Dissociation between Anterograde and Retrograde Conduction during Transvenous Cryoablation of Parahissian Accessory Pathways

Ablation of parahissian accessory pathways (APs) is a challenging procedure because of the high risk to provoke “iatrogenic” atrioventricular (AV) nodal block. The feasibility and safety of cryoablation (CA) have been already demonstrated both in patients with AV nodal reentry tachycardia and in those with anteroseptal APs. However, dissociation between anterograde and retrograde conduction after CA has not yet been described. We report two cases of CA of parahissian AP associated with transient dissociation between anterograde and retrograde conduction. (PACE 2011; 34:e98–e101)     

Incidence of Atrial Fibrillation in Patients with Different Mode of Pacing. Long-term Follow-up

We evaluated the incidence of atrial fibrillation in 189 patients (92males, 97females, mean age 75 ± 12yrs, range 41–100yrs) with pacemaker, during a mean follow-up of 5.5yrs (range 1–24yrs). The indications for implant were: complete AV block (115pts), second degree Möbilz 2 AV block (51pts). bifascicular block (5pts). sick sinus syndrome (14pts), symptomatic bradycardia (4pts). The mode of stimulation considered were VVI (105pt), VVI rate responsive (21pts), single lead VDD (43pts), DDD (20pts). The occurrence of retrograde VA conduction in patients with VVI or VVI rate responsive pacing was also evaluated. Atrial fibrillation occurred in 40 pts (21%). The highest incidence was evidenced in patients with sick sinus syndrome (9pts, 64%), and in patients with VVI stimulation (28pts, 27%). On the contrary, the lowest incidence was found in single lead VDD stimulation (4pts, 9%). The patients with dual chamber pacing showed a relatively high incidence of the arrhythmia (5pts, 25%). Atrial fibrillation occurred in 9 out of 32 patients with retrograde VA conduction, and in 22 out of 94 patients without retrograde conduction (28% versus 23%, p=NS). In conclusion, it is confirmed that patients with sick sinus syndrome are at high risk for atrial fibrillation. Single lead VDD stimulation seems to be the better mode of pacing in preventing atrial fibrillation, while dual chamber pacing showed minor efficacy. The presence of retrograde VA conduction could not predict the occurrence of the arrhythmia.     

The influence of HLA-matched sibling donor availability on treatment outcome for patients with AML: an analysis of the AML 8A study of the EORTC Leukaemia Cooperative Group and GIMEMA

To determine whether patients with a HLA-identical sibling donor have a better outcome than patients without a donor, an analysis on the basis of intention-to-treat principles was performed within the framework of the EORTC-GIMEMA randomized phase III AML 8A trial. Patients in complete remission (CR) received one intensive consolidation course. Patients with a histocompatible sibling donor were then allocated allogeneic bone marrow transplantation (alloBMT), the patients without a donor were randomized between autologous BMT (ABMT) and a second intensive consolidation (IC2). 831 patients <46 years old and alive >8 weeks from diagnosis were included. HLA typing was performed in 672 patients. AlloBMT was performed during CR1 in 180 (61%) out of 295 patients with a donor. Another 38 patients were allografted: five in resistant disease, 14 during relapse and 19 in CR2. ABMT was performed in 130 (34%) out of 377 patients without a donor in CR1, in six (2%) patients during relapse and in 38 (10%) patients during CR2. The disease-free survival (DFS) from CR for patients with a donor was significantly longer than for patients without a donor (46% v 33% at 6 years; P = 0.01, RR 0.78, 95% confidence interval 0.63–0.96). The overall survival from diagnosis for patients with a donor was longer, but not statistically significant, than for patients without a donor (48% v 40% at 6 years; logrank P = 0.24). When patients were stratified according to prognostic risk groups, the same trend in favour of patients with a donor was seen for survival duration and the DFS remained significantly longer for this group of patients.     

Determinants of Efficacy of Atrial Pacing in Preventing Atrial Fibrillation Recurrences

Atrial Pacing in Atrial Fibrillation. Introduction: Several studies have shown that single or dual site atrial pacing is effective in reducing he frequency of recurrent atrial fibrillation (AF) in selected patients. However, it is still unclear what the best predictors are of long-term efficacy of atrial pacing. Methods and Results: Forty-seven patients with paroxysmal AF requiring demand pacing underwent electrophysiologic study and dual chamber pacemaker implant. After 4 months of follow-up, patients were divided into two groups according to the presence (group 1) or absence (group 2) of symptomatic AF recurrences. Atrial pacing markedly reduced AF recurrences in all patients. Twenty-four patients were free of arrhythmia. The basal state conduction times (CT_s) and the incremental conduction times (ICT_s), during programmed electric stimulation between the high right atrium (HRA) and the coronary sinus ostium (CS_os) but not between the HRA and the His-bundle region, were significantly longer in group 1. There was no statistical difference in the effective refractory period (ERP) recorded at the HRA, the low right atrium (LRA), and the CS_s between the two groups, whereas the differences between the greatest and least recorded ERPs measured from the HRA, LRA, and CS_os (δERP) were significantly greater in group 1 patients. Two parameters were selected by discriminant multivariate analysis, namely δCT_os (ICT-CT between HRA and CS_os and δERP. The first bad a greater relative importance in predicting AF recurrence (r²= 0.33 and r²= O.1, respectively). Conclusion: Single site atrial pacing is effective in reducing AF recurrences, with decreasing efficacy in patients with greater right atrial conduction delay and wider refractoriness dispersion.     

A case of optic atrophy possibly induced by quinoline in acrodermatitis enteropathica

A 2-year-old girl with acrodermatitis enteropathica, developed optic atrophy during quinoline treatment (600 mg/day, later gradually increased to 1700 mg/day; a total dose of 280 g was given). The optic atrophy developed rapidly 9 months after the start of the quinoline treatment. The right eye was blinded and developed a convergent strabismus. Eight months after the quinoline had been stopped, the left eye began a slow and partial recovery of vision with an improvement in the appearance of the optic disc.