[Surface recording technique of His bundle potential in man].

A method is presented for the non-invasive recording of His bundle electrical activity from the body surface in man. Several bipolar ECG leads were employed: precordial, Frank "x" and Frank "z". Signals were filtered (30-300 Hz), highly amplified (5 x 104) and averaged. Digital averaging was performed on line by a microcomputer (OTE Biomedica Neuroaverager mod. 1172). Surface investigation was performed in 10 patients affected by different conduction pathology simultaneously with HBE recordings for diagnostic purpose and in 5 normal volunteers only incruently. Highly repeatable electrical deflections (B waves) were recorded in the PR segment. In all patients a good correspondence between surface (B wave) and intracardiac (H wave) was found. Atrial pacing and pharmacological test were used in order to ascertain the real source of B wave.