MVP and dropped P-waves

Tracing

N° 2

Manufacturer Medtronic Device PM Field MVP

Patient

Graph and trace

Tracing 2a: 12 lead ECG

DDD mode: atrial pacing and ventricular pacing
Programming of the MVP mode: atrial pacing not followed by a ventricular sensed event (first dropped atrial activity)
On the following cycle, atrial pacing and ventricular pacing with a short AV delay (80 ms)
Identical sequence: atrial pacing not followed by a ventricular sensed event, atrial pacing and ventricular pacing with a short AV delay
No ventricular sensed event in 2 of 4 preceding A-A intervals: automatic switch to DDD mode

Tracing 2b: EGM

Comments

This tracing shows the specificities of the operation of the first version of the MVP mode in a patient with atrioventricular block
This algorithm tolerates the presence of intermittent dropped P-waves; a single dropped P wave does not induce switching to DDD
The short AV delay (80 ms) with safety ventricular pacing on the cycle following the dropped atrial activity is the signature feature of this mode
There cannot be two consecutive dropped atrial activities
There is a single criterion for switching to the DDD mode; the device automatically switches from AAI to DDD mode, when no ventricular sensed event occurs in 2 of 4 preceding A-A intervals
The maximal duration of the ventricular pause depends on the sinus rate and on the programmed lower rate limit (more or less equal to half the programmed minimal rate)

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