New Development in Fiber Optics Gives Boost to Cardiac Research

A Harvard Medical School associate and his colleague have devised an instrument enabling them to examine the heart without using surgery.

The new device--a so-called "fiber optics instrument"--consists of a long thin tube that is inserted into the heart. The tube is made of a bundle of 70,000 glass fibers which transmit an image from the inserted end to the viewer.

Its inventors, Dr. Walter J. Gamble, associate in pediatrics at Harvard Medical School and associate in Cardiology at Children's Hospital, and Robert E. Innis, research physicist for American Optical Company--have been working on the cardiac device since 1963.

Direct Visualization

The fiber optics instrument allows heart defects and functions that cannot be detected by x-ray and electrocardiogram, to be seen and filmed, Dr. Gamble said. It makes possible direct visualization of the color, shape, texture, and motion of the heart, Dr. Gamble said, without necessitating surgery.

Some surgery is very dangerous if certain anatomic formations exist in a diseased heart, he said. The direct view of the heart, available through the fiber optics instrument, gives vital information without risking dangerous surgery.

Provides Own Light

The instrument is inserted into the blood vessels through the neck or leg. Light inside the heart and vessels is provided from a high intensity mercury are lamp and carried on down a second fiber optic system to the lenses.

After the instrument has been inserted, a balloon attached to the inserted end is inflated, pushing blood away from the heart walls. An 8 mm. camera films the heart and its motion, and enlarges the image 21 times.

The observer can see the heart from the external end of the tube, without using a camera; the camera is merely for enlarging the image.

Method Tried Before

The heart has been visualized without surgery once before by the use of a rigid stainless steel rod also introduced through the blood vessels. But the rigidity of this instrument made it difficult to manipulate. It was unable to pass through the variety of valves, blood vessels and chambers that the flexible fiber optics system can, Dr. Gamble said.

So far the instrument has only been tried on animals, Dr. Gamble said. None of them have been harmed, but he will continue testing. "I have to have a system that will do more good than harm to patients before I try it on them. I have to have a system that really works," he said.

Dr. Gamble and Mr. Innis are currently financed by a grant from the National Institute of Health.