Implantable defibrillators currently on the market apply between 600 and 900 volts to the heart, almost 10 times the voltage from an electric outlet, says Ajit H. Janardhan, MD, PhD, a cardiac electrophysiology fellow at Washington University in St. Louis School of Medicine.
After being shocked, he says, some patients get post-traumatic stress disorder. Patients may even go so far as to ask their physicians to remove the defibrillator, even though they understand that the device has saved their lives.
The huge shocks are not only unbearably painful, they damage the heart muscle and have been shown in many studies to be associated with increased mortality.
In an online edition of the Journal of the American College of Cardiology, Janardhan and Igor Efimov, PhD, professor of biomedical engineering in the School of Engineering & Applied Science, report on a low-energy defibrillation scheme that significantly reduces the energy needed to re-establish a normal rhythm in the heart’s main chambers.
They hope this electrotherapy will be much less painful than shocks from existing implantable defibrillators, and may even fall beneath the threshold at which patients begin to perceive pain.
The team just received a National Institutes of Health grant to develop a prototype low-energy defibrillator for humans and plans to begin clinical trials of the device shortly.
Losing the beat
