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Yuanna Cheng, M.D., Ph.D.Associate Staff
Department of Molecular Cardiology
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Areas of General Research Interest:
Optical imaging, Defibrillation, Cardiac arrhythmias
Current Program:
- Cardiac arrhythmogenesis and remodeling following left ventricular reconstruction;
- The role of electroporation in defibrillation
Investigators:
- Wang, Yves, B.S., Graduate Student
- Zhang, Hongyu, Ph.D., Postdoctoral Fellow
Collaborators:
- Igor Efimov, Ph.D. (Washington University)
- David Van Wagoner, Ph.D.
- Kiyotaka Fukamachi, M.D., Ph.D.
- Andrew Rollins, Ph.D. (Case Western Reserve University)
Research:
Defibrillation is very effective against lethal arrhythmias, and there has been a significant increase in the number of patients receiving such therapy. However, defibrillation is costly and increased utilization raises concerns regarding the safety and optimization of this therapy. These questions cannot be further addressed without first developing a better understanding of the basic mechanisms of defibrillation.
Recent research has resulted in a significant improvement in our understanding of these mechanisms, as summarized in the Virtual Electrode Polarization Hypothesis of defibrillation. According to this hypothesis, an electric shock simultaneously produces areas of both depolarized and hyperpolarized changes in transmembrane potential in cardiac tissue. The success or failure of the shock is determined by this shock-induced virtual electrode polarization pattern.
Our laboratory has made significant contributions in advancing this new concept based on data obtained from normal rabbit heart and ischemic and chronic myocardial infarcted hearts via optical imaging. In the context of this novel concept, we are elucidating the impact of left ventricular reconstruction surgery on arrhythmia vulnerability and defibrillation.
We are also investigating the mechanism of electroporation (shock-induced cardiac damage) and its role in defibrillation. For these purposes, fast fluorescence imaging, surgical maneuver, and immunohistochemistry and western blot techniques are routinely used.
Key References:
- Cheng Y. Optical mapping of shock-induced arrhythmogenesis in the rabbit heart with healed myocardial infarction: fluorescent imaging with a photodiode array. Methods Mol Med 2006;129:149-61.
- Ootaki Y, Yamada H, Daimon M, Kamohara K, Popovic ZB, Van Wagoner DR, Cheng Y, Fukamachi K. An Experimental Rabbit Model for Off-pump Left Ventricular Reconstruction following Left Ventricular Aneurysm. The Heart Surgery Forum, 9 (5): E786-E791, 2006.
- Li L, Nikolski V, Wallick DW, Efimov IR, Cheng Y. Mechanisms of enhanced shock-induced arrhythmogenesis in the rabbit heart with healed myocardial infarction. Am J Physiol, 289:H1054-H1068, 2005.
- Cheng Y, Li L, Nikolski V, Wallick DW, Efimov IR. Shock-induced arrhythmogenesis is enhanced by 2,3-butanedione monoxime as compared with cytochalasim D. Am J Physiol, 286: H310-H318, 2004.
- Cheng Y, Mowrey KA, Nikolski V, Tchou PJ, Efimov IR. Mechanisms of shock-induced arrhythmogenesis during acute global ischemia. Am J Physiol 282: H2141-2151, 2002.
- Cheng Y, Nikolski V, Efimov IR. Reversal of repolarization gradient does not reverse the chirality of shock-induced reentry in the rabbit heart. J Cardiovasc Electrophysiol, 11 (9): 998-1007, 2000.
- Efimov IR, Aguel F, cheng Y, Wollenzier B, Trayanova N. Virtual electrode polarization in the far field: implications for external defibrillation. Am J Physiol, 279: H1055-1070, 2000.
- Efimov IR, Cheng Y, Yamanouchi Y, Tchou PJ. Direct evidence of the role of virtual electrode incuded phase singularity in success and failure of defibrillation. J Cardiovasc Electrophysiol, 11 (8): 861-868, 2000.
- Cheng Y, Mowrey K, Van Wagoner DR, Tchou P, Efimov IR. Virtual electrode-induced reexcitation: A mechanism of defibrillation. Circ Res, 85:1056-1066, 1999.
- Efimov IR, Cheng Y, Van Wagoner DR, Mazgalev T, Tchou P. Virtual electrode-induced Phase singularity: A basic mechanism of defibrillation failure. Circ Res, 82: 918-925, 1998.
- Efimov IR, Cheng Y, Van Wagoner DR, Mazgalev T, Tchou P. Transmembrane voltage changes produced by real and virtual electrodes during monophasic defibrillation shock delivered by an implantable electrode. J Cardiovasc Electrophysiol 8: 1031-1045, 1997.