Table 4.
Echocardiographic Dyssynchrony Assessment
| Method | Threshold (ms) | Studies | Limitations | Attributes |
|---|---|---|---|---|
| Pulsed-wave Doppler | ||||
| IVMD | >44 | Achilli et al. (21): ↑ LVEF ≥ 5% + NYHA functional class |
Requires stable heart rate intervals Affected by RV function |
Highly reproducible |
| LV filling time/R-R interval |
<40% | Requires nearly parallel interrogation of MV inflow |
Highly reproducible | |
| M-mode echocardiography | ||||
| SPWD | >30 | Pitzalis et al. (22): ↑ LVEF ≥ 5% Marcus et al. (23): not predictive |
Difficult in patients with wall motion abnormalities (prior MI or scar) Cannot differentiate active + passive motion |
High temporal resolution High temporal resolution Easily trained No specialized software required |
| TDI: pulsed wave | ||||
| LVDYS | >102 | Penicka et al. (24): ↑ LVEF ≥ 25% Achilli et al. (21): not predictive |
Cannot differentiate active + passive motion Technically challenging Requires optimal image quality Angle dependent Cannot assess multiple segments Cannot assess multiple segments in 1 view |
High temporal resolution No special probe required |
| TPSV-SD (6 segments) | >31.3 | Jansen et al. (31): ↓ LVESV ≥ 15% | ||
| TOSV-DF | >60 | Soliman et al. (32): not predictive | ||
| Color TDI | ||||
| TPSV-DF (2 segments) | >60–65 | Bax et al. (12): ↓ LVESV ≥ 15% | Cannot differentiate active + passive motion Requires technical expertise |
High temporal resolution Multiple segments may be assessed in 1 view |
| TPSV-DF (6 segments) | >105–110 | Knebel et al. (20): ↓ LVESV ≥ 15% | ||
| SPWD | >130 | Bleeker et al. (33): ↓ LVESV ≥ 10% | ||
| Yu index | >31.4–33 | Yu et al. (25,26): ↓ LVESV ≥ 15% Gorcsan et al. (34): death/transplantation/ LVAD implantation |
||
| TSI | ||||
| TPSV-DF | >65 | Van de Veire et al. (35): ↓ LVESV ≥ 15% + NYHA, 6MWD |
||
| Yu index | >34.4 | Yu et al. (36): ↓ LVESV ≥ 15% | ||
| TDI strain | ||||
| TPSS-DF (radial) | >130 | Dohi et al. (37): ↑ SV ≥ 15% | Highly angle dependent Requires technical expertise Requires optimal image quality |
May differentiate between passive + active motion High temporal resolution |
| TPSS-SD (12 segments) | 60 | Mele et al. (38): ↓ LVESV ≥ 15% | ||
| Speckle tracking | ||||
| SPWD (radial) | >130 | Suffoletto et al. (27): ↑ SV ≥ 15% Gorcsan et al. (34): death/transplantation/LVAD implantation STAR study (28): death/transplantation/LVAD implantation Delgado et al. (29): mortality + HF hospitalization |
Requires optimal image quality with high frame rate Requires technical expertise Speckles must remain in imaging plane |
Angle independent May perform offline analysis on routine images May assess radial, longitudinal, and circumferential strain |
| RT3D echocardiography | ||||
| LVDYS index (16 segments) |
>5.6% | Marsan et al. (30): ↓ LVESV ≥ 15% | Slower frame rates Requires optimal image quality Inability to differentiate active + passive motion Lower temporal + spatial resolution Requires regular rhythm Requires special ultrasound probe |
More complete 3D analysis Angle independent Assess radial, longitudinal, and circumferential contraction Accurate LVEF assessment |
DF = difference; IVMD = interventricular mechanical delay; LV = left ventricular; LVAD = left ventricular assist device; LVDYS = left ventricular dyssynchrony; LVEF = left ventricular ejection fraction; MV = mitral valve; NYHA = New York Heart Association; RT3D = real-time 3-dimensional; RV = right ventricular; SPWD = septal to posterior wall delay; STAR = Speckle Tracking and Resynchronization; 3D = 3-dimensional; TPSS = time to peak systolic strain; TPSV = time to peak systolic velocity; TSI = tissue synchronization imaging; other abbreviations as in Tables 1 and 3.