrocardiographic Imaging (ECGI)

ST Segment Mapping in Ventricular Tachycardia

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