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Pacemaker: Difference between revisions
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In the first example image, the atria are being paced, but not the ventricles, resulting in a '''atrial paced rhythm'''. Accordingly the ventricular beat is delayed until the atrial signal has passed the AV node. In the second image the ventricles are paced directly, resulting in '''ventricular paced rhythm'''. 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. | In the first example image, the atria are being paced, but not the ventricles, resulting in a '''atrial paced rhythm'''. Accordingly the ventricular beat is delayed until the atrial signal has passed the AV node. In the second image the ventricles are paced directly, resulting in '''ventricular paced rhythm'''. 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. | ||
===Pacemaker Coding=== | |||
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. | ||
* The first letter represents the chamber where the signal is "sensed": O=none, A=atria, V=ventricle, D=dual (atrial and / or ventricle) | * The first letter represents the chamber where the signal is "sensed": O=none, A=atria, V=ventricle, D=dual (atrial and / or ventricle) | ||
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* The fifth letter indicates whether the pacemaker can pace both the atria and right chamber. This letter is seldomly used. | * The fifth letter indicates whether the pacemaker can pace both the atria and right chamber. This letter is seldomly used. | ||
===Commonly Used Pacemakers=== | |||
The most often used codes are: | The most often used codes are: | ||
* '''AAI''': the atria are paced, when the intrinsic atrial rhythm falls below the pacemakers threshold | * '''AAI''': the atria are paced, when the intrinsic atrial rhythm falls below the pacemakers threshold | ||