Journal of the Society of Motion Picture Engineers (1930-1949)

the actual tracings aiid thus corrects the maged trace. f Cameras. Two types of cameras were used. A modified Bell & Howell "70" Specialist camera with a speed of 200 frame/sec was employed when visualization of gross movements of the heart was desired. The lenses used with this camera were a 75-mm PanTechar, //2.3, and a 100-mm PanTechar, //2.3. For extremely detailed analysis the Wollensak Fastax, 16mm camera was used with a 4-in. Wollensak lens, //3.2. The Fastax was used for color pictures taken at 500, 1000 and 2000 frame/sec, and for black-and-white pictures at 5000 frame/sec. Electrocardiographic Equipment. An inkwriting, dual-channel Brush Magnetic Oscillograph was found to be most suitable for recording the electrocardiogram. This machine has a paper speed of 125 mm/sec which is five times faster than the standard electrocardiographic paper speed. Each complex was thus magnified for great accuracy of analysis. In addition to the two writing pens, a time marker pen was installed at the edge of the paper. A pip every j sec produced by a synchronous motor provided the time reference. Light Sources. In all high-speed photography, the problem of a suitable light source exists. In high-speed medical photography, adequate light must be combined with a minimal amount of heat because one is dealing with living tissue. Excessive heat, of course, is injurious to tissue and precautions must be taken to keep all experiments under at least near-physiologic conditions. For the Fastax pictures, a bank of from 7 to 20 General Electric 750-R lamps was used on the heart. Usually two or three of these focused on the electrocardiographic paper were sufficient. These lights generate intense heat and various attempts were made to overcome this — heat-absorbing glass, water cells, etc. However, in our setup, these were all awkward and difficult to manage. The simplest solution was to use 50-ft rolls of film in the Fastax camera and to turn on the lights after the camera was started and turn them off (by calculation) just before the film ran through. In this way, perhaps 1 5-20 ft of film were underexposed but the heart was subjected to the heat for only a very short time — from less than one second to a maximum of three and a half seconds. It was not uncomfortable to hold the hand in the light field for this period of time. Pictures taken at 200 frame/sec require less light; General Electric RSP-2 lamps were used for this camera speed. A bank of five lamps directed at the heart from a distance of approximately 3 to 4 ft and one lamp on the electrocardiographic paper at about 2 ft were sufficient for good color. The heat problem was obviated by taking continuous film runs of not more than 25 ft at a time. Thus again, the lights were on for only a minimal length of time and the heat to which the heart was exposed was well within the physiologic limit. For taking pictures of the beating human heart, the precautions and limitations which apply to photography of the experimental animals were even more strict. Thus we have been limited in the number and choice of the patients we have been able to study in this manner. However, a new type of lamp was loaned us recently through the kindness of John H. Waddell of the Wollensak Optical Co. This is the Fastlite, which is a compact unit with a built-in water cell. These lights have proved most satisfactory, for they are less cumbersome than the battery of hot lamps and they give an extremely intense light with a minimum of heat. Fields et al.: Cine-Electrocardiography 495