Semi-automated 3-dimensional intracardiac echocardiography: development and initial clinical experience of a new system to guide ablation procedures.
BACKGROUND
Pre-interventional three-dimensional (3D) reconstruction of the heart by CT or MRI provides important information on cardiac anatomy for electrophysiological interventions. However, updates of 3D-imaging modalities with high soft-tissue contrast are not available during ablation procedures.


OBJECTIVE
We describe the development and first clinical testing of a close to real-time visualization of cardiac anatomy by intracardiac echocardiography (ICE).


METHODS
An electronic phased-array 5-10 MHz ICE-catheter (AcuNav/Siemens/64 elements) was inserted via a straightened femoral vein sheath (12F) and placed in the right atrium in 5 pigs. A custom-made prototype stepper motor allowed automatic rotation around the longitudinal axis from 90 degrees to 360 degrees in 2-5 degrees steps. For every plane 2D images of a complete cardiac cycle were acquired, triggered by respiration and ECG. The ultrasound images were digitized and 3D-reconstruction was performed by a prototype software. After experimental validation the system was tested in 6 patients during electrophysiological studies.


RESULTS
From a single location in the right atrium, 3D-acquisition and reconstruction of both atria and ventricles with good image quality were achieved within 3-5 minutes. Doppler-mode facilitated identification of the great vessels including the pulmonary veins and their entry into the heart. 3D-visualization of ablation catheters was also possible in all patients and pigs.


CONCLUSIONS
Semi-automated 3D intracardiac echocardiography from a single site inside the right atrium provides the electrophysiologist with a detailed image of both atria and ventricles with repeated updates of the cardiac anatomy.
Knackstedt
Christian
C
Department of Cardiology, RWTH University Aachen, Aachen, Germany.
Franke
Andreas
A
Mischke
Karl
K
Zarse
Markus
M
Gramley
Felix
F
Schimpf
Thomas
T
Plisiene
Jurgita
J
Muehlenbruch
Georg
G
Spuentrup
Elmar
E
Ernst
Sabine
S
Willems
Stephan
S
Kirchhof
Paulus
P
Schauerte
Patrick
P
D000818:Animals; D001331:Automation; D006328:Cardiac Catheterization; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D019561:Echocardiography, Four-Dimensional / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006325:Heart Atria / Q000000981:diagnostic imaging; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012107:Research Design; D012984:Software; D013552:Swine; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*