cardiac electrophysiologist, cyclist, learner
By Dr John
From one of my favorite journals, Applied Physics Letters. (Just kidding.)
Could the vibration of the heart be harnessed into energy to drive a pacemaker generator?
Nifty stuff here. They just need to overcome that thorny issue of bio-compatibility.
JMM
From Medical News Today.
By Dr John
Cardiac devices are battery powered. Like your TV remote, they require change–every 5-10 years or so.
No worries…”it’s just a generator change” is a phrase one hears frequently in the cath lab. They are supposed to be easy cases.
But they are not always. And here is more recent evidence that the simple pacemaker/defibrillator replacement surgery—especially if a new lead is required—is more complicated than meets the eye.
In this report published in Circulation from 72 academic and private centers, major complications occurred in 4% (of a thousand) of patients who underwent generator change, and in a breathtaking 15% of those undergoing generator change with a new lead. Although there were no peri-procedure deaths, eight patients who died in the follow-up period were deemed “peri-procedural.”
When high complication rates are reported, doctors in the field, especially those in the sweet-spot of their practice years, would like to think their complication rates are lower. They may be, or they may not be. The data is the data.
The authors should be commended for reporting such humbling data. This is an important report, for both doctors and patients alike.
It reinforces my long-held view that ICDs are not like insurance policies. They carry substantial, and much under-estimated risk.
JMM
By Dr John
Years ago at the time of the original cardiac defibrillator implant (ICD), he was a vibrant active man who had suffered from an arrhythmia related to scar from a remote heart attack.
Things change. Life has chapters.
It is amazing what can happen to a person during the 5-7 year battery life of an ICD. In this case, I watched him gradually deteriorate over the years. A series of small strokes, mental decline, plus compression fractures of the vertebra results in a scooter chair existence in the nursing home. Additionally, medical problems like worsening of kidney function, pneumonias and congestive heart failure episodes all confer a lifespan measured in months.
Sadly, his little box with a blinking light in the single room at the nursing home tells us his ICD has reached ERI –elective replacement indicator or low battery. Although his ICD pacing rate is low, he still paces a lot. This low heart rate indicates a need for pacing support, so not changing his device at all is not a viable option.
The cath lab staff call this a “downgrade” of an ICD to a pacemaker, implying that because an ICD can deliver a 750 volt shock in the event of a malignant arrhythmia it is a better device–like trading in a Lexus for a Chevy. Yes, of course the word downgrade should be corrected, but the more important concept here is the inherent misconceptions of ICD therapy.
Patients with ICDs, or CRT-Ds, who at the time of generator change have sustained significant life limiting co-morbidities, no longer glean any significant benefit from these high voltage devices. Moreover, in these severely ill patients, an ICD may painfully prevent the peaceful, and merciful death that is ventricular fibrillation.
At the time of ICD generator change, we must remember the Kaplan-Meir curves of the ICD trials; which show statistical mortality benefits only for patients who can survive multiple years after implant. That the science supports us in these cases is a good thing, as it allows us to use words I often speak: “Sir, an ICD will no longer help you.” But even if one did not know these data, it would be obvious upon seeing a patient before surgery whether continued ICD therapy is still appropriate. Things change, and so should our medical decisions.
These modern times of amazing therapeutic technology have resulted in patients living longer. This enhanced chronological longevity makes it seemingly impossible to die of old age anymore. Due to sudden death prevention an ICD patient is even more likely to live long enough to acquire much comorbidity, and when their battery needs changing, they will need an electrophysiolgist with both good hands and good sense.
Yes, it is true that sharing life with a palliative care doctor helps me understand these issues.
Let’s not call a decision to discontinue ICD therapy a downgrade. Like stopping a medicine that is no longer indicated, we should not think we downgraded care, but rather enhanced it.
JMM
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