Recent history of vasovagal syncope in a young, referral-based population is a stronger predictor of recurrent syncope than lifetime syncope burden.

Introduction: accurate selection of patients for vasovagal syncope studies requires strong risk stratification and knowledge of the natural history of syncope. We aimed to test the hypothesis that recent history of vasovagal syncope compared to distant history better predicts subsequent recurrence of syncope.

Methods And Results: in all, 208 subjects with a positive tilt test and ≥ 3 lifetime syncope spells were followed for 1 year.

Syncope and structural heart disease: historical criteria for vasovagal syncope and ventricular tachycardia.

Introduction: to develop evidence-based criteria that distinguish syncope due to ventricular tachycardia (VT) from vasovagal syncope (VVS) in patients with structural heart disease (SHD).

Methods And Results: one hundred and thirty-four patients with syncope and SHD completed a 118-item questionnaire and underwent noninvasive and invasive diagnostic assessments in a prospective cohort study. The contributions of symptoms to diagnoses were estimated with logistic regression and a point score was developed and then tested using receiver-operator characteristic analysis.

The development and preliminary validation of a scale measuring the impact of syncope on quality of life.

Aims: To develop a brief syncope-specific measure of health-related quality of life.

Methods And Results: One hundred and fourteen patients with syncope completed a 48-item questionnaire derived from a generic measure of quality of life (the EQ-5D), the Syncope Functional Status Questionnaire, a depression scale (the CES-D) and historical symptoms. From these, clinical impact methodology was used to derive 12-item Impact of Syncope on Quality of Life (ISQL).

Effect of metoprolol on quality of life in the Prevention of Syncope Trial.

Introduction: Vasovagal syncope is common, often recurrent, and reduces quality of life. No therapies have proven useful to improve quality of life in adequately designed randomized clinical trials. Beta-blockers have mixed evidence for effectiveness in preventing syncope.

Design and use of a quantitative scale for measuring presyncope.

Introduction: Vasovagal syncope is common and distressing. One important symptom is presyncope, but there are no clinimetric measures of this. We developed the Calgary Presyncope Form (CPF) and used it to test whether metoprolol reduces presyncope in a randomized trial.

Worsening of symptoms before presentation with vasovagal syncope.

Introduction: Much of the natural history of vasovagal syncope is unknown. We determined whether patients presenting for care have had a recently worsened syncope frequency.

Methods And Results: We compared 208 subjects in the referral-based Prevention of Syncope Trial (POST) and 122 subjects who fainted > or =1 in a community survey study.

Prevention of Syncope Trial (POST): a randomized, placebo-controlled study of metoprolol in the prevention of vasovagal syncope.

Background: Previous studies that assessed the effects of beta-blockers in preventing vasovagal syncope provided mixed results. Our goal was to determine whether treatment with metoprolol reduces the risk of syncope in patients with vasovagal syncope.

Methods And Results: The multicenter Prevention of Syncope Trial (POST) was a randomized, placebo-controlled, double-blind, trial designed to assess the effects of metoprolol in vasovagal syncope over a 1-year treatment period.

Age of first faint in patients with vasovagal syncope.

Introduction: Understanding whether vasovagal syncope is a lifelong disorder might shed insight into its physiology and affect management strategies. Accordingly, we determined the age of the first syncopal spell in adult patients who sought care for syncope.

Methods And Results: Patients were 42 +/- 18 years old with 64% women.

Diagnostic criteria for vasovagal syncope based on a quantitative history.

Aims: Our goal was to develop historical criteria for the diagnosis of vasovagal syncope.

Methods And Results: We administered a 118-item historical questionnaire to 418 patients with syncope and no apparent structural heart disease. The prevalence of each item was compared between patients with positive tilt tests and those with syncope of other, known causes.

Activity-responsive pacing produces long-term heart rate variability.

Introduction: Long-term heart rate variability (HRV) measures, including the standard deviation of means of successive 5-minute epochs of R-R interval intervals (SDANN) and the power law slope (beta), are important prognostic measures, yet their physiologic basis is unknown. We tested the hypothesis that long-term HRV arises from physical activity in a randomized cross-over study in patients with rate-responsive pacemakers.

Methods And Results: Ten patients with complete heart block and dual-chamber pacemakers underwent 24-hour periods of ambulatory ECG in each of three pacing modes: atrially tracked, fixed-rate, and rate-responsive pacing.

Similarity of spontaneous and induced heart rate and blood pressure turbulence.

Background: Heart rate turbulence (HRT) is a transient tachycardia-bradycardia that follows premature ventricular complexes (PVCs). The physiology of turbulence is studied in the electrophysiology lab using induced premature ventricular stimuli but the reliability of this model for HRT is unknown.

Objectives: To compare heart rate and blood pressure signatures of induced and spontaneous HRT.

Outcome of patients with dual-chamber pacemakers implanted for the prevention of neurally mediated syncope.

Dual-chamber pacemaker insertion (PI) has been found to reduce the recurrence of neurally mediated syncope (NMS) in 3 randomized trials. However, the long-term benefits of PI are unknown. To assess the natural history of NMS, we followed a cohort of 40 patients who underwent PI for frequent NMS for 46 to 75 months.

Induction of heart rate and blood pressure turbulence in the electrophysiologic laboratory.

Heart rate turbulence (HRT) is a transient tachycardia and/or bradycardia that follows ventricular premature complexes (VPCs). Absent or blunted HRT is associated with a poor prognosis in patients with heart disease, but its physiology is unknown. We hypothesized that HRT might be mediated by baroreflexes following early depolarizations.

Historical criteria that distinguish syncope from seizures.

Objectives: We prospectively sought evidence-based criteria that distinguished between seizures and syncope.

Background: Loss of consciousness is usually due to either seizures or syncope. There are no evidence-based historical diagnostic criteria that distinguish them.