Indications for pacing in the treatment of bradyarrhythmias. Report of an independent study group.

Indications for permanent pacing in the bradyarrhythmias are summarized. In the absence of symptoms, pacing is justified only when Mobitz type II block or complete atrioventricular (AV) block is localized in the bundle-branch system. All other abnormalities of impulse generation or conduction (incomplete AV block of any type, atrial fibrillation with slow ventricular response, or sinus node dysfunction) must be shown to be stable and intrinsic and to cause CNS symptoms or hemodynamic compromise to justify pacing. Isolated intra-Hisian abnormality without failure of AV conduction is benign. Measurement of HV interval does not contribute significant information. Correlation of carotid sinus sensitivity with carotid sinus syncope is poor (5%). Bradyarrhythmia produced by minimal effective doses of an essential drug is a rare indication for pacing and requires special documentation. Inadequate indications, sources of error, and misconceptions are discussed. Generally, it is important to exclude drug effect, transient clinical states, and correctable systemic disease as causes of the abnormality before making a conclusion about pacing.