CARDIAC DEFIBRILLATION

1313 in various forms of physical and emotional stress.21 In of the patients mentioned above, paroxysmal left ventricular failure undoubtedly gave rise to considerable anxiety, but this was not apparent in all cases. The interpretation of slightly increased excretion of catecholamines or H.M.M.A. is difficult, since there may be very little increase in some patients with phaeochromocytoma 22 23 (figs. 2 and 3). In some cases H.M.M.A. has been greatly increased when catecholamines were normal le 29 or only slightly raised (fig. 2), but the converse is also true. In the case illustrated in fig. 3, although H.M.M.A. was consistently increased, the increase was relatively less than that of catecholamines in the first three urines, and the latter were more informative than H.M.M.A. in this case. Gitlow et a1.23 had 3 cases with catecholamines of 1170, 630, and 1050 g. per 24 hours with H.M.M.A.S of 5-6, 5-6, and 6-0 mg. per 24 hours respectively. Findings have been similar in noradrenaline-secreting neuroblastoma.25 The number of phaeochromocytomas reported in which both H.M.M.A. and catecholamines were estimated is increasing, and it is apparent that most of these tumours will be diagnosed by estimating either catecholamines or H.M.M.A., neither test having any obvious diagnostic advantage at present. In a few cases, it is clearly necessary to estimate both, though few laboratories could do this routinely in hypertensives. Hingerty’s method is the simplest and, despite its limitations, Bollman et al.18 found it as reliable in the diagnosis of phasochromocytoma as quantitative spectrofluorimetric estimation of catecholamines. The day-to-day variations in excretion of catecholamines in patients with sustained hypertension due to a phsochromocytoma is illustrated in figs. 2 and 3, and by another case in which catecholamines of 200, 1200, and 400 g. were obtained in three consecutive 24-hour urines. We believe that Hingerty’s method is adequate for screening hypertensives provided more than one urine is examined as a routine, estimation of H.M.M.A. or other metabolites being performed in cases where results are difficult to interpret. In 17 normal urines and the majority of urines from liypertensive patients, we have obtained values of less than 90 jg. per 24 hours, and regard values approaching the 180 (jLg. standard as an indication for further estimations of both catecholamines and H.M.M.A. occur some

Our thanks are due to our clinical colleagues for access records and for permission to include details of their cases.

Department of Pathology, The

Royal Hospital, Wolverhampton.

to case-

J. KELLEHER G. WALTERS.

NIGHT-CALL SERVICES SIR,-Ishould like to redress the balance somewhat by offering a short letter in favour of the night-call services. While agreeing with almost every item listed by " Diplomate " in last week’s Lancet (indeed I feel certain we both work for the same firm), I would nevertheless like to mention a few critical points. The work is varied, interesting, and stimulating and forms an ideal, and one hopes useful, recreation for a researchworker. In about 1700 calls I have been given a wrong address about half a dozen times, and on all but one of these occasions the address was wrongly transmitted from a doctor’s surgery to the headquarters of the organisation. I have never yet been " too late " for any reason. Information given by the headquarters is unavoidably vague; such information as there is seldom bears any relation to the situation found on arrival. Naturally, morphine and pethidine being schedule-iv poisons are not issued except under signature. I have certainly had to go to extraordinary lengths to get

anything approaching regular payment; but the threat of public and legal proceedings produces a gratifyingly quick response. I think that, provided one enjoys one’s medicine and is as 21. Elmadjian, F. in Symposium on Catecholamines; p. 409. Baltimore, 1959. 22. Litchfield, J. W., Peart, W. S. Lancet, 1956, ii, 1283. 23. von Euler, U. S., Ström, G. Circulation, 1957, 15, 5. 24. Gitlow, E. S., Mendlowitz, M., Khassis, S., Cohen, G., Sha, J. J. clin. Invest. 1960, 39, 221. 25. Voorhess, M. L., Gardner, L. I. J. clin. Endocrin. 21, 321.

have both an with a night-call service. I manage to put in 7 sessions a week and also do a full-time research job, receiving (net) Ell a week, plus full use and resale value of the car, and still have 4 free evenings a week. thick-skinned

as

interesting and

may be necessary,

one

a

profitable part-time job

A

REASONABLY

r’fYMTT!TBJT

can

T’D<:Tf:RATYrTATR

PARKING

SIR,-Your peripatetic correspondent (Nov. 25) seems to imply that if, because the specialist can’t arrive in time ", the number of patients dying is small, all is well, "

But should doctors not mind if even one patient’s life is put in jeopardy ? The other day, when called to an emergency, I was distressed because collecting my car added 10-15 minutes to the journey. I asked the appropriate-and no doubt harassed beyond bearing -department of the B.M.A. why general practitioners were allowed to keep their cars close at hand while consultants were not. The answer was that this distinction had been made " at Ministry level ", because it was often represented to a general practitioner that a case was urgent when in fact it was not, whereas (my italics) consultants are usually called only to genuine emer1!encies. Have we eone through the lookins-elass ? PORTIA HOLMAN.

SIR,-An

CARDIAC DEFIBRILLATION intriguing method of cardiac defibrillation,

described by Negovsky,l uses a single electrical impulse furnished by a high-capacity condenser discharge, which he states is effective even through the closed chest. Full description and illustrations of the method in the monograph by Gurvich2 indicates that the high voltage he uses (3000-6000) requires extraordinary insulation and precautions against current leakage which render it too unwieldy for emergency use. Recently developed electronic photoflash equipment uses the same principle of a condenser discharge, generally with a voltage of 450 or 600 volts, and very light battery-operated models are available whose energy output of 30 to 150 watt-seconds is of the same order of size as alternating-current defibrillators deliver. Has anyone tried these for cardiac defibrillation ? Witli some units it might be necessary to add an inductance to prolong the discharge to 1/100 second, which seems to be about the optimum time for myocardial stimulation. Livernois Clinic

Detroit, Michigan.

SAM. I. LERMAN.

MAGNESIUM SULPIIATE IN THE TREATMENT OF ANGINA

SIR,-From time to time letters have appeared in your journal inquiring about the efficiency of intramuscular magnesium sulphate in the treatment of coronary arterial disease,3 without any authoritative reply being forthcoming. Selye has demonstrated experimentally that magnesium has protective action against cardiac infarcts in rats4 and remarkable results have been reported in a series of 100 patients treated by Parsons in Tasmania. 56 For the past nine months I have given intramuscular injections of 1 ml. of 50% magnesium sulphate solution (B.D.H.) fortnightly without any side-effects to patients with severe angina or a history of coronary thrombosis, and in 1 case in conjunction with long-term anticoagulant therapy. a

1. Negovsky, V. A. Circulation, 1961, 23, 452. 2. Gurvich, N. L. Fibrillation and Defibrillation of the Heart. 3. Craddock, A. L. Lancet, 1960, ii, 1348. 4. Selye, H. Brit. med. J. 1958, i, 599. 5. Parsons, R. S. Med. Proc. 1959, 5, 487. 6. Brit. med. J. 1960, i, 292.

Moscow, 1957.