Transoceanic Radio Transmission of Electrocardiograms

Transoceanic Radio Transmission of Electrocardiograms JIM

C.

HIRSCHMAN, M.D., F .C.C.P., THOMAS AND ARTH UR F. SCHIFF, M .D.

J. BAKER,

M.D.

Miami, Florida

T

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a short distance of existing telephone wires in 1905.' This report describes the successful radio transmission of electrocardiograms over a distance of 4700 miles (7500 km), using the most simple equipment. The experiment was carried out for at least two reasons. The valuable information contained in the ECG ordinarily is available only to the clinician near the bedside when the tracing is taken. If the consultation of a second, perhaps more highly skilled, cardiologist is desired, the tracing must be carried or mailed to him, depending on the distance. Nearly instantaneous radio communication of the ECG would avoid this transportation dela y. Secondly, with the beginning use of computer centers,

REMAIN EFFECTIVE, MEDICINE MUST

compete successfully in an age of specialized knowledge. It participates also in an age of rapid communication. The resulting challenge is to rapidly verify and refine technical medical data so that it may be rapidly communicated to greatest advantage. This applies sharply to the collection and interpretation of electrocardio-

grams. The heart lends itself to telemetering more than most other organs because of its production of rhythmic electrical impulses. This electric activity of the heart was first recorded for clinical use by WiUem Einthoven in 1903 and it was he who successfully transmitted the electrical impulses over Radio tro.naa1t ted to IWrcV Ju1r 14 , 11185

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TRANSOCEANIC RADIO TRANSMISSION OF ELECTROCARDIOGRAMS

to store and even interpret biomedical data, rapid economic methods of getting the data to the computer should be explored constantly. METHODS

In recent years compactly housed audio tone oscillators have been manufactured. The pitch of these units ranges near 1500 CPS and this pitch will vary linearly in response to an appropriately applied D.C. signal. These instruments have been designed and used for land line telephone transmission of electrocardiograms. t.a At the receiving end, a companion unit demodulates the varying audio signal, thus converting it back into a duplicate of the original D.C. signal of the ECG. These curves can then be inscribed on paper, recorded on tape, or after digital conversion fed into a computer. The authors made use of one such audio tone oscillator* to transmit electrocardiograms long distances over amateur radio stations. The first attempt was made on a frequenc y of 29,000 kcs over a distance of ten miles (15 km). Standard amplitude modulation was used. The received ECG was an excellent reproduction and longer distances were soon attempted. Subsequent experimental transmissions of ECGs by radio were made between Detroit, Michigan and Miami, Florida, and between Mexico City and Miami, Florida. It was soon learned that humming noises in the equipment at either the transmitting or the receiving end would interfere with the

base line. As the technique was refined, it was learned ' that the medical goodwill ship S.S. HOPE had a functioning radio amateur station of reliable quality and was stationed 4700 miles from Miami in Conakry, Guinea, West Africa. The aid of the ship's staff and radio operator was enlisted for attempting a transoceanic transmission of an electrocardiogram. A willing physician courier transported one of the required audio tone transmitting units to the ship when he went to teach there. On the appointed day, those aboard the ship attached a patient to a standard ECG machine . The D.C. signal of the heart beat generated in this machine was tapped by an appropriate plug and connected to the audio oscillator. The varying tone thus produced was carried to the ship's radio room by the ship's internal telephone system. In the radio room the audio note was coupled to the radio amateur transmitter. This transmitter was of standard design. It was amplitude modulated and transmitting on 21,445 kcs. Transmission was with single side band and suppressed carrier. The transmitting power was 1000 watts P.E.P. Just prior to the transmission of the ECG, voice contact was established with the station in Miami, Florida. There a standard communications receiver was being used. The audio tone from this was "air coupled" to the demodulating unit . The resultant D.C. signal was coupled to a standard ECG machine for write-out of

·Cambridge Instrument Co., Ossining, N. Y.

V-4

B,2 FIGURE 2 : Enlargement of chest lead V-3 from Fig. I. Note comparison with original made in Afr ica.

FIGURE 3: Comparison between original tracing made in Africa with the duplicate made in Miami. Intraventricular conduction defect clearly sbown.

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HIRSCHMAN, BAKER AND SCHIFF

FIGURE 4: Standard ECG machine shown with the transistor D.C. to audio converter and its companion audio to D.C. deconverter (Cambridge).

the received ECG. In Miami, within a few minutes a complete 12 lead ECG had been received (Fig. 1 and 2). The pertinent clinical data followed by voice and an interpretation was transmitted back to the ship to confirm the communication. The following week, by appointed schedule, the process was repeated with two additional patients . On that day in Miami, a tropical thunderstorm produced static crashes which occasionally interrupted the

•

_ ...

•

base line, but in no way slowed the relay of the electrocardiogram. Within 15 minutes, two additional ECGs had been received and interpretations sent back to the ship. Sample leads are shown (Fig. 3) . The equipment used was standard in all respects. The transmitter in Africa was by Hallicrafters. Reception in Miami was with a Hammerlund. The audio tone transmitter and receiver and the ECG units were loaned by the Cambridge Instrument Company (Fig. 4) . A few months later, using the same techniques, the D.C. registration of phonocardiographs were transmitted from Ossining, N. Y. to Miami, Florida, again by amateur radio, a distance of 1400 miles (2100 km) (Fig. 5). DISCUSSION

5 : Phonocardiogram comparison, the transmitted above with the received below. This was a normal volunteer. Note high and low frequency sounds.

FIGURE

The establishment of a technique for long distance transmission of biomedical data enables the data to be channeled to centers where it may be interpreted and stored. In the case of medical data, the same circuits can be used for returning a

Volume 1967 52, No.2 August,

TRANSOCEANIC RADIO TRANSMISSION OF ELECTROCARDIOGft.&~S

diagnosis, a recommendation or a decision. The S.S. HOPE routinely has a complement of skilled and trained physicians. Under usual circumstances these would not require the counsel of far off specialists, but in the event of the absence of a cardiologist such radio communications would be an aid. The experiments were carried out in order to establish an available and relatively inexpensive and simple technique for the transmission of electrocardiograms and other similar biomedical variables which may be adapted to the system. It seems that this relatively simple system might be used by hospitals isolated in inaccessible regions. The technique may be valuable to ships at sea. In all likelihood more formal radio, radiotelephone, or cable circuits will be used but in an emergency or where no other circuit is available amateur bands may be considered. Obviously, amateur communications are strictly noncommercial. It has been noted that early in 1965 an electrocardiogram was transmitted from a ship to New York where it was relayed to Andover, Massachusetts, and then by television to Paris via Early Bird Satellite. This was a formidable and impressive feat of engineering. It seems rather complex and expensive for routine ECG traffic or potentially heavy circuit loads. A similar experiment was carried on in 1959 using radiophoto techniques.I Not only is the method described in our paper simpler and more versatile, but it has the advantage of reproducing the original D.C. signal with very little loss in fidelity. In addition, it requires relatively unskilled and quickly trained technicians. In this manner, it may be adapted to digital computer systems where telephone wire ECG transmissions are already in use.· In the present report, the success of the transmission of both the first and second attempts underscores the concept that continuous graph biomedical data can be communicated by intelligent but not necessarily highly trained technicians.

Aft.IQ,

18g

SUMMARY

The successful transmission of electrocardiograms from Guinea in Africa to Miami, Florida is reported. The equipment used is standard, not overly expensive, and readily available. The methods used are recommended for ships at sea, isolated hospitals, and emergency situations. The techniques can be applied to biomedical data of similar nature from other organs such as spirograms, pneumotachograms, and EEGs. In fact, they have been applied to phonocardiograms. Such radiocommunications increase the diagnostic coverage of emerging computer centers for mass health screening surveys and biomedical data interpretation. ACKNOWLEDGMENT: We gratefully acknowledge the assistance given for this project by Cambridge Instrument Company, their local representative Richard Wallace, and Project HOPE. RESUMEN

Se reporta la trasmisi6n efectiva de electrocardiogramas desde Guinea, Africa a Miami, Florida, EE.UU. EI equipo empleado es el usual, economico y de facil adquisici6n. Los procedimientos usados son recomendables para barcos en alta mar, hospitales en localidades aisladas y en casas extraordinarios. La tecnica puede ser aplicada a datos biomedicos de naturaleza similar de otros 6rganos, tales como espirogramas, neumatogramas y electroencefalogramas y de hecho 10 han sido en fonocardiogramas. La radiocomunicaci6n aumenta el radio de acci6n de los computadores en los nuevos centros diagn6sticos y de encuesta epidemio16gica en gran escala, RESUME

Relation de la transmission avec succes d'electrocardiogrammes de la Guinee a Miami (Floride). L'equipment utilise est standard, pas exagerement cofrteux, et l'on peut l'obtenir facilemente Les methodes utilisees sont conseillees pour les navires en mer, les hopitaux isoles, et les situations d'urgence. La technique peut-etre appliquee a des resultats bio-medicaux de nature similaire venant d'autres organes, par exemple spirogrammes, pneumogrammes et electro-encephalogrammeso In fait, ils ont ete appliques aux phonocardiogrammes. De telles communications par radio augmentent le domaine diagnostique des centres de calculateurs a venir, pour les examens de sante en masse, et l'interpretation bio-medicale, ZUSAMMENFASSUNG

Bench t iiber die erfolgreiche Obertragung von Elektrokardiogrammen ans Guinea in Afrika nach Miami in Florida. Es wird dabei die StandardAusriistung eingesetzt, die ohne besonderen Aufwand hinsichtlich der Kosten und ohne beson-

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Diseases of the Chest

HIRSCHMAN, BAKER AND SCHIFF

dere Umstande jederzeit greifbar ist, Die zur Anwendung gelangten Verfahren empfehlen sich fur Schiffe auf See, isoliert liegende Krankenhauser und Notfallsituationen. Die Technik liPt sich fur diagnostische Daten ihnlicher Art bei anderen Organen anwenden, z.B. Spirogrammen, Pneumotrachogrammen und EEG. Auch Phonokardiogramme lassen sich auf diese Weise iibertragen. Fur Massengesundheitsaufnahmen und biomedizinische Databehandlung erhohen solche Radioverbindungen das diagnostische Vermogen von emporkommenden Komputerzentralen. REPERENCES MATTHEWSON,

F. S. L.

AND JACIt,

telecardiogram," Am. Hearl

H.: "The

I., 49: 72, 1955.

2

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LEPESCHKIN,

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mentation," Prog. Car di ou as e: Dis., 5:498,

1963.

LEVINE, I. M., JassMAN, P. B. TURSHY, .B., MEISTER, M. AND DE ANGELIS, V.: "Tele-

phone telemetry of bioelectrical information," JAMA, 188: 794, 1964. 4 MONNIER, A. J., WRIGHT, I. S., LENEORE, J., et al.: "Ship to shore radio transmission of electrocardiograms and x-ray images," JAMA, 193: 144, 1965. 5 BRISKIER, A.: "Heart examination and consultation by radio and radiophoto transmissions," JAMA, 169: 1981, 1959. 6 COOPER, J. K. AND CACERES, C.: "Transmission of electrocardiograms to computers," Military Med., 125:457, 1964 For reprints, please write: Dr. Hinchman, 803 DuPont Building, Miami 33131.

CHANGES OF THE CARDIOVASCULAR SYSTEM IN INFECTIOUS MONONUCLEOSIS Investigation of the cardlovucular system In 1St patients with Infectious mononucleosis showed alterations In more than 50 per cent. These changes were: dullness of heart sounds, appearance of a systolic munnur at the apex of the pulmonary artery In 67.5 per cent, alteration of the rhythm of cardiac contractions in 82.9 per cent, reduced arterial pressure In 87 per cent and chaJlps In the ECG waves and intervals In 78 per cent of patients. In the majority of cases, the grade of cardiovascular

changes was directly related to the severity of the disease: how ever, the cardiovascular alteratlons were not of a stable nature: they become manifest at the peak of the disease and disappear In periods of one to five months from the onset of disease. Myocarditis was encountered In only one patient. NIKIFOROV,

V.

N..

MALKOVA,

T.

N.

AND

BARASH KOVA,

M. N.: "Changes of the cardiovascular system in infectious mononucleosis:' Clin. Mea. (USSR), 44:68, 1966.

ENDOCAVITARY ASPIRATION IN NONTUBERCULOUS LUNG PATHOLOGY Authors describe cases of simple pulmonary abscess, pulmonary abscess complicated by empyema. and a case of pulmonary suppuration of hydatid origin In which the treatment with endocavltary aspiration resulted In complete cure and consequent functional recovery of subjects. The authors also

discuss the Indications for endocavltary aspiration In other forms of nontuberculous chest pathology. MARTINO, A. AND PIAZZA, R.: "SuU'applicazione del procedimiento di aspirazione endocavitaria in patologia non tubercolare del polmone," Arch. Tisiol., 21:389, 1966.

DISTURBANCES IN FODDER FACTORY EMPLOYEES Dusts of complex composition (anlmal, vegetable and mineral) Involved In the technologic process of fodder concentrate frequently cause Un 80 per cent of the employees) occupational ailments more related to the Intensity of exposure than to the length of employment. Clinical manifestations, predominantly respiratory, are of an lrr1tatlve (60 to 68 per cent) and allergic (12 to 21 per cent) type. Among the latter, a relatively high n u m b e r of bronchial allergies (about 8 per cent) can be noticed and the intervention of the atopic factor can be ruled out. The followlns procedures have proved to be particularly useful In establlshlq the dlag-

nosls: a detailed allergic and occupational history, clinical aspects, skin reactions and bronchial provocation tests carried out by means of specific allergens of the technologic process (at the optimum concentration of 1 per 1,000). The authors consider as significant the agreement of at least three of these tests. PAUL, R., GHEOaGHIU, T., IOTA, C. G., OLARU, C., ZAMFIRESCu-GHEOaGHIU, M., MOLNBR, C., TAULESCU, E., BlaNAS, M., COSTACHE, A., POPESCU, I. G., CAPBTTI, E. AND APOSTOLESCU, I.: •'Contribution to the study of dis-

turbances among employees of concentrate fodder factories," R'II. ROMm., Mea. tn«, ~: 187, 1966.