Disturbances in the intraventricular conduction system in teenagers with type 1 diabetes. A pilot study.

UNLABELLED: Body Surface Potential Mapping (BSPM) is a multi-electrode synchronous method for examining electrocardiographic records on the patients' body surface that allows the assessment of changes in the heart conduction system. The aim of the study was to visualize and evaluate changes in the intraventricular system in adolescents with T1D.

PATIENTS AND

METHODS

Inclusion criteria: age > 12 years, T1D duration >3 years, HbA1c >8%.

EXCLUSION CRITERIA: diagnosis of autonomic neuropathy, heart structural defects, heart failure. BSPM data were processed into map plotting to illustrate differences in ventricular activation time (VAT, isochron lines).

RESULTS

33 teenagers (20 boys), mean age 15.0 ± 2.1 years, T1D from 6.8 ± 4.1 years were included. Mean HbA1c was 9.6 ± 2.0%. In the standard ECG recording abnormalities were not present. The distribution of isolines on the group-mean map plotted for T1D patients only initially resembles the course of isolines on the group-map for normal subjects (N = 30), in whom the electrical impulse stimulating the heart ventricles passes through the atrio-ventricular node, then symmetrically excites the branches of His bundle and finally the Purkinje fibers. In T1D patients, after proper onset of intraventricular stimulation, the isolines reflecting the both ventricles reach higher time values, which indicates problems in the propagation of the ventricular depolarization.