Congestive heart failure in mitochondrial diabetes mellitus

Congestive heart failure in mitochondrial diabetes mellitus

S!R—Buekens and colleagues’ study clearly shows no statistically significant difference in the rates of preterm delivery, low birthweight, and prematu...

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S!R—Buekens and colleagues’ study clearly shows no statistically significant difference in the rates of preterm delivery, low birthweight, and premature rupture of membranes between the control and experimental groups. Since it appears that routine cervical examination has no ill effect, how do these workers justify their conclusion that "routine repeated cervical assessment during pregnancy should not be recommended"? With the same logic, one might argue that, since there is no increased incidence of poor outcomes in the group subjected to routine cervical examinations, these exams should be done routinely during prenatal visits. Could Buekens and colleagues’ recommendation to the contrary represent a bias based on their individual practices? Perhaps there are benefits to routine cervical examination such as allaying patient and physician anxiety or providing better assessment of fetal position. John L

mutation may also be one of the causes of congestive heart failure in diabetics, and patients with mitochondrial diabetes mellitus should have an echocardiogram done even when their electrocardiogram and chest radiograph are normal. Reiko Yoshida, Yoshihiko Ishida, Toshiki Hozumi, Hiroshi Ueno, Miyako Kishimoto, Masato Kasuga, Tsutomu Kazumi Divisions of Metabolism, Endodrinology, and Cardiology, Department of Internal Medicine, Hyogo Medical Centre for Adults, Akashi 673, Japan; and Second Department of Internal Medicine, Kobe University School of Medicine, Kobe

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Kannel WB, Hjortland M, Castelli WP. Role of diabetes in congestive heart failure: the Framingham Study. Am J Cardiol 1974; 34: 29-34. Kishimoto M, Hashiramoto M, Araki S, Ishida Y, Kazumi T, Kasuga M. Diabetes mellitus carrying a mutation in mitochondrial tRNALeu(UUR) gene. Diabetologia (in press). Reardon W, Ross RJM, Sweeney MG, et al. Diabetes mellitus associated with a pathogenic point mutation in mitochondrial DNA. Lancet 1992; 340: 1376-79.

Bastien, W R Kiser

Department of Family Medicine, Naval Hospital, Jacksonville, FL 32214, USA

Lamotrigine

Congestive heart failure in mitochondrial diabetes mellitus SIR-An epidemiological study suggests a striking increase in the incidence of congestive heart failure in patients with diabetes.’ Severe myocardial dysfunction may be the first evidence of underlying coronary artery disease or hypertensive heart disease. Less common causes to be excluded include alcoholic cardiomyopathy, congenital heart

disease, thyroid disorders, pericardial disease, and myocarditis. We describe two diabetics with a point mutation of mitochondrial DNA who had hypertrophic cardiomyopathy which led to congenital heart failure in one of them. A 59-year-old man with diabetes for 10 years and taking an oral hypoglycaemic agent was admitted after 1 week of exertional dyspnoea and oedema. He was neither obese nor hypertensive. At age 56, echocardiography had revealed thickening of the left-ventricular wall (width of interventricular septum [IVS] 12 mm, normal 9-10), and low percentage fractional shortening (%FS) (22%, normal an index of wall motion of the left ventricle. >28%), However, his electrocardiogram and chest radiograph were then normal. On admission, his chest radiograph showed cardiac enlargement with a cardiothoracic ratio of 0-66, and this was associated with a further decrease in %FS to 13% with no change in IVS. He responded well to diuretics and captopril, and %FS rose to 22%. His electrocardiogram and chest radiograph now showed no abnormalities (cardiothoracic ratio 0-43). Coronary angiography was normal. The second case was a 43-year-old man with diabetes of 26 years’ duration on insulin. Although his %FS (32%), electrocardiogram, and chest radiograph were normal, his IVS was wider than normal (13 mm). Sensorineural hearing loss was confirmed bilaterally in both patients. By use of mitochondrial DNA from platelets, we amplified the region encoding tRNAs by polymerase chain reaction and sequenced it. We identified an A-to-G transition at nucleotide 3243 in the tRNAi.eu(UUR) gene in both patients. In right-ventricular endomycardial biopsy specimens of the first patient, obtained after informed consent, the proportion of mutant mitochondrial DNA was 60%, whereas it was 24% in platelets. There was no mutation other than the transition at 3243 between position 3230 and 3304. Endocrinological features of the two patients will be described elsewhere.2 An A-to-G transition at position 3243 of the tRNALeu(UUR) gene is associated with diabetes mellitus and deafness.3 This

in infantile spasms

SiR-Infantile spasms is an epileptic syndrome that affects infants in the first year of life. The most effective treatment is steroids, particularly for cryptogenic cases, but side-effects are frequent and the relapse rate is high, resulting in 20-71 % of patients continuing to have seizures.’ Open studies show that vigabatrin is effective, especially for patients with tuberous sclerosisAlthough a few patients benefit from valproate or benzodiazepines, it leaves a sizeable number intractable to therapy. There are a number of aetiological factors in infantile spasms and it is likely that the pathophysiology involves a combination of different mechanisms. Since lamotrigine is a promising drug for symptomatic generalised epilepsy," it seemed justified to explore the use of this drug in patients with intractable infantile spasms. We studied 30 patients (16 boys, 14 girls) with infantile spasms, most of which were intractable to steroids (21 cases), vigabatrin (23 cases), valproate (29 cases), and benzodiazepines (26 cases). All patients had daily spasms that were quantified by the parents. Age ranged from 1 month to 11years when lamotrigine was added, as reported elsewhere,s to the previous medication which remained unchanged for 3 months. Tolerability was excellent except for 2 patients who had somnolence in combination with carbamazepine and 1 who had ataxia. 1 patient aged 13 months presented with a rash when lamotrigine was administered. After 3 months of lamotrigine, spasms had ceased in 5 patients, decreased by over 50% in 4, increased by over 50%

NS=not

significant.

Table: Comparison of characteristics of patients with over 50% decrease in seizure frequency with those of non-responders

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