Pacemakers 
					========== 
þ Transvenous Pacer
 - best to do L subclavian (easiest) or R IJ via posterior approach
   (easiest to float given curve of wire); L IJ puts into thoracic duct,
   can rupture if blow up balloon in it.
 - use curve of lead to direct: start with curve pointing down; if using
   L IJ, twist 180 degrees when in about 15 cm 
 - when just out 10-12 cm, blow up balloon
 - rate and mA high, on demand or async
 - float with it ON
 - float until you get a capture (looks like PVC)
 - don't push too fast
 - if in to 40 cm and no capture, deflate balloon, retract, try again
 - once get capture, deflate balloon and advance 1 cm for firm fit
 - ask person with you to decrease mA to 5, to 3, to 2, to 1, to 0.5; if
   capture 0.5 that's great
 - if captures at 2, don't reinflate balloon, just pull back 1-3 cm and
   advance 1-3 cm
 - set for 3x whatever your capture threshold
 - document capture threshold
 - check CXR: lead should cross the spine; if not, in RA, but don't want
   it there. Should almost be touching diaphragm
 - forget hooking up to EKG machine
 - can use 5Fr, 6Fr, or 7Fr sheath; John Ward recommends 6Fr sheath; 7
   may leak, 5 a bit tight and hard to feel.
 - Don't have to put a pacer in Mobitz II or Wenckebach; if inferior MI,
   try fluids first before starting pacer
 - If lose capture, advance 1-2 cm. Unlikely to puncture ventricle.

þ Pacemakers:
 - Guidant, Medtronic, St Jude, Biotronik: get phone numbers
 - Parts: pulse generator, leads, cathode, anode (rare monopolar)
 - Single-chamber: rare. Can be either atrial or ventricular
 - Dual-chamber: most common.
 - Biventricular pacers: if two leads in ventricle on CXR.
 - Pacing lead > sleeve > tip: may report.
 - Types of pacer, specified by
   Pacer codes: 1. chamber paced, 2. chamber sensed, 3. response to sensing
   A for Atrium
   V for Ventricle
   D for Dual
   mostly DDD
 - hard to see on 12-leads if really having atrial capture
 - should be RBBB pattern
 - VVI:
  + inhibited by ventricular beats;
  + just paces ventricles (ignores P waves)
  + When batteries on DDD die, may go to VVI mode
 - Magnet:
  + pacemaker: turns off sensing, nothing more. Should get asynchronous pacing.
  + AICD: turns off defibrillator, does nothing to pacer.
 - If battery low, may pace but slower than usual.
 - Undersensing, oversensing.
 - Pacer sensitivity in millivolts.

þ Temporary transvenous pacers
 - 6.5 introducer ideal (large will leak)
 - best places are right IJ or left subclavian
 - standard is to start at mA of 80, rate of 80, go up on mA as needed.

þ When a V V I pacemaker is oversensing, it will not fire because it is
  incorrectly sensing ventricular activity.  If the proper magnet is applied
  over the pacemaker's pulse generator, it will stop any sensing and it will
  pace asynchronously.
  Weinberger, BM:  Pacemakers.  in Adler and Plantz (eds.): eMedicine
  Emergency Medicine Text
  http://www.emedicine.com/emerg/topic805.htm

þ A patient has his pacemaker set at 60 beats per minute (bpm), but his heart
  rate is only going 50 bpm.  Does this necessarily mean the pacemaker is
  malfunctioning? Not necessarily.  The pacemaker may have a feature called
  "hysteresis".  The pacemaker may be set to beat at a rate of 60 bpm, but
  will not start this pacing unless the patient's instrinsic rate drops below
  the "hysteresis rate", which is often 50 bpm.
  Weinberger, BM:  Pacemakers. in Adler and Plantz (eds.): eMedicine Emergency
  Medicine Text
  http://www.emedicine.com/emerg/topic805.htm

þ A patient has had his pacemaker powered by a lithium-iodide battery in place
  for 13 years.  Now the pacemaker is malfunctioning, and you suspect it might
  be that the battery is dying.  What is this pacemaker's expected battery
  life? The expected life of the commonly used lithium-iodide battery is 7-12
  years, so it is certainly possible that the pacemaker malfunction is due to
  a dying or dead battery.
  Weinberger, BM:  Pacemakers.  in Adler and Plantz (eds.): eMedicine
  Emergency Medicine Text
  http://www.emedicine.com/emerg/topic805.htm

þ During the lifetime of a pacemaker, when is a lead most likely to dislodge?
  Lead dislodgement is most likely to occur within 24-48 hours after placement
  of the pacemaker.
  Weinberger, BM:  Pacemakers.  in Adler and Plantz (eds.): eMedicine Emergency
  Medicine Text
  http://www.emedicine.com/emerg/topic805.htm

þ A patient with a pacemaker has a lead infected with Staphylococcus.  How
  does the age of the pacemaker affect the type of Staph species one would
  expect to find on the infected lead? Recently placed pacemakers are at
  greater risk of Staph aureus than Staph epidermidis infection.  Several
  months after placement of the pacemaker, however, Staph epidermidis becomes
  the organism more likely to cause this type of infection.
  Weinberger, BM: Pacemakers. in Adler and Plantz (eds.): eMedicine Emergency
  Medicine Text
  http://www.emedicine.com/emerg/topic805.htm