Pacing for vasovagal syncope after the second Vasovagal Pacemaker Study (VPS II): a matter of judgement.

Vasovagal or neurocardiogenic syncope is a common benign condition. In the majority of patients it regresses naturally, or can be controlled by conservative therapy. However there is a group of patients who remain severely affected despite lifestyle measures, counselling and medication. Pacing has been considered in these patients as a result of logic, observational studies, and three randomised but unblinded studies, VPS, VASIS and SYDIT. A randomised and blinded study, VPS II, was recently published, the results of which undermined the results of these preceding studies: despite a 30% trend towards reduced syncope in patients with active pacing, the result was not statistically significant. This left clinicians with a dilemma, whether or not to pace in patients with disabling syncope despite conservative therapy. We believe, based on a review of all currently available evidence, that there remains a role for pacing in the patient with evidence of significant cardioinhibition, particularly severe bradycardia or asystole, and ongoing disabling syncope in spite of conservative measures. When to pace in these patients is a matter of clinical judgement. The threshold for pacing should remain high, however, with extensive attempts of conservative and pharmacological measures and with appropriate discussions with patients prior to instituting pacing, regarding the risks and long-term implications of a pacemaker. More needs to be learned about optimal pacing modalities.