Research ArticleCardiovascular Disease

Noninvasive Electroanatomic Mapping of Human Ventricular Arrhythmias with Electrocardiographic Imaging

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Science Translational Medicine  31 Aug 2011:
Vol. 3, Issue 98, pp. 98ra84
DOI: 10.1126/scitranslmed.3002152

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A New View of the Beating Heart

Just as a tree’s shadow is an oversimplification of branches and foliage, the electrocardiogram, a decades-old tool for measuring the electrical activity of the heart, captures only an approximate view of the heartbeat, distorted by the intervening tissues between the heart and the few electrodes on the skin. This poses a problem when trying to treat heart diseases such as dangerous ventricular arrhythmias, which destabilize the heartbeat and can lead to sudden cardiac death. Now, with a technique called electrocardiographic imaging (ECGI), Wang and colleagues have married multiple electrical recordings from the skin of patients who have ventricular tachycardia (VT) with detailed computerized axial tomography (CAT) scans of the anatomy of their torso. From these data, the authors can back calculate what is happening, electrically speaking, on the surface of the misbehaving hearts, yielding an individual portrait of that patient’s beating heart so that treatment can be more effectively deployed.

Twenty-five patients with VT were scheduled to undergo electrical mapping of their hearts and then ablation of heart tissue to correct the electrical defect with an invasive catheter. The authors augmented this standard treatment by creating an image of their beating hearts with noninvasive ECGI, before the standard procedure. The ECGI and standard procedure identified the same origination point of the tachycardia in almost all of the patients, and ECGI was able to correctly categorize both focal and reentrant mechanisms of VT. The time resolution of ECGI enabled the authors to follow the response of the heart to different patterns of stimulation (or pacing), revealing presystolic activation near the site of origin. They could see variable beat-to-beat conduction patterns and showed that the abnormal conduction patterns often began in regions of scar tissue, relics of previous heart attacks.

ECGI yields information comparable to the current procedure for mapping abnormal heart activity with a catheter-fed electrode, repeatedly placed on the heart surface. But it has significant advantages over the current approach: The spatial resolution of the ventricular arrhythmia on the heart surface is high, and it takes into account patient-to-patient variability in body size and shape. Further, it is noninvasive and can map single heartbeats, allowing unprecedented visualization of the anatomy of the electrical activation and beat-to-beat variability. These advantages should enable more effective diagnosis of VT and more appropriate drug or ablation therapy, which can now be directed to the specific characteristics of the patient’s heart instead of a simplified shadow.

Footnotes

  • * These authors contributed equally to this work.

  • Citation: Y. Wang, P. S. Cuculich, J. Zhang, K. A. Desouza, R. Vijayakumar, J. Chen, M. N. Faddis, B. D. Lindsay, T. W. Smith, Y. Rudy, Noninvasive Electroanatomic Mapping of Human Ventricular Arrhythmias with Electrocardiographic Imaging. Sci. Transl. Med. 3, 98ra84 (2011).

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