Assessment of Cardiac Resynchronization Therapy by Non-Invasive Reconstruction of Cardiac Activation Times

Michael Seger, Michael Netzer, Christian Baumgartner, Friedrich Hanser, Bernhard Pfeifer, Thomas Berger, Florian Hintringer, Otmar Pachinger, Wolfgang Dichtl, Markus Stuehlinger, and Thomas Trieb


Cardiac Resynchronization Therapy, Biventricular Pacing, Noninvasive Reconstruction of Cardiac Electrical Activity, Illposed Inverse Problem


The computational reconstruction of cardiac activation times in a noninvasive manner was performed in ten patients with congestive heart failure (CHF), complete left bundle branch block (LBBB) patients undergoing cardiac resynchronization therapy (CRT) and ten patients without structural heart disease undergoing an EP study (control group). The noninvasive functional imaging technique employed in this study fused data from high-resolution ECG mapping with a model of the patient’s individual cardiac and thoracic anatomy obtained by magnetic resonance imaging. Single beat endoand epicardial ventricular activation sequences were computed during native rhythm and ventricular pacing. A bido main theory based algorithm was employed solving the underlying ill-posed inverse problem of electrocardiography. The control group showed a deterioration of the ventricular activation sequence during right ventricular pacing, which was found to be similar to the intrinsic activation pattern of CHF patients. CHF patients had a right-to-left septal activation with the latest activation in the epicardial lateral wall of the left ventricle. Biventricular pacing led to a resynchronization of biventricular activation sequences and to a significant decrease of the total left ventricularactivation duration compared to intrinsic conduction and RV pacing (129 ± 16 versus 157 ± 28 and 173± 25 ms; both p < 0.05). Endocardial and epicardial ventricular activation of structurally healthy individuals and of patients with CHF or LBBB can be visualized in a non invasive manner by the method proposed in this study. Thus noninvasive determination of individual patients’ ventricular activation properties might help to further improve positive responses to CRT by pacemaker therapy tailored to a patient’s specific needs.

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