Implementation
Following extensive validation in experimental preparations, ECGI was implemented for human application. ECGI requires two sets of data: (1) Electrocardiographic potentials over the entire torso and (2) the geometrical relationship between the heart and torso surfaces. Torso potentials are recorded using a computerized mapping system with either 224 Ag/AgCl body-surface electrodes embedded in a vest, or 250 conductive carbon electrodes organized in strips. The geometrical information is obtained using CT with scans usually set to axial resolution between 0.6 and 1 mm, and gated to the ECG. From the transverse slices, the geometry of the heart and torso surfaces is assembled in a common coordinate system.
Rudy. Y. Noninvasive ECG imaging (ECGI): Mapping the arrhythmic substrate of the human heart. Int J Cardiol. 2017 Jun 15;237:13-14. doi: 10.1016/j.ijcard.2017.02.104. Epub 2017 Feb 27. PMID: 28258845; PMCID: PMC5441950
Images of Human Cardiac Excitation and Arrhythmias
In humans, ECGI was validated by direct comparison to intraoperative mapping in patients undergoing open heart surgery. It was also evaluated by pacing from known cardiac sites. Following validation, ECGI has been applied to image normal and abnormal cardiac activity, including various types of atrial and ventricular arrhythmias. Many ECGI-based studies of cardiac arrhythmias are being conducted in our laboratory. Below, we show a few example images; details and additional studies are provided in our publications list.
Normal Human Atrial Activation
Ramanathan C, Ghanem RN, Jia P, Ryu K, Rudy Y. Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia. Nat Med. 2004 Apr;10(4):422-8. Epub 2004 Mar 14.
Normal Human Ventricular Activation
Ramanathan C, Ghanem RN, Jia P, Ryu K, Rudy Y. Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia. Nat Med. 2004 Apr;10(4):422-8. Epub 2004 Mar 14.
Normal Human Ventricular Repolarization
Ramanathan C, Jia P, Ghanem R, Ryu K, Rudy Y. Activation and repolarization of the normal human heart under complete physiological conditions. Proc Natl Acad Sci U S A. 2006 Apr 18;103(16):6309-14. Epub 2006 Apr 10.
Atrial Flutter
Ramanathan C, Ghanem RN, Jia P, Ryu K, Rudy Y. Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia. Nat Med. 2004 Apr;10(4):422-8. Epub 2004 Mar 14.
Ectopic Ventricular Tachycardia
Intini A1, Goldstein RN, Jia P, Ramanathan C, Ryu K, Giannattasio B, Gilkeson R, Stambler BS, Brugada P, Stevenson WG, Rudy Y, Waldo AL. Electrocardiographic imaging (ECGI), a novel diagnostic modality used for mapping of focal left ventricular tachycardia in a young athlete. Heart Rhythm. 2005 Nov;2(11):1250-2.