Survival against the odds: microbiology of root canals associated with post‐treatment disease

Most periapical lesions resolve after root canal treatment of teeth with primary infections. Over the last decade there has been a renewed focus on post‐treatment apical periodontitis and its etiology. This review describes the microbiota associated with persistent post‐treatment infection, including microbial identification, ecology, and environmental selection. Compared with untreated teeth, the infection pattern in root canals with post‐treatment disease shifts to a resistant, mainly Gram‐positive community. The main challenge in root canal re‐treatment is access to the residual apical infection. Elimination of the microbial flora, or a dramatic reduction and sufficient ecological shift to allow host tissue healing, remains the biological goal.     

Outcome of non‐surgical re‐treatment

The purpose of this review was to critically analyze the relevant literature in order to synthesize an overview on the clinical outcomes (radiographically judged periapical healing and tooth survival) following root canal re‐treatment and the factors influencing them. A further aim was to explain the findings on the basis of current knowledge and understanding. The relevant literature was captured and critiqued using the principles of a systematic review. The data were classified into a coherent structure for analyses and presentation but are not presented as a systematic review; rather, the authors have chosen a narrative style to enable integration of the clinical outcomes with relevant findings from laboratory and animal studies. Overall, the outcomes were similar to those for teeth undergoing primary treatment with common factors influencing the outcomes. The major differences between the outcomes of primary and secondary root canal (re‐)treatment reside only in the ability to predictably access and negotiate the root canal system to the (residual) apical infection. The data offer a very favorable prognosis for non‐surgical root canal re‐treatment performed to guideline standards.     

Cryoablation with an 8‐mm Tip Catheter for Pediatric Atrioventricular Nodal Reentrant Tachycardia Is Safe and Efficacious with a Low Incidence of Recurrence

Background: Cryoablation with 4‐ and 6‐mm tip ablation catheters has been demonstrated to be safe and effective in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT) in pediatric patients, albeit with a higher rate of clinical recurrence. Limited information is available regarding efficacy, mid‐term outcomes, and complications related to the use of the 8‐mm Freezor Max Cryoablation catheter (Medtronic, Minneapolis, MN, USA) in pediatric patients. Methods: We performed a retrospective review of all pediatric patients with normal cardiac anatomy who underwent an ablation procedure for treatment of AVNRT using the 8‐mm tip Cryoablation catheter at three large pediatric academic arrhythmia centers. Results: Cryoablation with an 8‐mm tip catheter was performed in 77 patients for treatment of AVNRT (female n = 40 [52%], age 14.8 ± 2.2 years, weight 62.0 ± 13.9 kg). Initial procedural success was achieved in 69 patients (69/76, 91%). Transient second‐ or third‐degree atrioventricular (AV) block was noted in five patients (6.5%). There was no permanent AV block. Of the patients successfully ablated with Cryotherapy, there were two recurrences (2/70, 2.8%) over a follow‐up of 11.6 ± 3.3 months. Conclusion: Cryoablation with an 8‐mm tip ablation catheter is both safe and effective with a low risk of recurrence for the treatment of AVNRT in pediatric patients. (PACE 2010; 33:681–686)     

Early Results of AV Sequential Pacing on Left Ventricular Outflow Obstruction after Senning Procedure

Dual chamber pacing was shown to decrease left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic cardiomyopathy 30 years ago. We report early results of AV sequential pacing from the LV apex in a patient with transposition of the great arteries who is post-Senning procedure. LVOT obstruction resulted from septal deviation and systolic anterior motion of the mitral valve. Pacing was indicated for sinus node dysfunction. AV sequential pacing with a short optimal A V interval of 60 ms demonstrated a 45% reduction in the degree of LVOT obstruction. This article suggests that LVOT obstruction after the Senning procedure can be palliated by asynchronous septal contraction induced by A V sequential pacing, even if the activation is from LV apex, and avoid or postpone surgery in selected situations.