Four Faces of DDD

VOO

-V pacing -no sensing -no responce to sensing -will just pace V at consistent pace regardless of anything else

Capture safety margin

2x voltage RV/RA 1.0 for CRT leads

Sensing safety margin

4:1 Atrial 2:1 RV

optimal level for atrial sensing at implant

>2mV

optimal level for R-wave sensing

>5mV

VVIR

V pace, V sense, inhibit response to sensing, rate modulation -paces when no sensed event

portion of timing cycle where device is looking for electrical activity

alert period

AOO

atria paces regardless of sensed events

pseudo-pseudo fusion beat

atrial output pulse on intrinsic R-wave or ventricular output pulse on P-wave

chronic A fib and VVIR pacing at 70 bpm--> how to threshold test?

can run like this or increase pacing rate

how to run a RV sensing test on CHB at AsVp (DDD)

change mode to VVI at lower rate than intrinsic (usually 30)

refractory period

changeable period of time that starts with pacing or sensing -absolute refractory period -relative refractory period

fusion beat

combination of intrinsic beat and paced beat

how do you adjust ApVs to run an atrial sensing test? (AsVs)

decrease pacing rate

relative refractory period/ Blanking period

device and sense but response is limited -DDD sees P-wave in refractory will not start an AVD but can count toward mode switch algorithm

DVIR

dual pacing, v sensing, inhibit, rate modulation

performing atrial threshold test on patient without visable captured p-waves in ApVp

increase AVD to promote intrinsic conduction

tracking p waves in DDD, how to threshold test?

increase rate over intrinsic

pseudofusion beat

pacing beat the fall on intrinsic beat and the intrinsic complex is not altered

Decrease AVD

preempt intrinsic conduction

Increase AVD

promote intrinsic conduction

Absolute Refractory

temporary disabling of the pacemaker sensing circuit following delivery of an output pulse -prevents over sensing