Selection of patients with complete heart block for permanent artificial pacing requires an estimate of the risk of death from heart block in untreated, "minimally symptomatic" patients with block. Of 26 such patients who were not given pacemakers at their initial evaluation, 12 remain minimally symptomatic after an average of 3 years after consideration for pacing. Nine patients subsequently developed symptoms, at which time artificial pacing was provided uneventfully. Five died suddenly and unexpectedly of apparent cardiac arrhythmia. The five patients who died had shown some premonitory symptoms and variation in ventricular activation focus to a greater extent than those 12 who had survived without pacemakers.
During the same time 33 patients received artificial pacing because of recurrent syncope or equivalent symptoms of circulatory failure. Of this group there were no operative deaths, three patients died later of unrelated disease with normal pulse rates, and two died with probable rhythm disturbance.
This experience indicates that, while most patients with atrioventricular (AV) block provide sufficient symptomatic warning to permit pacing when needed, the risk of sudden death even in the minimally symptomatic patient is considerable, and the risk of artificial pacing has been less. Any patient who has persistent or recurrent episodes of high degrees of AV block, if accompanied by any related symptoms or spontaneous ventricular irritability, should now receive a permanent, artificial pacemaker.