Table 3.
Parameters evaluated during active electrical pacing (CRT-ON) and temporary deactivation (CRT-OFF) expressed as average ± standard deviation, and significance (P-value) of statistical comparison by a two-tailed paired Student t-test (significance level P = 0.01)
| CRT-ON | CRT-OFF | P | |
|---|---|---|---|
| Heart rate (bpm) | 61.4 ± 7.2 | 60.5 ± 9.7 | NS |
| Ejection fraction (%) | 39.2 ± 12 | 37.7 ± 11 | NS |
| End-diastolic volume (mL) | 151.7 ± 94 | 161.5 ± 96 | NS |
| End-systolic volume (mL) | 101.8 ± 99 | 106.7 ± 86 | NS |
| Mitral E/Vp ratio | 1.78 ± 0.7 | 1.83 ± 0.7 | NS |
| Mitral E/A ratio | 0.90 ± 0.37 | 0.82 ± 0.28 | NS |
| Mitral E deceleration time (ms) | 215.1 ± 58 | 202 ± 54 | NS |
| VTI mitral inflow (m) | 0.227 ± 0.18 | 0.182 ± 0.03 | NS |
| Diastolic filling time (ms) | 546.9 ± 102 | 517.5 ± 158 | NS |
| VTI aorta outflow (m) | 0.24 ± 0.05 | 0.24 ± 0.06 | NS |
| Systolic ejection time (ms) | 302.1 ± 33 | 301.6 ± 36 | NS |
| E/e′ (septal) | 9.7 ± 2.1 | 10.0 ± 2.0 | NS |
| E/e′ (lateral) | 8.7 ± 3.5 | 9.1 ± 3.2 | NS |
| GLS (%) | −12 ± 3 | −12 ± 3 | NS |
| SDTTS (ms) | 145 ± 40 | 175 ± 43 | 0.001 |
| Flow momentum orientation φ (°) | 34.7 ± 6.5 | 43.3 ± 6.1 | 0.0001 |
| Flow energy dissipation (−) | 0.432 ± 0.47 | 0.346 ± 0.14 | NS |
E, mitral flow E wave peak velocity, evaluated by PW Doppler; Vp, mitral flow propagation velocity assessed by color M-Mode Doppler; A, mitral flow A wave peak velocity, evaluated by PW Doppler; VTI, velocity time integral; GLS, global longitudinal strain; SDTTS, standard deviation of time to peak of transverse strain.