Dr J. has written to this August readership on the topic of implantable cardioverter defibrillators, or ICDs. An ICD is an implantable device, much like a pacemaker, that in addition to pacemaker capability, can deliver rapid bursts of pacing or shocks in order to break a potentially lethal ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation). Because ICD’s can act as both a back-up pacemaker to treat slow heart rhythm problems and treat ventricular tachyarrhymias, Vice President Cheney dubbed his a “Pacemaker Plus.”
There are, by and large, two groups of patients who receive ICD’s, those who have had a ventricular arrhythmia (secondary prevention), and those who are at high risk of having a ventricular arrhythmia, but never have had one (primary prevention). The primary prevention group is by far the larger of the group and almost all of them have congestive heart failure (CHF) due to a low ejection fraction.
CHF is a chronic progressive decline in cardiac function due to a poorly squeezing, or sometimes a poorly relaxing heart. Patients can have varying degrees of fluid retention, shortness of breath and fatigue. Blood pressure medications act like chemotherapy for the heart, improving function and prolonging life. Water pills can manage symptoms.
So, when folks are diagnosed with CHF for the first time, the get an echocardiogram (ultrasound of the heart) and their ejection fraction is determined. They are started on medication, and if, after a few months, their EF doesn’t improve to above 35% (normal is >55%), they are eligible for an ICD. The reason for this is that folks with an EF 35% or less are at higher risk of sudden cardiac death. CHF patients die 3 ways, 1/3 die from sudden death due to an arrhythmia, 1/3 die from pump failure over time, and 1/3 something else (like getting hit by a bus).
The idea behind the ICD is to prevent patient with CHF who is otherwise reasonably compensated from dying suddenly while they are still highly functional. We rate CHF symptoms by the New York Heart Association classification. Class I have little or know symptoms. Class II, get short of breath with a reasonable amount of effort. Class III get short of breath doing anything more than their activities of daily living, and Class IV have symptoms at rest. Patients slide up and down this scale when they’re decompensated, but they are categorized as a Class based on where they are when they’re optimally tuned up. Ultimately everyone progresses down that scale. The typical life expectancy is about 5-10 years from diagnosis.
Now, not everyone who has an ICD has them go off. Some do, and it is often lifesaving. Rarely it is an inappropriate shock for an atrial arrhythmia, or sinus tachycardia. A smaller subset are plagued by shocks for frequent VT, despite enjoying a good NYHA functional class (I, or II, or even a high III). These can be managed by correcting an underlying cause of VT (low potassium, magnesium, an area of the heart with a coronary blockage that can be opened with a stent), or with an antiarrhythmic agent. Ultimately VT ablation can be a strategy.
Many are never shocked and otherwise do very well until they are at the end of their life. We have difficulty managing the fluid, and at the same time, their burnt out ventricle is the cause of their VT. Again, we can use the aforementioned strategies with medications, and even an ablation, if need be.
There gets to be a point in a subset of patients where the shocks are causing needless suffering as they are dying from pump failure. In this subset of patients, we turn off the defibrillation programming.
Now the reason for this longwinded preamble is to get across the point that in a small subset of CHF patients with ICDs, they get to a point where the therapy is actually causing more harm than good in a futile situation. This is not the majority of cases, even those where the patient ultimately expires from CHF. I also write this preamble to make the point that CHF is a complex disease to manage, with multiple permutations having the potential to unfold over time, and you don’t know where the patient is going to land until they do.
So, MSNBC has an article they posted on 10/7. It is entitled, Shocking Ending: Implanted defibrillators can bring misery to final hours. They write:
Now one anonymous cardiologist in the article said that turning off an ICD may be like ‘shutting off hope.’ Dr. J. has a colleague who said a similar thing to him, as Dr. J. was caring for his patient in the hospital. This wise old colleague feared that turning off the antitachycardia therapy would be like ‘hexing’ the patient. The reality was that the patient and family understood the prognosis, but went along with Dr. J. and his colleague’s joint recommendation of an antiarrhythmic to decrease the likelihood of shocks and returned a week later after the antiarrhythmic failed. By this point, Dr. J.’s colleague was accepting of his patient’s prognosis. The patient also enjoyed an additional, relatively symptom (shock) free week with their family before ultimately passing.
Dr. J. may telegraph some of these issues very early, but it has worked very well for his patients.
A good doctor knows when the writing is on the wall and prepares their patient for it. The management of these complex issues should ultimately be between the individual patient and the individual doctor. It is our responsibility to tackle these issues head on, and early, because if we don’t, someone else, especially if they have a financial interest in the issue, may tackle these tough issues for us.