Syncope recurrence and mortality: a systematic review.

AIMS: Data on adverse events and death rates following syncope are heterogeneous among studies, and knowledge of syncope prognosis could help to better define the correct management of patients. METHODS AND RESULTS: We performed a systematic review of literature by searching for prospective observational studies enrolling consecutive patients presenting to the Emergency Department because of syncope. The outcomes considered were syncope recurrence and short- and long-term mortality. Morbidity and a composite of morbidity and mortality were also assessed. Pooled event rates and 95% confidence intervals (CI) were calculated for each outcome using the random effects model. Twenty-five studies (11 158 patients) were included. The incidence of syncope relapse linearly increased from 0.3% at 30 days to 22% at 2 years follow-up. One-year mortality rate varied between 5.7 and 15.5%; the pooled estimate was 8.4% (95% CI: 6.7-10.2%). The incidence of adverse events (morbidity) varied between 6.1 and 25.2% at 10 days and 2 years, respectively. The short-term (10 days) pooled incidence of the composite of morbidity and mortality was 9.1% (95% CI: 6.6-12.5%). We found a high statistical heterogeneity between studies. CONCLUSION: This meta-analysis of prospective observational studies shows that the chance of being asymptomatic linearly progressively decreased over time after the first syncope. Short-term (10-30 days) mortality after syncope was <2% and that the overall 10-day rate of the composite endpoint of death and major events was ∼9%. The knowledge of syncope prognosis could help clinicians to understand syncope patients' prognosis and researchers to design future studies.

Current approach to the treatment of vasovagal syncope in adults.

Vasovagal syncope (VVS) is the most common cause of transient loss of consciousness. Although not associated with mortality, it causes injuries, reduces quality of life, and is associated with anxiety and depression. The European and North American cardiac societies recently published syncope clinical practice guidelines. Most patients with VVS do well after specialist evaluation, reassurance and education. Adequate hydration, increased salt intake when not contraindicated, and careful withdrawal of diuretics and specific hypotension-inducing drugs are a reasonable initial strategy. Physical counterpressure maneuvers might be helpful but can be of limited efficacy in older patients and those with short or no prodromes. Orthostatic training lacks long term efficacy and is troubled by non-compliance. Yoga might be helpful, although the biomedical mechanism is unknown. Almost a third of VVS patients continue to faint despite these conservative measures. Metoprolol was not helpful in a pivotal randomized clinical trial. Fludrocortisone and midodrine significantly reduce syncope recurrences with tolerable side effects, when titrated to target doses. Pacing therapy with specialized sensors appears promising in carefully selected population who have not responded conservative measures. Cardioneuroablation may be helpful but has not been studied in a formal clinical trial.

Implantable rhythm devices in the management of vasovagal syncope.

The ECG registration during syncope allows physicians either to confirm or exclude an arrhythmia as the mechanism of syncope. Implantable loop recorders have an over-writeable memory buffer that continuously records and deletes the patient's ECG for up to three years. Many studies have analyzed the utility of implantable loop recorders in recurrent unexplained or high risk syncope. These studies suggest that early use of the ILR provides more and earlier diagnoses and could help in selecting patients with vasovagal syncope and prolonged asystolic pauses who might benefit from pacemaker therapy. However many questions remain, including its performance in the community by physicians with a range of experience in diagnosing syncope. Furthermore there is no evidence that the use of the ILR changes outcome. Numerous attempts have been made to determine whether patients with predominantly cardioinhibitory syncope benefit from permanent pacemakers, especially if symptoms are frequent and debilitating. While the first open label trials of pacemakers in the treatment of vasovagal syncope showed promising results, this effect has not been confirmed by blinded randomized clinical trials. More recent data seem to suggest that patients over 40years with severe asystolic vasovagal syncope might benefit from permanent pacemakers.