Atrial fibrillation, flutter & the LA appendage
The atrium that drives the stroke risk: appendage thrombus and smoke, atrial size and function, and the ventricle that tachycardia can damage.
Numbers to remember
- TOE is needed to exclude LA appendage thrombus before cardioversion when anticoagulation has not been adequate [40,182]
- Appendage emptying velocity <20 cm/s and dense spontaneous contrast mark high thromboembolic risk [176]
- Average 5–10 beats for Doppler measurements in AF [2]
Questions echo must answer
- Structural heart disease behind the arrhythmiaValves (rheumatic mitral stenosis), LV function and hypertrophy, LA size [40,182].
- ThrombusThe LA appendage on TOE before cardioversion or ablation [35,176].
- Tachycardia-induced cardiomyopathyReduced EF that improves with rate or rhythm control [182].
- Filling pressureWith the AF-specific diastolic criteria [2].
Acquisition protocol
- TTELA volume index, LV EF, valves, RV.
- TOE: appendageMid-oesophageal views at 0, 45, 90 and 135°; PW emptying velocity at the appendage mouth [35].
- Spontaneous contrastGrade with the gain set appropriately.
- Atrial septumBefore transseptal procedures.
Diagnosis & severity
| Finding | Meaning |
|---|---|
| Thrombus | Echo-dense mass distinct from the pectinate muscles, seen in two planes [176] |
| Dense spontaneous contrast or sludge | High-risk; treat like thrombus for cardioversion decisions |
| Emptying velocity <20 cm/s | Stasis |
| Atrial flutter | Regular mechanical atrial contraction at the flutter rate |
Thresholds that change management
- Appendage thrombus → no cardioversion or ablation; anticoagulate and repeat TOE [40,182].
- Rheumatic mitral stenosis with AF → vitamin K antagonist, not a DOAC [6,182].
- Reduced EF with uncontrolled rate → consider tachycardia-induced cardiomyopathy; reassess after rate/rhythm control [182].
Pitfalls & mimics
- Pectinate muscles are linear and connected to the wall — not thrombus.
- Reverberation from the warfarin ridge can mimic a mass in the appendage.
- Multilobed appendage hides thrombus in one lobe — scan in several planes.
- Surgically ligated appendage may be only partly closed and still a source of thrombus.