Pacemaker: Difference between revisions

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[[Image:paced.gif|thumb| Atrial pacemaker spikes. The first venricular beat on this image is paced as well.]]
[[Image:paced.gif|thumb| Atriale pacemakerspikes. Het signaal moet eerst nog door de AV knoop voordat het de ventrikels bereikt. De eerste slag is wel ventriculair gepaced.]]
[[Image:paced2.gif|thumb| Ventricular pacemaker spikes]]
[[Image:paced2.gif|thumb| Ventriculaire pacemakerspikes]]
[[Image:Pacemaker2.jpg |thumb| VVI pacemaker rhythm]]
[[Image:Pacemaker2.jpg |thumb| VVI pacemakerritme]]
Een pacemaker worden geïmplanteerd als de pulsvorming of pulsgeleiding van het hart gestoord is. '''Pacemakerritme''' is op het ECG te herkennen aan '''pacemakerspikes''': verticale lijntjes die de electrische pulsen van de pacemaker weergeven.


In het eerste voorbeeld rechts worden de atria gepaced, zodat het QRS pas volgt nadat het signaal door de AV-knoop vertraagd is. In het tweede voorbeeld worden de ventrikels direct gepaced. Aangezien dit vrijwel altijd in de rechter ventrikel gebeurd heeft het QRS complex een LBTB patroon.
A pacemaker is indicated when the electrical impulse conduction or formation is dangerously disturbed. The paced '''pacemaker rhythm''' can easily be recognized on the ECG as it shows '''pacemaker spikes''': vertical signals that represent the electrical activity of the pacemaker.


Pacemakers worden vaak aangeduid met een NASPE code, die bestaat uit 3-5 letters.
In the first example image, the atria are being paced, but not the ventricles. Accordingly the ventricular beat is delayed until the atrial signal has passed the AV node. In the second image the ventricles are paced directly. As ventricular pacing occurs exclusively in the right ventricle the ECG shows a left bundle branch pattern. An exception to this rule is left ventricular pacing in patients with congenital anomalies and patients with an epicardial pacemaker that has been placed during surgery.
* De eerste letter geeft de kamer aan waarin '''gesensed''' wordt: O=geen, A=atrium, V=ventrikel, D=dual (atrium en / of ventrikel)
* De tweede letter de kamer aan waarin '''gepaced''' wordt: A=atrium, V=ventrikel, D=dual (atrium en / of ventrikel)
* De derde letter geeft de actie aan die volgt op de sense: O = geen, T = triggered, I = inhibited (als het hart zelf een slag maakt, doet de pacemaker niets) en D = dual (T + I).  
* De vierde letter geeft aan of de pacemaker een vaste frequentie heeft (O = none). Als de pacemaker 'intelligenter' is, dan staat er een R= rate modulation.
* De vijfde letter geeft aan of de pacemaker in zowel het atrium als de rechter kamer kan pacen. Deze letter wordt zelden gebruikt.


Veel voorkomende typen pacemakers:
Pacemakers can be categorized according to the NASPE coding system, that usually consists of 3-5 letters.
* AAI: de pacemaker pacet in de boezem als het ritme daar te traag wordt
* The first letter represents the chamber where the signal is "sensed": O=none, A=atria, V=ventricle, D=dual (atrial and / or ventricle)
* VVI: de pacemaker pacet in de kamer als het ritme daar te traag wordt
* The second letter represents the chamber that is being paced: A=atria, V=ventricle, D=dual (atria and / or ventricle)
* DDD: de pacemaker detecteerd of er depolarisatie plaatsvindt in het atrium of de ventrikel en kan in beide compartimenten pacen
* The third letter represents the action that follows the sensed signal: O = none, T = triggered, I = inhibited (i.e. if the heart beats by itself, the pacemaker is silent) and D = dual (T + I).
* DDDR: zie boven, deze pacemaker kan ook lichameljke activiteit detecteren en de hartfrequentie aanpassen.
* The fourth letter denotes whether the pacemaker has a fixed rate (0 = none) or has rate modulation (R).
* Biventriculaire pacemakers: leads in beide ventrikels om synchronie tussen de beide kamers te optimaliseren. Bijvoorbeeld bij een linker bundeltakblok of hartfalen. Dit is in het kader van CRT (cardiac resynchronisation therapy)
* The fifth letter indicates whether the pacemaker can pace both the atria and right chamber. This letter is seldomly used.
* ICD (Internal cardioversion Device)(eventueel in combinatie met een pacemaker): Is in staat VT/Vfib te detecteren en eventueel te defibrileren
 
The most often used codes are:
* AAI: the atria are paced, when the intrinsic atrial rhythm falls below the pacemakers threshold
* VVI: the ventricles are paced, when the intrinsic ventricular rhythm falls below the pacemakers threshold
* DDD: the pacemaker records both the atrial and ventricular rate and can pace one of each chambers when needed.
* DDDR: as above, but the pacemaker has a sensor that records a demand for higher cardiac output and can adjust the heart rate accordingly.
* Biventricular pacemakers: leads in both ventricles are present to synchronize contraction. This cardiac synchronization therapy can improve symptoms and survival in some heart failure patients.
* ICD (Internal Cardioversion Device): this device can detect and treat [[ventricular tachycardia]] and [[ventricular fibrillation]]. Usually the first treatment is anti-tachy pacing (pacing at a rate +- 10% above the ventricular rate in ventricular tachycardia, which can convert the rhythm to sinus rhythm). If this is not effective an defibrillator shock is delivered, usually with 16-36 Joules of energy. ICDs can save lives in patients who have a high risk of ventricular arrhythmias. All ICDs have optional pacemaker activity to treat bradycardias. New biventricular ICDs have 3 leads: an atrial lead, a left ventricular lead and a right ventricular lead.


==Externe Links==
==Externe Links==

Revision as of 19:25, 21 June 2007

Atrial pacemaker spikes. The first venricular beat on this image is paced as well.
Ventricular pacemaker spikes
VVI pacemaker rhythm

A pacemaker is indicated when the electrical impulse conduction or formation is dangerously disturbed. The paced pacemaker rhythm can easily be recognized on the ECG as it shows pacemaker spikes: vertical signals that represent the electrical activity of the pacemaker.

In the first example image, the atria are being paced, but not the ventricles. Accordingly the ventricular beat is delayed until the atrial signal has passed the AV node. In the second image the ventricles are paced directly. As ventricular pacing occurs exclusively in the right ventricle the ECG shows a left bundle branch pattern. An exception to this rule is left ventricular pacing in patients with congenital anomalies and patients with an epicardial pacemaker that has been placed during surgery.

Pacemakers can be categorized according to the NASPE coding system, that usually consists of 3-5 letters.

  • The first letter represents the chamber where the signal is "sensed": O=none, A=atria, V=ventricle, D=dual (atrial and / or ventricle)
  • The second letter represents the chamber that is being paced: A=atria, V=ventricle, D=dual (atria and / or ventricle)
  • The third letter represents the action that follows the sensed signal: O = none, T = triggered, I = inhibited (i.e. if the heart beats by itself, the pacemaker is silent) and D = dual (T + I).
  • The fourth letter denotes whether the pacemaker has a fixed rate (0 = none) or has rate modulation (R).
  • The fifth letter indicates whether the pacemaker can pace both the atria and right chamber. This letter is seldomly used.

The most often used codes are:

  • AAI: the atria are paced, when the intrinsic atrial rhythm falls below the pacemakers threshold
  • VVI: the ventricles are paced, when the intrinsic ventricular rhythm falls below the pacemakers threshold
  • DDD: the pacemaker records both the atrial and ventricular rate and can pace one of each chambers when needed.
  • DDDR: as above, but the pacemaker has a sensor that records a demand for higher cardiac output and can adjust the heart rate accordingly.
  • Biventricular pacemakers: leads in both ventricles are present to synchronize contraction. This cardiac synchronization therapy can improve symptoms and survival in some heart failure patients.
  • ICD (Internal Cardioversion Device): this device can detect and treat ventricular tachycardia and ventricular fibrillation. Usually the first treatment is anti-tachy pacing (pacing at a rate +- 10% above the ventricular rate in ventricular tachycardia, which can convert the rhythm to sinus rhythm). If this is not effective an defibrillator shock is delivered, usually with 16-36 Joules of energy. ICDs can save lives in patients who have a high risk of ventricular arrhythmias. All ICDs have optional pacemaker activity to treat bradycardias. New biventricular ICDs have 3 leads: an atrial lead, a left ventricular lead and a right ventricular lead.

Externe Links

Heart Rhytm Society



78. Atrial-paced rhythm

79. Ventricular-paced rhythm

80. Atrial-sensed ventricular-paced rhythm

81. AV dual-paced rhythm

82. Failure of appropriate capture, atrial

83. Failure of appropriate capture, ventricular

84. Failure of appropriate inhibition, atrial

85. Failure of appropriate inhibition, ventricular

86. Failure of appropriate pacemaker firing

87. Retrograde atrial activation

88. Pacemaker mediated tachycardia

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