2. What is ICD ?
• Impact on millions of individuals by slowing
their heart failure progression
• Improve their QOL
• Decrease hospitalization rate
• Implantable inside the body
• Cardioversion , Defibrilation and Pacing
• Correcting most of life-threatening cardiac
arrythmias
• First line treatment and prophylactic therapy
in SCD ( due to VF or VT )
4. How it works ?
• Programmed to detect abnormal heart
rhythms
• Deliver therapy via antitachycardial pacing
• Deliver high-energy or low-energy shocks
• ICD Generator ( Computer Chip or circuit
with a RAM Memory , Programmable
Software , Capacitor and Battery )
• Wire (s)
5. Process of Implantation
• Similar to implantation of a pacemaker
• Initially were implanted via Thoracotomy and were
applied in Epicardium or Pericardium
• Now , Generator is implanted under the skin in the
Left Upper Chest
• Wire ( s ) : connected to the Generator and passed
through a vein to the Right chamber of heart
• Single lead : Right Ventricle ( Single Chamber)
• Two leads : Right Ventricle and Right Atrium ( Dual
Chamber )
• Three leads : RV and RA and outer wall of the LV
( Biventricular )
8. Indications
• According to ACC , AHA and ESC
• Prevent Sudden Cardiac Death
• Primary or Secondary
1- LVEF 35 - prior MI – HF class II-III
2- Non-Ischemic DCMP – EF 30 – class II-III
3- NS-VT – prior MI – EF 40
4- Structural heart disease and spontaneous
Sustained VT ( stable or unstable )
5- Syncope of undetermined origin
Hemodynamically significant sustained VT or
VF
9. Problems
• Historically , needed to be replaced every
3-7 years
• Several device replacements (3-5 times) =
Complications due to each change-out +
Additional cost for each replacement
• Complications
12. Working Mechanism
• Constantly monitor the rate and rhythm
• Deliver therapy as electronic shock when
heart rate exceeds a preset number
• Some of them have software which
discriminates VF and VT
• Some of them can detect Upper chamber
rhythm disorders ( SVT like Afib and Flutter)
and Lower chamber ones ( like Torsade de
point ) and deliver therapy differently
16. Costly replacements
• Imagine : 54 year-old / average battery life =
4.4 yr / by 80 year = 5 device replacement
each replacement costs : 37000 $
total cost till the end = more than
190,000 $ + out-of-the pocket expenses
• If receive double battery life , total cost will
reduce by half
17. Net cost of prophylactic ICD
implantation in randomized
trials
Cost difference
Follow-up ( yr )FinalInitialTrial
4.021600 $25700 $MADIT-I
5.019000 $17500 $SCD-HeFT
3.539200 $$32600MADIT-II
5.033500 $29500 $COMPANION
18. Improving Battery life
• Historically , needed to be replaced every
3-7 years
• Boston Scientific Corporation – 2004 –
working on longevity and effectiveness of
batteries
Now : 10-year warranty ( twice the
capacity ) and still require the same low-
power consumption
19. Other barriers to ICD use
• Many have advanced cardiac disease and
substantial comorbidity and poor QOL
• May not wish to have ICD ( fear of SCD
less than protracted final illness )
• May not wish to undergo the
inconvenience of implantation ( additional
visits and monitor )
• Anxiety , depression and loss of control (
who received ICD shocks )
20. Barriers ( continue )
• Lack of highly-equipped centres in many
regions
• Lack of highly-trained cardiologists and
surgeons specifically for ICD implantation
in many regions
21. Clinical Trials
• A number of CTs have demonstrates the
superiority of ICD over AADs in the
prevention of death in malignant arrhythmias
:
• MADIT-I 2002
• MADIT-II 2004
• SCD-HeFT 2005
• COMPANION 2006
• Birine et al ( UOO ) : ICDs are underused in
North America
