Dual Chamber Pacing

one atrial beat for each ventricular beat

AV Delay & VA interval

• lower rate limit
• (60 bpm)

Base Rate

When AV conduction slows

Patients intrinsic atrial activity increase above the base rate and the ventricular rate paces to mach up to the max tracking rate

• AV Delay
• VA interval
• Base Rate
• MTR

Sequational pacing

tracking

Total Inhibition Bitch!

pacemaker timing cycle design to simulate the natural pause between the atrial and ventricular events by mimicking the PR interval

• *optimal time for ventricular filling = better cardiac output
• *allows time for mitral valve to close
• *enhances bloodflow (hemodynamics)

time between paced atrial event and paced ventricular event

time period between instrinic p wave and pace QRS

time between the firing of SA node and the waves getting to the atrial lead

25-50 ms

have to set sensed AV delay 25-50 ms shorter than paced AV delay

15-20%

250-275 ms

• prevents premature beats
• retrograde p-waves
• far-field ventricular signals
• pacemaker mediated tachycardias

• Post ventricular atrial blanking
• typical 100ms

• DDD pacemaker
• ability to conduct retrograde
• triggered event )loss of AV scynorne
• retrograde conduction longer than PVRAP

an endless loop tachycardia

• PVC
• loss of atrial capture
• atrial undersensing
• magnet removal

extended PVARP bitch

• force pacing by inceasing atrial pacing over intrinisc rate
• put in VVI mode
• look for an atrial sense event dirved from ventricular pacing
• measure RVAC interval

235ms

extends PVARP value to 480ms whenever a PVC occurs

at a certian amount of beats the pacemaker will automatically extend PVARP

guard against fairfeild r waves

sensing r wave from ventricle in atrium