[Iatrogenic sinus node disease and iatrogenic AV block]

The appearance of long lasting bradycardia due to damage of the sinus node (iatrogen sick sinus syndrome; or the atrioventricular conduction system, iatrogen AV block) is not a rare event after open heart surgery. In the course of 5093 heart operations the development of iatrogen sick sinus syndrome was observed in 234 patients (4.6%) and iatrogen AV block in 91 cases (1.8%). The incidence rate of iatrogen sick sinus syndrome or iatrogen AV block was quite divergent depending mostly on the type of operation. Comparing the data of our earlier (1977-1982) and later (1983-1991) cardiac surgical interventions, the prevalence of iatrogen sinus node disease and iatrogen AV block seems to decrease, mainly due to the progress in techniques of cardiac surgery. With the appearance of iatrogen sick sinus syndrome or AV block, urgent temporary pacing is indicated to prevent the deleterious hemodynamic effect of bradycardia. In the cases of persistent iatrogen sick sinus syndrome and iatrogen AV block, permanent pacemaker implantation is needed. It is remarkable that although the incidence rate of iatrogen sick sinus syndrome is greater than that of iatrogen AV block, in iatrogen sick sinus syndrome the regression is quite frequent, while in iatrogen AV block the 2nd or 3rd degree AV block is usually permanent. We performed pacemaker implantation in 56 cases of iatrogen sick sinus syndrome (24%) and in 57 patients of iatrogen AV block (63%). With pacemaker therapy the outcome of iatrogen sick sinus syndrome and iatrogen AV block is very favourable.