[Cardiac impulse generation and conduction in patients with long-term insulin-dependent diabetes mellitus]

In a selected group of 14 diabetic patients (seven women, seven men) with an average age of 38 years, average duration of diabetes 20 years, all with end-organ manifestations but without hypertension or previous myocardial infarct, His bundle electrography at resting conditions and during programmed electrical stimulation was carried out to determine whether diabetes mellitus, alone, affects meaningful disturbances of impulse generation and conduction. The sinus node recovery time, conduction time through the atrium, the AV-node and the His-Purkinje system as well as the effective and functional refractory periods of the atrium and AV-node were determined. At rest, all patients had normal findings. During atrial stimulation, two patients were found to have intraatrial conduction disturbances and one patient had impaired AV-nodal conduction reserve; the latter had diminished 1:1 conduction through the AV-node during atrial stimulation. In general, however, diabetes mellitus, alone, does not appear to be of clinically-relevant pathologic importance for the development of rhythm disturbances at the levels of the sinus node and/or the AV-node and His bundle system.