Implantable Heart Defibrillators Have Been Causing Brain Damage

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Hundreds of thousands of patients depend on small devices called implantable cardio-defibrillators (ICD) to keep their hearts beating regularly. Now it seems that when surgeons test the devices to make sure they work, they have inadvertently been causing brain damage.

In 2006 alone, the American Heart Association estimates that 114,000 people had surgery to install an ICD. During surgery, doctors test to be sure the device works by simulating irregular heart beats in the patient. If the ICD corrects the irregularity several times, they are satisfied that the device is working and close the patient up. Unfortunately, a study just published by the American Heart Association suggests that simulating those irregular heart beats lowers blood pressure in the brain and causes medium-term brain damage in patients.

The American Heart Association issued a release on the study, and explained:

After an ICD is inserted, doctors check its performance by medically causing repeated episodes of irregular heartbeat. The procedure, known as ventricular defibrillation testing, temporarily disrupts brain activity by causing a drop in blood pressure and blood flow to the brain, according to previous studies. However, the long-term thought-processing, or cognitive, effects of these disturbances were unclear.
"What's surprising is that this minor procedure, which has very short periods of ventricular defibrillation induction, results in significant decline in multiple areas of cognitive function," said Claire N. Hallas, Ph.D., lead author.


The Association explains:

Compared with pre-surgery scores on thought-processing exams, more than one-third of study participants had significant cognitive problems six weeks and six and 12 months after ICD surgery. Attention, short-term memory of visual words and objects, and auditory (spoken) words were most commonly affected. Although most patients regained their normal abilities by 12 months after surgery, onset of cognitive problems varied between patients. A small group - 10 percent - first developed difficulties 12 months after ICD surgery.


So the brain damage is not permanent, which is good news. But rescuing your heart still comes at the expense of keeping your brain healthy. The truly scary part is that so many of these surgeries were done before anyone realized how damaging they could be.

via American Heart Association