Use of the monoplane intracardiac imaging probe in high-risk infants during congenital heart surgery

Imaging options are limited in high‐risk infants with small or abnormal oropharyngeal anatomy during congenital heart surgery. Methods: All cases in which the monoplane intracardiac echo probe was used for transesophageal intraoperative imaging over a 15‐month period at a single institution were reviewed. Results: Eleven patients underwent intraoperative imaging using the intracardiac probe. Patient weight ranged from 1.96 kg to 4 kg. Adequate images of the anatomy relevant to the surgical repair were obtained in all cases. No adverse events related to probe use occurred. Conclusion: Transesophageal echocardiography using the monoplane intracardiac echo probe provides safe and effective imaging in patients who are not candidates for standard transesophageal echocardiography.     

Full performance of modern echocardiography within the heart: in-vivo feasibility study with a new intracardiac, phased-array ultrasound-tipped catheter.

BACKGROUND: Intracardiac echocardiography with full performance of high-resolution two-dimensional-, M-mode-, colour, pulsed and continuous wave Doppler and Doppler tissue imaging has not been previously demonstrated. AIMS: This first European in-vivo study was designed to determine the utility and feasibility of a new ultrasound-tipped catheter for intravascular and intracardiac echocardiography. METHODS: The miniaturized, multi-modal, multiple-frequency (5-10MHz) transducer tipped 10Fr (3.3mm) catheter was tested in five anaesthetized mongrel dogs linked to a standard echocardiographic platform. The catheter was introduced through an 11 Fr femoral venous sheath into the inferior vena cava and right heart chambers and the pulmonary artery under limited fluoroscopic and catheter ultrasound guidance. RESULTS: Abdominal and thoracic aorta as well as their branches, both ventricles and atrias with their appendices, all valves, pulmonary arteries and all veins could be visualized with excellent quality. All Doppler signals and the determined haemodynamics, global and regional wall motion and Doppler tissue imaging were of high diagnostic quality. Coronary flow reserve could also be determined. CONCLUSIONS: Intracardiac echocardiography is feasible and potentially useful for assessing functional and morphological disorders, and probably for the guidance of interventional procedures as well as monitoring of cardiac function. A new window to the heart has been opened.     

Intracardiac echocardiography to guide closure of atrial septal defects in children less than 15 kilograms.

BACKGROUND: Intracardiac echocardiography (ICE) is increasingly replacing transesophageal echocardiography (TEE) as the primary imaging technique to guide device closure of atrial septal defects (ASD). Owing to the length of the procedure, the use of TEE requires general anesthesia. Investigators have reported the usefulness of ICE in adults and children. However, little is known about the use of ICE in children whose weight is <15 kg. Therefore, this study examines the use of ICE guided secundum ASD closure in children <15 kg. METHODS: Nineteen patients with a median age of 3.1 years (range 1.8-4.8), and median weight of 13.2 kg (range 8.0-14.4) underwent transcatheter occlusion (Amplatzer occluder) of a secundum ASD using ICE guidance. ICE was performed using an Acunav catheter. The ICE catheter (10 F shaft) was introduced into an 11 F sheath in a contralateral femoral vein. Diagnostic as well as periprocedure imaging was obtained. RESULTS: Sixteen patients had single, and three had multiple defects. Median defect size as measured by ICE was 16 mm (range 2.5-25). The median balloon stretched diameter (obtained in eight patients) was 18 mm (range 10-21); the median size of the defect for these eight patients was 15 mm (range of 8-20). Both techniques for measuring the defect correlated well with r = 0.94. The ASD occluder size ranged from 7 to 26 mm with a median of 18 mm. The procedure was successful in 16 patients who had a device implanted and no residual shunt. ASD occlusion was not attempted in two patients due to deficient rims and in one patient, the attempt failed due to left atrial disk prolapse through the ASD. Four patients experienced transient complications during the catheter procedure, including supra ventricular tachycardia, sinus bradycardia, and two with complete heart block (resolving with device removal); all had subsequent successful device placement. No complications were attributed to the use of ICE and specifically, no vascular injury was noted. CONCLUSIONS: Comparable to results with larger patients, ICE provides adequate imaging (preprocedure diagnosis and periprocedure guidance) during device occlusion of secundum ASDs with no significant complications. Thus, ICE can successfully be used in the closure of ASD in smaller patients (<15 kg) and eliminate the need for endotracheal intubation.     

Unusual interatrial fistula discovered during device closure of an atrial septal defect

Atrial septal defect (ASD) closure is a common reason for referral to the cardiac catheterization laboratory. We report a case in which a relatively large Qp:Qs of 1.85:1 was demonstrated in the face of a small secundum ASD. This led to further investigation, ultimately leading to the discovery of an unusual atrial fistula. Rare cases of interatrial tunnels have been described in the literature, however, this is a unique case of a left atrial appendage to right atrial appendage fistula in the setting of a right juxtaposed left atrial appendage.     

Intracardiac versus transesophageal echocardiography to guide transcatheter closure of interatrial communications: Nationwide trend and comparative analysis

Objectives

This study aimed to assess current temporal trends in utilization of ICE versus TEE guided closure of interatrial communications, and to compare periprocedural complications and resource utilization between the two imaging modalities.

Background

While transesophageal echocardiography (TEE) has historically been used to guide percutaneous structural heart interventions, intracardiac echocardiography (ICE) is being increasingly utilized to guide many of these procedures such as closure of interatrial communications.

Methods

Using the Nationwide Inpatient Sample, all patients aged >18 years, who underwent ASD or PFO closure with either ICE or TEE guidance between 2003 and 2014 were included. Comparative analysis of outcomes and resource utilization was performed using a propensity score‐matching model.

Results

ICE guidance for interatrial communication closure increased from 9.7% in 2003 to 50.6% in 2014. In the matched model, the primary endpoint of major adverse cardiovascular events occurred less frequently in the ICE group versus the TEE group (11.1% vs 14.3%, respectively, P = 0.008), mainly driven by less vascular complications in the ICE group (0.5% vs 1.3%, P = 0.045). Length of stay was shorter in the ICE group (3 ± 4 vs 4 ± 4 days, P < 0.0001). Cost was similar in the two groups 18 454 ± 17 035$ in the TEE group vs 18 278 ± 15 780$ in the ICE group (P = 0.75).

Conclusions

Intracardiac echocardiogram utilization to guide closure of interatrial communications has plateaued after a rapid rise throughout the 2000s. When utilized to guide interatrial communication closure procedure, ICE is as safe as TEE and does not increase cost or prolonged hospitalizations.

     

Intracardiac echocardiography with ultrasound probe placed in the upper left pulmonary vein to guide left atrial appendage closure: First description

Intracardiac echocardiography (ICE) has become an effective alternative to trans‐esophageal echocardiography (TEE) as a guidance during interventional procedures for structural heart diseases, allowing to proceed under conscious sedation. To guide percutaneous left atrial appendage (LAA) closure, the ICE probe is usually placed in the right atrium, in the pulmonary artery or in the left atrium (LA); however, the views from the right atrium or the pulmonary artery are often suboptimal, debarring a complete visualization of the LAA and the surrounding structures, whereas the LA location requires trans‐septal puncture, may provoke LA wall mechanical stimulation and is often associated with unstable position of the ICE probe. In our case, after a second trans‐septal puncture, the ICE probe was placed in the upper left pulmonary vein; this was safely performed and provided an optimal imaging of the LAA, comparable to that obtained by TEE, thus warranting an adequate guide during all procedural steps.     

Transvascular and intracardiac two-dimensional echocardiography

Recent developments in transesophageal and catheter-based ultrasound instrumentation have allowed invasive ultrasound imaging. This experimental study presents a new application of invasive ultrasound, transvascular and intracardiac ultrasound imaging. In six pigs, we introduced a 7-mm, 5-MHz esophageal ultrasound probe into both the abdominal aorta and inferior vena cava and explored the imaging potential of this approach. Transvascular imaging from the aorta allowed visualization of the various cardiac structures, the neural canal and interspaces, and peritoneal anatomy. Advancement of the transducer to the level of the aortic valve or into the left ventricle yielded images of the cardiac valves and chambers. With transvascular imaging from the inferior and superior vena cava, the aorta, neural canal, pancreas, and liver were well visualized. Intracardiac imaging from the inferior venae cavae and various regions of the right heart, the left heart structures could be visualized. This in vivo feasibility study demonstrates the potential application of transducer-tipped catheters for transvascular and intracardiac imaging.     

Radiofrequency catheter ablation of ventricular tachycardia guided by intracardiac echocardiography.

AIMS: Ventricular tachycardia (VT) frequently has an anatomical substrate. Identification of areas prone to arrhythmogenicity facilitates radiofrequency catheter ablation (RFCA). Furthermore, direct monitoring of complications potentially increases safety of RFCA. The aim of this study was to evaluate the feasibility of guiding RFCA of VT with intracardiac echocardiography (ICE), in order to improve outcome and procedural safety. METHODS AND RESULTS: Eleven patients (age 59 +/- 15 years) with drug-refractory VT of various etiologies were studied. VT mapping and ablation were performed using standard techniques. ICE was performed with a multifrequency (5-10 MHz) phased-array transducer positioned in the right ventricle. Twenty different VTs were treated (CL 352 +/- 120 ms, 2.0 +/- 0.9 VT per patient). LV a- or dyskinesia was identified in all post-infarct patients. In patients with arrhythmogenic right ventricular dysplasia, right ventricular aneurysms and dyskinesia could be identified. In all patients catheter position and tip-tissue contact could easily be monitored with ICE. Procedural success (non-inducibility of hemodynamically stable VT) was achieved in all patients. Complications did not occur. CONCLUSION: ICE is feasible in guiding RFCA of VT of different etiologies. The use of ICE in adjunction with fluoroscopy and mapping procedures will facilitate treatment of VT and may contribute to the safety of the procedure.     

Use of intracardiac echocardiography for prediction of chronic pulmonary vein stenosis after ablation of atrial fibrillation

INTRODUCTION: Measurements of pulmonary vein (PV) flow with intracardiac echocardiography (ICE) immediately before and after PV isolation may be a useful method for predicting which patients will develop chronic PV stenosis. METHODS AND RESULTS: We assessed preablation and postablation flows in each of the four PVs using a phase-array ICE catheter in 95 patients (mean age 52 +/- 13) undergoing atrial fibrillation ablation. The ostium of each of the PVs was defined using angiography, electrical mapping, and ICE imaging. Ostial electrical isolation of all PVs was achieved using a 4-mm cooled-tip radiofrequency ablation catheter. Change in PV flow, when present, was examined as both an absolute value and as a percentage of the baseline flow. All patients underwent spiral computed tomography (CT) scans of the PVs 3 months after the procedure for detection of stenosis. The average preablation diastolic flows for the left superior, left inferior, right superior, and right inferior veins were 0.56, 0.54, 0.47, and 0.45 m/sec, respectively. These values increased to 0.74, 0.67, 0.58, and 0.59 m/sec postablation (P < 0.001). Of 380 PVs ablated, the CT scans revealed 2 (1%) with severe (>70%) stenosis, 13 (3%) with moderate (51%-70%) stenosis, and 62 (16%) with mild (< or = 50%) stenosis. The r value between flow and stenosis was only 0.09 (P = NS). CONCLUSION: Acute changes in PV flow immediately after ostial PV isolation do not appear to be a strong predictor of chronic PV stenosis.     

Echocardiographic assessment of atrial septal defects

Echocardiography has become the method of choice for the assessment of patients with a known or suspected atrial septal defect. The majority of patients with defects can be identified by this method. In patients with inconclusive transthoracic studies, transesophageal echocardiography is useful for identification or exclusion of a defect. Echocardiography is useful for quantification of left-to-right shunting, identification of associated anomalies, and estimation of pulmonary pressure. Cardiac catheterization can be reserved for patients who require measurement of pulmonary vascular resistance, those who have a significant risk of coronary artery disease, and those with complex congenital heart disease.     

Utility of on‐line three‐dimensional transesophageal echocardiography during percutaneous atrial septal defect closure

Key echocardiographic assessments during percutaneous atrial septal defect (ASD) closure are the maximal defect diameter, the presence or absence of tissue rims, and the spatial relationships between the implanted device and cardiac structures. These assessments drive device selection and may help identify situations that may place a patient at risk for device erosion or other complications. On‐line three‐dimensional (3D) transesophageal echocardiography (TEE) enables the rendering of nearly unlimited tissue planes within an acquired pyramidal‐shaped volume with minimal image post‐processing. We present several cases of percutaneous ASD closure guided by on‐line 3D TEE imaging that highlight the potential advantages of this new imaging technology. © 2009 Wiley‐Liss, Inc.     

Real-time, intracardiac, two-dimensional echocardiography: enhanced depth of field with a low-frequency (12.5 mhz) ultrasound catheter

Advances in catheter-based ultrasound imaging technology allow for a unique opportunity to develop two-dimensional intracardiac echocardiography, an imaging method that could have significant clinical applications. In this study, we evaluated the potential of a new, percutaneous, 9-Fr prototype intracardiac echocardiographic catheter with a 12.5-MHz rotating crystal in 13 dogs. In all dogs, we were able to easily advance the intracardiac echocardiographic catheter into the right and left hearts percutaneously and obtain dynamic images of cardiac structures in various imaging planes. With the intracardiac echocardiographic catheter in the right atrium, the whole chamber could be visualized. Minor manipulation allowed visualization of the right atrium, right ventricle, and tricuspid valve in a two-chamber view; further maneuvering yielded four-chamber views. With advancement of the catheter into the right ventricle and pulmonary artery, the right ventricular cavity, right ventricular outflow tract, and pulmonary artery could be imaged. The intracardiac echocardiographic catheter in the aortic root allowed visualization of the pulmonary artery and its bifurcation, superior portions of the atria, interatrial septum, aortic valve, and the proximal left coronary artery. With the intracardiac echocardiographic catheter in the left ventricle, short-axis images of the whole left ventricle were obtained. Manipulating the catheter tip within the left ventricle, we could visualize the left ventricle, left atrium (LA), and the mitral valve in the long axis. We were also able to visualize and identify experimentally-induced ischemic regional left ventricular dyskinesis (four of of five dogs), aortic valvular tear (five out of five dogs), and pericardial effusion with right atrial collapse (two out of two dogs). Intracardiac echocardiography was not associated with any complications. We conclude that percutaneous, low-frequency intracardiac echocardiography with a 12.5-MHz, 9-Fr catheter yields cardiac images in many imaging planes with a good depth of field, allows identification of valvular, myocardial, and pericardial abnormalities, and has excellent clinical potential in the assessment of many cardiovascular disorders.     

The sensitivity of contrast echocardiography in detecting intracardiac shunts

While contrast echocardiography has been shown to delineate intracardiac shunts, no information is available concerning the sensitivity of the method. This study establishes the relative sensitivity of the technique in detecting and localizing shunts by comparing the contrast echocardiograms with the simultaneously recorded cardiogreen dye curves in 26 children during cardiac catheterization. The echocardiograms substantiated isolated intracardiac shunting as small as 5%. There were no false-positive or false-negative echocardiograms in patients with or without shunt defects. This report demonstrates the contrast echocardiographic technique to be extremely sensitive in detecting intracardiac communications. It reviews the diagnostic patterns necessary for diagnosis and proposes the technique as a sensitive, safe, and accurate alternate method of study in the cardiac catheterization laboratory.     

Transseptal left heart catheterisation guided by intracardiac echocardiography

OBJECTIVE—To develop a novel approach of transseptal puncture guided by intracardiac echocardiography and to assess its efficacy.
METHODS—Transcatheter intracardiac echocardiography with a 9 MHz rotating transducer was performed to guide transseptal puncture in 12 patients (mean age 43.1 years, range 31-68) who underwent radiofrequency catheter ablation of left sided accessory pathways. Initially, the echocardiography and transseptal catheters were placed adjacent to each other in the superior vena cava and were withdrawn to the level of the fossa ovalis.
RESULTS—The successful puncture site was associated with visualisation of the fossa ovalis (12 patients, 100%) and the aorta (12 patients, 100%), tenting of the fossa (six patients, 50%), penetration of the needle visualised by the ultrasound catheter (12 patients, 100 %), and echocardiographic contrast material applied in the left atrium (12 patients, 100%). The characteristic jump of the needle onto the fossa ovalis was observed simultaneously with fluoroscopy and intracardiac ultrasound (12 patients, 100%). All procedures were successful. There were no complications associated with the transseptal procedure.
CONCLUSIONS—Intracardiac echocardiography is feasible to guide transseptal puncture. The optimal puncture site can be assessed by simultaneous detection of the characteristic downward jump of the transseptal needle onto the fossa ovalis by intracardiac ultrasound and fluoroscopy.


Keywords: intracardiac echocardiography; transseptal catheterisation     

Phased-array intracardiac echocardiography during pulmonary vein isolation and linear ablation for atrial fibrillation

INTRODUCTION: Fluoroscopic imaging provides limited anatomic guidance for left atrial structures. The aim of this study was to determine the utility of real-time, phased-array intracardiac echocardiography during radiofrequency ablation for atrial fibrillation. METHODS AND RESULTS: In 29 patients undergoing pulmonary vein isolation (n = 16) or linear (n = 13) left atrial radiofrequency ablation for atrial fibrillation, intracardiac phased-array echocardiography was used to visualize left atrial anatomy and the pulmonary veins, as well as ablation and mapping catheters during ablation procedures. In the 16 pulmonary vein isolation patients, the mean pulmonary vein ostial diameters measured by venography and intracardiac echocardiography were similar for all veins positions, except that left common pulmonary vein diameters were larger as measured by echocardiography (2.50 +/- 0.29 cm) than by venography (1.79 +/- 0.50 cm, P = 0.001). The ostial diameters measured by echocardiography and venography were not correlated, however (r = 0.23, P = 0.19). As directed by echocardiography, only 1 of 25 circular mapping catheters (4%) used in 16 patients was replaced due to inappropriate sizing of the pulmonary veins. Mean pulmonary vein Doppler flow velocities increased after ablation for left-sided veins but ostial diameters were unchanged. In the linear ablation patients, the entire extent of the linear electrode array could be visualized in only 3 of 52 of catheter positions (6%) in the 13 patients. A portion of the catheter could be seen in only 50% of all target catheter positions. CONCLUSION: Phased-array intracardiac echocardiography (1) allows sizing and positioning of pulmonary vein mapping catheters, (2) provides measures of pulmonary vein ostial diameters, (3) continuously monitors pulmonary vein Doppler flow velocities, and (4) has limited use in positioning linear ablation catheters in the left atrium.