Catheter-induced A-V nodal block occurring during electrophysiologic study.

We describe a patient who underwent electrophysiologic study for evaluation of recurrent syncope. No abnormalities were found but high-grade A-V block proximal to the His bundle depolarization developed abruptly as the coronary sinus electrode catheter was being withdrawn. The A-V block disappeared gradually over a 12-hour period, progressing to type I second-degree A-V block, and then to first-degree A-V block (due to prolonged A-V nodal conduction), prior to resuming normal conduction.

Bilateral skin conductance, finger pulse volume, and EEG orienting response to tones of differing intensities in chronic schizophrenics and controls.

Skin conductance (SCOR), finger pulse volume (FPV-OR), and EEG orienting responses were examined to repeated tones of either 60- or 90-dB intensity in chronic schizophrenics, nonschizophrenic psychiatric patients, and normals. SCOR reaffirmed previous findings with schizophrenics displaying significantly more frequent nonresponsiveness to 60-dB tones, and faster habituation among patients who did respond. Increased stimulus intensity decreased the incidence of nonresponsiveness to the level of controls, but did not alter the rapid habituation of schizophrenics.