Editing Pacemaker (section)

== Advancements in function ==
[[File:X-ray of pacemaker with right atrial and ventricular lead.jpg|thumb|350px|Posteroanterior and lateral [[chest radiograph]]s of a pacemaker with normally located leads in the right atrium (white arrow) and right ventricle (black arrowhead), respectively]]
A major step forward in pacemaker function has been to attempt to mimic nature by utilizing various inputs to produce a rate-responsive pacemaker using parameters such as the [[QT interval]], pO<sub>2</sub> – pCO<sub>2</sub> (dissolved [[oxygen]] or [[carbon dioxide]] levels) in the arterial-venous system, physical activity as determined by an [[accelerometer]], [[body temperature]], [[Adenosine triphosphate|ATP]] levels, [[adrenaline]], etc.
Instead of producing a static, predetermined heart rate, or intermittent control, such a pacemaker, a 'Dynamic Pacemaker', could compensate for both actual respiratory loading and potentially anticipated respiratory loading. The first dynamic pacemaker was invented by Anthony Rickards of the [[The Heart Hospital|National Heart Hospital]], London, UK, in 1982.<ref>{{cite journal | title=Anthony Francis Rickards | journal = Heart | pmc = 1768450 | year = 2004 | volume = 90 | pages=981–82 | doi = 10.1136/hrt.2004.045674 | issue=9}}</ref>

Dynamic pacemaking technology could also be applied to future [[artificial heart]]s. Advances in transitional tissue welding would support this and other artificial organ/joint/tissue replacement efforts. Stem cells may be of interest in transitional tissue welding.{{Citation needed|date=April 2013}}

Many advancements have been made to improve the control of the pacemaker once implanted. Many of these have been made possible by the transition to [[microprocessor]] controlled pacemakers. Pacemakers that control not only the ventricles but the [[Atrium (heart)|atria]] as well have become common. Pacemakers that control both the atria and ventricles are called dual-chamber pacemakers. Although these dual-chamber models are usually more expensive, timing the contractions of the atria to precede that of the ventricles improves the pumping efficiency of the heart and can be useful in congestive heart failure.

Rate responsive pacing allows the device to sense the physical activity of the patient and respond appropriately by increasing or decreasing the base pacing rate via rate response algorithms.

The DAVID trials<ref>{{cite journal |vauthors=Wilkoff BL, Cook JR, Epstein AE, Greene HL, Hallstrom AP, Hsia H, Kutalek SP, Sharma A | title = Dual-chamber pacing or ventricular backup pacing in patients with an implantable defibrillator: the Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial | journal = JAMA | volume = 288 | issue = 24 | pages = 3115–23 | date = December 2002 | pmid = 12495391 | doi = 10.1001/jama.288.24.3115 | doi-access = free }}</ref> have shown that unnecessary pacing of the right ventricle can exacerbate [[heart failure]] and increases the incidence of atrial fibrillation. The newer dual-chamber devices can keep the amount of right ventricle pacing to a minimum and thus prevent worsening of the heart disease.