RV Lead Noise Discrimination and Lead Integrity Alert (LIA)

Question 1

RV Lead Noise Discrimination safely withhold what percentage of inappropriate ICD detection due to lead fracture?

Answer 1

83.7% or appr 84%

Question 2

How does the RV Lead Noise Discrimination algorithm work?

Answer 2

• applies only at detection and starts when VT count = 2 or VF count = 3
• looks at rolling window of 12 VS events on the near field EGM (RVtip-RVring)
• compares NF window to FF EGM (CAN to RVcoil or RVcoil to SVC)
• algorithm will label NF signal as “Noise” only if both the below are true regarding the FF signals:
  1) the avg of the 2 smallest signals < 1mV
  2) the avg amp of the 2 smallest signals is < 1/6 of the max amplitude on same channel
• if 3/12 NF signals are labeled as “Noise” then all 12 are classified as “Noise”

Question 3

What 3 actions does the device take when RV Lead Noise Discrimination determines that lead noise is present?

Answer 3

• withholds VT/VF detection
• triggers an RV Lead Noise Alert
• sends CareAlert Notification to patients physician if patient is in the care link network

Question 4

Is RV Lead Noise Discrimination applied at initial detection, redetect or both?

Answer 4

• only at initial VT/VF detection or NID
• when VT count = 2
• when VF count = 3

Question 5

Where will lead noise oversensing be seen?

Answer 5

on the near-field EGM (RVtip-RVring) sensing channel

Question 6

How many beats does the RV Lead Noise Discrimination feature evaluate to determine if noise is present?

Answer 6

• looks at 12 consecutive beats

- if at least 3/12 are classified as noise then all 12 beats are labeled as noise and detection will be withheld

Question 7

When will the RV Lead Noise discrimination feature label signals as “noise”?

Answer 7

• algorithm will label signal as “Noise” only if both the below are true regarding the FF signals:
  1) the avg of the 2 smallest signals < 1mV
  2) the avg amp of the 2 smallest signals is < 1/6
  of the max amplitude on same channel
• if 3/12 NF signals are labeled as “Noise” then all 12 are classified as “Noise”

Question 8

What are the programmable options for the RV Lead Noise Discrimination feature?

Answer 8

• On
• Off
• On + timeout (45 secs or 0.75 min)

Question 9

What will be seen in the marker channel to see if the RV Lead Noise Discrimination feature withholds therapy?

Answer 9

the letter “N” will be seen in the marker channel

Question 10

How often does the RV Lead Noise alert sound?

Answer 10

• once at the programmed time and q4hrs starting at next 4 value on the clock until the device is interrogated
• ex: alarm triggered at 3 am, q4hr beeps start at 0400

Question 11

Which EGM source does the RV Lead Noise Discrimination feature use to evaluate FF signals?

Answer 11

• EGM2 with nominal setting of CAN to RVcoil

- can also use SVCcoil to RVcoil for dual coil leads

Question 12

Where can you look to see if RV Lead Noise Discrimination feature determined if noise was present?

Answer 12

• Look at the following on the Quick Look II screen:
  ) number of Ventricular Oversensed Episodes (VOS)
  ) the observations window
• look at VOS episode in the arrhythmias episodes list

Question 13

True or False: Ventricular Over Sensing episodes (VOS) are always caused by RV lead noise?

Answer 13

• False; may be RV lead noise or T-wave oversensing

Question 14

What 3 primary functions does the RV Lead Integrity Alert (LIA) perform?

Answer 14

• monitors impedances
• issues alerts
• collects extended diagnostic data

Question 15

What are the LIA trigger criteria?

Answer 15

• if 2/3 of the below occur within 60 days of each other
  1 ) 1 abn impedance (75% increase or 50% decrease) in last 2 wks
  2) sensing integrity count of 30 ≤ within 3 consecutive
  days
  3) 2 ≤ fast NS-VTs with V-V intervasl < 220ms

Question 16

What does the Sensing Integrity Counter (SIC) monitor?

Answer 16

• the # of short V-V intervals that are faster than 120-130ms
• used by the Lead Integrity Alert feature to monitor lead and sensing status

Question 17

If noise is suspected, which EGM’s should you look at for confirmation?

Answer 17

• look at both RVtip to RVring and CAN to HVB (RVcoil)

Question 18

The Lead Integrity Alert requires 2 ≤ fast NS-VT with what cycle length to trigger an alert?

Answer 18

V-V of < 200ms

Question 19

What happens when the Lead Integrity Alert criteria are met?

Answer 19

• alert tone will sound immediately then q4hrs (7 alerts per day until the device is interrogated)
• care alert notification is sent if pt has home monitor

Question 20

What are the automatic post-alert programming changes that occur when the Lead Integrity Alert criteria are met?

Answer 20

• VF NID is change to 30/40
• Monitor NID is changed to 32
• AT/AF detection is changed to “Monitor” if programmed “On”
• suspends detections during wireless interrogations to avoid oversensing