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→Pacemaker codes
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===Pacemaker codes=== | ===Pacemaker codes=== | ||
Pacemakers can be categorized according to the NASPE coding system that usually consists of 3-5 letters. | Pacemakers can be categorized according to the NASPE coding system that usually consists of 3-5 letters. | ||
{| class="wikitable" border="1" | |||
|- | |||
! I | |||
! II | |||
! III | |||
! IV | |||
! V | |||
|- | |||
| Chamber(s) paced | |||
| Chamber(s) sensed | |||
| Response to sensing | |||
| Rate modulation | |||
| Multisite pacing | |||
|- | |||
| O = none | |||
A = atrium | |||
V = ventricle | |||
D = dual (A+V) | |||
| O = none | |||
A = atrium | |||
V = ventricle | |||
D = dual (A+V) | |||
| O = none | |||
T = triggered | |||
I = inhibited | |||
D = dual (I+T) | |||
| O = none | |||
R = rate adaptive | |||
| O = none | |||
A = atrium | |||
V = ventricle | |||
D = dual (A+V) | |||
|} | |||
'''Explanations of table:''' | |||
* III: | |||
'''Triggered:''' A sensed event triggers a pacemaker output pulse | |||
'''Inhibited:''' Detection of physiological heart activitity will inhibit an electrical pacemaker impulse | |||
'''Dual:''' A pacemaker with dual response to sensing will inhibit a pacemaker output pulse if it senses an intrinsic event in that same chamber, but it will trigger a pacemaker output pulse in the ventricle if it senses an intrinsic event in the atrium (after a programmed atrioventricular interval) | |||
* IV: | |||
'''Rate modulation:''' In some patients, rate adaptive pacing is programmed “on” to ensure that when patients exercise increases, the pacemaker ensures that the heart rate increases to provide additional cardiac output. There are many ways to sense physiological exercise, including motion sensors and ventilation sensors. | |||
===Commonly used pacemakers=== | |||
* '''AAI:''' The atria are paced, when the intrinsic atrial rhythm falls below the pacemaker's threshold. | |||
* '''VVI:''' The ventricles are paced, when the intrinsic ventricular rhythm falls below the pacemaker's threshold. | |||
* '''VDD:''' The pacemaker senses atrial and ventricular events, but can only pace the ventricle. This type of pacemaker is used in patients with a reliable sinus node, but with an AV-block. | |||
* '''DDD:''' The pacemaker records both atrial and ventricular rates and can pace either chamber when needed. | |||
===Uni- and bipolar sensing and stimulation=== | |||
Sensing and stimulation of the myocardium demands a closed electrical circuit. A pacemaker can sense and stimulate in a unipolar and bipolar fashion: | |||
* Unipolar: Pacemaker circuit between 1 electrode at the distal end of lead and the pacemaker pulse generator (large circuit ± 40-60 cm). | |||
- Advantage: large pacemaker spikes (easier interpretation pacemaker ECG) | |||
- Disadvantage: extracardiac stimulation (pectoral muscle), sensing of extracardiac signals (such as ventricular depolarisations in the atrial sensing channel (far field R waves) or non-physiological noise) | |||
* Bipolar: Pacemaker circuit between 2 electrodes at the distal end of the lead (small circuit ± 10-15 mm) | |||
- Advantage: more reliable sensing | |||
- Disadvantage: small pacemaker spikes (difficult interpretation pacemaker ECG) | |||
==ICD== | ==ICD== | ||
*Overzicht trials met link naar pubmed | *Overzicht trials met link naar pubmed | ||