Background                                                                                                                  

Cardiac resynchronization therapy (CRT) reduces mortality in patients (pts) with systolic heart failure and left bundle branch block. Most effective mortality reduction was seen with a biventricular (BiV) pacing above 98%.

Objective

Reduced BiV pacing is a common and challenging problem of heterogeneous causes. The present real-life data evaluate the effectiveness of measures taken in routine practice to increase BiV pacing.

Methods

Data of consecutive pts with reduced BiV pacing was analyzed. Non-invasive (intensified medical therapy, device re-programming) or interventional (cardioversion, ablation) measures were taken to optimize BiV pacing. The impact on BiV pacing was assessed by consecutive routine follow-up (FU) visits.

Results

In 123 pts (73±10 years, 84% male, LVEF 29±5%) the baseline BiV pacing was 85±13%. FU was 6±5 months. The most common assumed cause was AF in 49/123 pts (40%), PVC in 45/123 pts (36%), VT in 14/123 pts (11%), suboptimal programming in 10/123 pts (8%) and other reasons in 5/123 pts (5%). Overall, an increase of 12% (range -2% to +79%) with a BiV pacing of 97.6±2.1% after intervention was achieved. In 75 pts (61%) a BV pacing ≥98% and in 41 pts (33%) ≥99% was achieved.

Non-invasive measures to increase BiV pacing were intensified medical therapy in 58/123 pts (47%) and exclusive device reprogramming in 10/123 pts (8%). Interventional measures were taken in 55/123 pts (44%); 6 pts AF Ablation, 17 pts AV-node ablation, 17 pts PVC ablation and 14 pts VT ablation, 1 pt slow-pathway ablation). More non-invasive measures were taken (55% vs. 45%; p=<0.001). Invasive approaches in general were significantly more effective to increase BiV pacing (16.9±7.3% vs. 7.8±3.4%; p=<0.001) than non-invasive means alone.

PVC ablation achieved a significantly better improvement in BiV pacing than intensified beta-blocker therapy (12.7±11.5% vs. 4.1±3.7%; p=<0.001).

Furthermore, a subgroup analysis of AF pts revealed a higher increase of BiV pacing after AV-node ablation compared to medical rate (25.8±18.9% vs. 11.6±9.7%; p=0.006) or rhythm control (25.8±18.9% vs. 7.1±3.7%; p=0.002).

Conclusion

Clinical routine methods are effective to achieve satisfactory BiV pacing. Non-invasive methods alone can be applied but close clinical follow-up is crucial. Interventional measures are significantly more effective and should therefore be considered early for all subsets of pts.