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SLOW PULSE-RATE AND DIGITALIS TOXICITY
220 COT DEATHS AND MINERAL SALTS
SLOW PULSE-RATE AND DIGITALIS TOXICITY
SiR,—The demonstration of an association between changes in water hardness and rates for "cot deaths" in Scunthorpel prompts us to record some preliminary measurements we have made on the metal concentrations in the heart muscle of infants dying suddenly under 2 years of age, and regarded as cot deaths. We had earlier shown that the magnesium concentration in the heart muscle was low in people dying suddenly from ischaemic heart-diseaseand Caddell had suggested that magnesium deficiency might be a causative factor in cot deaths.3 We measured the concentration of magnesium and several other metals in small samples of the left ventricle-taken at necropsy from seven infants who had died suddenly at ages ranging from 3 weeks to 15 months. The samples were ashed and the resulting solutions analysed by atomic-absorption spectro-
SIR,-Dr Williams and his colleagues found that 7% of their digoxin-treated cases had bradycardia. But how many of the 42 patients who had no cause for the slowing of the heart were aged 65 or older? Elderly subjects often show sinus bradycardia, although, of course, pulse-rates lower than 50/min may indicate digitalis toxicity.2 The three reported cases with complete heart block were presumably given digoxin for its positive inotropic effect. Use of the drug in this condition, however, is potentially dangerous, because the vagal drive can further slow the heart-rate. In 1951, a man aged 63 had complete heart block with a raised jugular venous pressure and Cannon waves. His pulse-rate, after he was given only 0.5 mg of digoxin orally, fell from 50 to 18/min, and he developed very frequent Adams-Stokes attacks for 35 min.3 Decrease of the heart-rate is obviously contraindicated in complete heart block and I have not used digitalis again for this disorder. Sophisticated treatment is not always an advantage. Organic compounds are nearer to living cells than purified chemicals. For instance, refined sugar is absorbed faster than starch. Is it wise to discard prepared digitalis, unless it is proved to be less effective than digoxin? Digoxin is more expensive, and the assay results have been disappointing.4 Digitalis folia is absorbed differently from the pure drug, and therefore peak-levels in the heart muscle are perhaps more easily avoided. Digitalis cannot be as accurately standardised, but the sensitivity from case-to-case probably varies considerably. Clinical assessment is still the lynch-pin, and digitalis may be the safer drug.
metry. 2 4 METAL CONCENTRATIONS IN HEART MUSCLE
St Luke’s Hospital, Guildford GU1 3NT
*Results as mean :t S.D.
The table gives the mean values for magnesium, calcium, potassium, sodium, iron, manganese, and copper in these samples and in a group of normal adult controls from the same There was a slight increase in sodium concentration in the cot-death samples, but this was not statistically significant. There was, however, a significant (t=2.4) decrease in potassium concentration and a significant (t=3.42) increase in the calcium concentration in the heart muscle from cot deaths. The dry weight was measured for one cot-death sample, and the percentage dry/wet weight was 25.0 as compared with 21.7±1.0for twenty normal adult samples. We have not yet measured the concentration of metals in the heart from infants dying from other causes by analysis of variance indicates that there is no significant variation of metal concentration with age for older normal controls. The differences in mean values between the cot-death samples and normal adults are similar to the differences we have found in adults dying suddenly from ischaemic heart-disease.4 The differences in the ratios of magnesium/calcium and potassium/sodium in the heart may be a contributory cause of sudden death both in sudden death from ischaemic heart-disease and in cot deaths. There is evidence for cardiac abnormalities in "near miss" cot deaths.S Softening hard water will decrease the magnesium and calcium content of the drinking-water as well as increasing the sodium content. The decrease in magnesium and increase in sodium in the drinking-water might cause changes in the electrolyte balance in the heart similar to those we have found in cot deaths, and thus increase the rate for cot deaths. area.
Departments of Biochemistry, and Chemistry, University of Hull, Hull HU6 7RX
G. A. MACGREGOR
(and no. of samples).
BARBARA CHIPPERFIELD J. R. CHIPPERFIELD
1. Robertson, J. S., Parker, V. Lancet, 1978, ii, 1012. 2. Chipperfield, B., Chipperfield, J. R. ibid. 1973, ii, 293. 3. Caddell, J. L. ibid. 1972, ii, 258.
4. Chipperfield, B., Chipperfield, J. R. Am. Heart J. 1978, 95, 732. 5. Guilleminault, C., Ariagno, R., Souquet, M., Dement, W. C., Lancet, 1976, i, 1326.
EAR-LOBE CREASE
SiR,—The presence of a diagonal ear-lobe crease seems to be associated with vascular disease.5-8 However, earlier work was
done
on
people seeking
medical
help for
one reason or
another, and we do not know of any survey in apparently healthy people. We have studied 300 healthy individuals (factory workers, teachers and university students) and recorded RESULTS
*T-wave changes indicating ischaemia.
tBy chi-squared test. the presence or absence of diagonal ear-lobe creases and data on certain risk factors for vascular disease sought by fundoscopy, measurement of blood-pressure and fasting blood glucose, cholesterol, and triglyceride, and electrocardiography. The E.c.G. and the fundoscopy were done by a cardiologist and 1. Williams, P., Aronson, J., Sleight, P. Lancet, 1978, ii, 1340. 2. Lewis, T. Diseases of the Heart. London, 1942. 3. MacGregor, G. A. Br. Heart. J. 1959, 21, 225 (case 1). 4. Lancet. 1978. ii. 1188. 5. Frank, S. T. New Engl. J. Med. 1973, 289, 327. 6. Lichstein, E., Chadda, K. D., Naik, D., Gupta, P. ibid. 1974, 290, 615. 7. Christiansen, J. S., Mathiesen, B., Andersen, A. R., Calberg, H. ibid. 1975,
293, 308. 8. Andresen, A. R.,
Christiansen, J. S., Jensen, J. K. ibid. 1976, 294, 1183.
SLOW PULSE-RATE AND DIGITALIS TOXICITY
SiR,—The demonstration of an association between changes in water hardness and rates for "cot deaths" in Scunthorpel prompts us to record some preliminary measurements we have made on the metal concentrations in the heart muscle of infants dying suddenly under 2 years of age, and regarded as cot deaths. We had earlier shown that the magnesium concentration in the heart muscle was low in people dying suddenly from ischaemic heart-diseaseand Caddell had suggested that magnesium deficiency might be a causative factor in cot deaths.3 We measured the concentration of magnesium and several other metals in small samples of the left ventricle-taken at necropsy from seven infants who had died suddenly at ages ranging from 3 weeks to 15 months. The samples were ashed and the resulting solutions analysed by atomic-absorption spectro-
SIR,-Dr Williams and his colleagues found that 7% of their digoxin-treated cases had bradycardia. But how many of the 42 patients who had no cause for the slowing of the heart were aged 65 or older? Elderly subjects often show sinus bradycardia, although, of course, pulse-rates lower than 50/min may indicate digitalis toxicity.2 The three reported cases with complete heart block were presumably given digoxin for its positive inotropic effect. Use of the drug in this condition, however, is potentially dangerous, because the vagal drive can further slow the heart-rate. In 1951, a man aged 63 had complete heart block with a raised jugular venous pressure and Cannon waves. His pulse-rate, after he was given only 0.5 mg of digoxin orally, fell from 50 to 18/min, and he developed very frequent Adams-Stokes attacks for 35 min.3 Decrease of the heart-rate is obviously contraindicated in complete heart block and I have not used digitalis again for this disorder. Sophisticated treatment is not always an advantage. Organic compounds are nearer to living cells than purified chemicals. For instance, refined sugar is absorbed faster than starch. Is it wise to discard prepared digitalis, unless it is proved to be less effective than digoxin? Digoxin is more expensive, and the assay results have been disappointing.4 Digitalis folia is absorbed differently from the pure drug, and therefore peak-levels in the heart muscle are perhaps more easily avoided. Digitalis cannot be as accurately standardised, but the sensitivity from case-to-case probably varies considerably. Clinical assessment is still the lynch-pin, and digitalis may be the safer drug.
metry. 2 4 METAL CONCENTRATIONS IN HEART MUSCLE
St Luke’s Hospital, Guildford GU1 3NT
*Results as mean :t S.D.
The table gives the mean values for magnesium, calcium, potassium, sodium, iron, manganese, and copper in these samples and in a group of normal adult controls from the same There was a slight increase in sodium concentration in the cot-death samples, but this was not statistically significant. There was, however, a significant (t=2.4) decrease in potassium concentration and a significant (t=3.42) increase in the calcium concentration in the heart muscle from cot deaths. The dry weight was measured for one cot-death sample, and the percentage dry/wet weight was 25.0 as compared with 21.7±1.0for twenty normal adult samples. We have not yet measured the concentration of metals in the heart from infants dying from other causes by analysis of variance indicates that there is no significant variation of metal concentration with age for older normal controls. The differences in mean values between the cot-death samples and normal adults are similar to the differences we have found in adults dying suddenly from ischaemic heart-disease.4 The differences in the ratios of magnesium/calcium and potassium/sodium in the heart may be a contributory cause of sudden death both in sudden death from ischaemic heart-disease and in cot deaths. There is evidence for cardiac abnormalities in "near miss" cot deaths.S Softening hard water will decrease the magnesium and calcium content of the drinking-water as well as increasing the sodium content. The decrease in magnesium and increase in sodium in the drinking-water might cause changes in the electrolyte balance in the heart similar to those we have found in cot deaths, and thus increase the rate for cot deaths. area.
Departments of Biochemistry, and Chemistry, University of Hull, Hull HU6 7RX
G. A. MACGREGOR
(and no. of samples).
BARBARA CHIPPERFIELD J. R. CHIPPERFIELD
1. Robertson, J. S., Parker, V. Lancet, 1978, ii, 1012. 2. Chipperfield, B., Chipperfield, J. R. ibid. 1973, ii, 293. 3. Caddell, J. L. ibid. 1972, ii, 258.
4. Chipperfield, B., Chipperfield, J. R. Am. Heart J. 1978, 95, 732. 5. Guilleminault, C., Ariagno, R., Souquet, M., Dement, W. C., Lancet, 1976, i, 1326.
EAR-LOBE CREASE
SiR,—The presence of a diagonal ear-lobe crease seems to be associated with vascular disease.5-8 However, earlier work was
done
on
people seeking
medical
help for
one reason or
another, and we do not know of any survey in apparently healthy people. We have studied 300 healthy individuals (factory workers, teachers and university students) and recorded RESULTS
*T-wave changes indicating ischaemia.
tBy chi-squared test. the presence or absence of diagonal ear-lobe creases and data on certain risk factors for vascular disease sought by fundoscopy, measurement of blood-pressure and fasting blood glucose, cholesterol, and triglyceride, and electrocardiography. The E.c.G. and the fundoscopy were done by a cardiologist and 1. Williams, P., Aronson, J., Sleight, P. Lancet, 1978, ii, 1340. 2. Lewis, T. Diseases of the Heart. London, 1942. 3. MacGregor, G. A. Br. Heart. J. 1959, 21, 225 (case 1). 4. Lancet. 1978. ii. 1188. 5. Frank, S. T. New Engl. J. Med. 1973, 289, 327. 6. Lichstein, E., Chadda, K. D., Naik, D., Gupta, P. ibid. 1974, 290, 615. 7. Christiansen, J. S., Mathiesen, B., Andersen, A. R., Calberg, H. ibid. 1975,
293, 308. 8. Andresen, A. R.,
Christiansen, J. S., Jensen, J. K. ibid. 1976, 294, 1183.