This study was undertaken to evaluate the epidemiological features and the prognostic implications of syncope in young athletes. A cohort of 7568 young athletes (5132 males, 2436 females, aged 16.2±2.4) underwent...This study was undertaken to evaluate the epidemiological features and the prognostic implications of syncope in young athletes. A cohort of 7568 young athletes (5132 males, 2436 females, aged 16.2±2.4) underwent a pre-partici-pation evaluation. A syncopal spell in the last 5 years was reported by 474 athletes (6.2%). Syncope was unrelated with exercise in 411 athletes(86.7%), post-exertional in 57(12.0%) and exertional in 6 (1.3%). All episodes of non-exertional or post-exertional syncope had the typical features of neurally-mediated fainting. The 6 athletes with exertional syncope underwent further testing allowing the diagnosis of hypertrophic cardiomyopathy in one case, and of right ventricular outflow tract tachycardia in another. The remaining 4 athletes only showed a positive response to tilt-testing. All athletes were followed for 6.4±3.1 years, during 48 066.6 person-years of follow-up. The recurrence rate was 20.3 per 1000 subject-years in athletes with non-exertional, and 19.2 per 1000 subject-years in athletes with post-exertional syncope. The incidence of first report of syncopewas 2.2 per 1000 subject-years for non-exertional and 0.26 per 1000 subjects-years for post-exertional spells. No other adverse event was noted during follow-up. In young athletes, syncope occurring before the initial pre-participation screening has a neurally-mediated origin in most cases and shows a low recurrence rate. Exercise-related syncope is infrequent and is not associated with an adverse outcome in subjects without cardiovascular abnormalities. The incidence of new syncope during competitive activity is particularly low.展开更多
therapies for atrial tachyarrhythmias(ATs) by measuring the cumulative time(burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We stu...therapies for atrial tachyarrhythmias(ATs) by measuring the cumulative time(burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We studied AT burden variability in patients paced for sinus node disease(SND) in order to interpret currently published data appropriately and to evaluate reliable sample sizes. Methods and results: One hundred and five patients with AT and SND received a dual chamber pacemaker with antitachyarrhythmia- pacing capability, and were followed for 13 months. Seventy- eight patients(74% ) suffered AT recurrences. Device- gathered diagnostic measures were used to simulate results of randomized studies both with crossover and parallel design. The sample size required for statistically significant results was calculated as a function of the expected therapy- induced burden reduction. AT burden intra- patient variability was high: 43% of patients showed intrinsic fluctuations hiding any therapy- induced burden reduction lower than 30% . Demonstrating therapeutic breakthrough through a 6 month study would require 290 patients with crossover design and 5800 patients with parallel design. Doubling the study period requires 400 and 3000 patients, respectively. Conclusion: Patients with AT and paced for SND showed high intra- patient burden variability, which could possibly hide an AT burden reduction induced by a therapy. Previous studies involving non- pharmacological therapies utilizing AT burden end- points could lack the power to reach statistical significance.展开更多
文摘This study was undertaken to evaluate the epidemiological features and the prognostic implications of syncope in young athletes. A cohort of 7568 young athletes (5132 males, 2436 females, aged 16.2±2.4) underwent a pre-partici-pation evaluation. A syncopal spell in the last 5 years was reported by 474 athletes (6.2%). Syncope was unrelated with exercise in 411 athletes(86.7%), post-exertional in 57(12.0%) and exertional in 6 (1.3%). All episodes of non-exertional or post-exertional syncope had the typical features of neurally-mediated fainting. The 6 athletes with exertional syncope underwent further testing allowing the diagnosis of hypertrophic cardiomyopathy in one case, and of right ventricular outflow tract tachycardia in another. The remaining 4 athletes only showed a positive response to tilt-testing. All athletes were followed for 6.4±3.1 years, during 48 066.6 person-years of follow-up. The recurrence rate was 20.3 per 1000 subject-years in athletes with non-exertional, and 19.2 per 1000 subject-years in athletes with post-exertional syncope. The incidence of first report of syncopewas 2.2 per 1000 subject-years for non-exertional and 0.26 per 1000 subjects-years for post-exertional spells. No other adverse event was noted during follow-up. In young athletes, syncope occurring before the initial pre-participation screening has a neurally-mediated origin in most cases and shows a low recurrence rate. Exercise-related syncope is infrequent and is not associated with an adverse outcome in subjects without cardiovascular abnormalities. The incidence of new syncope during competitive activity is particularly low.
文摘therapies for atrial tachyarrhythmias(ATs) by measuring the cumulative time(burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We studied AT burden variability in patients paced for sinus node disease(SND) in order to interpret currently published data appropriately and to evaluate reliable sample sizes. Methods and results: One hundred and five patients with AT and SND received a dual chamber pacemaker with antitachyarrhythmia- pacing capability, and were followed for 13 months. Seventy- eight patients(74% ) suffered AT recurrences. Device- gathered diagnostic measures were used to simulate results of randomized studies both with crossover and parallel design. The sample size required for statistically significant results was calculated as a function of the expected therapy- induced burden reduction. AT burden intra- patient variability was high: 43% of patients showed intrinsic fluctuations hiding any therapy- induced burden reduction lower than 30% . Demonstrating therapeutic breakthrough through a 6 month study would require 290 patients with crossover design and 5800 patients with parallel design. Doubling the study period requires 400 and 3000 patients, respectively. Conclusion: Patients with AT and paced for SND showed high intra- patient burden variability, which could possibly hide an AT burden reduction induced by a therapy. Previous studies involving non- pharmacological therapies utilizing AT burden end- points could lack the power to reach statistical significance.
