Electrolyte abnormalities cause fatal cardiac arrhythmias in patients with diabetic ketoacidosis. A patient is reported with electrocardiogram (ECG) abnormalities characteristic of toxic hyperkalemia and hypocalcemia. The ECG abnormalities were noted during the first hour after arriving at the hospital. The laboratory values confirming the electrolyte abnormalities were not available for more than 1 h after the ECG indicated the danger of myocardial toxicity. During the initial 2 h of therapy the patient was urinating and not in shock. ECG monitoring of this patient prevented the routine administration of intravenous potassium, which was potentially lethal. The clinical importance of electrolyte levels in the management of diabetic ketoacidosis is the prevention of cardiac arrhythmias. ECG monitoring should be a minimal standard in the management of diabetic ketoacidosis.

Six children, aged between 3 and 19 years, with congenital complete heart block without associated cardiac disease were studied by His bundle electrography. All were symptomatic with resting ventricular rates over 40 beats/min, and electrocardiograms that showed a normal axis and QRS complex. His bundle to ventricular activation was within the normal range in all and the block was proximal to the bundle of His. Ventricular and atrial pacing did not result in retrograde or antegrade conduction. All the patients were thought to have a lesion proximal to the site where the bundle of His potential was recorded and, therefore, were unlikely to develop symptoms or require treatment. Additional Indexing Words: QRS frontal vectorVentricular conduction Long-term survival CONGENITAL complete heart block is a rare but important form of atrioventricular (A-V) block.' Although most children with it are asymptomatic and the lesion is compatible with longevity,24 Stokes-Adams attacks and death do occur.5' 6 A clinical study is in progress to determine the natural history of this entity,7 but the mortality in infancy and childhood is estimated at not less than 5%8 Most reports1 6, 7do not separate heart block with associated cardiac disease from From the

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