ICE intracardiac echocardiography , Intruments and catheters ice techniques , ice views , ice application , recent advances in intracardiac echocardiography

1. Intracardiac Echocardiography (ICE)
Dr. Himanshu Rana

2. Background
On the technical basis of IVUS,
• the development of ICE advanced
• to meet the demand for precise catheter placement in EPS interventions
The physics of ICE are the same as for all US applications:
1. Mechanical waves with frequencies >20,000 Hz;
2. Laws of reflection and refraction while crossing borders b/w materials of
different densities &
3. Miniaturized transducers & techniques that create images

4. Advantages over TEE
ICE is a unique imaging modality able to provide
• high-resolution real-time visualization of cardiac structures,
• Continuous monitoring of catheter location within the heart,
• early recognition of procedural complications i.e. PE,thrombus
• excellent patient tolerance,
• Reduction of fluoroscopy time, &
• lack of need for GA or a second operator

5. ICE technologies
Radial or rotational ICE (Boston Scientific):
• single piezoelectric crystal
• 6- to 10-French catheter
• provides cross-sectional images in a 360◦ radial plane perpendicular to
long axis of catheter
• Imaging frequencies of 9 to 12 MHz,
• near-field imaging of up to 6 to 8 cm but limited for far-field imaging.
Phased-array ICE (Linear-EPMedSystems & Siemens; Circular- JoMed):
• multiple piezoelectric crystal
• Consists of a 64-element transducer
• 8- or 10-French steerable catheter
• can be deflected in 4 directions (anterior, posterior, right, and left)
• produces a wedge-shaped image displayed on conventional US
workstation

7. Advantages of Phased-array ICE
• greater depth of penetration (up to 15 cm),
• greater maneuverability, &
• ability to acquire Doppler and color flow imaging.
Because of these advantages, phased-array ICE is preferred in the majority
of interventional cardiology procedures.

8. Procedure
• An 11 Fr sheath is recommended to introduce the 10 Fr ultrasound
catheter which is 90 cm long.
• Passing the catheter from the femoral vein to the heart can be easily
performed without fluoroscopy by the experienced operator.
• Biplane fluoroscopy is recommended to safely advance the catheter
without a guide wire.
• The basic rule to advance ICE catheter in vascular or cardiac chambers is
– to always maintain an echographic clear space (black) ahead of catheter &
– avoid pushing when an echogenic space (white) is ahead of catheter.
– If an acute angle is observed at the tip of transducer, gentle retroflection
should be applied to maintain a long-axis view of the vein.
– but, if an obtuse angle is ahead of the transducer, anteroflection should be
applied.

9. • The disposable catheter is equipped with a
miniaturised 5 to 10 MHz transducer and can
be navigated through IVC into RA, RV, & the PA.
• The 64-element vector phased-array
transducer permits longitudinal scans and
provides a 90° sector image with tissue
penetration to a depth of up to 15 cm with the
image sector being perpendicular to the long
axis of the catheter
Procedure contd..
• By convention, ICE images are usually displayed with the marker on the
left side of the image sector, meaning the shaft of the catheter is to the
left of the image and the tip of the catheter is on the right.

11. Echocardiographic views
• Although images quite similar to TOE can be obtained, the relatively
“loose” position of the ultrasound probe in the heart may give the
inexperienced operator a feeling of disorientation.
• To overcome this, structured introduction and steering/manipulation of
the ultrasound tipped catheter can ultimately provide orientation,
supported by recognition of the anatomical landmarks.

12. • The catheter is placed in the middle part of the RA, thus visualising the
RA, tricuspid valve, and RV (fig A).
• This view can be used a “basic point of orientation”, from which other
views can be derived.
• Also known as the ‘Home view’.

15. • Counterclockwise rotation with catheter positioned in superior part of RA
provides imaging of the terminal crest
• Whereas clockwise rotation of the catheter from the inferior RA provides a
view of the Eustachian ridge with the tricuspid–caval isthmus (fig B)
• These are important target structures in atrial flutter ablation

16. • Turning catheter around its axis (clockwise fashion as seen from
operator), imaging of aortic valve, RVOT & PA is feasible (fig C).
• Long axis views of both aorta and pulmonary trunks can be imaged in the
same plane, which is not feasible with TOE.

17. • Then the LV is visualized anterior to the most septal portion of the RA,
and the opening of the coronary sinus becomes evident (Fig B).
• In this view, the long axis of the LVOT is identified, & the posterior LV is in
view just below the noncoronary cusp.
• Color Doppler is performed to assess for baseline AS/AR.

18. • By rotating the catheter clockwise
from the low right atrium, a short
axis view of the coronary sinus can
be obtained (fig D).
• while left-to-right movements of
the ICE catheter provide a long axis
view of this structure (fig E​).
• When the catheter is further
rotated, the next important
anatomical structure to be
recognised is the atrial septum
(important for septal puncture)

19. • Additional clockwise rotation allows Visualization of the MV & IAS, with
theleft atrial (LA) appendage anteriorly and the CS posteriorly(FigC )

20. • By counterclockwise movement
of the catheter from this position,
imaging of the left atrium (LA),
mitral valve, and left ventricle (LV)
is performed (fig F).
• By increasing the depth setting of
the catheter with the transducer
directed at the left atrial posterior
wall, imaging of the left and right
pulmonary veins and the lt. atrial
• As is it sometimes difficult to distinguish between the LAA and the left
superior PV, Doppler capacities can be used to differentiate.
appendage (LAA) is performed from the position of the atrial septum
(important for pulmonary vein (PV) ablation).

21. • Finally, by advancing the catheter into the RV, detailed imaging of the LV
can be obtained. Both long and short axis views of the LV can be obtained
(fig G, H).

22. Applications for ICE
Ablation procedures for AF,
• direct visualization of the pulmonary veins, atrial-venal junction & ablation
catheter tip location
• continuous monitoring for RF energy delivery during ablation,
• hemodynamic performance of the myocardium & pericardial space
monitoring
Transseptal puncture procedure
• RA ICE provides clear
visualization of the fossa
ovalis,
• tenting by the trans-septal
catheter &
• presence of saline bubbles in
the LA once penetrated by
the Brocken-brough needle.

23. Applications contd…
Understanding of AVNRT mechanisms by
• confirming the association of a dilated coronary sinus ostium with the
slow pathway.
• It provides realtime visualization of the ablation catheter in relation to a
particular anatomic structure, allowing for continuous assessment of
catheter–tissue contact
• Lesion formation is typically visualized in the tissue as the development
of increased echogenicity during ablation

24. Applications contd…
Optimizing CRT
• to assess LV septal/left free-wall strain rates and aortic flow/velocity
for the evaluation of dys-synchrony &
• During the implant of coronary sinus placed, LV pacing leads to
assess the effects of pacing on ventricular wall motion and
resynchrony efforts.
• To accurately place a RA pacing lead above the fossa ovalis to
shorten the p-wave duration. This cannot reliably be accomplished
using fluoroscopy alone.

25. Applications contd…
Emerging role in others, including
• mitral valvuloplasty,
• transcatheter aortic valve replacement(TAVR), &
• left atrial appendage closure.
Recently, 3D volumetric ICE system has also been developed,
• for greater anatomic information &
• promising role in structural interventions

26. Mitral valvuloplasty
• During the procedure, ICE is used to rule out LAA thrombus, guide
the transseptal catheterization, confirm optimal balloon position,
monitor balloon inflation, and assess the valve before and after
valvuloplasty
• start with the catheter in the mid-RA and rotate axially ≈60 to 70
degrees to the atrial septal long-axis view, often with a small to
moderate amount of anterior flexion.
• From this view, the gradient is measured by continuous wave
Doppler, and the presence of mitral regurgitation is assessed with
color Doppler.

27. Transcatheter aortic valve replacement(TAVR)
• Three standard ICE planes have been defined for guidance during
transcatheter aortic valve replacement:
– longitudinal,
– short axis, and
– transventricular.
• The first is obtained by advancing the transducer to the junction of the
SVC and RA with counterclockwise rotation and anterior flexion of the
catheter. It provides a longitudinal imaging of the LV outflow tract, aortic
valve, aortic root, and sinotubular junction, and it is the main ICE view to
maintain throughout the procedure.
• After deployment of the valve prosthesis, the short-axis view is obtained
with the ICE catheter in the RA, and the tip is tilted by 90 degrees toward
the aortic annulus. This view is particularly useful to check for trans- or
paravalvular leaks using color Doppler.
• The third view is the transventricular long-axis view of the LV, obtained by
advancing the ICE catheter into the RV followed by clockwise rotation. This
view is helpful to confirm adequate wire position prior to predilatation, to
estimate

28. Applications contd…
• One of the critical roles of ICE in interventional cardiology is the early
recognition of procedural complications
• if sudden hypotension develops immediate assessment of the heart with
ICE can rapidly differentiate between the possible causes, and prompt
actions can be taken to minimize the adverse consequences.
Pericardial effusion
• It may be the consequence of perforation of cardiac structures such as
the CS, LAA, or cardiac walls at the time of transseptal puncture or during
catheter manipulation.
• ICE allows detection of pericardial effusion before the occurrence of
hemodynamic changes
• Small pericardial effusions usually are seen first along the inferior RV and
posterior RA.
• Further fluid accumulation expands to the apical region, then to the
anterior region and finally surrounds the heart completely.

29. Applications contd…
• Thrombus formation on sheaths and catheters can also be detected by
ICE, prompting interventions before embolism has taken place.

30. Intracardiac echocardiography (ICE):
key points
• Promising technique to accurately visualise intracardiac structures that
cannot be visualised using only fluoroscopy, without the need for
anaesthesia
• Performed via a percutaneous approach, with an ICE catheter positioned
exclusively in the RA or RV
• Currently, the application has expanded to several percutaneous
procedures. ICE facilitates these procedures by providing online
information of intracardiac structures in relation to catheters, puncture
needles, and devices

31. Key points contd…
• Limitations of phased array ICE are the inability to scan in a
multiplane fashion & high cost of single use catheter
• The implementation of standard views of imaging planes may
further expand the clinical use
• The effect of ICE on fluoroscopy and procedure times needs to be
established.