CARDIAC PACING FOR PREVENTION OF RECURRENT VASOVAGAL SYNCOPE

Purpose: To review the status of cardiac pacing for the treatment of patients with recurrent vasovagal syncope. Data Sources: A MEDLINE search for English- and French-language articles published between 1980 and 1994 about cardiac pacing for prevention or treatment of vasovagal syncope. The term cardiac pacing was used in conjunction with the terms vasovagal, neurally mediated, or neurocardiogenic syncope, but not with the term carotid sinus hypersensitivity. Study Selection: Case reports and series from peer-reviewed journals were selected if they documented the presence of vasovagal syncope and assessed pacing effectiveness using tilt-table testing, clinical followup, or both. Four case reports and four series met these criteria. Data Extraction: Findings were summarized individually. Statistical analysis of combined data was inappropriate given differences among studies in patient selection, testing, and follow-up. Results: Pacing may be useful in selected patients with predominantly cardioinhibitory vasovagal responses. Pacing alone may eliminate symptoms in 25% of these patients and may prevent abrupt cardiovascular collapse in others (such as those in whom syncope occurs with minimal or no premonitory sensation). However, interpretation of most available reports has been limited both by the uncertainty associated with using the tilt-table technique to assess pacing effectiveness and by relatively short-term follow-up. Conclusions: The usefulness of cardiac pacing for patients with recurrent vasovagal syncope remains only partly understood. Randomized controlled trials are needed for this and other aspects of the treatment of this condition. Additionally, substantial room remains for innovation both in earlier recognition of imminent vasovagal syncope by implantable devices and in specifically designing cardiac pacing algorithms for treatment of this condition.