| BACKGROUND:Cardiac resynchronization therapy (CRT), Automated Implantable Cardioverter Defibrillator (AICD) and left ventricular assist device (LVAD) were the three common devices that benefits patients with advanced heart failure. The role of atrioventricular nodal (AVN) ablation in improving CRT outcomes, including survival benefit in CRT recipients with atrial fibrillation, as well as the combined effects of LVAD and AICD therapy were uncertain.OBJECTIVE:The purpose of this study was to determine the impact of AVN ablation on clinical and survival outcomes in a large atrial fibrillation and heart failure population that met the current indication for CRT and to determine whether AVN ablation is an independent predictor of survival in CRT recipients. Also, the second purpose was to determine the effect of AICD implantation on outcomes in patients with end-stage heart failure who have undergone LVAD placement. METHODS:Of 154 patients with atrial fibrillation who received CRT-D,45 (29%) underwent AVN ablation, whereas 109 (71%) received drug therapy for rate control during CRT. On the other hand,51 patients who underwent LVAD implantation were the study population in the second part of our study. Clinical data were assessed, and survival data were obtained from the national death and location database, respectively, in these two parts.RESULTS:CRT comparably improved left ventricular ejection fraction (8.1%±10.7% vs 6.8%±9.6%, P=0.49) and left ventricular end-diastolic diameter(-2.1±5.9 mm vs-2.1±6.7 mm, P= 0.74) in both+AVN-ABL and-AVN-ABL groups. Improvement in NYHA class was significantly greater in the+AVN-ABL group than in-AVN-ABL group (-0.7±0.8 vs-0.4±0.8, P=0.04). Survival estimates at 2 years were 96.0% (95%confidence interval [CI] 88.6%-100%) for+AVN-ABL group and 76.5%(95% CI 68.1%-85.8%) for-AVN-ABL group (P= 0.008). AVN ablation was independently associated with survival benefit from death (hazard ratio [HR] 0.13,95% CI 0.03-0.58, P= 0.007) and from combined death, heart transplant, and left ventricular assist device (HR 0.19,95% CI 0.06-0.62, P= 0.006) after CRT. On the other hand, of 51 patients (age 60±12 years,80% male) receiving LVAD at our center during the study period,36 got ICD before LVAD implantation. Compared to those who did not receive an AICD pre-LVAD implantation (no-ICD group), the AICD group had a higher prevalence of hypertension (39% vs 0%, p=0.005), hyperlipidemia (72% vs 33%, p=0.01), psychiatric diseases (43% vs 0%, p=0.002), and digoxin therapy (64% vs 33%, p=0.046) in keeping with a more chronic disease course. In paired analyses, improvement in RV enlargement was greater in the AICD group than the no-ICD group after LVAD) (-0.19±0.85 vs 1.14±1.07, p= 0.007). Overall survival after LVAD was more favorable in ICD group than no-ICD group (p=0.033). Cox proportional analysis revealed smoking (RR=0.287, p=0.029), AST level (RR=1.007, p=0.004), LVEF (RR= 1.042, p=0.031) and LV end diastolic diameter (RR=0.972, p=0.044), mitral valve A velocity (RR=13.267, p=0.050), tricuspid regurgitation velocity (RR=0.317, p=0.023) and its maximum instant gradient (RR=0.932, p=0.006) to be predictors of survival independent of AICD implantation.CONCLUSION:1. Among patients with atrial fibrillation and heart failure receiving CRT, AVN ablation for definitive biventricular pacing provides greater improvement in NYHA class and survival benefit.2. Overall survival and improvement in right ventricular dimensions were more favorable in patients with ICD in the setting of LVAD. This appeared to be accounted for at least in part by ICD therapies delivered post LVAD implantation.3. Larger-scale randomized trials are needed to assess the clinical and survival outcomes of these therapy. |
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