Download Editorial Comment Preventing Sudden Death with Implantable

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Editorial Comment
Preventing Sudden Death with Implantable Defibrillators
in Octogenarians: Too Much Too Late?
Roy M. John, MBBS, PhD, FRCP, FACC, FHRS
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston,
MA, USA
Address for Correspondence: Roy M. John, MD, PhD, Cardiac Arrhythmia Service, Brigham
and Women's Hospital, 75 Francis Street, Boston, MA 02115. Email: [email protected]
Key words: sudden cardiac death, implantable defibrillators, octogenarians
Implantable cardioverter defibrillators (ICD) are highly effective in the prevention of sudden
arrhythmic deaths. [1-3] The recurrence rate following an out of hospital cardiac arrest or
ventricular tachycardia is as high as 24-44% over the ensuing 18-36 months that secondary
prevention is an important consideration in patients without a clearly defined reversible cause
such as acute ischemia or major metabolic derangement. In this context, the ICD has been
shown to be superior to anti-arrhythmics drugs including amiodarone, in a number of clinical
trials. [1,4,5] The value of an ICD is probably better expressed as the numbers needed to treat
(NNT) to save a life. In the AVID trial, 9 patients had to be treated to save a life over a period
of 3 years. The use of ICDs for primary prevention in patients at high risk for arrhythmic
events is more controversial. The event rate is lower, and the benefit less pronounced as
reflected in a larger NNT. In the MADIT II trial of patients with coronary artery disease and
severe LV dysfunction, the NNT was 18 to save one life over a period of 20 months. In the
SCD-HeFT study of heart failure patients with LVEF < 0.35, the NNT was 14 over 5 year. In
all cases, a non-arrhythmic cause limiting life expectancy to less than 1 year rarely justifies
the use of an ICD. The use of ICDs in patients with advanced age, the subject of this editorial,
is not well defined in clinical trials either because of exclusion for age over 80 or low
representation of this age group. The current "appropriate use" guidelines suggest that an ICD
may be appropriate in patients over the 80 years, based on individual considerations. [6]
ICDs have a flip side. They are expensive and are associated with negative effects on quality
of life. The adverse effects of an ICD include inappropriate shocks, infections, and hardware
malfunction including the highly publicized recall advisories. Inappropriate shocks are a
major cause of depression and post-traumatic stress disorder. Thus, the benefit of mortality
reduction from an ICD comes at the cost of some morbidity. In addition, there appears to be a
critical window in the course of heart disease when the ICD is most effective. In the AVID
trial, the largest of the secondary prevention studies, benefit was mostly confined to patients
with left ventricular ejection fraction between 0.20 and 0.35. Sudden deaths form an
important component of heart failure mortality in individuals with better functional class and
these patients stand to benefit most from an ICD. The value of the ICD recede as heart failure
worsens; pump failure and electromechanical dissociation takes over as the predominant
component of death in NYHA class IV heart failure. In the absence of an indication for
cardiac resynchronization therapy, implanted defibrillators confer minimal benefit in
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 15 (1): 1-3 (2015)
John RM, “Preventing Sudden Death with ICD in Octogenarians”
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advanced heart failure unless transplantation or long term assist devices are planned. [6]
In the current issue of the journal, Wilson et al. [7] present analysis of a single center
experience with ICD implantation in octogenarians in the United Kingdom over a 6 year
period to 2012. For unclear reasons, only data on 50 of 74 ICD recipients are presented.
Annual mortality for the cohort was 14% representing a higher than usual mortality for an
ICD population. Interestingly, most documented deaths were non-cardiac (5 patients died with
pneumonia) reflecting co-morbidities and increased susceptibility to fatal infections in this age
group. The data from the present study are largely in concert with prior publications of the use
of ICDs in elderly patients. [6, 8]
Although mortality from cardiovascular disease has declined, the total disease burden has
increased. People live longer but tend to be sicker. While the use of an ICD for secondary
prevention is philosophically more acceptable for an otherwise healthy elderly patient, the use
of the ICD for primary prevention generates more debate. Older patients are known to be at
higher risk for sudden death. In addition, resuscitation from a cardiac arrest of the elderly is
more likely to result in neurological damage and disability. Preventive measure would thus, be
expected to be most effective for this population. However, these arguments have to be
tempered against the fact that the elderly have a higher mortality from non-arrhythmic causes
and the ICD may merely convert a sudden death to a non-sudden, potentially more distressing
mode of demise. Against this backdrop must be included the wishes of a well-informed
patient. An analysis based on SCD-HeFT and MADIT trials derived the following scenario for
every 100 patients undergoing primary prevention ICD over a period of 5 years: 30 will die
non-arrhythmic deaths, 7-8 patients will be saved by the ICD, 15-20 will receive a shock they
do not need, 5-15 will experience other complications from the device, and the rest will not
experience their device at all. [9] Explained in such terms, a patient is better placed to balance
the risks and benefits of a device that often adds little to quality of life and has a modest effect
on extending longevity.
Finally, we all recognize that the trajectory of senescence with advancing age is not always
linear or uniform. Many 80 year-olds maintain an active and productive life style. For these
patients, an ICD could be considered roughly equivalent to any therapy that reverses an acute
illness. On the other end of the spectrum is the frail elderly patient with a poor quality of life
and associated co-morbidities. For such a patient, implantation of an ICD could be a case of
"too much, too late".
References
1. The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators A Comparison
of Antiarrhythmic-Drug Therapy with Implantable Defibrillators in Patients Resuscitated from
Near-Fatal Ventricular Arrhythmias. N Engl J Med 1997; 337:1576-1584.
2. Moss AJ, Zareba W, Hall WJ, et al. Prophylactic implantation of a defibrillator in patients
with myocardial infarction and reduced ejection fraction. N Engl J Med 2002; 346: 877-883.
3. Bardy GH, Lee KL, Mark DB, et al. Amiodarone or an implantable cardioverterdefibrillator for congestive heart failure. N Engl J Med 2005; 352: 225-237.
4. Kuck KH, Cappato R, Sibels J, Ruppel Ruppel R. for the CASH Investigators. Randomized
comparison of antiarrhythmic drug therapy with implantable defibrillators in patients
resuscitated from cardiac arrest. Circulation 2000; 102: 748-754.
5. Connolly SJ, Gent M, Roberts RS, Dorian P, et al. Canadian Implantable Defibrillator
Study. A randomized trial of the implantable cardioverter defibrillator against amiodarone.
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Circulation 2000; 101: 1297.
6. ACCF/HRS/AHA/ASE/HFSA/SCAI/SCCT/SCMR 2013 Appropriate Use Criteria for
Implantable Cardioverter Defibrillators and Cardiac Resynchronization Therapy. J Am Coll
Cardiol 2013; 61: 1318-1368.
7. Wilson DG, Ahmed N, Nolan R, Frontera A, Thomas G, Duncan E. Implantable
cardioverter-defibrillators in octogenarians: clinical outcomes from a single centre. Indian
Pacing Electrophysiol J. 2015;15:4-14.
8. van Rees JB, Willem Borleffs CJ, Thijssen J, de Bie MK, van Erven L, Cannegieter SC,
Bax J J, Schalij MJ. Prophylactic implantable cardioverter-defibrillator treatment in the
elderly: therapy, adverse events, and survival gain. Europace 2012; 14: 66-73.
9. Stevenson LW, Desai AS. Selecting patients for discussion of the ICD in primary
prevention for sudden death in heart failure. J Cardiac Fail 2006; 12: 407-412.
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