Syncope in a child owing to intramural course of the left coronary artery

Coronary abnormalities are a rare cause of syncope or sudden death in childhood or adolescence. We report on a 14-y-old girl who had suffered for many years from repeated syncope after or during exertion. She had to be resuscitated twice. The left coronary artery arose from the right coronary aortic sinus and took a proximal intramural course. After successful reimplantation, the patient has now been free of symptoms for 12 mo. The pitfalls of differential diagnosis of this rare anomaly are discussed. Conclusion: Investigation of the coronary anatomy is indicated in otherwise unexplained chest pain, syncope or life-threatening events.     

Predicting the outcome of patients with unexplained syncope undergoing prolonged monitoring

Patients with unexplained syncope are often considered candidates for prolonged monitoring or empiric pacing when noninvasive and invasive investigations fail to provide a diagnosis. Identifying the outcome of patients undergoing prolonged monitoring that would ultimately benefit from empiric pacing may permit a cost-effective approach to resolution of syncope. Two hundred and six patients (age 57 +/- 18 years, 57% male) underwent prolonged monitoring with an implanted loop recorder for syncope of unknown origin. The median number of previous syncopal episodes was four (mean 29 +/- 133). Prior tilt testing was performed in 63% of patients, and electrophysiological testing in 46%. Symptoms recurred during follow-up in 142 patients (69%). Recurrence was associated with bradycardia leading to pacemaker implantation in 35 patients (17.0%), tachycardia in 12 (5.8%), sinus rhythm in 63 (30.6%), neurally mediated syncope based on rhythm and clinical assessment in 22 (11%), and failed activation in 10 (5%). Logistic regression analysis of baseline variables found that age was the only independent variable that predicted the need for pacing, associated with a 3% increase in risk per advancing year of age (odds ratio 1.027, P = 0.026). Despite this finding, no age group could be identified in which the likelihood of requiring pacing exceeded 30%. Logistic regression also found that patients with structural heart disease were less likely to experience recurrent symptoms during monitoring (49% vs 78%, P = 0.001) and that advancing age was associated with earlier recurrence of symptoms (P = 0.01). The etiology of recurrent syncope is diverse and cannot be predicted by baseline clinical variables. Empiric pacing appears to have little role in the management of this patient population.     

A refractory case of vasovagal syncope treated with theophylline

We report the case of a 23 year-old female with neurocardiogenic syncope refractory to treatment with other agents who responded to theophylline. Despite inconsistent clinical trial evidence to support its use, theophylline may prove useful in individual cases.     

Respiratory changes in vasovagal syncope

INTRODUCTION: Respiratory changes accompany the cardiovascular changes during head-up, tilt test-induced vasovagal syncope. METHODS AND RESULTS: Using the 45-minute 60 degrees head-up Westminster protocol, 29 patients were studied (mean age 53.9+/-20.0 years; 19 females). Two groups resulted: tilt-induced vasovagal syncope positive and negative. The cardiorespiratory parameters blood pressure (BP), heart rate (HR), tidal volume, and minute volume were measured. Comparisons of the cardiorespiratory parameters were made within the positive group and negative group, and then between the two groups. There were 14 in the positive group and 15 in the negative group. Baseline measurements were normalized to 1.0. Comparing the late tilt periods between the positive and negative groups, there were differences in BP (P < 0.002), HR (P < 0.002), tidal volume (P < 0.05), and minute volume (P < 0.002). In the positive group comparing early with late intervals: BP 1.11+/-0.09 versus 0.49+/-0.17, P < 0.0001; HR 1.18+/-0.12 versus 0.85+/-0.35, P < 0.009; tidal volume 1.39+/-0.34 versus 2.17+/-1.00, P < 0.015; and minute volume 1.24+/-0.26 versus 3.3+/-2.03, P < 0.0025. There were no comparable cardiorespiratory changes in the negative group. CONCLUSION: There were significant differences in the respiratory and cardiovascular parameters measured between those who were positive and those who were negative for tilt-induced vasovagal syncope. Within the positive group, in addition to the falls in HR and BP, there were significant increases in minute volume and tidal volume during late tilt. This suggests that there may be a role for respiratory sensors in vasovagal syncope that may permit earlier and hence possibly more effective therapy for selected patients.     

Tpeak-Tend interval as a new risk factor for arrhythmic event in patient with Brugada syndrome

Objective:To evaluate Tpeak-Tend (Tp-e) interval in surface standard ECG as a new risk factor for arrhythmic event in patient with Brugada syndrome. Methods: 23 male patients with Brugada syndrome and 20 male patients with paroxysmal supraventricular tachycardia (PSVT) as the control group were investigated in this study. Tp-e interval in surface standard ECG was compared between BrS and PSVT patients. Results: Tp-e interval in BrS patients was significantly longer than that in PSVT patients (109.57±22.86 ms vs. 88.50±13.08ms, P＜0.05). There was significant difference in Tp-e interval between 16 BrS patients with arrhythmic events (including syncope, clinical ventricular fibrillation [VF] and programmed electrical stimulation [PES]-induced VF) and 7 BrS patients without arrhythmic events and PSVT patients (118.12±20.40ms vs.90.00±15.27ms, P＜0.05; 118.12±20.40ms vs. 88.50±13.08ms, P＜0.05). However, Tp-e interval was similar in BrS patients without arrhythmic events and PSVT patients (90.00±15.27ms vs 88.50±13.08ms, P＞0.05). Conclusion: The prolongation of Tp-e interval could serve as a new noninvasive event predictor for arrhythmic events in patients with Brugada syndrome.     

斜板试验诊断小儿血管迷走性晕厥的价值及饮水试验的防治效果

目的探讨小儿血管迷走性晕厥(VVS)的诊断及防治方法。 方法分析1999-10—2004-07上海交通大学附属儿童医院开展斜板试验(TT)(倾斜角度80°，试验时间持续30min)的状况，对不明原因晕厥组74例 及正常对照组54例进行前瞻性研究，对TT阳性组加做阳转阴试验，予以饮水试验，并随访。 结果基础TT在不明原因晕厥组中阳性41例，阳性率为55.4%,对照组为0(P<0.001)。阳性组表现血管抑制型21例,心脏抑制型7例，混合型13例； 28/41(68.3%)例患儿经饮水后阳转阴；随访38例TT阳性患儿，总有效率86.8%。 结论TT对诊断小儿血管迷走性晕厥有较高的敏感性(55.4%)和特异性(100%)。阳转阴试验为防治小儿血管迷走性晕厥提供了理论和实验依据，饮 水试验是一种简单有效可行的防治措施。     

盐酸格拉司琼对兔血管迷走性晕厥的干预作用

目的 研究盐酸格拉司琼对兔血管迷走性晕厥（VVS）的干预作用。方法 将24只健康新西兰大白兔随机分为血管迷走性晕厥组（晕厥组）和格拉司琼干预组（格拉司琼组），每组12只。晕厥组采用9g／L盐水静脉注射；格拉司琼组采用格拉司琼注射液静脉注射干预。建立兔血管迷走性晕厥模型，每只均在放血过程中取4个时间点为T1、T2、T3、T4，比较组间各时间点放血时间、血5-羟色胺（5-HT）质量浓度和总放血量，并监测整个实验过程中心率、血压变化。结果 1．格拉司琼能延长兔子放血过程中血压反射性升高和失代偿降低时间，使总放血时间也延长（组间12、113、T4比较Pa〈0．01）。2．组间12的平均血压和心率均无明显差异。3．在放血过程中5-HT顾量浓度有上升趋势，在血压明显下降时明显升高（晕厥组T3 vs T1 P〈0．0001，T4 vs T3 P〈0．001）；格拉司琼对血压升高最快时相和降低最快时相5-FIT的生成无明显影响。4．格拉司琼组较晕厥组至T4时的总放血量明显增加[76．10±15．36）mL vs （55．30±13．52）mL，P〈0．05]。5．实验结束时晕厥组10只兔子抽搐，最终血压、心率消失死亡（83％）。格拉斯琼组有11只兔子无明显抽搐，因呼吸停止死亡（92％）。结论 盐酸格拉司琼能显著减弱或避免Bezold-Jarisch反射的出现，增强兔子对失血模型中脑缺血和急性机体供血不足的耐受性，从而达到预防和治疗VVS的目的。     

Evaluation of a Single Stage Nitroglycerin Tilt Table Test for Diagnosis of Neurally Mediated Syncope

The purpose of this study was to compare clinical outcomes between a single stage head-up tilt table test (HUT) with infusion of 3.44 microg/kg per hour of nitroglycerin and a conventional multistage test with infusion of nitroglycerin from 1.72 microg/kg per hour to 5.16 microg/kg per hour in five successive stages. Thirty-seven patients with recurrent syncope underwent both tests in a prospective, randomized, crossoverfashion. During single stage HUT, a positive response occurred in 24 (64.9%) patients with unexplained syncope, an exaggerated response occurred in 3 (8.1%), a negative response in 7 (18.9%), and drug intolerance in 3 (8.1%). During the multistage HUT, these percentages were 62.2%, 16.2%, 13.5%, and 8.1%, respectively. Twenty healthy control subjects were involved in both tests, One of the control subjects had a positive response to single stage HUT, and two (10%) patients to multistage HUT. The duration of the test in single stage HUT was shorter than that in multistage HUT (8.6 +/- 10.3 vs 38.6 +/- 32.1 minutes, P < 0.01). The results showed that the single stage HUT was a fairly sensitive, specific, and a time-efficient test for provoking neurally mediated syncope.     

Postural tachycardia syndrome complicating pregnancy

Objective.?To review clinical experience at our institution on postural tachycardia syndrome (POTS) complicating pregnancy.

Methods.?In a retrospective review, we identified nine pregnancies in seven patients with POTS syndrome at our institution.

Results.?Patients who did not require treatment for POTS before conception were less likely to have an exacerbation of symptoms or need reintroduction of treatment. Exacerbations of POTS during pregnancy are variable. Of our patients with exacerbations of symptoms, increases in the existing pharmacologic treatments, such as increasing β-blocker dosage, was effective in palliation of symptoms. There were seven vaginal deliveries. Two patients delivered without neuraxial anesthesia; the other five deliveries were done using epidural anesthesia without associated complications. POTS does not seem to contribute to pregnancy-related complications. Importantly, there were no adverse intrapartum events attributable to POTS.

Conclusions.?Pregnant women with POTS may undergo safe regional anesthesia and vaginal delivery. This contradicts earlier reports in the literature recommending cesarean delivery.     

Treatment of vasovagal syncope: pacemaker or crossing legs?

A 50-year-old male patient continued to experience syncope after implantation of a pacemaker. During cardiovascular examination, the patient showed a typical vasovagal response, with normal pacemaker function. Leg crossing, which prohibits the pooling of blood in the legs and abdomen, at the onset of symptoms helped to prevent this response. The authors recommend a course of leg crossing as a measure to treat vasovagal syncope.