Fifty-nine patients aged 39-80 years underwent implantation of a cardiac pacemaker and were followed for up to 9 years (average duration of pacing 39 months). Atrioventricular conduction disturbances (complete atrioventricular block, 2 : 1 atrioventricular block, bifascicular block, and atrial fibrillation with slow ventricular rate) were present in 49 patients and sick sinus syndrome (sinus arrest or sino-atrial block, and bradycardia-tachycardia syndrome) in 10. Pacing was required because of Adams-Stokes attacks in 41 patients, 2 of whom also had congestive heart failure. It was required in 6 because of frequent dizziness, in 10 because of congestive heart failure, and in 2 because of low cardiac output. The symptomatic improvement after cardiac pacing was well recognized in most of our patients, and 32 (54 percent) of the 59 patients pursued normal physical and daily activity. Although the efficacy of pacemaker therapy was of limited value in some patients with congestive heart failure or underlying or coexisting diseases, the beneficial effects following pacemaker implantation were: (1) abolishment of transient neurologic symptoms such as Adams-Stokes attack, (2) relief from a constant fear of a recurrence of an Adams-Stokes attack or sudden cardiac death, and (3) improvement in restricted physical activity due to low cardiac output. Thus, we conclude that pacemaker implantation in most patients with bradyarrhythmias is beneficial not only for the treatment of the acute problem but also because it prolongs life and greatly enhances its quality. However, in spite of the beneficial effects after pacemaker implantation, we still observe a number of complications connected with the use of a permanent pacemaker. Therefore, our policy is to implant a permanent pacemaker following the execution of sufficient studies of the bradyarrhythmia and the etiology of symptoms, and then under taking long-term follow-up of the patients.