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To the Editor:—
The report by Rabbino, Likoff, and Dreifus on "Complications and Limitations of Direct-Current Countershock" (JAMA190:417 [Nov 2] 1964), and your editorial in the same issue, both regard the possibility that ventricular fibrillation or tachycardia may, in effect, be caused by direct-current countershock but fail to suggest that these complications may result from lapses in technique rather than from digitalis or as unexplained events.Most equipment for direct-current countershock uses the R wave as the point of reference for synchronization to deliberately minimize the likelihood of the discharge occurring at the vulnerable T wave area. It is apparently not well recognized that the machines are not actually able to distinguish R waves from any other wave form and that the discharge follows the highest wave in the cycle, assuming this will always be an R wave. It can readily be seen that there are many circumstances
Meltzer LE, Kitchell JR, Dreifus LS. Danger in Cardioversion: Height of R and T Waves. JAMA. 1965;191(3):253-254. doi:10.1001/jama.1965.03080030097023