New device steadies excessive heart rate

Press, 29 August 1984, Page 27

New device steadies excessive heart rate

NZPA-Reuter Boston A team of Indiana doctors say they have seen encouraging results in tests with a new type of implantable pacemaker that corrects abnormally fast heart rates using low-voltage electric shocks to the heart. However, the researchers said in the “New England Journal of Medicine” that further improvements must be made before the device could be put into widespread use. The new pacemaker is called a cardioverter. Unlike a conventional pacemaker, which speeds up a slow heartbeat or gives a steady rhythm to an irregular heartbeat, the device gives carefully timed shocks to the heart to break up an abnormally rapid heart rate that develops in some patients.

If the heart rate is too fast and lasts too long, it can lead to fainting or death. The cardioverter consists of a palm-sized battery and computer implanted under the skin of the chest and a wire that is threaded into the heart. The wire measures the heartbeat and sends that information to the tiny computer. If the computer detects a fast heartbeat, it sends an electrical charge to the heart through the wire, jolting the heart into a normal rhythm. A doctor can also send a signal remotely to the computer to send an electrical charge into the heart. The research team, led by Dr Douglas Zipes, of the Indiana University School of Medicine, said the device, implanted in eight volun-

teers, had generally worked well. However, in one case, the shock to the rapidly beating heart caused the heart to beat erratically instead. The computer responded with further shocks but did not correct the new problem. Emergency room workers finally had to give their own shocks to get the heart to beat normally again. The researchers said their preliminary tests show the idea was feasible, but doctors should not depend on the device to automatically correct a rapid heart They said the next generation of devices must be more discriminating in their ability to detect the different types of abnormal heart beats and be able to restore a regular rhythm to a heart that is beating erratically.