[Prognostic significance of impaired intra-and infra-bundle of His conduction in the heart].

BACKGROUND

So far no final solution was found as regards the relationship of impaired conduction in the His-Purkynĕ system and the incidence of cardiac and in particular sudden deaths. The objective of the present work was to assess by long-term prospective follow-up of subjects with a normal and pathological prolongation of the intra- and infrahisian conduction in the heart, based on the electrogram of the bundle of His, the importance of these findings for assessment of the patient's prognosis.

METHODS AND RESULTS

After elimination of subjects with ventricular preexcitation the authors included in the group 340 patients (243 men, 97 women, aged 16-81 years, mean 49 +/- 16), where they recorded the electrogram of the bundle of His (without cardiac stimulation, during graded and programmed stimulation of the atria, after i.v. administration of ajmaline). In 206 cases they implemented at the same time programmed stimulation of the ventricles. The HV interval or the length of the H wave were in 286 patients normal and in 54 patients protracted. All patients were followed up by the authors for 6 to 144 months (mean follow up period 56.1 months). In the group of subjects with normal intra- and infrahisian conduction, as compared with the group with protracted conduction in the same area, the number of cardiac deaths was lower, i.e. 10.1 %, as compared with 22.2 %, sudden "cardiac" deaths (death within one hour after the onset of symptoms), i.e., 6.6 % as compared with 11.1 %, and sudden bradyarrhythmic" deaths (sudden "cardiac" death except subjects with diagnostic programmed ventricular stimulation), i.e. 2.8 % as compared with 11.1 %.

CONCLUSIONS

The results support significantly the prognostic impact of pathological conduction in the His-Purkynĕ system as regards the occurrence of cardiac deaths and sudden "brady arrhythmic" deaths (p < 0.05). Conversely, the differences as regards the occurrence of sudden "cardiac" deaths were not significant.