Download Indications for ICDs

The Electrical Management of Cardiac Rhythm Disorders
Tachycardia
Indications for ICD
Implantation
Guidelines
● ACC/AHA/ESC 2006 Guidelines for Management of
Patients with Ventricular Arrhythmias and Prevention of
Sudden Cardiac Death
○ Full document is 100 pages
○ Executive summary is 44 pages
○ Available online or from SJM Library
● Class I, II (IIa and IIb), and III
○ Class I: implant recommended
○ Class II: evidence mixed
○ Class III: implant not recommended
● Evidence levels A, B, C
○ A is most stringent, C is least
Guidelines
● Guidelines specify that devices should be used in
patients receiving “optimal medical therapy” meaning the
most appropriate state-of-the-art pharmacological therapy
for their condition
● Guidelines specify that ICDs should only be implanted in
patients “who have reasonable expectation of survival
with good functional status for more than one year”
Main Pathologies
● LV dysfunction relating to a prior myocardial infarction
(MI)
● Congenital heart disease
● Metabolic and inflammatory conditions, including
○ Myocarditis
○ Rheumatic disease
○ Endocarditis
○ Diabetes
○ End stage renal failure
● Pericardial disease
● Valvular heart disease
LV Dysfunction and Prior MI
● Patients with coronary heart disease (CHD) are at risk of
SCD
● SCD can occur in this population even if the patient does
not have severe LV dysfunction
● Three main types of arrhythmias occur in this population
○ Nonsustained ventricular tachycardia (NSVT)
○ Sustained VT
○ Cardiac arrest associated with VT/VF
LV Dysfunction and Prior MI
● ICD therapy is recommended for patients with
○ LVEF ≤ 40%
○ Spontaneous NSVT or inducible to sustained
monomorphic VT
● And also for patients with
○ LVEF ≤ 30% as a result of prior MI (more than 40 days
earlier)
○ NYHA Class II or III
LV Dysfunction and Prior MI
● What about patients who just have NSVT?
○ May be asymptomatic
○ There is no evidence that suppressing NSVT confers
any mortality benefit
● If the patient has sustained VT
○ Consider the symptoms
○ How well does the patient tolerate the VT?
○ Frequency of VT episodes
● What about patients on antiarrhythmic drugs?
○ Antiarrhythmics suppress ambient arrhythmias but do
not prevent all arrhythmias
○ May have pro-arrhythmic effects
○ Can be prescribed together with ICD therapy
LV Dysfunction and Prior MI
● Class I Indications (recommended)
○ If coronary revascularization cannot be carried out and
there is evidence of prior MI and significant LV
dysfunction, patients resuscitated from VF should
receive an ICD
○ Primary-prevention patients with LV dysfunction due to
prior MI (more than 40 days earlier) with LVEF ≤ 3040% and NYHA Class II or III
○ Patients with LV dysfunction due to a prior MI who
have hemodynamically unstable VT (LVEF scores not
specified)
LV Dysfunction and Prior MI
● Class I Indications (summarized)
○ Patients must have had a prior MI (at least 40 days
ago)
○ Patients must have LV dysfunction from that MI
○ Plus they must also have
• Documented VF (resuscitation from a previous episode)
• Hemodynamically unstable VT
• NYHA Class II or III
● For clinicians
○ Heart attack survivors need to know that they are at
high risk for arrhythmias, especially dangerous
ventricular tachyarrhythmias
○ It is important to know the LVEF score of heart attack
survivors to know if they are indicated for ICD therapy
LV Dysfunction and Prior MI
● Class IIa Indications (mixed evidence, but more pro than
con)
○ LV dysfunction due to prior MI (at least 40 days earlier)
• LVEF ≤ 30% to 35%
• NYHA Class I
○ Recurrent sustained VT in post-MI patients with
normal or near-normal ventricular function
● The guidelines also say it is a Class IIa indication
○ To prescribe adjunctive therapies for ICD patients
such as
• Catheter ablation
• Surgical resection
• Drug therapy with amiodarone or sotalol
LV Dysfunction and Prior MI
● Heart attack survivors with LV dysfunction should be
considered for an ICD if they have
○ Class I
• Documented VF (resuscitation from a previous episode)
• Hemodynamically unstable VT
• NYHA Class II or III
○ Class IIa
• NYHA Class I and
• LVEF ≤ 30% to 35%
LV Dysfunction and Prior MI
● Class IIb (evidence mixed, more against than for)
○ Patients with LV dysfunction from a prior MI and
hemodynamically unstable VT with an LVEF ≤ 40%
may receive catheter ablation or amiodarone instead
of ICD therapy in the event
• They cannot be implanted with an ICD for some reason
• They refuse ICD therapy
Congenital Heart Disease
● Anatomic and physiologic defects in the heart
● Includes a wide range of conditions
● Those most associated with arrhythmias are
○ Tetralogy of Fallot
○ D- transposition of the great arteries
○ L- transposition of the great arteries
○ Aortic stenosis
○ Functional single ventricle
● SCD risk is relatively low in this patient population
○ Lack of data to guide patient management decisions
● Positive EP study is necessary
Congenital Heart Disease
● Class I Indications (recommended)
○ Patients with congenital heart disease who survived
cardiac arrest and after evaluation of the event it is
found not attributable to reversible causes
○ Patients with congenital heart disease and
spontaneous sustained VT should undergo invasive
hemodynamic and EP evaluation
• Catheter ablation or surgical resection to address VT
• If that does not work, ICD implantation
Congenital Heart Disease
● Class IIa Indications (mixed evidence, but more pro than
con)
○ A congenital heart disease patient with unexplained
syncope and impaired ventricular function should
undergo hemodynamic and EP evaluation. If the
cause of the syncope is not reversible, the patient
should receive an ICD
● Class IIb Indications (more con than pro)
○ A congenital heart disease patient with ventricular
couplets or NSVT should undergo EP testing to
determine the risk of arrhythmia
Congenital Heart Disease
● Patients with congenital heart disease are considered
suitable candidates for ICD therapy after invasive
hemodynamic and EP evaluation if
○ They already survived cardiac arrest (Class I)
○ They have spontaneous sustained VT and catheter
ablation or surgical resection are not desired or
possible (Class I)
○ They have unexplained syncope not due to a
reversible cause and impaired ventricular function
(Class IIa)
● It is not recommended (Class IIb) for patients with
congenital heart disease and ventricular couplets or
NSVT to undergo EP testing to evaluate their risk of
arrhythmias
Metabolic and Inflammatory Conditions
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Myocarditis, rheumatic disease, and endocarditis
Infiltrative cardiomyopathy
Endocrine disorders and diabetes
End-stage renal failure
Obesity, dieting, anorexia
Myocarditis
● Myocarditis involves inflammation of the myocardium
○ Associated with infections
○ Acute myocarditis is associated with arrhythmias,
including potentially life-threatening ventricular
tachyarrhythmias
○ Heart block or other bradyarrhythmias may occur in
acute myocarditis (persistent heart block is rare)
● Chagas disease is associated with progressive heart
failure
○ Includes conduction defects up to and including
complete heart block
○ Life-threatening ventricular tachyarrhythmias are
possible
● These conditions may require both pacing and
defibrillation
Myocarditis
● Class I (recommended)
○ Temporary pacing for patients with symptomatic
bradycardia and/or heart block during the acute phase
of myocarditis
● Class IIa (mixed but more pro than con)
○ ICD implantation for patients with myocarditis but not
in the acute phase who have life-threatening
ventricular tachyarrhythmias (that is, who have other
ICD indications)
● Class III (not recommended)
○ ICD implantation is not recommended in the acute
phase of myocarditis
Myocarditis
● For patients in the acute phase of myocarditis
○ Temporary pacing may be indicated if the patient has
symptomatic bradycardia and/or heart block
○ ICD implantation is not recommended (Class III)
● For patients with myocarditis not in the acute phase
○ An ICD may be appropriate (Class IIa) if the patient is
indicated for one according to the guidelines, in other
words, if the patient has life-threatening ventricular
tachyarrhythmias
○ Patients with myocarditis but otherwise no ICD
indication should not get an ICD
○ However, patients with myocarditis should not be
denied an ICD if they are otherwise indicated for one
Infiltrative Cardiomyopathy
● Patients with infiltrative cardiomyopathy are at increased
risk for potentially life-threatening ventricular
tachyarrhythmias and SCD
● Patients with infiltrative cardiomyopathy should be treated
the same as patients without that condition with respect
to device therapy
○ If otherwise indicated for pacing, such patients should
be paced
○ If otherwise indicated for an ICD, such patients should
get an ICD
● This condition, in and of itself, is not an indication for a
device
Endocrine Disorders and Diabetes
● Insufficient or excessive hormonal activity in these
patients can predispose patients to the risk of VT and
SCD
● Endocrine disorders may accelerate the progression of
underlying structural heart disease which, in turn, can
increase the risk of arrhythmias
● Patients with endocrine disorders, including diabetes,
should be treated the same as patients without endocrine
disorders with respect to devices
○ If the patient has a standard pacing indication, he or
she should be paced
○ If the patient has a standard ICD indication, he or she
should get an ICD
End-Stage Renal Failure
● About 40% of patients with end-stage renal failure die
from cardiovascular causes
○ 20% of these deaths are attributable to SCD
● Arrhythmias should be treated conventionally in such
patients (the same as patients who do not have endstage renal failure), especially those awaiting kidney
transplant
○ If indicated for a pacemaker, they should be paced
○ If indicated for an ICD, they should get an ICD
Obesity, Dieting, Anorexia
● Eating disorders are all strongly associated with SCD
● The severely obese are 40 to 60 times more likely to
experience SCD than the non-obese population
● Anorexia mortality rates are 5% to 20%
○ About one-third of these are due to cardiac causes
○ There are no specific data available on SCD rates
among anorectics
● Such patients should be treated the same as patients
without eating disorders with respect to devices
Pericardial Disease
● Ventricular arrhythmias that develop in patients with
pericardial disease should be treated in the same manner
that such arrhythmias are treated in patients with other
disease
● ICD and pacemaker implantation are appropriate if the
patient has standard indications
● Pericardial disease is not, in and of itself, an indication for
a device
Valvular Disease
● Many patients with valvular disease have rhythm
disorders
● There is a lack of evidence to suggest that valve
replacement or valve repair reduces the incidence of
rhythm disorders in these patients
● For that reason, patients with valve disease should
continue to receive appropriate treatment for their rhythm
disorders, which may include device implantation
Dilated Cardiomyopathy (DCM)
● Dilated cardiomyopathy occurs when the shape and
muscular quality of the heart change
○ The heart becomes enlarged, flabby, floppy
○ Impairs the ability of the heart to pump efficiently
● Five-year mortality rate for DCM patients is 20%
○ SCD is a major contributor to that death rate
● Ventricular tachyarrhythmias are common
○ SCD risk is highest among patients with other
indicators of more advanced cardiac disease, i.e. DCM
patients with heart failure, etc.
Dilated Cardiomyopathy (DCM)
● Class I (ICD is recommended)
○ Nonischemic DCM patients with significant LV
dysfunction and sustained VT or VF
○ Nonischemic DCM patients with an LVEF ≤ 30%-35%
who are NYHA Class II or III
● Class IIa (evidence mixed, but more pro than con)
○ Nonischemic DCM patients with unexplained syncope
and significant LV dysfunction
○ Nonischemic DCM patients with sustained VT and
normal or near-normal ventricular function
● Class IIB (evidence mixed, but more against)
○ Nonischemic DCM patients with an LVEF ≤ 30-35%
who are NYHA Class I
Dilated Cardiomyopathy (DCM)
● Primary and secondary prevention patients in this
population
● ICDs are recommend in patients with nonischemic DCM
and
○ Sustained VT or VF and
• With LV dysfunction (Class I)
• With normal ventricular function (Class IIa)
○ Unexplained syncope with LV dysfunction (Class IIa)
○ LVEF ≤ 30-35% and
• NYHA Class II or III (Class I)
• NYHA Class I (Class IIb)
Hypertrophic Cardiomyopathy (HCM)
● HCM involves a stiffening of the ventricles and thickening
of the heart walls
○ SCD risk is directly related to LV wall thickness
○ Mortality rate is 40% or higher if the LV wall exceeds
30 mm in thickness
● Increased risk of ventricular tachyarrhythmias in this
population, although many patients are asymptomatic
Hypertrophic Cardiomyopathy (HCM)
● Major risk factors for HCM patients
○ Cardiac arrest (VF)
○ Spontaneous, sustained VT
○ Family history of premature sudden death
○ Unexplained syncope
○ LV wall thickness ≥ 30 mm
○ Abnormal exercise blood pressure
○ Nonsustained spontaneous VT
Source: Zipes et al. ACC/AHA/ESC Practice Guidelines. JACC 2003; 42: 1687-713.
Hypertrophic Cardiomyopathy (HCM)
● Class I (recommended)
○ HCM patients with sustained VT or VF
● Class IIa (mixed evidence, more pro than con)
○ HCM patient with one or more of the “risk factors”
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VF or spontaneous sustained VT
Unexplained syncope
LV wall thickness more than 30 mm
Spontaneous NSVT
Abnormal exercise BP
Family history of premature sudden death
● Primary and secondary ICD indications for HCM patients
Arrhythmogenic RV Cardiomyopathy
● ARVCM involves right-sided cardiomyopathy associated
with rhythm disorders
● Sometimes called RV dysplasia
● To date, no data from large randomized clinical trials to
offer evidence for therapeutic decisions
● Ventricular arrhythmias occur frequently in patients with
ARVCM
● ICD patients with this condition usually experience a
relatively high number of therapy deliveries
Arrhythmogenic RV Cardiomyopathy
● Class I (recommended)
○ Patients with ARVCM and documented sustained VT
or VF should get an ICD
● Class IIa (evidence mixed, more pro than con)
○ Patients with ARVCM and one or more of the following
should get an ICD:
• Extensive disease (such as those with LV involvement)
• One or more family members with history of SCD
• Undiagnosed syncope where VT or VF cannot be ruled out
○ If ICD implantation is not feasible in such patients,
amiodarone or sotalol should be prescribed
Heart Failure (HF)
● Heart failure (HF) is a syndrome rather than a disease
● HF patients with some degree of LV dysfunction are at
high risk of ventricular tachyarrhythmias
○ SCD may account for as much as half of deaths in this
population
○ Biventricular pacing (CRT) reduces morbidity in this
population and one study (CARE-HF) showed it
improved mortality
○ However, CRT without defibrillation in this population
remains controversial
Heart Failure (HF)
● Class I (recommended)
○ Patients with an LVEF ≤ 40% who have survived VF or
hemodynamically unstable VT should get an ICD
○ Patients with LV dysfunction due to a prior MI (more
than 40 days earlier) with an LVEF ≤ 30%-40% and
NYHA Class II or III
○ Patients with nonischemic heart disease, an LVEF ≤
30%-35% and NYHA Class II or III
○ Amiodarone, sotalol and/or beta-blockers are
recommended adjuncts to ICD therapy in these
patients
Heart Failure (HF)
● Class IIa (evidence mixed, more pro than con)
○ Patients with NYHA Class III or IV with a QRS width >
120 ms should get a CRT-D device
○ Patients with NYHA Class I, LV dysfunction due to a
prior MI, an LVEF ≤ 30% to 35%
○ HF patients with recurrent stable VT and normal or
near-normal LVEF scores
○ Patients with NYHA Class III or IV, LVEF ≤ 35%, with
a QRS width ≥ 160 ms (or at least 120 ms in the
presence of other evidence of ventricular
dyssynchrony) are indicated for a CRT device without
defibrillation
Heart Failure (HF)
● Class IIb (evidence mixed, more against than for)
○ Patients with nonischemic heart disease and an LVEF
≤ 30% to 35% and NYHA Class I should get an ICD
● The HF population includes both primary-prevention and
secondary-prevention indications
Device Indications Based on LVEF Scores
● ≤ 40%
○ Documented VT or VF (Class I)
● ≤ 35%
○ NYHA Class III or IV plus QRS ≥ 160 ms or ≥ 120 with
other evidence of ventricular dyssynchrony should get
a CRT device without defibrillation (Class IIa)
● ≤ 30%-35%
○ NYHA Class II or III with nonischemic heart disease
(Class I)
○ LV dysfunction from a prior MI (Class I)
○ NYHA Class III or IV with a QRS > 120 ms should get
a CRT-D device with defibrillation (Class IIa)
○ NYHA Class I with LV dysfunction due to a prior MI
(Class IIa)
○ NYHA Class I (Class IIb)
Device Indications Based on NYHA Class
● NYHA Class I
○ LV dysfunction due to a prior MI and LVEF ≤ 30%-35% (Class IIa)
○ LVEF ≤ 30%-35% (Class IIb)
● NYHA Class II
○ Nonischemic heart disease and LVEF ≤ 30%-35% (Class I)
● NYHA Class III
○ Nonischemic heart disease and LVEF ≤ 30%-35% (Class I)
○ QRS > 120 ms and LVEF ≤ 30%-35% should get CRT-D (Class IIa)
○ QRS ≥ 160 ms (or 120 ms with evidence of ventricular dyssynchrony)
and LVEF ≤ 35% should get CRT-P (Class IIa)
● NYHA Class IV is only indicated for a CRT system (CRTP or CRT-D)
○ QRS > 120 ms and LVEF ≤ 30%-35% should get CRT-D (Class IIa)
○ QRS ≥ 160 ms (or 120 ms with evidence of ventricular dyssynchrony)
and LVEF ≤ 35% should get CRT-P (Class IIa)
Genetic Arrhythmia Syndromes
● Some patients have genetic conditions that put them at
increased risk of ventricular tachyarrhythmias and SCD
even though they have no structural heart damage or
other conventional risk factors
○ Long QT Syndrome
○ Brugada Syndrome
● Relatively rare
● Increased attention and study
Long QT Syndrome (LQTS)
● Hereditary disorder characterized by abnormally
prolonged QT segment on the ECG
● Patients are at high risk of cardiac events
○ Syncope
○ Dangerous ventricular arrhythmias
○ SCD
● Affects patients at all ages but may be diagnosed in
pediatric population
● Beta-blockers are indicated (Class I) for LQTS
○ Pacing may be required if beta blockade induces
symptomatic bradycardia
○ ICDs may also be indicated
LQTS Indications
● Patients with Long QT Syndrome are indicated for an ICD
if
○ There is a documented episode of cardiac arrest
(Class I)
○ There is documented VT and/or syncope despite beta
blockade (Class IIa)
● The use of an ICD as primary prevention in LQTS
patients is a Class IIb indication (mixed evidence with
weight of evidence against therapy)
Brugada Syndrome
● Hereditary disorder characterized by an abnormal surface
ECG
● Patients have a heart that is structurally normal
● Elevated risk of ventricular arrhythmias
○ Typically polymorphic VT or VF while at rest or asleep
○ Increased risk of SCD
○ More common in some ethnic groups than others
(Asians are more likely to have this condition than
other groups)
Brugada Syndrome Indications
● Patients with Brugada Syndrome should get an ICD if
○ They have documented cardiac arrest (Class I)
○ They have documented VT even if it did not result in
cardiac result (Class IIa)
○ There is spontaneous ST-segment elevation on the
ECG and they have experienced syncope (Class IIa)
Miscellaneous Indications
● Patients with structurally normal hearts and normal or
near-normal ventricular function are indicated for an ICD
(Class IIa) if they have sustained VT
● Athletes should be evaluated like other patients but with
attention given to their unique level of exertion
○ Carefully evaluate athletes who experience syncope!
● Geriatric patients should be treated with respect to device
therapy the same as younger patients
○ However, the guidelines do not recommend ICD
therapy in patients who are not likely to live for at least
one year with good functional status
Pediatric Patients
● Class I indications for an ICD
○ Cardiac arrest
○ Documented sustained ventricular tachyarrhythmias
○ Genetic high risk
○ Cardiac arrest (Class I)
● Class IIa indications for an ICD
○ Spontaneous sustained ventricular arrhythmias with
impaired LV function (LVEF ≤ 35%) (Class IIa)
Conclusion
● New guidelines are an attempt to standardize device
therapy in U.S.A. and Europe
○ Based on recent clinical trials
○ Years of experience treating SCD with devices
● However, guidelines are guidelines
○ Clinical judgment must be exercised in each individual
case
○ Many factors come into play including
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Clinical condition
Drug regimen
Comorbid conditions or other diseases
Prognosis
Patient and family preferences