To the Editor.— In response to the article by Barrett and Hey ( 214: 1323,1970), I find it very difficult to implicate diazepam as the toxic agent producing the ventricular arrhythmias described. In the first case, the patient had a history of "chronic bronchitis" and may well have had hypoxia or respiratory acidosis, or both, which was aggravated by the anesthetic agent. These are well-known conditions leading to various cardiac arrythmias. In the second case there seemed to be some evidence of digitalis intoxication, or at least ventricular irritability, which may have persisted into the following day, when cardioversion was performed. This is suggested by the fact that a slow nodal rhythm followed the cardioversion for a period of time. Incidentally, the ventricular rhythm appeared to be ventricular tachycardia and not "ventricular fibrillation" in the second case (Fig 2, B ). Finally, it is possible that the quinidine could have precipitated the