Follow-up: Assessment & diagnostics

Question 1

Yes / No

During follow up a device patient remarks of symptoms that correlate to pacemaker syndrome. You note retrograde P-waves during VVI threshold testing - could this be a cause?

Answer 1

Yes.

Retrograde P-waves are a risk marker of pacemaker syndrome as they contribute to haemodynamic compromise.

Question 2

During follow up you note retrograde P waves during VVI threshold testing and observe multiple PMT episodes - are the two linked?

Answer 2

Yes.

Retrograde P-waves frequently initiate PMT or ELT.

Question 3

What % of SSS patients have retrograde P-waves?

Answer 3

70-80%.

Question 4

What % of AV Block patients have retrograde P-waves?

Answer 4

35%.

Question 5

What range (in msec) do retrograde P-waves typically conduct?

Answer 5

100-400ms.

Question 6

True / False

VA conduction time has decremental properties with exercise.

Answer 6

True.

Question 7

True / False

VA conduction time is not influenced by autonomic factors or drugs.

Answer 7

False.

Question 8

What could be programmed to help reduce incidence of PMT / ELT?

Answer 8

PVARP.

Extend the PVARP to encompass the retrograde P-wave, thus preventing tracking.

Question 9

What will happen to the upper rate with an extended PVARP.

Answer 9

Upper rate will be reduced.

PVARP + AVI = TARP. TARP dictates 2:1 block rate.

Question 10

Which formula helps with correct programming of the PVARP to encompass retrograde P-waves?

Answer 10

VA conduction time + 50ms.

Question 11

Application of a magnet (either separate or within the header) is important for what two reasons?

Answer 11

1. Initiates communication circuit to the programmer
2. Closes reed switch which initiates magnet rate pacing - important to confirm battery status

Question 12

Medtronic uses the memonic PBLSTOP to ensure nothing is missed during FU, what does it stand for?

Answer 12

P - Presenting rhythm, rate and % pacing

B - Battery status

L - Lead data

S - Sensing

T - Threshold

O - Observations, Events, Diagnostics

P - Programming and print

Question 13

For a patient with normal chronotropic response, what kind of distribution should be observed on the HR Histogram?

Answer 13

Symmetrical bell shaped distribution.

Question 14

For a patient with blunted chronotropic response but with appropriate RR sensor programming, what kind of distribution should be observed on the HR Histogram?

Answer 14

Asymmetrical half bell shaped distribution.

Question 15

In a patient with blunted chronotropic response and with poor RR sensor programming, what kind of distribution should be observed on the HR histogram?

Answer 15

Almost all pacing is at the base rate, with little above it.

Question 16

True / False

PVCs may indicate intact AV conduction with atrial undersensing.

Answer 16

True - PVC markers may be inaccurate for this reason.

A PVC is defined as a ventricular event with no preceding A event, however the A event might have occurred, just the device didn’t see it.

Question 17

True / False

A large % of AsVp state guarantees the patient has CHB.

Answer 17

False.

It may simply be that the AVD is programmed too short, thus a Vp delivered as the device won’t ‘wait’ long enough for the atrial stimulus to conduct.

Question 18

What may cause a continuous A-Tachy to be recorded as multiple episodes by the device?

Answer 18

Intermittent atrial sensing.

The device ‘thinks’ the Tachycardia has stopped because its stopped being able to ‘see’ it. In reality its continued and the device ‘redirects’ it once the amplitude increases again. Check dates and times of all events to see if they’re close together.

Question 19

True / False

A long PVARP may cause 2:1 undersensing of flutter.

Answer 19

True.

Atrial events may fall within the blanking or refractory periods, causing incorrect counting.

Question 20

Why do devices typically fail to correctly detect AVNRT?

Answer 20

A and V signals line up so close to each other that the A event likely falls within the V-blanking period; thus is not detected.

Question 21

List 3 differential diagnosis of atrial tachycardia as recorded by the device.

Answer 21

V Far Field Oversensing P-wave double counting Sinus Tachycardia EMI oversening Lead Fracture Myopotential oversensing Runs of Atrial Ectopics.

Question 22

Approximately what percentage of patients are considered non responders to CRT?

Answer 22

30%.

Question 23

Normal interventricular conduction gives rise to equal pre-ejection times of the pulmonary artery and aortic artery. With complete LBBB in the context of CRT, what changes?

Answer 23

Significant prolonging of aortic pre-ejection time.

Question 24

With respect to CRT, is anodal capture possible if both the RV and LV leads are programmed in the bipolar configuration?

Answer 24

No.

Anodal capture only possible with a shared ring electrode.

Question 25

Explain anodal capture.

Answer 25

When a large current density forms around the RV Anode due to a high LV Cathodal Output. This current density stimulates the RV myocardium. ## Footnote *Can only occur when the RV and LV share a common ring electrode.*

Question 26

Loss of atrial tracking should be avoided as this can lead to a reduction of CRT therapy, thus a typically higher atrial tracking rate should be programmed in CRT vs. conventional pacemakers.

Answer 26

True. ## Footnote *Atrial tracking rates \>140-150bpm should be programmed to prevent loss of atrial tracking and respondent CRT pacing.*

Question 27

# True / False PVARP extension algorithms should be programmed on for CRT patients.

Answer 27

False. ## Footnote *Long PVARP increases risk of dropped P-waves, which could lead to reduced CRT pacing in those with intrinsic conduction.*

Question 28

# True / False A short PVARP should be programmed with CRT patients.

Answer 28

True. ## Footnote *PVARP \<250ms is recommended to increase likelihood of P-wave tracking. PMT is rare in CRT patients thus short PVARP is not of concern as in conventional pacemakers.*

Question 29

A patient presents in clinic with CRT pacing \<80% respondent to AF with RVR despite optimal medical therapy. What therapies could be recommended to increase CRT %?

Answer 29

1. Terminate the AF with ablation / cardio version 2. Leave the AF and ablate the AV node

Question 30

With respect to CRT, list 3 treatments for late atrial sensing.

Answer 30

1. Triggered LV pacing from RV site 2. AV Ablation 3. Programming specific sensed and paced AV delays

Question 31

At physiologic rates it is unusual to see RV pacing latency above \_\_\_\_\_msec.

Answer 31

40msec. ## Footnote *Prolonged LV latency however is more common due to pathophysiology of substrates such as scar tissue.*

Question 32

# True / False Pacing latency is often rate and output dependent.

Answer 32

True.

Question 33

Fluid overload is a major HF prognosis indicator. How can a device help monitor this?

Answer 33

Fluid is measured via thoracic impedance. This measure is taken from lead tip to can in all devices.

Question 34

# Down / Up In the context of HF - If a patient is overloaded with fluid, their thoracic impedance will go \_\_\_.

Answer 34

Down. ## Footnote *Fluid is a good conductor. More fluid = less resistive conduction = lower impedance.*

Question 35

# Down / Up In the context of HF - If a patient is dry/has reduced fluid, their thoracic impedance will go \_\_\_.

Answer 35

Up. ## Footnote *Fluid is a good conductor. Less fluid = more resistive conduction = higher impedance.*

Question 36

In worsening heart failure which of the following statements are true? 1. Nocturnal heart rate decreases / thoracic impedance increases 2. Nocturnal heart rate increases / thoracic impedance increases 3. Nocturnal heart rate decreases / thoracic impedance decreases 4. Nocturnal heart rate increases / thoracic impedance decreases

Answer 36

4. Nocturnal heart rate increases / thoracic impedance decreases. ## Footnote *Excess fluid enters chest when laid down and heart has to increase output to offload it (reason why HF patients sleep upright with many pillows). More fluid in thoracic cavity will lower impedance as fluid is a good conductor.*

Question 37

Visible noise solely on the shock / FarField IEGM is most commonly associated with what?

Answer 37

Myopotentials arising from muscular activity.

Question 38

Visible noise solely on the pace/sense IEGM is most commonly associated with what?

Answer 38

Integrity problems associated to that lead - either conductor fracture / insulation failure.

Question 39

Visible noise on both shock / FarField & pace/sense IEGMs are most commonly associated with what?

Answer 39

Noise on both IEGMs is predominantly respondent to external sources.

Question 40

# True / False A sinus beat with a loss of atrial sensing will be registered by the device as a PVC

Answer 40

True. ## Footnote *A lack of p-wave sensing means the r-wave will be sensed without a preceeding As. Thus will be labeled a PVC.*