Occasional Appearance of Qrs Complexes with Ventricular Pre-excitation.

There are infrequent instances when cardiac beats with the electrocardiographic characteristics of the pre-excitation type appear occasionally in an otherwise normal tracing (Sanghvi and Misra, 1958). A recent observation helped us to clarify the problem of diagnosis and interpretation, and we present the following case history because of its practical and theoretical interest. B. T., a 48-year-old barmaid, complained of amenorrhoea of two years' duration, exertional dyspncea, and paroxysms of tachycardia, mostly nocturnal and of variable duration. Electrocardiograms were recorded in August, September, and November 1962. The first record (August) is illustrated in Fig. 1, and shows sinus rhythm with an average rate of 75 to 80, and the RR intervals range between 0O8 and 0 75 sec. Atrio-ventricular conduction (PQ = 0-18 sec.) and QRS duration (0 09 sec.) were both normal. Besides the normally conducted sinus beats, there were occasional beats preceded by P waves of normal configuration similar to the P waves with normally con-