[Relation between the surface ECG and the bundle of His electrogram in 200 patients].

The relationship was assessed between different types of conduction disorders in surface ECG and pathological changes of intervals in electrograms of the His bundle during spontaneous cardiac action and during artificial right atrial stimulation in 200 patients (130 men, 70 women). For the detection of prognostically less favourable intra- and infraHisal conduction disorders it was found important to study the bundle of His electrographically in the following types of surface ECG: complete block of the right Tawara node with left posterior and left anterior hemiblock, complete block of the left Tawara node, left posterior hemiblock, atrio-ventricular block of the 1st degree (particularly when associated with intraventricular conduction disorder), IInd - degree atrio-ventricular block 2:1 (3:1), less so atrio-ventricular block of the IIIrd degree. Even apparently normal surface ECG can sometimes conceal major damage to the His-Purkinje system. Invasive electrophysiological tests are justified by the presence of syncopes or their equivalents due to unknown causes.