Approval for the zephyr pulse generators models: xl dr 5826, dr 5820 and sr 5620.  The device is indicated in the following permanent conditions, when associated with symptoms including, but not limited to: syncope, presyncope, fatigue, disorientation, or any combination of those symptoms.  Rate modulated pacing is indicated for patients with chronotropic incompetence, and for those who would benefit from increased stimulation rates concurrent with physical activity.  Dual-chamber pacing (models 5826, 5820 only) is indicated for those patients exhibiting: sick sinus syndrome, chronic symptomatic second- and third-degree av block, recurrent adams-stokes syndrome, or symptomatic bilateral bundle branch block when tachyarrhythmia and other causes have been ruled out.  Atrial pacing is indicated for patients with sinus node dysfunction and normal av and intraventricular conduction systems.  Ventricular pacing is indicated for patients with significant bradycardia and: normal sinus rhythm with only rare episodes of a-v block or sinus arrest, chronic atrial fibrillation, severe physical disability.  Af suppression (models 5826, 5820 only) is indicated for suppression of paroxysmal or persistent atrial fibrillation episodes in patients with one or more of the above pacing indications.