This document discusses various implantable cardiac devices including pacemakers, implantable cardioverter-defibrillators (ICDs), cardiac resynchronization therapy (CRT), and cardiac assist devices. It describes the components, indications, and complications of pacemakers and ICDs. It also covers topics such as pacemaker/ICD terminology, programming, interactions with defibrillation, and transcutaneous pacing. Cardiac assist devices are briefly discussed, noting examples like LVADs, BiVADs, and total artificial hearts.

1. Implantable Cardiac Devices
Mohamed Elwakil, MD
MRCEM, EGYBEM
Associate consultant of emergency medicine

2. TYPES
• Pacemaker
• ICD
• CRT
• Cardiac Assist Devices

3. Pacemakers

4. Introduction
Pace /peɪs/ :move or develop (something) at a particular rate or
speed.
Modern Pacemakers are devices that detect the electrical activity of
the heart (sense) and stimulate it to contract at a faster rate.
First described in 1952,
Permanent transvenous pacing devices were introduced into clinical
practice in the early 1960s.

5. Indications
• symptomatic heart block
• symptomatic sinus bradycardia
• atrial fibrillation with a symptomatic
bradycardia (low ventricular response rate)
in the absence of medications that affect
atrioventricular (AV) conduction.

7. Pacemaker Components
• All pacemaker systems have three basic
components:
1. the pulse generator, which houses the power
source (battery);
2. the electronic circuitry;
3. the lead system, which connects the pulse
generator to the endocardium.
• Nearly all implanted pacemakers are lithium
powered which function normally for 4 to 10 or
more years.

9. • Permanent pacemakers have endocardial
leads that are positioned in contact with
the endocardium of the right ventricle and,
in the case of a dual-chamber device, the
right atrium, with a subclavian or cephalic
vein approach used for insertion.

12. Pacemaker Terminology
• In 1974, A letter code was established
• Five-letter code scheme
• The 1st 3 codes letters are used most
commonly

16. Single chamber examples

21. Dual chamber examples

28. Complications
• If a patient with a pacemaker has a fever of
unclear cause, pacemaker lead infection and
endocarditis should be considered.
• Pain in the arm ipsilateral to the site of
insertion should suggest acute
thrombophlebitis.

30. • Pacemaker malfunction
soon after implantation
(within 6 to 8 weeks)
• Is usually a result of a
lead problem, such as a
lead displacement, or a
pacemaker programming
failure, such as a pacing
rate too slow for the
patient’s needs.
Pacemaker malfunction

31. Quiz ?
“end-of-life” pacing characteristics of a depleted battery

32. ACLS and Pacemaker
• Electrical defibrillation at recommended shock
strengths (200, 300, and 360 J) can be safely
performed in the patient with a pacemaker.
• The safe distance is (>10 cm) from the pulse
generator. Alternatively, defibrillation electrodes can be
placed in an anteroposterior configuration.
• Temporary transcutaneous pacing may be needed if
the pacemaker cannot be reprogrammed or normal
pacing does not resume spontaneously.

33. Transcutaneous Pacing
• Temporary cardiac pacing using pads or paddles
applied externally to the chest.
• INDICATIONS:
1. bradycardia unresponsive to drug therapy
2. 3rd degree heart block
3. Mobitz type II second-degree heart block when
haemodynamically unstable or operation planned
4. overdrive pacing
5. asystole

34. Transcutaneous Pacing, cont.
METHOD OF INSERTION AND/OR USE
1. place pads in AP position
2. connect ECG leads
3. set pacemaker to demand
4. turn pacing rate to > 30bpm above patients intrinsic rhythm
5. set mA to 70
6. Pain killer +- sedation
7. start pacing and increase mA until pacing rate captured on
monitor and mechanically.
8. if pacing rate not captured at a current of 120-130mA ->
resite electrodes and repeat the above.
9. once pacing captured, set current at 5-10mA above
threshold

35. Pacemaker

37. Implantable Cardioverter-
defibrillators
ICD

38. Implantable Cardioverter-defibrillators
ICD
• The first devices for endocardial defibrillation
were implanted in surviving victims of sudden
cardiac death in 1980.
• Drug therapy is still required after ICD
implantation to suppress ventricular
dysrhythmias, minimize the frequency of ICD
shocks, improve patients’ tolerance, and
decrease energy use.
• All ICDs are also ventricular pacemakers.

39. indication

40. • The most common complaint of ICD patients is the
occurrence of frequent shocks.
• An increase in the frequency of episodes may occur in
the setting of hypokalemia, hypomagnesemia,
ischemia (with or without infarction), or the
proarrhythmic effect of drugs administered to decrease
the frequency of ventricular tachyarrhythmias.
• Many ICD patients, particularly those with newly
implanted devices, report that their device has
discharged, but subsequent device interrogation
reveals that no discharge occurred
Complications

42. ACLS and ICD
• An ICD does not prevent sudden death in all
patients at risk, and a patient with an ICD may
arrive in cardiac arrest (2% annual incidence in
patients with implanted devices).
• Resuscitation efforts in the patient with an ICD
should be undertaken.
• Deactivation with magnet application is important
in the immediate post-resuscitation period.
Ventricular dysrhythmias are common at this time
due to prolonged global myocardial ischemia.

44. Biventricular Pacing
CRT

46. cardiac resynchronization
therapy
• Is a therapy for patients with left-sided heart
failure (ejection fracture under 35%) and
ventricular dyssynchrony.
• Indications
1. patients with (NYHA) class II, III or IV heart
failure
2. left ventricular dysfunction
3. left bundle branch block

47. complication
• coronary sinus dissection occurred in 0.3% to
4.0% of patients and coronary vein or
coronary sinus perforation in 0.8% to 2.0% of
patients
• Cardiac tamponade, less than 1% of patients.
• Dislodgement of the left ventricular electrode
with resultant loss of pacing occurs as an
early complication in approximately 10% of
patients

48. Cardiac Assist Devices

50. Overview
• Mechanical ventricular assistance devices
have been used as a“bridge” to
transplantation since the 1960s.
• Devices: Jarvik 2000 and HeartMate II
• Types
1. The left ventricular assist device (LVAD)
2. The biventricular assist device (BiVAD)
3. Total artificial heart (TAH).

51. • Most left ventricular assist device (LVADs) do
not produce pulsatile flow; therefore, these
patients will not have a palpable pulse.
• Patients with a total artificial heart (TAH) have
no native heart and no cardiac electrical
activity. Electrocardiogram (ECG) for the TAH
will read asystole. Defibrillation and pacing
will not be effective. Chest compressions will
not be effective and may be harmful.

53. Take Home
• Pacemaker malfunction arises in a limited number of
ways: failure to pace, oversensing, undersensing, and
pacing at an inappropriate rate (too fast or too slow).
• paced ventricular complexes are conducted with a left
bundle branch block pattern, A right bundle branch
pattern is abnormal and suggests lead displacement.
• Magnet application does not turn off a pacemaker, it
turns off the sensing or inhibition function. Fixed-rate
pacing that is independent of or in competition with the
underlying native rhythm will ensue. Removal of the
magnet restores the inhibitory activity of the
pacemaker and returns it to demand pacing mode.

54. • Defibrillation is safe in patients with a
pacemaker or implantable cardioverter-
defibrillator (ICD). Paddles should be
placed at least 10 cm from the
subcutaneous implant site of the device.

56. References
• Rosenen`s 2018, Implantable Cardiac Devices
• Pacemaker Codes and Modes – Explained,
https://www.youtube.com/watch?v=L-
lMhDQTq7w&index=18&list=WL
• https://lifeinthefastlane.com/ccc/transcutane
ous-pacing/
• https://en.wikipedia.org/wiki/Ventricular_assi
st_device