His Bundle Recordings in Patients with Bundle Branch Block and Transient Neurologic Symptoms

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Abstract
His bundle electrograms were recorded in 19 patients with bundle branch block (BBB) and transient neurologic symptoms allowing for determination of intra-atrial (P-A), atrioventricular (A-V), nodal (A-H) as well as infranodal conduction (H-Q) times. The patients were initially monitored in a coronary care unit and have been followed for a mean period of 8 ± 4 months. In six patients (Group I) neurologic symptoms were observed in the absence of electrocardiographic evidence of A-V block. In six patients (Group II) the cause of symptoms was uncertain; two of these patients had relief of symptoms after permanent cardiac pacemaker insertion and were presumed to have episodic high grade A-V block. In seven subjects (Group III) complete A-V block was documented as the cause of the symptoms; these patients were studied when 1:1 antegrade A-V conduction returned. There was no significant difference between mean P-A, A-H, and QRS durations among the patients in the three groups. Mean H-Q (89 ± 20 msec) for Group I...