Fig. 20.1
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Answers
- 1.
The image shows a 12-lead ECG with pacing spikes before P waves (a spike) and QRS complexes (v spike), at a rate of 60/min indicating a dual chamber pacemaker.
- 2.
The definition of pacemaker dependency varies in the literature. It can be defined as the absence of an intrinsic (or escape) rhythm for 30 s during temporary pacing at 30 beats per minute with the pacemaker switched off [1]. To determine if the patient is pacemaker dependent, it is essential to identify the indication for the pacemaker implantation (complete heart block and syncope, for instance, would infer dependency) [1]. In addition, pacemaker interrogation in pacemaker-dependent patients would reveal pacing 100% of the time.
- 3.
This is nomenclature describing the pacemaker therapy modes. Permanent pacemaker nomenclature is based on recommendations by the North American Society of Pacing and Electrophysiology (NASPE) and by the British Pacing and Electrophysiology Group (BPEG).
Table 20.1
NASPE/BPEG pacemaker code
I Chamber paced | II Chamber sensed | III Response to sensing | IV Rate responsiveness | VI Multisite pacing |
|---|---|---|---|---|
0 = none | 0 = none | 0 = none | 0 = none | 0 = none |
A = atrium | A = atrium | T = triggered | R = rate modulation | A = atrium |
V = ventricle | V = ventricle | I = inhibited | V = ventricle | |
D = dual (A+V) | D = dual (A+V) | D = dual (T+I) | D = dual (A+V) | |
S = single (A or V) | S = single (A or V) |
AAI pacemaker is useful for sinus bradycardia if the AV node function is normal.
VVI pacemaker is useful in atrial fibrillation with slow ventricular response.
DDD is useful if there is complete AV block with a normal sinus node.
Pacing modes with AV synchrony are AAI, DVI, DDI, and DDD.
Pacing modes that sense atrial activity and trigger ventricular activity are VAT, VDD, and DDD. They are used during slow ventricular rates or AV nodal block. These modes are synchronous modes.
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