Implantation of Lumenless Pacing Leads at the Inter-atrial Septum and Right Ventricular Outflow Tract with Deflectable Catheter-sheath

Current permanent right ventricular and right atrial endocardial pacing leads are implanted utilizing a central lumen stylet. Right ventricular apex pacing initiates an abnormal asynchronous electrical activation pattern, which results in asynchronous ventricular contraction and relaxation. When pacing from right atrial appendage, the conduction time between two atria will be prolonged, which results in heterogeneity for both depolarization and repolarization. Six patients with Class Ⅰ indication for permanent pacing were implanted with either single chamber or dual chamber pacemaker. The SelectSecure 3830 4-French （Fr） lumenless lead and the SelectSite C304 8.5-Fr steerable catheter-sheath （Medtronic Inc., USA） were used. Pre-selected pacing sites included inter-atrial septum and right ventricular outflow tract, which were defined by ECG and fluoroscopic criteria. All the implanting procedures were successful without complication. Testing results （mean atrial pacing threshold： 0.87 V; mean P wave amplitude： 2.28 mV; mean ventricular pacing threshold： 0.53V; mean R wave amplitude： 8.75 mV） were satisfactory. It is concluded that implantation of a 4-Fr lumenless pacing lead by using a streerable catheter-sheath to achieve inter-atrial septum or right ventricular outflow tract pacing is safe and feasible.

Complications and Costs Associated with Initiation of Anti-coagulation Therapy Using Warfarin--An Observation Study

To evaluate the safety and cost of anticoagulation therapy in patients newly initiated on warfarin in two institutions in Singapore. All patients newly started on warfarin between December 2011 and May 2012 were recruited and followed up for a period of 6 months. All hospitalization attributed to complications of warfarin therapy, number of INR （international normalized ratio） greater than 4 and total cost of warfarin therapy were collected and analysed. A total of 321 patients were newly initiated on warfarin for standard indications were recruited. At the end of 6 month period, 8.4% of patients were hospitalized for complication related to warfarin therapy. For patients who had stable INR while on warfarin, this rate was almost 2 times lower （3.8% vs 8.4%）. In our study group, patients started on warfarin as inpatients had higher rates of bleeding （15.1% vs 6.7%） and more 1NRs greater than 4 （0.7 per patient vs 0.11 per patient）. The cost of initating warfarin was USD660 over the first 6 months of therapy. Patients newly initiated on warfarin were at a heightened risk of bleeding complications as compared to patients already stable on warfarin therapy. This also translates to considerable costs of warfarin initiation.