Treatment of Stokes-Adams Syndrome
Permanent cardiac pacemaker implantation is the definitive treatment for Stokes-Adams syndrome, as it prevents recurrence of syncope and may improve survival. 1
Immediate Recognition and Diagnosis
Stokes-Adams syndrome manifests as transient loss of consciousness with spontaneous recovery due to cerebral hypoxia from decreased cardiac output, often presenting with seizure-like activity. 2 The underlying causes include:
- High-degree atrioventricular (AV) block (50-60% of cases) 3
- Sinoatrial (SA) block or sick sinus syndrome (30-40% of cases) 3
- Paroxysmal ventricular tachycardia or fibrillation (0-5% of cases) 3
Document the arrhythmia during symptoms with ECG monitoring—this is essential but symptom-rhythm correlation is less critical in intrinsic AV block than in sinus node disease, as there is consensus that pacing prevents recurrence regardless. 1
Definitive Treatment: Permanent Pacemaker
Class I Indications (Must Implant)
Cardiac pacing is indicated in patients with syncope and second-degree Mobitz II, advanced, or complete AV block. 1 This applies even without documented symptom-ECG correlation when intrinsic AV conduction disease is present. 1
For patients with documented third- or second-degree AV block due to intrinsic disease of the AV conduction system, there is general consensus that pacing prevents recurrence of syncope and may improve survival. 1
Pacemaker Mode Selection
Dual-chamber pacemaker with preservation of spontaneous AV conduction is indicated (Class I, Level A) for reducing risk of atrial fibrillation and stroke, avoiding pacemaker syndrome, and improving quality of life compared to single-chamber ventricular pacing. 1
For patients with permanent atrial fibrillation and AV block, ventricular pacing with rate-response function is recommended. 1
Timing of Implantation
Elective pacemaker implantation should be performed in patients with persistent third-degree heart block who have had one or more episodes of Stokes-Adams syncope. 4 The negligible surgical morbidity and mortality justify broad indications for implantation. 4
In patients with intrinsic intermittent AV block, cardiac pacing is indicated even in the absence of documentation of symptom-ECG correlation. 1
Emergency Management
For patients developing intractable or recurrent bouts of asystole before permanent pacemaker placement:
- Intravenous isoproterenol as a temporizing measure 4
- External pacemaker attached to transvenous catheter electrode 4
- Temporary pacing until permanent device can be implanted 4
Important Clinical Distinctions
Differentiate intrinsic (organic) AV block from extrinsic (reflex/vagal) block, as this affects prognosis and pacing benefit. 1 Features supporting intrinsic AV block include:
- Underlying heart disease or bundle branch block 1
- Documentation of infra-Hisian block by electrophysiologic study 1
- Block initiated by atrial/ventricular premature beats 1
- Tachy-dependent or brady-dependent AV block 1
Patients with Stokes-Adams attacks before pacemaker implantation have a higher incidence of deficient underlying heart rhythm (ventricular asystole ≥4 seconds) and are more likely to become pacemaker-dependent. 5
Prognosis Without Treatment
Medical management of third-degree heart block with Stokes-Adams syndrome does not provide reliable protection, and life expectancy averages only about two years after diagnosis without pacemaker implantation. 4 This underscores the critical importance of permanent pacing.
Additional Considerations
For patients with tachycardia-bradycardia syndrome (sick sinus syndrome variant), supplementary antiarrhythmic treatment may be required, and long-term anticoagulation should be considered in selected cases. 3
Pacemaker implantation should be performed promptly in Stokes-Adams syndrome, as oral drug treatment is ineffective and the condition carries risk of sudden cardiac death. 3, 2