What is DOT-CRT ❓
LOT-CRT patients were subclassified into “successful LOT-CRT” (LBBAP; presence of r’ in electrode electrocardiography [ECG] V1) and “deep septal optimized therapy” (DOT-CRT) (functional deep septal capture).
Understanding LV Diastolic Dysfunction via Mitral Inflow Doppler:
Mitral inflow Doppler patterns reflect LV diastolic function. Pulsed-wave Doppler at the mitral valve leaflets shows E (early filling) and A (atrial contraction) waves.
Here’s how the patterns change:
1️⃣ Normal Filling:
- E/A >1
- Deceleration Time (DT) <220 ms
- Normal relaxation and compliance.
2️⃣ Grade I – Mild Dysfunction (Impaired Relaxation):
- E/A <1
- DT >220 ms
- Relaxation is delayed, atrial kick becomes dominant.
3️⃣ Grade II – Moderate Dysfunction (Pseudonormal):
- E/A >1 (appears normal!)
- DT 150–200 ms
- LA pressure increases to "normalize" filling—requires Tissue Doppler to unmask.
4️⃣Grade III – Severe Dysfunction (Restrictive Pattern):
- E/A >1.5
- DT <150 ms
- Very high LA pressures, stiff LV—hallmark of poor prognosis.
⚠️Always correlate with tissue Doppler (E/e’), LA size, pulmonary vein flow, and clinical picture. A pseudonormal pattern can be misleading without these.
Ref:
Ho CY, Bulwer BE. In: Solomon SD, Bulwer BE. Essential Echocardiography. Humana Press, 2007:124.
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🫀 #CardioNugget
The “Lobster Claw” Sign 🦞 in HOCM
In HOCM, the LV outflow tract is narrowed mid-systole due to systolic anterior motion (SAM) of the mitral valve + septal hypertrophy.
📉 This leads to a bimodal LV ejection velocity pattern on Doppler—initial acceleration, followed by a mid-systolic drop (from dynamic obstruction), then a late rise.
🎯 The result? A “lobster claw” or “spike and dome” contour—diagnostic of dynamic obstruction!
🧠 Pro tip: Seen best with continuous wave Doppler across the LVOT. If you see a claw, think obstruction!
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🫀 M-Mode of the Mitral Valve
✅ Normal – smooth AMVL/PMVL movement in diastole
⚠️ SAM – anterior leaflet moves toward septum in systole (think HCM)
⚠️ Prolapse – leaflet bulges back into LA in systole
📍 S = Systole | D = Diastole
📍 AMVL = Ant. leaflet
| PMVL = Post. leaflet