We thank Junming Yan, consultant of Johnson&#38;Johnoson, who is responsible for research grants.This work was funded by the Jilin Provincial Department of Science and Technology (20220402076GH).

This research procedure closely adhered to the rules of human research ethics committee of China-Japan Union Hospital of Jilin University. Patients who underwent radiofrequency ablation of atrial fibrillation were searched on the Carto system (3D mapping system). Then, the PACS system was used to determine whether the patient underwent left atrial CT examination before surgery to ascertain that each selected patient had left atrial CT images for comparison. Soundstar is the ICE catheter used in this study, and a Cartosound module is available in the 3D mapping system. Each patient provided written informed consent before ICE 3D modeling.
1. Preparation before scanning
<ol>
	<li>Check patient information, such as accurate heart rate, rhythm, blood pressure, and oxygen saturation. Let the patient be supine with the arms on both sides and the thighs slightly abducted.</li>
	<li>Provide deep conscious sedation with fentanyl (200 &#181;g/mL) to all patients throughout the procedure. Select the right femoral vein as the puncture point, which is disinfected and paved for local anesthesia with 2% lidocaine.</li>
	<li>Set up the ICE catheter: Connect the ICE catheter tail line with the 3D mapping system and an ultrasonic machine. Open the Study interface in the 3D mapping system and select P500 in Connected Machines.</li>
	<li>Place the ICE catheter (Diameter: 10f; ultrasound mode: B-mode) inside the femoral vein. During the pushing process, monitor the ultrasound in real-time to ensure that the catheter is in a safe space.</li>
	<li>Pass the ablation catheter to the right atrium to develop the right atrium and coronary sinus model. Place the coronary sinus electrode by combining it with ICE guidance.</li>
	<li>After the ICE catheter enters the right atrium, ensure that the left atrium and left atrial appendage structure are displayed on the 3D mapping system display screen using the short and long axes of the left atrium while excluding the left atrial thrombus.</li>
	<li>Determine the optimal puncture site under ICE guidance after inserting the atrial septal puncture needle. Then, perform transseptal puncture.
	<ol>
		<li>Use the Home view to confirm that the ICE reached the right atrium. Then the software displays the left PV section. Click Right Bend to demonstrate the inferior vena cava and atrial septum.</li>
		<li>Move the puncture needle sheath to point in the four o&#39;clock direction. Retract the needle sheath to the oval fossa while monitoring ICE, and the &#34;tent sign&#34; is visible.</li>
		<li>Adjust the ICE catheter to reveal the left PV as a &#34;rabbit ear sign.&#34; Under ICE guidance, slowly withdraw the needle sheath to the lower edge of the oval fossa.</li>
		<li>Rotate the puncture needle clockwise to break through the oval fossa. Then, inject heparin saline through the atrial septum puncture needle. 
		&#8203;NOTE: Salt blisters were observed in the LA, indicating successful puncture of the atrial septum.</li>
	</ol>
	</li>
</ol>
2. 3D modeling of the left atrium and pulmonary vein
NOTE: The ICE constructs the left atrium model in two directions.
<ol>
	<li>After pushing the ICE catheter into the femoral vein, pass it through the inferior and superior vena cava and enter the right atrium.</li>
	<li>Push the ultrasound catheter to the middle of the right atrium on the short axis and rotate clockwise. Now, the ultrasound fan points toward the one o&#39;clock (Home view) direction depicting the right atrium and the right ventricle.</li>
	<li>Tighten the Tension Knob to achieve locking tension tuning. Then turn to the Home view and click Antecurvature (A) to fully display the tricuspid annulus. Attach to the tricuspid annulus for gating training and use the end-breath phase modeling.</li>
	<li>From the Home view, turn clockwise to the left atrial anterior wall, leading to the appearance of the left atrial appendage.</li>
	<li>Continue the clockwise turn to the left atrium, leading to the appearance of the left upper and lower pulmonary veins, displayed as a &#34;rabbit ear sign.&#34; Then, turn it clockwise and counterclockwise to precisely gather the image of the left pulmonary veins by identifying the anterior and posterior venus boundaries.</li>
	<li>Continue to turn clockwise to the left atrium, establishing the posterior wall, and in the process, the esophagus appears as the &#34;double track sign.&#34;</li>
	<li>Turn to the left atrium along the clockwise direction to observe the right lower pulmonary vein, displayed as a &#34;3-word sign&#34;. Then, turn it clockwise and counterclockwise to precisely capture the image of the right pulmonary veins by identifying the anterior and posterior boundaries.</li>
	<li>On the long axis, click Palintrope (P) to make the tip of the catheter at the same height as the coronary sinus mouth. This supplements the left atrium model. Adjust Left Bend/Right Bend (L/R) to observe the front wall of the long axis of the left atrium. This image captures the anterior wall of the left atrium.</li>
	<li>Mark the important anatomical locations, including pulmonary vein ostia, left atrial appendage, and other vital sites accordingly (Video 1).</li>
</ol>
3. Image acquisition and measurement of the pulmonary vein area
<ol>
	<li>Left atrial CT
	<ol>
		<li>Open the PACS system by double-clicking the icon. Click on Advanced Query to enter the patient name and inspection item. Click OK to find the image.</li>
		<li>Click on Tune to transfer the image to the vue pacs system (picture archiving and communication system).</li>
		<li>Transfer the 3D volume reconstruction image to the work box and click Export Image to save the left atrial posterior anterior (PA), left later (LL), and right lateral (RL) position images within the folder.</li>
		<li>After returning to the previous program, transfer the left atrial arterial phase enhancement sequence to the work box, and click on the image displayed as 3D.</li>
		<li>Double-click on the 3D image, then click on 3D in the toolbar. Select the Resection Tool to remove the ribs, spine, aorta, and other structures to expose the left atrium and pulmonary vein system.</li>
		<li>Expose the pulmonary vein vestibule. Click on Figure in the toolbar and select Area to calculate the cross-sectional area of the pulmonary vein vestibule.</li>
	</ol>
	</li>
	<li>ICE
	<ol>
		<li>Open the 3D mapping system. Then, click on Review Study and enter the name of the patient. Finally, use Search for Current Patient to identify the image.</li>
		<li>Click on OK to open the work interface.</li>
		<li>Click on Study &#62; Continue Study and select the Model and Channel sequences.</li>
		<li>Click on Capture Preferences, then select Region and adjust the image to &#34;Posterior-anterior&#34;, &#34;Left lateral,&#34; &#34;Right lateral,&#34; &#34;Left anterior oblique (LAO),&#34; and &#34;Right anterior oblique (RAO).&#34;</li>
		<li>Click on Picture, select the photo area, and click OK to save the picture.</li>
		<li>Click on the Map option and select Save Map. Then, use Eraser in the toolbar to remove the left and right pulmonary veins.</li>
		<li>Click on the image, select Area Measurement and measure the area of the pulmonary vein vestibule.</li>
	</ol>
	</li>
</ol>

ICE-Based 3D Remodeling for the Left Atrium and Pulmonary Vein

<ol><li>Xu, Y., Sharma, D., Li, G., Liu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Atrial+remodeling%3A+new+pathophysiological+mechanism+of+atrial+fibrillation%5BTitle%5D)+AND+%22Medical+Hypotheses%22%5BJournal%5D)">Atrial remodeling: new pathophysiological mechanism of atrial fibrillation.</a> Medical Hypotheses. 80 (1), 53-56 (2013).</li>
<li>George, J. C., Varghese, V., Mogtader, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intracardiac+echocardiography%3A+evolving+use+in+interventional+cardiology%5BTitle%5D)+AND+%22Journal+of+Ultrasound+in+Medicine%22%5BJournal%5D)">Intracardiac echocardiography: evolving use in interventional cardiology.</a> Journal of Ultrasound in Medicine. 33 (3), 387-395 (2014).</li>
<li>Jingquan, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intracardiac+echocardiography+Chinese+expert+consensus%5BTitle%5D)+AND+%22Frontiers+in+Cardiovascular+Medicine%22%5BJournal%5D)">Intracardiac echocardiography Chinese expert consensus.</a> Frontiers in Cardiovascular Medicine. 9, 1012731(2022).</li>
<li>Anter, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparison+of+intracardiac+echocardiography+and+transesophageal+echocardiography+for+imaging+of+the+right+and+left+atrial+appendages%5BTitle%5D)+AND+%22Heart+Rhythm%22%5BJournal%5D)">Comparison of intracardiac echocardiography and transesophageal echocardiography for imaging of the right and left atrial appendages.</a> Heart Rhythm. 11 (11), 1890-1897 (2014).</li>
<li>Rossillo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Novel+ICE-guided+registration+strategy+for+integration+of+electroanatomical+mapping+with+three-dimensional+CT%2FMR+images+to+guide+catheter+ablation+of+atrial+fibrillation%5BTitle%5D)+AND+%22Journal+of+Cardiovascular+Electrophysiology%22%5BJournal%5D)">Novel ICE-guided registration strategy for integration of electroanatomical mapping with three-dimensional CT/MR images to guide catheter ablation of atrial fibrillation.</a> Journal of Cardiovascular Electrophysiology. 20 (4), 374-378 (2009).</li>
<li>Okumura, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Three-dimensional+ultrasound+for+image-guided+mapping+and+intervention%3A+methods%2C+quantitative+validation%2C+and+clinical+feasibility+of+a+novel+multimodality+image+mapping+system%5BTitle%5D)+AND+%22Circulation%3A+Arrhythmia+and+Electrophysiology%22%5BJournal%5D)">Three-dimensional ultrasound for image-guided mapping and intervention: methods, quantitative validation, and clinical feasibility of a novel multimodality image mapping system.</a> Circulation: Arrhythmia and Electrophysiology. 1 (2), 110-119 (2008).</li>
<li>Liu, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+evolving+utility+of+intracardiac+echocardiography+in+cardiac+procedures%5BTitle%5D)+AND+%22Journal+of+Atrial+Fibrillation%22%5BJournal%5D)">The evolving utility of intracardiac echocardiography in cardiac procedures.</a> Journal of Atrial Fibrillation. 6 (6), 1055(2014).</li>
<li>Bartel, T., Edris, A., Velik-Salchner, C., Müller, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intracardiac+echocardiography+for+guidance+of+transcatheter+aortic+valve+implantation+under+monitored+sedation%3A+a+solution+to+a+dilemma%5BTitle%5D)+AND+%22European+Heart+Journal.+Cardiovascular+Imaging%22%5BJournal%5D)">Intracardiac echocardiography for guidance of transcatheter aortic valve implantation under monitored sedation: a solution to a dilemma.</a> European Heart Journal. Cardiovascular Imaging. 17 (1), 1-8 (2016).</li>
<li>Haissaguerre, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Spontaneous+initiation+of+atrial+fibrillation+by+ectopic+beats+originating+in+the+pulmonary+veins%5BTitle%5D)+AND+%22New+England+Journal+of+Medicine%22%5BJournal%5D)">Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins.</a> New England Journal of Medicine. 339 (10), 659-666 (1998).</li>
<li>Kaseno, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+impact+of+the+CartoSound%C2%AE+image+directly+acquired+from+the+left+atrium+for+integration+in+atrial+fibrillation+ablation%5BTitle%5D)+AND+%22Journal+of+Interventional+Cardiac+Electrophysiology%22%5BJournal%5D)">The impact of the CartoSound® image directly acquired from the left atrium for integration in atrial fibrillation ablation.</a> Journal of Interventional Cardiac Electrophysiology. 53, 301-308 (2018).</li>
<li>Enriquez, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Use+of+intracardiac+echocardiography+in+interventional+cardiology%3A+working+with+the+anatomy+rather+than+fighting+it%5BTitle%5D)+AND+%22Circulation%22%5BJournal%5D)">Use of intracardiac echocardiography in interventional cardiology: working with the anatomy rather than fighting it.</a> Circulation. 137 (21), 2278-2294 (2018).</li>
</ol>

The authors have no conflicts of interest to declare.

Intracardiac echocardiography (ICE) is a noncontact three-dimensional reconstruction tool. It determines the appropriate ablation plane and reduces the incidence of pulmonary vein stenosis. Moreover, ICE improves the effectiveness of catheter ablation by assessing the distal position of the ablation catheter and its relative association with the anatomical structures. These structures include the left atrium and pulmonary vein and the diameter and morphology of the pulmonary vein.
ICE-guided atrial fibrillation catheter ablation can decrease intraoperative X-ray irradiation, reduce atrial septal puncture time, detect early complications, and provide timely treatment to avoid severe consequences than atrial fibrillation ablation guided by traditional 3D modeling. Compared with transesophageal echocardiography (TEE), ICE identifies left atrial appendage thrombus more accurately with more evident imaging treatment. Thus, ICE may completely replace TEE in determining left atrial appendage thrombus4. During the procedure, ICE can accurately identify the real-time anatomical structure of the left atrium (LA) and pulmonary veins (PVs)5. However, when the ICE catheter is sent, its position should be observed through imaging. Additionally, an appropriate distance should be maintained from the vascular wall to prevent unnecessary damage to the blood vessels. ICE did not elevate the subjective score satisfaction of the atrial septal puncture. This is associated with the experience of atrial septal puncture practitioners. Our surgeons are more experienced, and these practices should be explored in new surgeons.
A detailed understanding of the left atrium anatomy is necessary for safe and effective radiofrequency ablation of atrial fibrillation. Okumura6 et al. observed that the 3-D modeling constructed by CT or MRI possesses different chamber conformations due to changes in the left atrium chamber state during the time interval between CT image acquisition and intervention. Poor CT image quality may further increase inaccuracy at higher heart rates, especially in ventricular imaging. The ICE phased array catheter helps integrate the two-dimensional image within the 3D electroanatomic mapping system, with a more intuitive display of the anatomical relationship and real-time catheter position. Furthermore, the left atrium and pulmonary vein can be obtained without preoperative imaging or through the interval channel7. This helps clinicians map more accurately, quickly, and safely. The essential steps in this method are accurate puncture of the atrial septum and appropriate adjustment of the ultrasound catheter direction to accurately display the left atrium-related structures such as pulmonary veins, left atrial appendage, etc. This study compared the images of ICE and FAM modeling methods, and we observed that the model obtained using ICE fine modeling (3.40 &#177; 0.81) was more refined than the FAM 3D modeling (3.02 &#177; 0.72). The disadvantages of ICE include training requirements, and becoming proficient in its use typically involves a relatively long learning curve8, particularly proficiency in the ICE fine modeling process. There should be specific technical support. Thus, experienced operators are recommended when performing the atrial septal puncture. The left atrial appendage is poorly developed when the ICE catheter is located in the right atrium. However, the left atrial appendage can be displayed when ICE is placed in the coronary sinus. There is a risk of dissection and venous perforation, and ICE is more expensive than IEE.
Haissasaguerre9 et al. observed that most premature atrial contractions causing frequent episodes of atrial fibrillation tend to originate from the pulmonary vein. Contrast agents are required to determine the location of the pulmonary vein orifice in traditional radiofrequency ablation of atrial fibrillation. Direct LA imaging facilitated clear visualization, especially of the left pulmonary veins (LPVs). This could permit better image integration and navigation of the ablation catheter for circumferential pulmonary vein isolation (CPVI)10. When the pulmonary vein vestibule is isolated, real-time imaging and functional monitoring help improve the safety and accuracy of surgery. ICE can determine the number of pulmonary veins, diameter, anatomical variation, and other features11. We observed that the area of the pulmonary vein was associated with CTA in both FAM and ICE images by determining the area of the pulmonary vein vestibule. The linear regression suggested P &#60; 0.05, and the 95% confidence interval bias was narrower in ICE-acquired models than in FAM-acquired models (-238cm2 to 323cm2 Vs. -363cm2 to 386cm2, respectively). ICE is more accurate and less variable because of noncontact modeling. The pressure change during contact may cause atrial deformation in catheter contact modeling, with different pressures for each contact, describing the source of the difference. Fine modeling of pulmonary veins using ICE can lead to CT modeling accuracy, observing the location, area, and degree of ablation in real time, than in FAM modeling and achieving complete pulmonary vein isolation.
At present, ICE is widely used in various catheter interventional operations. ICE provides accurate cardiac anatomy images, decreases radiation exposure, removes the need for general anesthesia3, and enhances patient tolerance. In the future, with the imaging quality of ICE, including 3D and 4D imaging capabilities, improving the resolution and image clarity, shrinking catheter diameter, and gradual price decline, it will widely increase its usage in clinical practice.

Atrial fibrillation (AF) is commonly associated with atrial remodeling, including mechanical remodeling, electrophysiologic remodeling, and structural remodeling1. Structural remodeling will dramatically affect the anatomy of the atrium. Hence, assessing the left atrial anatomy in AF patients is essential for AF ablation procedures and any procedure targeting the left atrium. For the FAM 3D modeling, the 3D modeling of the heart is reconstructed based on the spatial position change of its position corresponding to the fixed magnetic field by continuously displacing the magnetic catheter in the heart. In contrast, ICE 3D modeling integrates the two-dimensional image in the cardiac cavity with the 3D electroanatomic mapping system by positioning the sensor at the head end of the ICE phase array catheter. Thus, the ultrasonic sector represents 3D modeling to demonstrate the anatomical relationship and real-time catheter position.
Based on our clinical experience, intracardiac echocardiography (ICE) can identify the atrial wall boundary and further establish the 3D remodel. However, most ICE usage during AF ablation or 3D remodeling just provides a brief profile of the atria or pulmonary veins. Originally, ICE was applied to guide the interventional closure of atrial septal defect and patent foramen ovale2. ICE can clarify the location and shape of the atrial septal and has been used for various interventional procedures requiring atrial septal puncture3. These include radiofrequency catheter ablation of atrial fibrillation, mitral valve interventional therapy, etc. ICE can precisely identify pulmonary vein boundaries and atrial walls to establish a more detailed 3D model3. It is unclear whether this method could provide operators with a more precise atrial anatomy assessment, especially for the pulmonary vein antrum and transseptal sites. In this study, we compared the left atrium CT image and 3D remodel established using traditional methods and precise ICE procedures to determine additional information.

<table><tbody><tr><td>CARTO V6</td><td>Johnson&amp;amp;Johnson</td><td>6.0.80.45</td><td></td></tr><tr><td>CARTO V7</td><td>Johnson&amp;amp;Johnson</td><td>7.1.80.33</td><td></td></tr><tr><td>PACS system</td><td>Philips(China) Investment Co.,Ltd</td><td>N/A</td><td></td></tr><tr><td>Soundstar</td><td>Johnson&amp;amp;Johnson</td><td>N/A</td><td></td></tr></tbody></table>

three-dimensional modeling of the left atrium and pulmonary veins with a precise intracardiac echocardiography approach

Intracardiac echocardiography (ICE) is a novel tool for estimating cardiac anatomy during pulmonary vein isolation procedures, particularly the left atrium (LA) anatomy and pulmonary vein structures. ICE is widely used to establish a three-dimensional (3D) left atrial structural model during ablation procedures. However, it is unclear whether using ICE in a precise 3D modeling method can provide a more accurate left atrial 3D model and the transseptal approach. This study proposes a protocol to model the left atrium and pulmonary veins with ICE and fast anatomical mapping (FAM) catheter remodeling. It evaluates the accuracy of the models produced using the two methods through observer scoring. We included 50 patients who underwent ICE-based 3D remodeling and 45 who underwent FAM 3D remodeling based on pulmonary vein isolation procedures. The pulmonary vein antrum remodeling is estimated by comparing the antrum area acquired by remodeling and left atrial computed tomography angiography (CTA). The observer scores for the modeling in the ICE and FAM groups were 3.40 &#177; 0.81 and 3.02 &#177; 0.72 (P &#60; 0.05), respectively. The pulmonary vein antrum area obtained using the ICE- and FAM-based methods showed a correlation with the area acquired by left atrium CT. However, the 95% confidence interval bias was narrower in ICE-acquired models than in FAM-acquired models (-238 cm2 to 323 cm2 Vs. -363 cm2 to 386 cm2, respectively) using Bland-Altman analysis. Therefore, precise ICE possesses high accuracy in estimating the left atrial structure, becoming a promising approach for future cardiac structure estimation.

From January 2021 to June 2022, we selected 114 patients who underwent radiofrequency ablation of atrial fibrillation at our hospital. Patients were excluded based on the following criteria: no 3D volume reconstruction image of left atrial CT (n = 11), no transseptal puncture ICE image (n = 4), and incomplete reconstruction of the left atrium and pulmonary vein images (n = 4). Finally, 50 patients with ICE 3D modeling and 45 with FAM 3D modeling as control group was included in this study.
Two professional electrophysiologists analyzed all the 3-D modeling images. We compared the degree of anatomical anastomosis between Carto modeling and left atrial computed tomography angiography imaging. The 3D images of FAM modeling and refined ultrasound modeling (Figure 1) were scored (0 points: completely inconsistent; 5 points: completely consistent). The transseptal puncture position appropriateness (Figure 2) was scored for conventional and refined ultrasound-guided methods (0 points: totally inappropriate, requiring re-puncture; 5 points: Very appropriate). The maximum cross-sectional area of the pulmonary vein vestibule gathered using conventional and refined ultrasound modeling was compared with the maximum cross-sectional area obtained by left atrial CT. The modeling observer scores were 3.40 &#177; 0.81 and 3.02 &#177; 0.72 (P &#60; 0.05) in the ICE and FAM groups, respectively. The observer scores for selecting transseptal puncture sites were 4.62 &#177; 0.73 and 4.29 &#177; 0.97 (P &#60; 0.05) in the ICE and FAM groups, respectively (Figure 3). The pulmonary vein antrum area acquired using the ICE- and FAM-based methods correlates with the area acquired by left atrial CT. However, the 95% confidence interval bias was narrower in ICE-acquired models than in FAM-acquired models using Bland-Altman analysis (-238 cm2 to 323 cm2 Vs. -363 cm2 to 386 cm2, respectively)(Figure 4).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65353/65353fig01.jpg" /> 
Figure 1: 3D modeling images of the left atrium, pulmonary vein, and transseptal puncture. (A-F) Comparison of the 3D modeling of ICE and left atrial CT. (G-L) Comparison of the 3D modeling of FAM and left atrial CT. (PA: Posterior-anterior; LL: Left lateral; RL: Right lateral). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65353/65353fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65353/65353fig02.jpg" /> 
Figure 2: The transseptal puncture positioning maps. (A-C) The ICE-guided transseptal puncture positioning maps; (D-F) The FAM-guided transseptal puncture positioning maps. (LAO: Left anterior oblique; RAO: Right anterior oblique; RL: Right lateral). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65353/65353fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/65353/65353fig03.jpg" /> 
Figure 3: The observer scores for modeling and selecting transseptal puncture sites. (A) The observer scores for modeling in the ICE and FAM groups were 3.40 &#177; 0.81 and 3.02 &#177; 0.72 (P &#60; 0.05), respectively; (B) The observer scores for selecting transseptal puncture sites in the ICE and FAM groups were 4.62 &#177; 0.73 and 4.29 &#177; 0.97 ( P &#60; 0.05), respectively. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65353/65353fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/65353/65353fig04v2.jpg" /> 
Figure 4: Comparison of the two modeling methods for measuring the pulmonary vein area. (A) Linear regression analysis of the pulmonary vein antrum area acquired using the ICE-based method and left atrial CT; (B) Linear regression analysis of the pulmonary vein antrum area obtained by the FAM-based method and left atrial CT; (C) Bland-Altman plots of the ICE-acquired models compared to the left atrial CT. The 95% confidence interval bias was -238 cm2 to 323 cm2; (D) Bland-Altman plots of the FAM-acquired models compared to the left atrial CT. The 95% confidence interval bias was -363 cm2 to 386 cm2. (LPV: Left pulmonary vein; RPV: Right pulmonary vein <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65353/65353fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Video 1: Specific process for marking important anatomical locations. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/65353/MyVideo_1.mp4" target="_blank">Please click here to download this File.</a>

Watch this Scientific Journal Video about Advancements in Intracardiac Echocardiography for Atrial Anatomy Assessment at JoVE.com

Author Spotlight: Advancements in Intracardiac Echocardiography for Atrial Anatomy Assessment 

Accurate intracardiac echocardiography (ICE) shows significant accuracy in estimating the left atrial structure, a prospective and promising cardiac structure estimation method. Here we propose a protocol for three-dimensional modeling of the left atrium and pulmonary veins with ICE and fast anatomical mapping (FAM) catheter remodeling.

Three-Dimensional Modeling of the Left Atrium and Pulmonary Veins with a Precise Intracardiac Echocardiography Approach

Intracardiac echocardiography (ICE) is a novel tool for estimating cardiac anatomy during pulmonary vein isolation procedures, particularly the left ...

three-dimensional-modeling-left-atrium-pulmonary-veins-with-precise

Universidad San Sebastian

Research

JoVE Journal

Medicine

817 Views.  China-Japan Union Hospital of Jilin University. Accurate intracardiac echocardiography (ICE) shows significant accuracy in estimating the left atrial structure, a prospective and promising cardiac structure estimation method. Here we propose a protocol for three-dimensional modeling of the left atrium and pulmonary veins with ICE and fast anatomical mapping (FAM) catheter remodeling.

Video: Author Spotlight: Advancements in Intracardiac Echocardiography for Atrial Anatomy Assessment 

Bronchial Thermoplasty:  A Novel Therapeutic Approach to Severe Asthma

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks. Bronchial thermoplasty is delivered by the Alair System and is performed in three outpatient procedure visits, each scheduled approximately three weeks apart. The first procedure treats the airways of the right lower lobe, the second treats the airways of the left lower lobe and the third and final procedure treats the airways in both upper lobes. After all three procedures are performed the bronchial thermoplasty treatment is complete.
Bronchial thermoplasty is performed during bronchoscopy with the patient under moderate sedation. All accessible airways distal to the mainstem bronchi between 3 and 10 mm in diameter, with the exception of the right middle lobe, are treated under bronchoscopic visualization. Contiguous and non-overlapping activations of the device are used, moving from distal to proximal along the length of the airway, and systematically from airway to airway as described previously. Although conceptually straightforward, the actual execution of bronchial thermoplasty is quite intricate and procedural duration for the treatment of a single lobe is often substantially longer than encountered during routine bronchoscopy. As such, bronchial thermoplasty should be considered a complex interventional bronchoscopy and is intended for the experienced bronchoscopist. Optimal patient management is critical in any such complex and longer duration bronchoscopic procedure. This article discusses the importance of careful patient selection, patient preparation, patient management, procedure duration, postoperative care and follow-up to ensure that bronchial thermoplasty is performed safely.
Bronchial thermoplasty is expected to complement asthma maintenance medications by providing long-lasting asthma control and improving asthma-related quality of life of patients with severe asthma. In addition, bronchial thermoplasty has been demonstrated to reduce severe exacerbations (asthma attacks) emergency rooms visits for respiratory symptoms, and time lost from work, school and other daily activities due to asthma.

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks.

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled ...

Anatomical Reconstructions of the Human Cardiac Venous System using Contrast-computed Tomography of Perfusion-fixed Specimens

A detailed understanding of the complexity and relative variability within the human cardiac venous system is crucial for the development of cardiac devices that require access to these vessels. For example, cardiac venous anatomy is known to be one of the key limitations for the proper delivery of cardiac resynchronization therapy (CRT)1 Therefore, the development of a database of anatomical parameters for human cardiac venous systems can aid in the design of CRT delivery devices to overcome such a limitation. In this research project, the anatomical parameters were obtained from 3D reconstructions of the venous system using contrast-computed tomography (CT) imaging and modeling software (Materialise, Leuven, Belgium). The following parameters were assessed for each vein: arc length, tortuousity, branching angle, distance to the coronary sinus ostium, and vessel diameter.
	CRT is a potential treatment for patients with electromechanical dyssynchrony. Approximately 10-20% of heart failure patients may benefit from CRT2. Electromechanical dyssynchrony implies that parts of the myocardium activate and contract earlier or later than the normal conduction pathway of the heart. In CRT, dyssynchronous areas of the myocardium are treated with electrical stimulation. CRT pacing typically involves pacing leads that stimulate the right atrium (RA), right ventricle (RV), and left ventricle (LV) to produce more resynchronized rhythms. The LV lead is typically implanted within a cardiac vein, with the aim to overlay it within the site of latest myocardial activation. 
	We believe that the models obtained and the analyses thereof will promote the anatomical education for patients, students, clinicians, and medical device designers. The methodologies employed here can also be utilized to study other anatomical features of our human heart specimens, such as the coronary arteries. To further encourage the educational value of this research, we have shared the venous models on our free access website: <a href="http://www.vhlab.umn.edu/atlas" target="_blank">www.vhlab.umn.edu/atlas</a>.

The objective of this research is to recreate and then access the anatomy of the human cardiac venous system using 3D reconstructions generated from contrast-computed tomography scans.

A detailed  understanding of the complexity and relative variability within the human  cardiac venous system is crucial for the development of cardiac ...

Bioengineering

Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice.
Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software.
Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

The following protocol describes the methodology for the acquisition and analysis of echocardiographic images used to obtain the Left Atrial Volume (LAV), Aorta (Ao) diameter, and Pulmonary Artery (PA) diameter in mice. This technique is a non-invasive, non-terminal procedure that allows assessment of the cardiopulmonary function.

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic ...

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk stratification in various cardiac disorders. Recently, 3D echocardiography became available in routine cardiology practice; however, high-quality image acquisition and subsequent analysis have a steep learning curve. The present article aims to guide the reader through a detailed 3D protocol by presenting tips and tricks and also by highlighting the potential pitfalls to facilitate the widespread but technically sound use of this important technique concerning the LV. First and foremost, we show the acquisition of a high-quality 3D dataset with optimal spatial and temporal resolution. Then, we present the analytical steps toward a detailed quantification of the LV by using one of the most widely applied built-in software. We will quantify LV volumes, sphericity, mass and also systolic function by measuring ejection fraction and myocardial deformation (longitudinal and circumferential strain). We will discuss and provide clinical examples about the essential scenarios where the transition from a conventional echocardiographic approach to a 3D-based quantification is highly recommended.

In this article, we provide a step-by-step acquisition and analysis protocol for the volumetric assessment and speckle-tracking analysis of the left ventricle by 3D echocardiography, particularly focusing on practical aspects that maximize the feasibility of this technique.

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk ...

Three-Dimensional Echocardiographic Method for the Visualization and Assessment of Specific Parameters of the Pulmonary Veins

The dimensions of the pulmonary veins are important parameters when planning pulmonary vein isolation (PVI), especially with the cryoballoon ablation technique. Acknowledging the dimensions and anatomical variations of the pulmonary veins (PVs) may improve the outcome of the intervention. Conventional 2D transoesophageal echocardiography can only provide limited data about the dimensions of the PVs; however, 3D echocardiography can further evaluate relevant diameters and areas of the PVs, as well as their spatial relationship to surrounding structures. In previous literature data, parameters influencing the success rate of PVI have already been identified. These are the left lateral ridge, the intervenous ridge, the ostial area of the PVs and the ovality index of the ostium. Proper imaging of the PVs by 3D echocardiography is a technically challenging method. One crucial step is the collection of images. Three individual transducer positions are necessary to visualize the important structures; these are the left lateral ridge, the ostium of the PVs and the intervenous ridge of the left and right PVs. Next, 3D images are acquired and saved as digital loops. These datasets are cropped, which result in the en face views displaying spatial relationships. This step can also be employed to determine the anatomical variations of the PVs. Finally, multiplanar reconstructions are created to measure each individual parameter of the PVs.
Optimal quality and orientation of the acquired images are paramount for the appropriate assessment of PV anatomy. In the present work, we examined the 3D visibility of the PVs and the suitability of the above method in 80 patients. The aim was to provide a detailed outline of the essential steps and potential pitfalls of PV visualization and assessment with 3D echocardiography.

The dimensions of the pulmonary veins (PV) are important parameters when planning pulmonary vein isolation. 2D transoesophageal echocardiography can only provide limited data about the PVs; however, 3D echocardiography can evaluate relevant diameters and areas of the PVs, as well as their spatial relationship to surrounding structures.

The dimensions of the pulmonary veins are important parameters when planning pulmonary vein isolation (PVI), especially with the cryoballoon ablation ...

Morphological and Functional Assessment of the Right Ventricle Using 3D Echocardiography

Traditionally, it was believed that the right side of the heart has a minor role in circulation; however, more and more data suggest that right ventricular (RV) function has strong diagnostic and prognostic power in various cardiovascular disorders. Due to its complex morphology and function, assessment of the RV by conventional two-dimensional echocardiography is limited: the everyday clinical practice usually relies on simple linear dimensions and functional measures. Three-dimensional (3D) echocardiography overcame these limitations by providing volumetric quantification of the RV free of geometrical assumptions. Here, we offer a step-by-step guide to obtain and analyze 3D echocardiographic data of the RV using the leading commercially available software. We will quantify 3D RV volumes and ejection fraction. Several technical aspects may help to improve the quality of RV acquisition and analysis as well, which we present in a practical manner. We review the current opportunities and the limiting factors of this method and also highlight the potential applications of 3D RV assessment in current clinical practice.

Here, we provide a step-by-step acquisition and analysis protocol for the 3D volumetric assessment of the right ventricle, mainly focusing on the practical aspects that maximize the feasibility of this technique.

Traditionally, it was believed that the right side of the heart has a minor role in circulation; however, more and more data suggest that right ...

Echocardiographic Evaluation of Atrial Communications before Transcatheter Closure

Transthoracic (TTE) and transesophageal echocardiography (TEE) is the standard imaging method for atrial septal defect (ASD) and patent foramen ovale (PFO) detection, for patient selection for transcatheter ASD/PFO closure,&#160;for intraoperative guidance and for long-term follow-up. The size, shape, location and the number of the atrial communications schould be determined. The accuracy of PFO detection can be improved by using agitated saline together with maneuvers to transiently increase the right atrial (RA) pressure. The appearance of microbubbles in the left atrium (LA) within 3 cardiac cycles after opacification of the RA is considered positive for the presence of an intracardiac shunt. Three dimensional TEE identifies further septal fenestrations and describes the dynamic morphology of ASD/PFO and atrial septal aneurysm. Follow-up evaluations with TTE is recommended at 1, 6, and 12 months after the procedure, with a subsequent evaluation every year. Previous studies showed an increased incidence of atrial arrhythmias early after device closure. Speckle tracking analysis may help to understand functional left atrial remodeling following percutaneous closure and its impact on atrial arrhythmias.

Transthoracic (TTE) and transesophageal (TEE) echocardiography represent the basic imaging tools for interatrial septum examination. Three dimensional (3D) TEE provides incremental information in the assessment of the interatrial septum. Further advanced echocardiography techniques using speckle tracking echocardiography are applied for sensitive volumetric and functional assessment of the heart chambers.&#160;

Transthoracic (TTE) and transesophageal echocardiography (TEE) is the standard imaging method for atrial septal defect (ASD) and patent foramen ovale ...

Development and Evaluation of 3D-Printed Cardiovascular Phantoms for Interventional Planning and Training

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training physicians&#39; wire-skills as well as improving planning of interventional procedures. The aim of this study was to develop a manufacturing process of patient-specific 3D-printed models for cardiovascular interventions.
To create a 3D-printed elastic phantom, different 3D-printing materials were compared to porcine biological tissues (i.e., aortic tissue) in terms of mechanical characteristics. A fitting material was selected based on comparative tensile tests and specific material thicknesses were defined. Anonymized contrast-enhanced CT-datasets were collected retrospectively. Patient-specific volumetric models were extracted from these datasets and subsequently 3D-printed. A pulsatile flow loop was constructed to simulate the intraluminal blood flow during interventions. Models&#39; suitability for clinical imaging was assessed by x-ray imaging, CT, 4D-MRI and (Doppler) ultrasonography. Contrast medium was used to enhance visibility in x-ray-based imaging. Different catheterization techniques were applied to evaluate the 3D-printed phantoms in physicians&#39; training as well as for pre-interventional therapy planning.
Printed models showed a high printing resolution (~30 &#181;m) and mechanical properties of the chosen material were comparable to physiological biomechanics. Physical and digital models showed high anatomical accuracy when compared to the underlying radiological dataset. Printed models were suitable for ultrasonic imaging as well as standard x-rays. Doppler ultrasonography and 4D-MRI displayed flow patterns and landmark characteristics (i.e., turbulence, wall shear stress) matching native data. In a catheter-based laboratory setting, patient-specific phantoms were easy to catheterize. Therapy planning and training of interventional procedures on challenging anatomies (e.g., congenital heart disease (CHD)) was possible.
Flexible patient-specific cardiovascular phantoms were 3D-printed, and the application of common clinical imaging techniques was possible. This new process is ideal as a training tool for catheter-based (electrophysiological) interventions and can be used in patient-specific therapy planning.

Here we present development of a mock circulation setup for multimodal therapy evaluation, pre-interventional planning, and physician-training on cardiovascular anatomies. With the application of patient-specific tomographic scans, this setup is ideal for therapeutic approaches, training, and education in individualized medicine.

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training ...

The Use of 3D Echocardiography in Surgical Planning of the Mitral Valve in Pediatric Cardiology

Mitral valve disease in pediatric cardiology is complex and can involve a combination of annular, leaflet, chordae tendineae and papillary muscle abnormalities. Transthoracic two-dimensional echocardiography (2DE) remains the primary diagnostic imaging technique utilized in pediatric surgical planning. However, given that the mitral valve is a three-dimensional (3D) structure, the addition of 3D echocardiography (3DE) to better define the mechanisms of stenosis and/or regurgitation is advantageous. Transthoracic 3DE technology has improved with advances in probe technology and ultrasound scanners, producing images with good spatial resolution and adequate temporal resolution. Specifically, the addition of pediatric 3D transducers with higher frequencies and a smaller footprint provides better 3DE imaging in children. Improved efficiency of 3DE acquisition and analysis allow 3D assessment of the mitral valve to be more easily integrated by the sonographer, the cardiologist and the surgeon in mitral valve assessment. This improvement was also made possible by the postprocessing software optimization.
In this method paper, we aim to describe the transthoracic 3DE assessment of the mitral valve in children and its use in the surgical planning of pediatric mitral valve disease. Firstly, the 3DE assessment begins by selecting the correct probe and by obtaining a view of the mitral valve. Then, the appropriate data acquisition method should be selected based on the individual patient. Next, optimization of the data set is critical in order to properly balance spatial and temporal resolution. During live scanning or following acquisition, the data set can be cropped using innovative tools that allow the user to quickly obtain an infinite number of cut planes or volumetric reconstructions. The cardiologist and surgeon can view the mitral valve en face; thus, accurately reconstructing its morphology in order to support medical or surgical planning. Finally, a review of some clinical applications is proposed, showing examples in pediatric mitral valve managements.

3D echocardiography of the mitral valve in pediatric cardiology produces full anatomic reconstructions that contribute to improved surgical management. Here, we outline a protocol for 3D acquisition and post-processing of the mitral valve in pediatric cardiology.

Mitral valve disease in pediatric cardiology is complex and can involve a combination of annular, leaflet, chordae tendineae and papillary muscle ...

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement

The measurements of the right ventricle (RV) and pulmonary artery (PA), for selecting the optimal prosthesis size for transcatheter pulmonary valve replacement (TPVR), vary considerably. Three-dimensional (3D) computed tomography (CT) imaging for device size prediction is insufficient to assess the displacement of the right ventricular outflow tract (RVOT) and PA, which could increase the risk of stent misplacement and paravalvular leak. The aim of this study is to provide a dynamic model to visualize and quantify the anatomy of the RVOT to PA over the entire cardiac cycle by four-dimensional (4D) cardiac CT reconstruction to obtain an accurate quantitative evaluation of the required valve size. In this pilot study, cardiac CT from sheep J was chosen to illustrate the procedures. 3D cardiac CT was imported into 3D reconstruction software to build a 4D sequence which was divided into eleven frames over the cardiac cycle to visualize the deformation of the heart. Diameter, cross-sectional area, and circumference of five imaging planes at the main PA, sinotubular junction, sinus, basal plane of the pulmonary valve (BPV), and RVOT were measured at each frame in 4D straightened models prior to valve implantation to predict the valve size. Meanwhile, dynamic changes in the RV volume were also measured to evaluate right ventricular ejection fraction (RVEF). 3D measurements at the end of the diastole were obtained for comparison with the 4D measurements. In sheep J, 4D CT measurements from the straightened model resulted in the same choice of valve size for TPVR (30 mm) as 3D measurements. The RVEF of sheep J from pre-CT was 62.1 %. In contrast with 3D CT, the straightened 4D reconstruction model not only enabled accurate prediction for valve size selection for TPVR but also provided an ideal virtual reality, thus presenting a promising method for TPVR and the innovation of TPVR devices.

This study assessed a new methodology with a straightened model generated from the four-dimensional cardiac computed tomography sequence to obtain the desired measurements for valve sizing in the application of transcatheter pulmonary valve replacement.

The measurements of the right ventricle (RV) and pulmonary artery (PA), for selecting the optimal prosthesis size for transcatheter pulmonary valve ...