Table 1
Recommendations of CRT in sinus rhythm
| RECOMMENDATIONS | Class | Level |
|---|---|---|
| CRT is recommended in patients in sinus rhythm with symptomatic HF, LVEF less than 35%, R-wave width longer than 150 ms and LBBB morphology, despite optimal medical treatment (reduction of symptoms and morbimortality) | I | A |
| CRT must be considered in patients in sinus rhythm, symptomatic HF, LVEF less than 35%, QRS width between 130 and 149 ms with LBBB morphology despite optimal medical treatment (reduction of symptoms and morbimortality) | II a | B |
| CRT is recommended in patients in sinus rhythm with symptomatic HF, LVEF less than 35%, QRS over 150 ms and morphology DIFFERENT than LBBB, despite optimal medical treatment (reduction of symptoms and morbimortality) | II a | B |
| CRT must be considered for patients in sinus rhythm, symptomatic HF, LVEF less than 35%, QRS width between 130 and 149 ms with morphology DIFFERENT than LBBB despite optimal medical treatment (reduction of symptoms and morbimortality) | II b | B |
| Patients with narrow QRS candidates to CRT, AV node ablation | II b | C |
| Patients with AF and HF candidates to CRT when LVEF less than 35% in FC IIII-IV with optimal treatment, QRS width less than 130 ms with a strategy assuring adequate BiV capture (90-95%). AV node ablation could be added with this purpose | II a | B |
| CRT is recommended instead of RV pacing for patients with HFrEF (less than 40%) in any functional class, with indication of ventricular pacing and with high degree AV block, with the purpose of reducing morbidity. This includes patients with AF | I | A |
Figure 1
a and b. a. Left panel: Chart of electrical synchrony evaluation by Synchromax® method. Curves are divided according to the synchrony index value: between 0 and 0.4 are synchronous; between 0.41 and 0.7 are intermediate; and between 0.71 and 1 are dyssynchronous. Note the different curves in each column. b. Right panel: Screen delivered by the device for electrical synchrony evaluation
Figure 2
Online electrical synchrony evaluation by Synchromax ® method in patients with CRT. Post-implant optimization. Different synchrony curves and indexes are evident after V-V interval programming
Figure 3
Synchromax curves in true left bundle branch block (LBBB) (index 1) and pseudo LBBB (index 0.4)
Figure 4
a and b. a. Cross correlation time and amplitude between DII and V6. Parameters evaluated:
- Maximum QRS amplitude correlation
- QRS width correlation 70% amplitude
- Correlation of changes to the peak of the signal.
- QRS duration from spike to last QRS
- Area under QRS V6 with cross-correlation between II and V6 b. Synchrony index.
Table 2
His selective and no selective criteria. CHUNG et al., 2023 HRS, APHRS, LAHRS, guideline on cardiac physiologic pacing
| Baseline | Normal QRS duration | His-Purkinje conduction disease | |
|---|---|---|---|
| With correction | Without correction | ||
| Selective HBP |
|
|
|
| Nonselective HBP |
|
|
|
| Pacing type | Criteria |
|---|---|
| Left ventricular septal pacing |
|
| Left bundle branch area pacing |
|
1† RWPT and LVAT here should be assessed starting from the stimulation artifact rather than from the inferred QRS onset. CT = computerized tomography; HBP = His bundle pacing; LBB = Left bundle branch; LBBB = left bundle branch block; LBBP = Left bundle branch pacing; LBBAP = left bundle branch block area pacing; LV = left ventricle/ventricular; LVAT = Left ventricular activation time; RWPT = R-wave peak time; V6 RWPT = R-wave peak time in lead V6.
Table 3
Left bundle branch capture criteria
| Pacing type | Criteria |
|---|---|
| Left ventricular septal pacing |
|
| Left bundle branch area pacing | 1. Evidence of LV septal pacing added to any of the following left branch capture criteria:
Left bundle capture criteria
|
| Left bundle branch area pacing | 2. Evidence of LV septal pacing added to any of the following left branch capture criteria:
Left bundle capture criteria
|