Just How Stable Are Escape Rhythms after Atrioventricular Junction Ablation?

Background: Atrioventricular (AV) node ablation with implantation of a permanent pacemaker is an established mode of therapy in the treatment of atrial fibrillation. However, concern exists regarding subsequent dependency on an entirely paced rhythm and the possible sequela of unheralded pacemaker failure. Data regarding escape rhythm lability, an important feature of pacemaker dependency, are limited. Aims and Methods: The purpose of this study was twofold: (1) to determine the characteristics of escape rhythms at predefined serial time intervals following AV node ablation and pacemaker implantation, and (2) to identify risk factors predictive of unstable escape rhythms. Patients undergoing AV node ablation and pacemaker implantation were assessed for the presence or absence of an escape rhythm during pacemaker interrogation at five predetermined serial time points. Baseline demographics and comorbid conditions were evaluated as potential predictors of those with labile escape rhythms. Results : Seventy‐nine percent of the 96 patients studied had an underlying escape rhythm (≥30 beats per minute) immediately postablation. Although the percentage of patients with an escape rhythm increased at each follow‐up interval, the number of patients who consistently demonstrated an escape rhythm declined with each follow‐up, with 28% of patients lacking an escape rhythm at some time point, i.e., labile escape rhythm. There were no significant predictors of a labile escape rhythm. Conclusion: Among patients who have undergone AV node ablation and pacemaker implantation, 72% have a stable escape rhythm over time, but others are at risk for pacemaker dependency, as predicted by an underlying absent or labile escape rhythm. (PACE 2010; 939–944)     

Effects of a problem‐solving counseling program to facilitate intensified walking on Koreans with type 2 diabetes

Aim: This study aimed to evaluate the immediate and long‐term effects of a 12 week problem‐solving (PS) counseling program to facilitate intensified walking with machinery monitoring on persons with type 2 diabetes mellitus in Korea. Methods: The study used a quasi‐experimental design. The participants were 57 patients with diabetes from three endocrinology or internal medicine clinics in an urban city of South Korea. Moderate‐intensity walking and PS counseling were recommended to both groups. The difference between the two groups was whether the intensity of the exercise was monitored by an ambulatory heart rate monitor (experimental group) or was self‐regulated (comparison group). Those programs were evaluated in relation to BMI, glycemic control (blood glucose level, glycosylated hemoglobin [HbA1c]), a vascular complication index (total cholesterol, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, triglycerides, tissue plasminogen activator [t‐PA], plasminogen activator inhibitor‐1 [PAI‐1], Parma Cardiovascular Risk Index), and coping strategies at 3 and 6 months. Results: The experimental group members showed dramatic decreases in their glucose and HbA1c levels at 3 months. The values of t‐PA decreased significantly at baseline, compared to at 3 months. The levels of PAI‐1 continuously declined and the Parma Cardiovascular Risk Index score did not change significantly from baseline to at 3 months, but showed significant effects at 6 months. Conclusion: A combined program of intensified walking, using a heart rate monitor, with PS counseling is more helpful to prevent complications than self‐regulated exercise for persons with type 2 diabetes in Korea.     

Direct and Telemetered Lead Impedance

Objectives: We undertook this study to determine whether telemetered lead impedance measurements (LIM) can be correlated with direct LIM and to determine the stability of LIM over time when measured directly and via telemetry. Methods: Direct LIM and telemetered LIM were measured in 91 patients; 101 leads during initial implantation and 40 leads during pulse generator replacement. Differences in direct LIM measured during initial implant and pulse generator replacement (direct-direct) were compared in 41 patients (28 atrial leads and 37 ventricular leads). The stability of telemetered LIM obtained immediately postoperatively, at 1 month and 1 year, postimplantation was assessed in 50 patients (23 atrial and 49 ventricular leads). Results: In atrial leads acute direct LIM was 633.9 ± 18.4 Ω versus 575.8 ± 18.5 Ω for telemetered LIM (r = 0.58), and chronic direct LIM was 670.9 ± 49.3 Ω versus 607.0 ± 36.3 Ω for telemetered LIM (r = 0.87). In ventricular leads acute direct LIM was 747.3 ± 16.9 Ω and 684.7 ± 16.4 Ω for telemetered LIM (r = 0.69), and chronic direct LIM was 674.8 ± 29.9 Ω and 625.2 ± 28.5 Ω for telemetered LIM (r = 0.68). The mean direct–direct UM rose 124 Ω (P < 0.001) in atrial leads and 10 Ω (P = NS) in ventricular leads. Telemetered LIM for atrial leads was 581.0 ± 27.6 Ω immediately postimplantation compared to 625.7 ± 34.8 Ω at 1 month and 754.1 ± 43.0 Ω at 1 year. Telemetered LIM for ventricular leads was 661.3 ± 17.5 Ω at implant, 684.6 ± 20.7 Ω at 1 month and 724.7 ± 22.7 Ω at 1 year. Conclusions: There is a good but limited correlation between direct and telemetered LIM. Mean direct LIM obtained at initial implantation is similar to that measured at pulse generator replacement. The telemetered LIM is stable over the first month postimplantation but tends to rise during the first year of follow-up and substantial changes in impedance are not uncommon in individuals with normal function. There is a tendency for LIM to rise with lead maturation. If telemetered LIM is to be followed over time, a baseline telemetered value should be obtained immediately postoperatively.     

Percutaneous Retrieval of Dislodged Left Atrial Appendage Occlusion Devices through the Transseptal Approach

Percutaneous left atrial appendage (LAA) occlusion is a promising treatment option in patients with atrial fibrillation who have a high risk of embolic stroke and are not eligible for chronic oral anticoagulation therapy. This procedure, however, can induce several complications. Device embolization can result in a serious situation, requiring immediate and safe device removal. We report two cases in which dislodged LAA occlusion devices were flitting in the left atrium or entrapped in the mitral valve leaflets and were successfully retrieved through a transseptal approach without complications.     

Calpain‐dependent cleavage of SHP‐1 and SHP‐2 is involved in the dephosphorylation of Jurkat T cells induced by Entamoeba histolytica

Host cell death induced by Entamoeba histolytica is an important mechanism for both host defence and microbial immune evasion during human amoebiasis. However, the signalling pathways underlying cell death induced by E. histolytica are not fully understood. This study investigated the involvement of the protein tyrosine phosphatases (PTPs) SHP‐1 and SHP‐2 in the dephosphorylation associated with E. histolytica‐induced host cell death. Incubation with E. histolytica resulted in a marked decrease in protein tyrosine phosphorylation levels and degradation of SHP‐1 or SHP‐2 in Jurkat cells. Pre‐treatment of cells with a calpain inhibitor, calpeptin, impeded the amoeba‐induced dephosporylation and cleavage of SHP‐1 or SHP‐2. Additionally, inhibition of PTPs with phenylarsine oxide (PAO) attenuated Entamoeba‐induced dephosphorylation and DNA fragmentation in Jurkat T cells. These results suggest that calpain‐dependent cleavage of SHP‐1 and SHP‐2 may contribute to protein tyrosine dephosphorylation in Jurkat T cell death induced by E. histolytica.