No abstract

Scanu et al., in their letter to the editor, describe a patient with an implanted minute ventilation rate responsive pacemaker (Telectronics Meta) functioning at an upper rate during Cheyne-Stokes respiration.' They have incorrectly described this as an "inappropriate rate response of the minute ventilation rate responsive pacemaker." In fact, and as they admit in their letter, the problem was one of inappropriate programming of the pacemaker. A slope value of 40 is almost never indicated in clinical practice, and will naturally lead to a rapid increase in pacing rate to the upper rate setting with minimal changes in minute ventilation, let alone the marked variations seen in Cheyne-Stokes respiration. In our experience,^ slope values in the range of 15-24 are appropriate for almost all patients. The occasional patient with a barrel chest due to chronic airways obstruction will require a higher slope value up to 30, but we have never seen or heard of a patient requiring a slope value of 40 for appropriate rate response function.The shorter time constant (1 minute] of the pacemaker's minute ventilation averaging process is too long to allow a faithful rate response in most patients with Cheyne-Stokes respiration, but even in this situation an appropriate slope value should result in a least a partial rate response in such patients. The key to correct function of the Meta MV pacemaker is optimal selection of the slope value which is readily determined using the peak exercise measure function during an exercise test.Subclavian vein puncture is used by many physicians as the preferred mode of access to the central circulation. When carried out by experienced operators it is generally a safe procedure,' but new complications continue.^ Surprisingly, there is no report of direct damage to the thoracic duct even though it enters the left subclavian vein close to the desired puncture site. One report, however, does describe chylothorax following right subclavian puncture; the authors suggesting that this complication arose due to an anatomical variant.^ We describe a patient admitted for permanent pacemaker insertion in whom laceration of the thoracic duct following left subclavian vein puncture resulted in a fatal outcome.A 79-year-old female with complete heart block underwent permanent pacemaker insertion. The left cephalic vein was small and friable and therefore, using an infraclavicular approach, the left subclavian vein was entered without difficulty using a 7-cm 14G needle. A Seldinger wire and a size 10 Fr Teflon peel away introducer sheath were then introduced. The pacing lead was advanced to the right ventricular apex and the pacemaker generator located in the left infraclavicular pouch. The patient made an uneventful recovery and was discharged home. Ten days following the procedure, she was readmitted with swelling over the generator site and a chylous discharge from the wound. A temporary pacing wire was inserted via the right internal jugular vein and the left-sided system was removed. Under general anesth...