Integrated multimodal-catheter imaging unveils principal relationships among ventricular electrical activity, anatomy, and function

Abstract

Multiple imaging modalities are employed independent of one another while managing complex cardiac arrhythmias. To combine electrical, anatomical, and functional imaging in a single catheter system, we developed a balloon catheter that carried 64 electrodes on its surface and an intracardiac echocardiography (ICE) catheter through a central lumen. The catheter system was inserted, and the balloon was inflated inside the left ventricle (LV) of eight dogs with 6-wk-old infarction, created by occlusion in the left anterior descending coronary artery. Anatomy was constructed by ICE imaging (9 MHz) through the balloon. Single-beat noncontact mapping (NCM) was performed via the multielectrode array to reconstruct unipolar endocardial electrograms during sinus rhythm. Standard contact mapping (CM) of the endocardium was also carried out for reference. Myocardial infarction in anterior LV extending from the middle to apical regions was localized both by ICE and NCM and validated by CM and pathology. The overall difference in the activation times between NCM and CM was 3 +/- 1 ms. Unipolar voltage in infarcted middle anterior LV was smaller than the voltage in normal middle inferior LV both by NCM (11 +/- 4 vs. 16 +/- 3 mV; P = 0.002) and CM (11 +/- 3 vs. 20 +/- 4 mV; P < 0.001). Unipolar voltage was also inversely related to infarct transmurality, both by NCM (r = -0.87; P = 0.005) and CM (r = -0.94; P < 0.001). The infarct area by ICE (7.7 +/- 2.9 cm(2)) was in agreement with CM (bipolar voltage, <1 mV; and area, 7.6 +/- 3.3 cm(2); r = 0.80; P = 0.016). Meanwhile, the voltage threshold that depicted the infarct area by NCM was directly related to the smallest unipolar voltage reconstructed within the infarct (r = 0.96; P < 0.001). In conclusion, combining NCM and ICE imaging in a single catheter system is feasible. The preclinical development of such an integrated system and its evaluation in experimental myocardial infarction demonstrate capabilities for single-beat mapping at multiple sites as well as the online assessment of anatomy and myocardial function.

Model study of imaging myocardial infarction by intracardiac electrical impedance tomography

“…In this regard, intracardiac echocardiographic catheter imaging may be useful for determining this information. [1] To better understand cardiac electrophysiologic properties in relation to underlying anatomy, multiple noninvasive as well as catheter-based imaging techniques are presently employed before, during, or after catheterization that are however performed independent of one another. The catheter-based EIT method described in this study could evolve clinically as a useful technique in diagnosing, monitoring, and guiding applications appropriate for the cardiac catheterization laboratory.…”

“…However, voltage mapping provides variable results on the endocardial-to-epicardial transmural extent of the scar. [1] Electrical impedance tomography (EIT) determines the resistive properties inside a biological medium and uses various electrode configurations to pass a small electric current and measure corresponding potential. The EIT method is suitable for detecting tissue composition, and has been applied predominantly from outside the medium by noninvasively placing electrodes at fixed locations on the surface exterior (such as the chest or the head).…”

Interventional Endocardial Motion Estimation from Electroanatomical Mapping Data: Application to Scar Characterization

“…Segments with scar core were defined as those with mean maximum bipolar voltage lower than 0.5 mV [21]. Segments without scar core were defined as those with mean maximum bipolar voltage higher than 1 mV [22]. Displacement projections in longitudinal, circumferential, and radial directions, together with longitudinal and circumferential strains, were also averaged for every segment.…”

Speckle Tracking in Intracardiac Echocardiography for the Assessment of Myocardial Deformation

“…These capabilities have made ICE an attractive imaging modality to better understand complex rhythm disorders in relation to underlying anatomy and physiological outcome [5], [6]. Clinically, ICE is predominantly implemented on the basis of a catheter carrying at its distal end a rotating transducer that operates at a frequency of 9 MHz and provides two-dimensional (2-D) tomographic images of the heart’s interior, or a catheter with a phased transducer array operating at a lower ultrasound frequency for deeper penetration (5.5–10 MHz) and provides a 2-D sector view of the heart (80° −90° opening angle).…”