Transcript Do Bolus Thrombolytics Carry a Higher Risk of Intracranial

ICDs – Secondary prevention
The EP Show:
Which ICD for which patient?
Part 1: Secondary prevention
Eric Prystowsky MD
Director, Clinical Electrophysiology Laboratory
St Vincent Hospital
Indianapolis, IN
Helmut Klein MD
Head of Division of Cardiology
Otto-von-Guericke Universität Magdeburg
Magdeburg, Germany
Paul Dorian MD
Professor of Medicine
Division of cardiology
St. Michael's Hospital
Toronto, ON
EP Show – Aug 2003
ICDs – Secondary prevention
Secondary prevention
Secondary prevention patients
•Documented history of cardiac arrest
due to ventricular abnormality
•Documented sustained ventricular
tachycardia with symptoms requiring
intervention
•Syncope due to a ventricular arrhythmia
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
Patients at risk
Any patient with a sustained life-threatening
arrhythmia without reversible cause is at
very high risk without treatment
Prognosis of patients with sustained
ventricular tachycardia in the presence of
heart disease is as bad as for those with a
history of cardiac arrest
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
Clinical trials
Medical therapy
ICD
All-cause mortality
(%)
45
40
35
30
25
20
15
10
5
0
EP Show – Aug 2003
AVID
CIDS
CASH
ICDs – Secondary prevention
Consensus
Consensus has been reached that someone
who is at high risk of sudden cardiac death is
best treated by an ICD
•Questions remain about how to treat a
patient suffering cardiac arrest in the
context of another severe illness
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
Amiodarone?
In a debate Stuart Connelly suggested
amiodarone is a reasonable alternative for
patients with EF >35%
11-year mortality follow-up of CIDS
Annual
mortality rate
EP Show – Aug 2003
ICD
(%)
Amiodarone
(n=60) (%) (n=60)
4.8
8.4
HR
2.01
(p=0.0231)
Dorian P et al. AHA 2002
ICDs – Secondary prevention
Two questions
What is the role of amiodarone in Europe?
Are we really able to determine what is and
isn't reversible cause?
"Maybe we're not so smart in
picking up reversible causes."
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
Amiodarone in Europe
Amiodarone in patients with better EF:
•Was originally thought the ideal ICD
candidate would have better EF
• Reality is that incidence of sudden death
is much higher in patients with low EF,
and ICDs are much more effective there
Europe is coming over to the idea of ICDs as
the main approach
Klein
EP Show – Aug 2003
ICDs – Secondary prevention
Ventricular function changes
"You never know when the ventricular
performance changes and gets worse.
Impaired ventricular function is not a
sign that starts with one symptom and
then you know."
A patient can have a small ischemic event
without noticing and suddenly drop in
ejection fraction
Klein
EP Show – Aug 2003
ICDs – Secondary prevention
ICDs first
Patients who have had a cardiac arrest,
regardless of reason, need an ICD
Amiodarone can be used as additional
therapy or for those who may have
recurring sustained ventricular tachycardia
to limit ventricular intervention
Klein
EP Show – Aug 2003
ICDs – Secondary prevention
Follow-up
A major limitation of the the major ICD
trials is that follow-up was only two to
three years but the disease is a chronic one
"The severity of the underlying heart
disease is a moving target,
and the sad reality is that the
trajectory of the severity of heart
disease is such that most patients over
the long term will get worse."
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
ICDs over time
The trials don't tell us, but the probability
of benefiting from an ICD will increase over
time
Improvements in heart-failure therapy
mean most patients receiving ICDs for
secondary prevention do live five years or
more
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
Long-term mortality
11-year mortality follow-up of CIDS
Measure
Annual
mortality rate
Total number
of deaths
EP Show – Aug 2003
ICD
Amiodarone
(n=60)
(n=60)
4.8%
8.4%
16
28
HR
2.01
(p=0.0231)
NA
Dorian P, et al. AHA 2002
ICDs – Secondary prevention
Reversible cause
There are still some reversible causes that
are undisputed and are acceptably called
"reversible cause":
• A patient comes in with clearly
identifiable AMI and has VF in the first 6
to 24 hours is a true reversible cause
• For a hyperkalemia patient, is a K of
2.9 reversible?
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
Hypokalemia
During cardiac arrest potassium is taken up
inside cells, and so the initial potassium
measurement in most patients will be low
"It's probably better to think of
hypokalemia as a trigger, rather
than as a cause, of the cardiac arrest."
Dorian
EP Show – Aug 2003
ICDs – Secondary prevention
Potassium
If it is truly hypokalemia you ought to
repeat the measurement six to eight hours
later
•If K is now 4.0 with minimal repletion
of potassium then patient needs an ICD
•If K is still in the mid- to high-2 range
six to eight hours later then they
probably really do have hypokalemia
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
Single or dual chamber?
We accept you must be careful what you
call reversible, and ICDs are the treatment
of choice
• Do we use single or dual chambers,
and have the data from DAVID changed
your approach?
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
Unnecessary pacing
"Continuously pacing means that you
create an asynchronous ventricular
contraction."
Avoiding pacing when possible is better
than just sensing the atrium and pacing the
right ventricle continuously
If there is compelling reason such as sinusnode dysfunction then dual-chamber pacing
could be used
Klein
EP Show – Aug 2003
ICDs – Secondary prevention
Single- or dual-chamber ICD?
"We changed our mind just recently
because of the DAVID trial."
Klein
Proportion of single- and dual-chamber
pacing?
•Klein: 80% single/20% dual
•Dorian: 30% to 40% single/60% to
70% dual
EP Show – Aug 2003
ICDs – Secondary prevention
Dual-chamber ICDs
Dual-chamber ICDs offer the ability to
discriminate between supraventricular
tachycardia and tachycardia
Programmed for minimum pacing:
backup rate <50 beats/minute and
longest AV delay possible
"That allows us to then derive the
benefit for the atrial signal for
discrimination without the cost of the
unwanted ventricular pacing."
EP Show – Aug 2003
Dorian
ICDs – Secondary prevention
Minimize pacing
Must minimize the amount of time pacing
the ventricle, don't pace unless you have to
• Decision on single vs dual chamber
will depend on the individual implanter
and the particular patient
"How you actually select who gets the
atrial lead will depend on your own
philosophy."
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
Economics
With less economic pressure, I lean toward
using a dual-chamber ICD with minimal
programming
"I would be the first to admit to you
that if someone shut me down
economically for any reason, that I
could either get two defibrillators or one
with dual-chamber capability, I'd take
two defibrillators."
Prystowsky
EP Show – Aug 2003
ICDs – Secondary prevention
The EP Show:
Which ICD for which patient?
Part 2: Primary prevention
Eric Prystowsky MD
Director, Clinical Electrophysiology Laboratory
St Vincent Hospital
Indianapolis, IN
Helmut Klein MD
Head of Division of Cardiology
Otto-von-Guericke Universität Magdeburg
Magdeburg, Germany
Paul Dorian MD
Professor of Medicine
Division of cardiology
St. Michael's Hospital
Toronto, ON
EP Show – Aug 2003