MEDTRONIC SINGLE CHAMBER PACEMAKER EXPLAINED IN DETAIL

1. PACEMAKERS
BY
PRIYANKA SUBRAHMANIAN
NHC-CCU

2. Conduction system of heart

3. DEFINITION
Pacemakers are the electronic devices that can be used to initiate
the heartbeat when the heart’s intrinsic electrical system cannot
effectively generate a rate adequate to support cardiac output

4. INDICATION
Heart rate is slow, causing hemodynamic compromise
 Sick sinus syndrome
 Sinus bradycardia or atrial fibrillation with slow heart rate response
(generally < 40bpm)
 Heart block
3rd degree
2nd degree type 2 (Mobitz)
 Malignant Tachyarrhythmia caused by bradycardia
Torsades de Pointes

5. TYPES OF PACEMAKERS
 Single chamber
 Dual chamber
 Biventricular
 Temporary pacemaker
 Permanent pacemaker

6. TYPES……..Cont’d
Single chamber Dual chamber
Permanent
pacemaker

7. FUNCTIONS OF PACEMAKER
Sensing
The device ‘sees’ a native heart beat
Expressed in Millivolts (mV).
Pacing
The device delivers a shock to stimulate a heart beat
Expressed in Milliamperes(mA)

8. COMPONENTS
 The Pacemaker System is a simple electrical circuit consisting of
PULSE GENERATOR PACING LEAD

9. PULSE GENERATOR
 The pulse generator is designed to generate an electrical current
that travels through pacing lead and exits through electrode that is in
direct contact with the heart. This electrical current initiates a
myocardial depolarization.
 The power source for a temporary external pulse generator is
standard 9-volt alkaline battery inserted into the generator

10. PACING LEAD
 Standard pacing leads are bipolar
 Single use.
 3 to 6 Fr in diameter
 Usually placed in RV apex
 Some have inflatable balloon between electrodes
-which allows the lead to float & follow circulation.
-once it reaches RV , deflate it to prevent entering pulmonary
artery.

11. Bipolar pacing lead

12. PACING ROUTES
Transcutaneous pacing
Transthoracic pacing
Epicardial pacing
Transvenous pacing

13. TRANSVENOUS PACING
 Transvenous pacing
It involves threading an electrode catheter through a vein
into the right atrium or right ventricle.
Four venous access , that can be used.
 Femoral approach
 Subclavian
 Internal jugular
 External jugular

14. PACEMAKER TERMINOLOGY
Fixed rate (Asynchronous)
 It delivers an electrical impulse at a present fixed rate to the
heart and functions independently of cardiac activity.
Demand (synchronous)
 The pulse generator delivers artificial stimulus only when
needed or on demand and therefore does not compete with
patient’s rhythm

15. Dual chamber
• Dual-chamber pacemakers have two leads, placed in the right
atrium and right ventricle.
Single chamber
• Single-chamber pacemakers may be atrial or ventricular.
• Atrial pacemakers are used where slow heart rate is due only to
sinoatrial disease, i.e. where conduction between the atria and
ventricles is intact.

16. MEDTRONIC SINGLE CHAMBER TEMPORORY
PACEMAKER
1 Lead Terminals
2 Green LED – Sensed Event
3 Yellow LED – Paced Event
4 Pulse Output Amplitude (0.3 … 12 V)
5 Mode Selector
6 Button to activate high-rate stimulation
7 Sensitivity Control
8 Stimulation Rate, ppm (Basic Rate)
9 Red LED – Errors, Low Battery
10 Cover
11 Ridge for Arm Strap

17. Dials of Medtronic pacemaker
Sensitivity
(1 – 20 mV, f=asynchronous
Rate (30-180 ppm)
Pulse Amplitude (0.3 – 12 Volts)
Mode: OFF / VVI / High Rate

18. RATE
 Basic Rate Range: 30-180 p/min (ppm)
High Rate Pacing Range: 2x: 60-360 ppm 4x:
120-720 ppm

19. OUTPUT
 It is the amount of electrical current that is delivered to the heart
to initiate depolarization.
 Myocardial response to the pacing stimulus is called capture.
 Measured in milliamperes [mA]
 0.3-12 Volts
LED illuminates YELLOW when pacing
pulse delivered.

20. SENSITIVITY
 The sensitivity control regulates the ability of the
pacemaker to the heart’s intrinsic electrical activity.
 Sensitivity is measured in millivolts (mV)
Sense LED illuminates GREEN when intrinsic activity
sensed.

21. When programming sensitivity, as you lower the number
you make the pacemaker more sensitive, (can “see”
more).

22. MODE
 Off
 VVI: (or AAI) without sound
 VVI Beep: (or AAI) audible signal during sensing and pacing
(two different tones)
 X2: stimulation delivered at twice the basic rate when High
Rate button depressed
 X4: stimulation delivered at four times the basic rate when
High Rate button depressed

23. VVI explained
A VVI pacemaker
 Paces the ventricle
 Senses the ventricle
 In response to a sensed event it INHIBITS the pacing
response
(So if it doesn’t SENSE a native heart beat in a specified
period, it will deliver a pace.)

24. Preparation for the procedure
 Record patient’s baseline ECG & vitals .
 Explain the procedure & get an informed consent.
 Skin preparation
 Fluroscopy
 Keep under close ECG monitoring
 Crashcart to keep aside.
 Radiation shields(lead aprons)

25. Gather Equipment
 Pacing lead , pacer box & connection cable
 Skin preparation solution
 Sterile Gloves , Gown & mask
 Local Anesthetic(1%Xylocain Injection)
 One part needle
 Sheath(6Fr).
 Syringes , needle , suture material , scalpel.
 Sterile gauze.
 Transparent dressing.

26. Assembling pacemaker
 Insert 9V alkaline battery
 Connecting leads/cables
Adapter or bifurcation cable
Extension or patient cable
(Reusable & Disposable)

27. Assembling pacemaker……cont’d
 Connector pins on the lead(s) must be fully inserted in the
patient connector block
 Black to negative & red to positive
 Finger tighten only (no tools required)

28. Procedure explained
 IV Aceess
 Placement of sheath
 Pacing lead insertion
* Desirable location for pacing RV is usually the apex
* Catheter should pass tricuspid valve to reach RV
 Connect to pacemaker.
* (Rate , sensitivity , output setting)
 Securing of the lead to skin.
 Apply transparent dressing.

29. Determining OUTPUT THRESHOLD
 Gradually turn down output until ventricular capture is
lost
 The last point before losing capture is the threshold
 Pacemaker output should be set as 3-4 times the
threshold
(ie if the threshold is 2 ; set output at 6)

30. Confirmation of lead
Radiography (chest Xray)

31. ECG - Look for Pacing spikes (stimulus from the pacemaker ,
which is recorded in ECG as short narrow deflection)

32. Ongoing management
 Daily inspection of the site for signs of infection
 Threshold checking
 Daily ECG
 Low battery indicator
 Connections are secure
 Setting ( rate, output, sensitivity )
 Setting ( demand or asynchronous )
 Pulse perfusion distal to insertion site
 Presence of Muscle twitching or hiccup

33. COMPLICATIONS
 Blood loss/hematoma
 Infection
 Arrhythmia (especially during insertion)
* PVC’s are common
* sustained & non-sustained VT
* Heart block
* Bundle branch block
 Pneumothorax
 Myocardial perforation → leads to cardiac tamponade requiring
emergency pericardiocentesis

34. Complication………cont’d
 Loss of capturing ; Causes can be related to
1)Patient’s condition (Hypoxia , acidosis , electrolyte
imbalances leads to increased threshold)
2)Lead position(catheter dislodgement , poor endocardial
contact ,perforation etc)
3)Generator malfunction
4)Battery depletion
CAPTURED BEAT NON CAPTURED BEAT

35. BATTERY
 Use a fresh battery with each patient
9 V alkaline battery
or
9 V lithium battery
 Monitor battery status Low battery LED blinks red
and the device will beep when battery is getting low

36. Low battery warning
 The Low Batt/Error LED will flash red (every 5 s) and device will beep
(every 5 min) .
 Replace battery when possible .
 If device turned off after the low battery warning begins, the battery
must be replaced before the device can be turned on again .

37. Replacing the battery
Replacing the Battery
• Do not replace battery while connected to patient
• Slide the compartment lid (12) to the side
• Remove the battery from the compartment and
disconnect from the battery clip
• Connect new battery with correct polarity to the battery
clip
* DOES NOT PROVIDE PACING WHEN BATTERY IS
REMOVED

38. Atrial high rate pacing
Overdrive suppression of tachyarryhthmia
 Ensure leads/wires in atrium •Set Basic Rate: 30-180 ppm
 Set Mode: x2 or x4
 Press and hold High Rate to deliver RAP
x2 = Basic Rate x2 Range = 60 - 360 ppm
x4 = Basic Rate x4 Range = 120 - 720 ppm
 Release High Rate button to stop