This document discusses the role of echocardiography in cardiac resynchronization therapy (CRT). It covers: 1) Using echocardiography pre-CRT implantation to evaluate dyssynchrony and predict response to CRT. Greater dyssynchrony indicates higher likelihood of response. 2) Using echocardiography post-CRT implantation to optimize device settings like atrioventricular delay and interventricular delay to maximize benefits. Methods like measuring aortic velocity time integral are used. 3) A hospital's experience with timing follow-up echocardiography post-implantation and optimization at baseline, 3 months, and every 6 months or as needed. Results showed CRT improved

1. Echo-Based Optimization of
CRT Therapy
嘉義長庚 心臟內科
潘國利

2. The role of echocardiography in CRT
• Pre-CRT implantation
- Dyssynchrony evaluation to predict the CRT responder
- More dyssynchrony, more response
• Post-CRT implantation
- Optimization of dyssynchrony to get benefit from CRT therapy
- 飲食,生活 衛教

3. Pre-CRT implantation
- Dyssynchrony evaluation to predict the CRT responder

4. AV conduction delayLBBB_Eletric dyssynchrony

5. M-mode Color M-mode

6. Intra-ventricular
Color code tissue doppler

7. Septal to posterior wall strain delay > 130 ms

8. Inter-ventricular
Interventricular mechanical delay (IVMD) > 40ms

9. Post-CRT implantation
- Optimization of dyssynchrony to get benefit from CRT therapy
- A-V ; V-V
Atrio-ventricular
Intra-ventricular
Inter-ventricular

10. Optimal AV delay
Completion of the atrial contribution to diastolic filling
LV contraction occurs immediately following mitral valve closure

12. Effect of AV Delay on LV
Diastolic Filling Pattern
Short AV Delay
50 ms
•A-wave truncated
•Less time for filling
•Atrial contraction against
a closed Mitral valve
Long AV Delay
280 ms
•Fused A and E wave
•Less time for filling
•Pre-systolic Mitral
regurgitation
Optimized AV Delay
200 ms
•Max diastolic filling time
•Mitral closure occurs at end of A-
wave

13. 2 AV-optimization methods
Iterative Method
•Easy to perform
•Accurate
Ritter Method
•Confusing
•Limited accuracy for Bi-V
devices
•Often times iterative method
must be employed to get the
“best” setting

14. Step 1: Shorter the programmed AV delay to see truncated A wave
Step 2: Lengthenthe programmed AV delay to no A-wave cutoff
Iterative Method

15. Ritter Method
Step 1: Shorter the programmed AV delay to see truncated A wave
Step 2: Lengthen the programmed AV delay to see E A fusion

17. Diastolic MR (Ishilawa method)
Aim to minimize diastolic MR
Optimal AV delay= Long AV delay-duration ofdiastolic MR

18. V-V Optimization
• Invasive left ventricular dP/dtmax
• Echo base_ LVOT TVI measure
• Echo base_ Doppler/ M-mode guided synchrony
Optimal cardiac output

19. Cardiac Output = Stroke volume x Heart rate
Stroke Volume= LVOT area X
Velocity Time Integral (VTI)
Since LVOT is a constant the
larger VTI the larger stroke
volume
DLVOT
Time (sec)
VTI (cm) = Area under
velocity curve/time
Velocity
cm/sec

20. 18.27 20.71
18.9 18.9
V-V Optimization
Best VTI
22.67

21. M-Mode guided V-V Optimization
T(2) - T(1) = IVMD .546-.488 = 58ms delay
In the InSync III Marquis ICD study
the following methodology was used:
•M-Mode of septal and posterior wall
at the papillary muscle level
•Measure from onset of Q-wave to
peak excursion of both septal and
posterior wall across several different
V-V paced intervals
•Calculate the difference between the 2
segments
•V-V Opt = the setting with the
smallest delay
Peak posterior
excursion
Peak septal
excursion
Electrical
activation
Note: In the study they measured from Q-wave to
the peak of the excursion. In practice, all you
really need to measure is the separation between
the peaks.

22. Device timing optimization
Stroke volume
(Aortic VTI)
Trans-mitral flow
Intra-ventricular synchrony

23. Rev Esp Cardiol. 2012;65(6):504–510
CRT Follow-up

24. Timing of optimization
• Best evidence-based practice is to follow the CARE-HF protocol and
optimize AV delay using iterative methods combined with VV delay at
Baseline ( pre-discharge )
3 months
every 6 months there after

26. 嘉義長庚經驗
Timing of echo optimization
Post-
implantation
3 month *2 Every 6 month
Echo prn F/U and echo-base optimization
Worsen S/S of heart failure

27. 嘉義長庚經驗_CRT改善左心室代償性變化
0
50
100
150
200
Fc
171.1±20.4
130.1±15.8*
0
10
20
30
40
50
EF(%)
25.6±6.9
47.5±19.1*
54
56
58
60
62
64
66
68
LVIDd(mm)
66.4±7.9
59.3±11.9*
0
1
2
3
4
QRS(ms)
3.47±0.5
1.82±0.7*
0
1
2
3
HF Admission
2.4±1.2
0.9±1.4* Pre CRT
Post CRT
* P<0.001

28. CRT No CRT
Number 54 53
Age y) 71.9±8.3 65.1±13.3
Sex (male) 25 (47%) 53 (61%)
LVIDd (mm) 66.4±7.9 61.8±8.9
EF (%) 25.6±6.89 30.43±8.41

29. 謝謝聆聽