Intramural Foci During Long Duration Fibrillation in the Pig Ventricle

Li, Li; Qi, Jin; Huang, Jian; Cheng, Ke-Di; Ideker, Raymond E.

doi:10.1161/circresaha.107.170399

Cited by 51 publications

(56 citation statements)

References 51 publications

(47 reference statements)

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“…These focal activities could arise from sources near the surface of the endocardium (such as Purkinje fibers and working ventricular myocardium), intramural foci or sources spanning the entire wall thickness (such as transmural scroll waves). 8,19 Simulation studies also suggested that this activation pattern could be caused by intramural activation, such as Purkinje-muscle reentry and intramural reentry, with breakthrough at the surface of the endocardium. 20,21 In the present study, Lugol subendocardial ablation produced tissue necrosis at a level of only 0.2 mm.…”

Section: Activation Patterns Of Refdsmentioning

confidence: 99%

“…Mapping of the transmural activation sequence with plunge electrodes or using ventricular wedge preparations may answer this question. 14,19,26,27 Second, it was difficult to distinguish Purkinje fiber activations from working ventricular myocardium activations through the optical mapping system we used. Therefore, the exact role of this specialized conduction system for the genesis of REFDs was not verified in the present study.…”

Section: Study Limitationsmentioning

confidence: 99%

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Repetitive Endocardial Focal Discharges During Ventricular Fibrillation With Prolonged Global Ischemia in Isolated Rabbit Hearts

Lin

Hsieh

et al. 2009

Circ J

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Background: Ventricular fibrillation (VF) during prolonged (>5 min) global ischemia (GI) could be due to repetitive endocardial focal discharges (REFDs). This hypothesis was tested in isolated rabbit hearts. Methods and Results: With optical mapping, simultaneous endocardial (left ventricle, LV) and epicardial (both ventricles) activations during VF with prolonged GI were studied (protocol I, 8 hearts). Lugol solution was applied to the LV endocardium in additional 5 hearts after 5-min GI (protocol II). During prolonged GI, sustained VF (>30 s) was successfully induced in 7 protocol I hearts. The dominant frequency of summed optical signals at the LV endocardium was higher than at the epicardium (P<0.05). Mapping data showed that after 5-min GI, REFDs were present in >90% for recording time. There were 18 windows of optical recording showing spontaneous VF termination. In 10, once REFDs ceased, the VF episode terminated immediately. Electrical defibrillation was also performed on 3 hearts. Eight shocks showed early VF recurrence after successful defibrillation. REFDs were consistently involved in the initiation period of recurrence. In protocol II, Lugol subendocardial ablation diminished REFD genesis during re-induced VF. These VF episodes were all non-sustained. Conclusions: REFDs at the LV endocardium were important for both VF maintenance and post-shock recurrence during prolonged GI in this model. (Circ J 2009; 73: 1803 -1811

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Section: Activation Patterns Of Refdsmentioning

confidence: 99%

Section: Study Limitationsmentioning

confidence: 99%

Repetitive Endocardial Focal Discharges During Ventricular Fibrillation With Prolonged Global Ischemia in Isolated Rabbit Hearts

Lin

Hsieh

et al. 2009

Circ J

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“…We (14) recently developed a 3-D electrical mapping technique that, combined with 3-D wavefront analysis programs, allows quantitative wavefront analysis. The aims of the present study were to use these techniques in canines to 1) test the hypothesis that the subendocardium is the source of the intramural wavefronts during long-duration VF, 2) determine if there is more than one type of activation pattern during longduration VF, and 3) further define the relationship between PF and WM activations during long-duration VF.…”

mentioning

confidence: 99%

Activation becomes highly organized during long-duration ventricular fibrillation in canine hearts

Qi²,

Dosdall³

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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Ideker RE. Activation becomes highly organized during long-duration ventricular fibrillation in canine hearts. Am J Physiol Heart Circ Physiol 298: H2046 -H2053, 2010. First published April 9, 2010 doi:10.1152/ajpheart.01196.2009Little is known about the threedimensional (3-D) intramural activation sequences during long-duration ventricular fibrillation (VF), including the role of the subendocardium and its Purkinje fibers (PFs) in long-duration VF maintenance. Our aim was to explore the mechanism of long-duration VF maintenance with 3-D electrical mapping. We recorded 10 min of electrically induced VF in the left ventricular anterior free wall of six 10-kg, open-chest dogs using a 3-D transmural unipolar electrode matrix (9 ϫ 9 ϫ 6, 2-mm spacing) that allowed us to map intramural activation sequences. At 2.5 Ϯ 1.8 min of VF, although the body surface ECG continued to exhibit a disorganized VF pattern, intramurally a more organized, synchronous activation pattern was first observed [locally synchronized VF (LSVF)]. This pattern occurred one or more times in all dogs and was present 33.4 Ϯ 31.4% of the time during 5-10 min of VF. As opposed to the preceding changing complex activation sequences of VF, during LSVF, wavefronts were large and highly repeatable near the endocardium, first exciting the endocardium almost simultaneously and then rapidly spreading toward the epicardium with different levels of conduction block en route. During LSVF, PF activations always preceded working myocardium activations near the endocardium. In conclusion, long-duration VF in dogs frequently becomes highly organized in the subendocardium, with activation fronts arising in this region and passing intramurally toward the epicardium, even though the surface ECG continues to exhibit a disorganized pattern. PFs appear to play an important role during this stage of VF.intramural ventricular fibrillation; locally synchronized ventricular fibrillation; Purkinje fibers SUDDEN CARDIAC ARREST is a leading cause of death in the industrialized world (25). Many lethal cardiac arrests are caused by ventricular fibrillation (VF) (25). The mean time from collapse until defibrillation in the prehospital setting, where most cardiac arrests occur, ranges from 4 to 10 min (21,22). Yet, relatively few studies have dealt with activation sequences during VF lasting Ͼ1 min [long-duration VF (20)], and little is known about the mechanisms of long-duration VF maintenance.Some studies have suggested an important role of Purkinje fibers (PFs) during long-duration VF maintenance (1,4,20,23). As in humans, PFs in canines are primarily located in the subendocardium (19). In canines, an endocardial-epicardial gradient of the activation rate develops during long-duration VF (1, 4, 23), with discrete, regular, rapid deflections persisting in the subendocardium (23), possibly caused by PFs. After endocardial ablation with Lugol's solution to eliminate PF activations, subendocardial PF signals were no longer recorded, and the transmural activation rate gradient dis...

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“…It is thought that in the future optrodes will play an important role in more carefully examining transmural dispersion of repolarization, an important factor in arrhythmogenesis in a variety of cardiac diseases (Antzelevitch, 2007;El-Sherif et al, 1996;Milberg et al, 2005;Shimizu et al, 1997). Optrodes may also be important in the study of the dynamics of arrhythmic circuits, since they are often present deeper in the myocardial wall (Allison et al, 2007;Li et al, 2008;Valderrábano et al, 2001). However, like plunge electrodes optrodes must also be inserted into the tissue and therefore cause damage which may by itself alter activation patterns.…”

Section: Recent Advances In Cardiac Optical Mappingmentioning

confidence: 99%