Echocardiographic assessment for Cardiac Resynchronization Therapy

Questions 11–40 continue in the same ultra-high-difficulty NEET-SS style, covering:

• AV & VV optimization methods
• LVOT-VTI–guided programming
• EchoCRT trial traps
• AF-related CRT non-response
• Scar vs dyssynchrony differentiation
• GLS vs EF discordance
• RV dysfunction impact on CRT
• Fusion & pseudo-capture echo clues

A. INDICATIONS & BASELINE ECHO (1–20)

1. Is echocardiography mandatory for CRT indication?
   Yes, to document LVEF ≤35%, but QRS morphology/duration drives indication.
2. Can CRT be offered if EF is 36–40% with severe dyssynchrony?
   No. Echo dyssynchrony does not override EF criteria.
3. Best echo method for EF in CRT workup?
   Biplane Simpson’s method.
4. Does GLS replace EF for CRT eligibility?
   No. GLS is prognostic, not an eligibility criterion.
5. Why does severe LV dilation reduce CRT response?
   Indicates advanced remodeling with limited reversibility.
6. Is RV function relevant before CRT?
   Yes. Severe RV dysfunction predicts poor response.
7. Minimum echo views required pre-CRT?
   PLAX, PSAX, A4C, A2C, LVOT Doppler.
8. Why is EF overestimated in LBBB?
   Dyssynchronous septal motion falsely augments Simpson tracing.
9. Role of contrast echo before CRT?
   Improves EF accuracy in poor windows.
10. Does functional MR support CRT decision?
    Yes, because CRT can reduce functional MR.
11. Does organic MR improve with CRT?
    No. Only functional MR improves.
12. Is LV mass index relevant?
    High LV mass predicts attenuated reverse remodeling.
13. Does restrictive filling contraindicate CRT?
    No, but predicts reduced response.
14. Does pulmonary hypertension affect CRT outcome?
    Yes, especially if RV-driven.
15. Does CRT benefit HFpEF?
    No proven benefit.
16. Is echo useful in narrow QRS HF?
    No. EchoCRT showed harm.
17. Does dyssynchrony exist without LBBB?
    Yes, but response is inferior.
18. Echo sign suggesting advanced myocardial disease?
    Global low strain without regional delay.
19. Role of LV geometry (spherical index)?
    More spherical LV → worse CRT response.
20. Does LV thrombus contraindicate CRT?
    No, but affects imaging and lead planning.

B. MECHANICAL DYSSYNCHRONY (21–40)

21. Is echo dyssynchrony recommended for CRT selection?
    No (PROSPECT).
22. Most predictive dyssynchrony marker today?
    Septal flash and apical rocking.
23. Best view to identify septal flash?
    Parasternal long-axis.
24. What is septal flash physiologically?
    Early inward septal motion due to LBBB.
25. What is apical rocking?
    Side-to-side apical motion from opposing wall timing.
26. Why are these markers superior to TDI delays?
    They are visual, reproducible, and pathophysiologic.
27. Cut-off for SPWMD?

130 ms (historical, low reliability).

28. Why did TDI fail clinically?
    Angle dependence and poor reproducibility.
29. Why is strain timing superior to velocity timing?
    Measures deformation, not motion.
30. Radial vs longitudinal strain for CRT?
    Both useful; longitudinal preferred.
31. Does dyssynchrony predict mortality reduction?
    Indirectly, via remodeling.
32. Why dyssynchrony disappears immediately after CRT?
    Electrical resynchronization precedes remodeling.
33. Can dyssynchrony exist with narrow QRS?
    Yes, but CRT is harmful.
34. Best echo marker of interventricular dyssynchrony?
    RV–LV pre-ejection delay >40 ms.
35. LV pre-ejection period significance?

140 ms suggests LV delay.

36. Does septal flash guarantee response?
    No, but strongly predicts.
37. Dyssynchrony vs scar—key distinction?
    Scar does not correct with pacing.
38. Echo clue of scar-related dyssynchrony?
    Absent strain despite timing delay.
39. Can dyssynchrony recur after CRT?
    Yes, with lead failure or fusion beats.
40. Is dyssynchrony assessment exam-relevant?
    Yes, despite guideline downgrade.

C. LV LEAD TARGETING & SCAR (41–60)

41. Why is LV lead position critical?
    Incorrect position explains many non-responders.
42. Ideal LV lead segment?
    Latest-activated viable myocardium.
43. Most common empirical LV lead site?
    Lateral/posterolateral wall.
44. Why is patient-specific targeting superior?
    Reduces non-response.
45. Best echo tool for lead targeting?
    Speckle-tracking strain.
46. Why avoid apical LV lead placement?
    Worse hemodynamics and response.
47. Echo sign of scarred segment?
    Low amplitude strain + akinesia.
48. How does scar impair CRT?
    Prevents electrical capture and mechanical correction.
49. Role of contrast echo in scar detection?
    Limited; CMR is superior.
50. Can echo replace CMR for scar mapping?
    No, but can suggest viability.
51. Does septal scar reduce CRT benefit?
    Yes, especially in ischemic cardiomyopathy.
52. Is ischemic cardiomyopathy a contraindication?
    No, but response is lower.
53. Echo clue of suboptimal LV lead?
    Persistent septal flash post-CRT.
54. What does worsening MR after CRT suggest?
    Poor lead timing or placement.
55. Does coronary sinus anatomy limit CRT?
    Yes, indirectly affecting echo response.
56. Echo sign of effective LV capture?
    Immediate mechanical synchrony.
57. How soon can echo confirm capture?
    Immediately post-implant.
58. Is LV lead repositioning guided by echo?
    Increasingly yes.
59. Does echo guide His/left bundle pacing?
    Yes, via synchrony assessment.
60. Key exam concept:
    Electrical success ≠ mechanical success.

D. AV & VV OPTIMIZATION (61–75)

61. Is routine echo optimization mandatory?
    No, but useful in non-responders.
62. Best echo method for AV delay optimization?
    Mitral inflow E–A separation.
63. Ideal AV delay produces what pattern?
    Complete E and A without truncation.
64. Echo sign of AV delay too short?
    A-wave truncation.
65. AV delay too long?
    E–A fusion.
66. Preferred parameter for VV optimization?
    LVOT VTI.
67. Why LVOT VTI?
    Direct stroke volume surrogate.
68. Is VV optimization routinely needed today?
    Less so due to device algorithms.
69. Echo clue of fusion beats?
    Beat-to-beat LVOT VTI variability.
70. Why AF complicates optimization?
    Irregular RR intervals.
71. CRT strategy in AF?
    Ensure >95% BiV pacing, often AV node ablation.
72. Echo sign of inadequate BiV pacing?
    Persistent dyssynchrony.
73. Does optimization improve mortality?
    Uncertain; improves hemodynamics.
74. Echo timing vs device timing—conflict?
    Yes, echo reflects mechanical outcome.
75. Exam pearl:
    Optimize filling first, output second.

E. RESPONSE, NON-RESPONSE & TRIALS (76–100)

76. When to assess CRT response on echo?
    3–6 months.
77. Best echo definition of response?
    LVESV reduction ≥15%.
78. Why LVESV over EF?
    Less load-dependent, prognostic.
79. Does EF always increase in responders?
    No.
80. Early echo marker of response?
    Resolution of septal flash.
81. Late marker of response?
    Reverse remodeling.
82. Most powerful prognostic echo change?
    LVESV reduction.
83. What defines a super-responder?
    Near normalization of EF and LV size.
84. Most common cause of non-response?
    Suboptimal lead position.
85. Pseudo-non-response means?
    Technical issues, not biology.
86. Echo clue of lead dislodgement?
    Reappearance of dyssynchrony.
87. Does MR reduction predict survival?
    Yes, indirectly.
88. Does RV function improve after CRT?
    Sometimes, via LV unloading.
89. Trial proving echo dyssynchrony unreliable?
    PROSPECT.
90. Trial showing harm in narrow QRS?
    EchoCRT.
91. Trial linking remodeling to outcome?
    MADIT-CRT, REVERSE.
92. Is CRT beneficial without remodeling?
    Rarely.
93. Echo clue of irreversible cardiomyopathy?
    No strain reserve anywhere.
94. Does CRT reduce arrhythmias?
    Indirectly, via remodeling.
95. Echo vs ECG—who wins for selection?
    ECG.
96. Echo vs ECG—who wins for response assessment?
    Echo.
97. Key teaching point:
    CRT is a mechanical therapy for an electrical disease.
98. Why echo remains essential despite guideline limits?
    Explains success or failure.
99. Single most exam-relevant echo parameter post-CRT?
    LVESV.
100. Ultimate echo goal of CRT?
     Reverse LV remodeling and synchrony restoration.

If you want next:

• These 100 FAQs converted into WordPress accordion
• Ultra-hard case-based CRT echo vignettes
• One-liners (100) for last-week revision
• Another PNG: “Responders vs Non-responders on Echo”

Just say the word.

table

Below is a high-yield, exam-oriented TABLE on Echocardiographic Assessment in Cardiac Resynchronization Therapy (CRT), condensed from the advanced FAQs and structured for rapid revision, viva, and NEET-SS/DM cardiology exams.

ECHOCARDIOGRAPHY IN CRT — MASTER TABLE

ULTIMATE EXAM TAKE-HOME

• CRT is an electrical therapy assessed mechanically
• ECG selects, echo validates
• LVESV reduction > EF improvement
• Septal flash + apical rocking = modern dyssynchrony markers