A group of cells that produce neural or endocrine activity in order to produce a rhythmical biological activity. It may be replaced by an artificial electrical device. Where the organ is not specified this is invariably the heart, but some regard the interstitial cells of Cajal as pacemakers within the gastrointestinal system.
The first successful implantable pacemaker, designed by Wilson Greatbatch, was fitted in 1960 in the veterans hospital in Buffalo. A previous effort in 1958 at the Karolinska Institute had failed quickly.
- Percussion pacing
The main types practically are
- Single lead - as in the classic relatively cheap and cheerful VVI pacemaker often adequate option to treat complete heart block
- Dual lead - necessary for synchrony of atrial and ventricular contraction which increases cardiac output and allows more physiological cardiac function. This can be important in heart failure.
- Leadless - under development aiming for a lower complication rate than conventional permanent pacemakers
- Defibrillators - Will also have potential pacemaking functionality.
|D≡dual A & V||D≡dual A & V||D≡dual triggered/inhibited||M≡multiprogrammable||D≡dual paced & shock|
|S≡Special(see note)||S≡Special(see note)||O≡off|
S designation is only valid in manufacturers description of a pacemaker that can use either an atrial or ventricular lead. Once the lead is attached the code becomes A or V.
S designation is only valid in manufacturers description of a pacemaker that can sense using either an atrial or ventricular lead. Once the lead is attached the code becomes A or V.
|Magnet application usually temporarily turns off sensing function into an asynchronous mode such as AOO, VOO, DOO. The rare T mode is used to observe the location of sensing of intrinsic events and can be very useful||Only R mode is usually specified as other modes are implicate. P mode is limited to single chamber pacemakers. M mode has usually rate, sensing, output, refractory periods, hysteresis and mode options||Most bradycardia devices are assumed to be ????O devices and a fifth code position is only commonly used in defibrillators|
The complication rate of lead permanent implantable pacemakers approaches 10%. Complications include infection, cardiac perforation, venous occlusion, tricuspid regurgitation. Leads can dislodge, fracture and fail. Pulse generators can erode and provide long term sources of infection. The complication rate of leadless pacemakers may be lower.
Removal is mandatory before cremation as batteries may explode at the temperatures reached. This may damage the crematorium equipment. Usually in the subcutaneous space in right infra-clavicular area, but few may be epigastric. The devices can also migrate laterally or inferiorly.
- ↑ Obit: Telegraph: http://www.telegraph.co.uk/news/obituaries/medicine-obituaries/8794961/Wilson-Greatbatch.html</a>
- ↑ Knops RE, Tjong FV, Neuzil P, Sperzel J, Miller MA, Petru J, Simon J, Sediva L, de Groot JR, Dukkipati SR, Koruth JS, Wilde AA, Kautzner J, Reddy VY. Chronic performance of a leadless cardiac pacemaker: 1-year follow-up of the LEADLESS trial. Journal of the American College of Cardiology. 2015 Apr 21; 65(15):1497-504.(Link to article – subscription may be required.)
- ↑ Ritter P, Duray GZ, Steinwender C, Soejima K, Omar R, Mont L, Boersma LV, Knops RE, Chinitz L, Zhang S, Narasimhan C, Hummel J, Lloyd M, Simmers TA, Voigt A, Laager V, Stromberg K, Bonner MD, Sheldon TJ, Reynolds D. Early performance of a miniaturized leadless cardiac pacemaker: the Micra Transcatheter Pacing Study. European heart journal. 2015 Jun 4.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Reddy VY, Exner DV, Cantillon DJ, Doshi R, Bunch TJ, Tomassoni GF, Friedman PA, Estes NA, Ip J, Niazi I, Plunkitt K, Banker R, Porterfield J, Ip JE, Dukkipati SR. Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker. The New England journal of medicine. 2015 Sep 17; 373(12):1125-35.(Link to article – subscription may be required.)
- ↑ Gale CP, Mulley GP. Pacemaker explosions in crematoria: problems and possible solutions. Journal of the Royal Society of Medicine. 2002 Jul; 95(7):353-5.
- ↑ Gale CP, Mulley GP. A migrating pacemaker. Postgraduate medical journal. 2005 Mar; 81(953):198-9.(Link to article – subscription may be required.)
- ↑ http://www.pulsetoday.co.uk/story.asp?storyCode=4001909§ioncode=19>