Mitral Annulus Dynamics in HOCM: Insights from 3D Transesophageal Echocardiography Before and After Septal Myectomy
Introduction
Hypertrophic obstructive cardiomyopathy (HOCM) is a complex disease where:
👉 Left ventricular outflow tract (LVOT) obstruction
👉 Mitral valve abnormalities
interact to create dynamic hemodynamic changes.
Traditionally, the focus has been on:
- Septal hypertrophy
- Systolic anterior motion (SAM)
However, an often underappreciated component is:
➡️ Mitral annulus dynamics
With 3D transesophageal echocardiography (3D TEE), we can now explore this in detail.
📄 Original Research Article
Read the full study here: https://onlinelibrary.wiley.com/doi/10.1111/echo.70314
🎥 Learn Advanced 3D Mitral Valve Quantification (MVN Tutorial)
To understand how mitral annulus geometry and dynamics are actually measured:
🔒 Available inside CIC advanced courses
🎯 This tutorial covers:
- 3D mitral valve modeling (MVN)
- Annular geometry analysis
- Dynamic tracking across cardiac cycle
- Q-Lab offline analysis
Study Objective
This study aimed to evaluate:
👉 Mitral annulus dynamics in HOCM patients
👉 Impact of septal myectomy on annular geometry and motion
using intraoperative 3D TEE
Study Design
- 📊 26 patients with HOCM
- 🏥 Underwent septal myectomy
- 🔍 Compared:
- Preoperative vs postoperative
- Across full cardiac cycle
📌 Measurements included:
- Annular diameters (AP, AL–PM)
- 3D area & perimeter
- Annulus height
- Aorto-mitral angle
- Saddle shape
👉 As shown in Figure 1 (page 3), these parameters are derived from full 3D annular reconstruction
Key Findings
🔹 1. Enlarged Mitral Annulus in HOCM
Compared to controls, patients showed:
- Larger AP diameter
- Larger AL–PM diameter
- Increased annular area & perimeter
🔹 2. Loss of Normal Annular Dynamics
Normal physiology:
- Early systolic contraction
- Saddle-shaped deepening
HOCM patients:
- Reduced systolic contraction
- Flattened annulus
- Impaired dynamic motion
🔹 3. No Immediate Improvement After Myectomy
Despite:
👉 Massive LVOT gradient reduction
(≈ 88 → 9 mmHg, highly significant)
❌ No significant change in:
- Annular size
- Annular motion
- Dynamic behavior
📌 Clearly shown across all parameters in Table 3 (page 7)
Understanding the Mechanism
This study provides strong support for:
🧠 Leaflet Drag Theory (Not Venturi)
- Flow pushes leaflets toward septum
- Not suction
🔬 Role of Annulus:
- Enlarged annulus → more leaflet mobility
- Reduced contraction → less stabilization
- Altered geometry → promotes SAM
3D TEE: The Game Changer
Why 3D is essential:
✔️ Full annular geometry
✔️ Dynamic tracking across cardiac cycle
✔️ Quantitative modeling
📌 As demonstrated in Figure 3 (page 8), software allows full dynamic 3D reconstruction with time curves
Clinical Implications
🔹 1. Better Understanding of LVOT Obstruction
Not just septum → also annulus + leaflets
🔹 2. Improved Surgical Planning
- Identify patients needing more than myectomy
- Consider mitral intervention
🔹 3. Postoperative Assessment
- Don’t expect immediate annular normalization
- Follow-up is essential
🔹 4. Future Direction
👉 Predictive modeling of:
- Device interaction
- Surgical outcomes
- Long-term remodeling
From Research to Practice (CIC Approach)
This is where advanced tools like:
- MVN (Mitral Valve Navigation)
- 3D modeling
- Offline analysis
become essential
👉 (explained step-by-step in the lecture above)
🎓 Master Advanced 3D Structural Echo
If you want to master:
- Mitral annulus dynamics
- HOCM imaging
- MVN modeling
- Structural echo decision-making
👉 Explore CIC Online Echocardiography Courses
🔗 https://ciceg.net/cic-courses/
✔️ Advanced 3D imaging
✔️ Real surgical cases
✔️ Software-based training
✔️ Designed for cardiologists worldwide
Conclusion
This study demonstrates that:
👉 Mitral annulus is a key player in HOCM pathophysiology
Key messages:
- Annulus is enlarged and dysfunctional
- Dynamics are impaired
- Myectomy improves gradient but NOT annular function immediately
➡️ This shifts our understanding from:
“Septum-only disease” → “Integrated valve–ventricle disease”
