植入型心电监测仪在不明原因晕厥中的临床应用：单中心前瞻性研究

目的探讨植入型心电监测仪(ICM)在不明原因晕厥中的诊断价值。方法前瞻性观察性研究2017年7月至2021年10月在中国医学科学院阜外医院心律失常中心诊断为不明原因晕厥, 并植入ICM的患者45例, 其中男29例, 女16例。中位年龄52.6岁, 年龄范围11～87岁。所有患者每3个月随访1次, 随访内容包括是否再次发生晕厥及晕厥前兆事件、ICM程控读取随访期间记录到的事件。若患者出现晕厥, 则及早行ICM程控。结果随访(15.0±12.3)个月, 15例(15/45, 33.3%)患者再发晕厥或晕厥前兆, 其中9例为心动过缓导致的(窦性停搏7例, 高度房室传导阻滞2例), 2例为室性心动过速(室速), 1例为心房颤动(房颤), 另有3例意识丧失发作时ICM未记录到心律失常事件, 后经脑电图证实为癫痫。在心源性晕厥患者中, 9例植入永久起搏器, 2例选择药物治疗, 有1例室速患者发生心脏性猝死。结论 ICM可有效提高不明原因晕厥患者的诊断效率。     

置入式Holter诊断不明原因晕厥的应用研究

目的探讨置入式Holter(ILR)在诊断不明原因晕厥和指导治疗中的临床价值。方法入选2002年10月至2005年5月求治的不明原因晕厥患者10例,男性4例,女性6例,平均年龄(41±22)岁。有2次以上晕厥或近似晕厥史平均为(4.5±1.4)次/例,经常规检查未能明确晕厥原因。均选用Medtronic公司RevealPlus(9526型ILR。结果10例患者平均随访(17.8±6.6)个月,ILR有效监测时间平均(15.3±3.6)个月,监测期内6例患者再发晕厥或近似晕厥24次。7例患者手动触发19段心电图,ILR自动触发记录460段心电图,共记录211段心电图为心律失常事件。根据症状-心律相关性,7例患者明确为心律失常性晕厥,1例患者明确为非心律失常性晕厥;2例仍不能明确晕厥原因。提示ILR诊断晕厥的效率为80%。10例依据ILR监测结果得到相应治疗,晕厥发作减少或消失。结论ILR用于诊断不明原因晕厥和先兆晕厥安全、高效、长程,可证实或排除患者的部分晕厥或近似晕厥系心律失常所致;具有微创、简单、监测期长、信息量大等优点,可作为现有晕厥诊断方法的重要补充。加强患者的依从性和动态优化工作参数,将进一步提高ILR的诊断价值。     

动态心电图在不明原因晕厥诊断中的价值

目的探讨动态心电图(Holter)在不明原因晕厥诊断中的应用价值。方法对146例不明原因的晕厥患者进行24小时Holter检查。全部患者经病史、体检、常规心电图和体位性低血压试验等均未发现晕厥的直接原因。结果146例患者经Holter检查,55例(37.67%)出现心律失常,25例(17.12%)出现晕厥发作,22例(15.06%)晕厥发作与心律失常有关。尤其与心电图RR间期有一定的相关性。25例晕厥患者中,RR间期≥3.0秒者共57次,其中31次发生晕厥;而RR间期<3.0秒者256次,无1例发生晕厥(P<0.01)。结论一些不明原因晕厥的发作与心律失常有关。Holter检查对不明原因晕厥的病因诊断仍然是一种有价值的工具。     

植入型心电记录器成功发现晕厥病因一例

为不明原因晕厥患者安装植入型心电记录器（insertable loop recorder,ILR）在国内已有少量报道,但能明确记录到与晕厥相关的心律失常发生,继而确定病因者仍为数不多。本文报道1例植入ILR后18个月记录到窦性停搏的病例。     

伴长RR间期患者动态心电图监测临床分析

目的探讨动态心电图分析长RR间期预测心源性猝死有效的方法。方法对105例动态心电图检查结果出现长RR≥2000ms者结合其日常生活日志进行回顾性分析。结果 105例患者出现长RR的状况如下:1长RR间期可出现在房颤伴长RR40例,窦性停搏18例,窦房传导阻滞15例,房室传导阻滞(包括Ⅰ度、Ⅱ度、Ⅲ度及高度房室传导阻滞)31例,早搏后长间歇10例;2最长RR可达6.74 s;3长RR间期多见于夜间睡眠期(0:00~5:00),白天清醒期少见;4长RR3 000 ms时患者会出现黑曚、晕厥等症状。结论动态心电图长RR分析对于预测临床上心源性猝死是简单有效的方法。     

射频消融治疗阵发性心房颤动伴长间歇患者的长期随访研究

目的 随访射频消融治疗阵发性心房颤动（房颤）伴长间歇的临床转归.方法 2006年5月至2008年9月共入选18例（男12例,女6例）阵发性房颤伴发作终止时窦性停搏≥3 s的患者,年龄37～72（56.8±11.7）岁,病程2～276（69.6±71.3）个月.所有患者均有房颤终止时窦性停搏≥3 s的临床资料,平均长RR间期3.1～8.0（4.5±1.6）s,部分患者伴有黑矇、晕厥先兆或者晕厥症状.首次消融患者,在三维标测系统指导下行肺静脉前庭隔离术达到肺静脉-左心房电学隔离;术后常规程序刺激诱发,若合并室上性心律失常或者非肺静脉触发灶,同时消融.术前,术后3d,1、3、6个月分别常规检查动态心电图,检测心率变异性（HRV）指标.结果 18例患者共进行了27次消融,8例1次手术成功,5例行2次手术,2例行3次手术,3例复发未再行手术治疗.首次消融术中,3例诱发典型心房扑动,同时行后位峡部消融,达到双向阻滞;3例术中出现显性去迷走[血压＜ 90/60 mm Hg（1 mm Hg=0.133 kPa）,心率＜60次/min].10例复发患者中,1例合并左心房后壁的局灶房颤,第3次消融时成功.平均随访（34.1±7.5）个月,术后2例发生窦性心动过速;3例房颤复发,其中1例为起搏器植入术后,1例房颤复发患者终止后有10.4 s的长间歇,植入单腔起搏器,另外1例房颤复发但无症状,未作特殊处理,临床密切随访.共12例完成6个月动态心电图随访的患者符合分析要求.术前反应迷走神经功能的HRV指标相邻RR间期差的均方根（rMSSD）,RR间期平均值的标准差（SDNN）,高频（HF）,低频（LF）/HF分别为（42.0±11.1）ms,（136.0±24.9）ms,12.5±3.9,1.32±0.26.术后随访发现其指标均下降并持续至少3个月,但在6个月时恢复.结论 房颤发作时能够抑制窦房结功能,导致长间歇;射频消融治疗祛除房颤这一原始因素后,窦房结功能常有一定程度的恢复.     

快速室上性心律失常后长间歇的临床分析

分析快速室上性心律失常后长间歇患者的临床特点及治疗。1350例射频消融术患者中,有12例表现为快速室上性心律失常后长间歇及反复黑矇/晕厥,对这些患者的临床资料进行分析并对其临床症状、动态心电图及心脏彩超结果进行随访。结果:12例患者电生理检查提示窦房结功能正常,均成功进行射频消融治疗,其中房室旁道5例,左、右房性心动过速各1例,房室结双径路1例,I型心房扑动1例,阵发性心房颤动(简称房颤)3例。射频消融术后随访,阵发性房颤组有1例(1/3,占33.3%)仍见短阵房颤或房性早搏后长间歇,另1例患者安装永久起搏器治疗,其他未见缓慢性心律失常及晕厥发作。结论:快速室上性心律失常后长间歇,可能是独立于病窦综合征之外的一种临床疾病。射频消融治疗快速室上性心律失常后,一般可改善缓慢性心律失常。     

风湿性心脏瓣膜病持续房颤伴长RR间歇的病例回顾分析

目的探讨风湿性心脏瓣膜病(风心病)持续心房纤颤(房颤)伴长RR间歇(RR间期≥1.5s)患者的临床特点及永久心脏起搏器治疗的指征。方法对我院2003年1月至2006年1月收住院的94例风心病持续房颤患者的临床资料进行回顾性分析。结果①94例患者长RR间歇组37例(39.4%),无长间歇组57例(60.6%)。②临床症状:无症状7例(7.4%),劳力性呼吸困难(包括活动后气短、喘憋)45例(47.9%),心悸23例(24.5%),胸闷17例(18.1%),头晕1例(1.1%),晕厥1例(1.1%)。③长RR间歇组年龄(P<0.01)、风心病程(P<0.05)、房颤持续时间(P<0.01)均较无长RR间歇组高,左室收缩末内径减小(P<0.05)。最长RR间期与最小心室率(P<0.01)、平均心室率(P<0.01)和长RR间歇发生频数(P<0.01)相关。④长RR间歇组β受体阻滞剂和两种以上负性传导药物联合使用率以及高血压伴发率均较无长间歇组高,而瓣膜手术率低,永久心脏起搏器治疗12例。结论头晕、晕厥是风心病持续房颤伴长RR间歇患者相对特异的临床症状。年龄大、病程长、左室收缩末内径减小、伴发高血压及使用β受体阻滞剂或两种以上负性心率药物的风心病房颤患者,需警惕合并长RR间歇。清醒状态下RR间期>3.0s、有相关临床症状或同时应用多种负性心率药物的患者,需考虑永久心脏起搏器治疗。     

阵发性房颤终止后长间歇患者心电图指标分析

目的探讨阵发性房颤终止后长间歇患者窦性心律时心电图指标的特征及长间歇可能的机制。方法阵发性房颤的患者170例,根据房颤发作终止后是否出现≥2 s的RR长间歇,分为长RR间歇组(长间歇组)70例和无长RR间歇组(对照组)100例。比较两组年龄、性别、房颤病史、基础疾病、黑矇或晕厥的发生率、心脏超声学指标、抗心律失常药物使用情况的差异。同时比较两组患者窦性心律时的心电图指标,包括24 h窦性平均心率、静息心率、Ⅱ导联P波时限和振幅、PR间期、QRS时限、QT间期、QTc间期、ST段形态、T波形态、有无传导异常、有无右束支和左束支传导阻滞、有无Brugada波和J波。结果两组患者黑矇或晕厥的发生率有明显差异(P<0.001);两组患者的窦性24 h平均心率、窦性静息心率、PR间期、QT间期及QTc间期的平均水平差异有统计学意义(P<0.05)。结论阵发性房颤患者房颤终止后窦性心律时心电图出现心率减慢、PR间期延长、QT间期和QTc间期延长者有出现阵发性房颤终止后长间歇的可能。     

动态心电图长RR间期≥3s患者中植入起搏器的情况分析

目的通过对动态心电图(DCG)长RR间期≥3s患者中植入起搏器的情况进行分析,探讨DCG对长RR间期患者植入起搏器的临床参考价值。方法回顾DCG检查达到有效记录时间且记录中至少发生1次长RR间期≥3 s的患者,统计其中植入起搏器的比例并回顾植入起搏器患者(起搏组)的临床资料,比较起搏器组和长RR间期≥3 s组年龄和性别上的分布、导致最长RR间期的心律失常类别等方面的情况,回顾植入起搏器患者的临床特点、治疗和转归。结果 292例DCG长RR间期≥3 s组中植入起搏器的患者为85例,植入起搏器的比例为29.1%;起搏器组患者均有反复发作的胸闷、头晕或心悸、黑矇等症状,其中27例(31.8%)有晕厥史。两组在年龄和性别分布上无差异〔(70.4±12.9)岁vs(67.3±13.0)岁,49.4%男性vs 57.5%男性,P0.05〕。起搏器组(n=85)和长RR间期≥3 s组(n=292)中导致最长RR间期的心律失常类别按发生率高低最多见的均为持续性心房颤动/心房扑动期间(28.2%,44.9%)、窦性停搏(28.2%,26.4%)和阵发性心房颤动/心房扑动终止后(21.2%,10.6%)。所有患者均于起搏器植入术后症状好转出院,随访中无死亡等不良事件。结论通过分析长RR间期≥3 s患者中导致最长RR间期的心律失常类别,结合患者的临床症状和病史,可为患者植入起搏器提供依据。     

Initial clinical experience with implantable loop recorders.

The purpose of this study was to review the initial experience of a university hospital with Implantable Loop Recorders (ILR) for diagnosis of recurrent unexplained syncope or presyncope. Twelve patients with syncope or presyncope of unknown etiology (who had a negative tilt table test, electrophysiologic study, and neurologic work-up) underwent implantation of ILR. All implants were performed using the Reveal ILR (Medtronic AVE, Santa Rosa, California). The 8 cc device is 61 mm long, 19 mm wide, 8 mm thick and weighs 17 grams. It has 18 months of battery life and has 2 electrodes with 38.5 mm spacing. The device is nonvascular and is implanted approximately 2 fingerbreadths below the clavicle in a subcutaneous pocket (1.5 inches long) and is secured via polydacron suture to the pre-pectoral fascia/pectoralis muscle. Twelve patients with a mean age of 61 +/- 22 years received the ILR. Ten patients had syncope and 2 had presyncope. Three patients had coronary artery disease and 2 had dilated cardiomyopathy. ILRs were implanted for a mean follow-up period of 7.2 +/- 5.8 months (range, 1 day to 18 months). Two patients still continue to be monitored at the time of this report. The mean number of events prior to ILR was 6.0 +/- 5.4. Eight patients (66%) had recurrent syncope after implantation. One patient was not available for follow-up. There were no significant complications from the implant. In 5/12 patients (42%), the ILR helped to diagnose the etiology of the syncopal episode. Syncope was secondary to asystole in three patients, junctional bradycardia in another patient, and seizure activity in a fifth patient (high-frequency noise recorded on the electrocardiogram during sinus rhythm). The 4 patients with ILR-documented bradyarrhythmias underwent permanent pacemaker implantation and are alive and well. ILR implantation is a simple, useful and safe method in assisting with the diagnosis of recurrent unexplained syncope or presyncope after an inconclusive electrophysiologic and neurologic evaluation.     

High incidence of tachyarrhythmias detected by an implantable loop recorder in patients with unexplained syncope

BACKGROUND: Syncope is a complex clinical syndrome that may be challenging with respect to a definite diagnosis. The implantable loop recorder (ILR) is a useful tool to define but also to exclude an arrhythmic aetiology. AIM: To investigate the causes of recurrent syncope or near-syncope with respect to underlying arrhythmias in non-selected consecutive patients monitored with an ILR. METHODS: A retrospective study was conducted including 55 patients (34 men, 21 women; age 60+/-19 years) with unexplained syncope who received an ILR for prolonged monitoring at our institution between April 1998 and October 2006. RESULTS: Forty (73%) patients had a recurrence of syncope or near-syncope. Structural heart disease was present in 18 (33%) patients, 4 of them having an ejection fraction <35%. An arrhythmia was detected as the cause of syncope in 25 (46%) patients. The ILR was successful in establishing a symptom-rhythm correlation in 63%. The mean follow-up period from implantation to occurrence of the detected arrhythmias was 9+/-8 months. Bradyarrhythmias were recorded in 12 (22%) patients, whereas tachyarrhythmias were found in 13 (24%) patients. Narrow QRS tachycardia was the underlying arrhythmia in 6 patients and wide QRS tachycardia in 7 patients. A pacemaker was implanted in all 12 patients with bradyarrhythmias. Implantable cardioverter defibrillator (ICD) therapy was indicated in 6 patients with adjunctive catheter ablation in 3 of them. Four patients presenting with paroxysmal supraventricular tachycardia were treated with radiofrequency catheter ablation. CONCLUSION: The ILR helped efficaciously to determine the correct diagnosis and appropriate treatment of recurrent syncope. A considerably high proportion of tachyarrhythmias was detected in this non-selected consecutive population. The majority of patients with tachyarrhythmic syncope required defibrillator implantation and/or radiofrequency ablation.     

Electrocardiographic events preceding onset of atrial fibrillation: insights gained using an implantable loop recorder

INTRODUCTION: Previous reports demonstrate that individual patients may have distinctive electrocardiographic patterns preceding atrial fibrillation (AF) onset. However, these observations are based on single recordings, and are thus limited by their "snapshot" derivation; it is unclear whether patterns observed on these recordings are consistent over time. We hypothesized that the use of an implantable loop recorder (ILR) would be feasible for serial, long-term characterization of electrocardiographic events preceding AF onset. METHODS AND RESULTS: An ILR was implanted in 29 patients with AF. Patients were instructed to activate the device immediately upon experiencing AF symptoms. Analysis focused on the electrocardiographic segment immediately preceding AF; each segment was classified as one of six patterns: short/long, normal sinus rhythm, absolute sinus bradycardia, relative sinus bradycardia, absolute sinus tachycardia, or relative sinus tachycardia. From a total of 318 device activations, 105 AF onsets were suitable for analysis, acquired from 21 patients over a mean follow-up interval of 7 months. Although AF was frequently triggered by an atrial premature beat that emerged during normal sinus rhythm, most patients demonstrated a variety of onset patterns. Degeneration of uniform atrial tachycardia to AF was rare. Significant delay in device activation relative to AF onset was common, as was activation in the absence of AF. CONCLUSIONS: Using the ILR, serial, long-term characterization of electrocardiographic events preceding AF onset was feasible, and typically demonstrated a varied pattern within individuals. There was significant incongruity between symptomatic and electrocardiographic AF burden. As described here, ILR technology is inadequate for the purpose of accurate characterization of AF burden.     

Diagnostic assessment of recurrent unexplained syncope with a new subcutaneously implantable loop recorder. Reveal-Investigators.

AIM: Patients with recurrent syncope undiagnosed after extensive non-invasive and invasive testing pose a diagnostic and therapeutic dilemma. Holter monitoring is nondiagnostic in 90% of cases. Recent developments in loop recorder technology permit long-term ECG monitoring in patients with recurrent unexplained syncope. The aim of this study was to report the worldwide experience with a new subcutaneously implantable loop recorder, implanted in 133 patients with unexplained syncope and negative laboratory investigations. METHODS AND RESULTS: The implantable loop recorder monitors continuously a single lead electrogram using two sensing electrodes on the device shell. The device was implanted in 133 patients, 67 male and 66 female with recurrent syncope. During a mean follow-up of 10.8 +/- 4.3 months after device implantation, 83 patients (62%) experienced syncope or pre-syncope. In the remaining 50 patients no diagnosis could be made because either no events occurred, the patients were lost to follow-up, had adverse events, or died prior to diagnosis. In 72 of the 83 patients with syncope during follow-up (87%), loop recording definitively determined whether an arrhythmia was the cause of symptoms or not. Diagnosis included bradycardia in 21 patients, pacemaker dysfunction in one patient, and tachycardia in 10 patients. One patient experienced multiple rhythm disturbances. Syncope was non-arrhythmic in 40 patients. The remaining 11 patients failed to press the activator. Therapy was instituted in all patients, in whom an arrhythmic cause was found. Severe anticipated device related complications occurred in three patients. CONCLUSION: An implantable loop recorder is useful for establishing a diagnosis when symptoms are recurrent but too infrequent for conventional monitoring techniques.     

Significance of tilt table testing in patients with suspected arrhythmic syncope and negative electrophysiologic study

BACKGROUND: The diagnostic significance of a tilt table test (TTT) in patients with a suspected arrhythmic etiology for syncope and negative electrophysiologic study (EPS) has not been previously assessed comparing the TTT results with the findings of prolonged monitoring using an implantable loop recorder (ILR). We sought to assess the diagnostic yielding of TTT in patients with suspected arrhythmic syncope and negative EPS. METHODS AND RESULTS: In 81 patients with suspected arrhythmic etiology for syncope and negative EPS, TTT was performed and an ILR implanted regardless the results of TTT. TTT was positive in 38 patients. During follow-up, syncope or presyncope recurred in 32 patients (39.5%). No differences were found in recurrence rates in patients with positive and negative TTT (31.5% vs 46.5%, P = ns). According to rhythm registered during ILR activation, mechanisms of syncopal events were classified as: arrhythmic (atrioventricular [AV] block and ventricular tachycardia; n = 18), neurally mediated (sinus bradycardia and sinus pause; n = 9), and indeterminate (normal sinus rhythm; n = 5). There was no statistical association between the results of TTT and the mechanism of syncope. CONCLUSIONS: In patients with a suspected arrhythmic etiology for syncope and a negative EPS, TTT is of little value to predict the mechanism of syncope and the ILR implantation seems to be a useful and safe diagnostic strategy.     

Initial experience with an implantable loop recorder in patients with unexplained syncope

Patients with recurrent syncope undiagnosed after extensive noninvasive and invasive testing pose a diagnostic and therapeutic dilemma. Holter monitoring is non-diagnostic in 90% of cases. Recent developments in loop recorder technology permit longterm ECG monitoring in patients with recurrent unexplained syncope. The implantable loop recorder monitors a single lead electrogram continuously using 2 sensing electrodes on the device shell. The device was implanted in 20 patients (11 male, 9 female) with the history of recurrent syncope. During a mean follow-up of 12+/-6 months after device implantation, 11 patients (55%) experienced syncope (8 pts) or presyncope (3 pts). In the remaining 9 patients, no syncope occurred. In all 11 patients with syncope or presyncope during follow-up, loop recording definitively determined whether an arrhythmia was the cause of symptoms or not. Diagnosis included bradycardia in one patient, tachycardia in two patients, in one patient two rhythm disturbances were revealed: frequent ventricular premature beats with bigemini and atrial flutter. Two patients had a neurocardiogenic syncope. Syncope was nonarrhythmic in 5 patients. An implantable loop recorder is useful for establishing the diagnosis if symptoms are recurrent but too infrequent for conventional monitoring techniques.     

Incidence, diagnostic yield and safety of the implantable loop-recorder to detect the mechanism of syncope in patients with and without structural heart disease.

AIM: To evaluate the incidence, diagnostic yield and safety of implantable loop recorders (ILRs) in patients with or without structural heart disease (SHD). METHODS AND RESULTS: Two-hospitals, observational, prospective study in consecutive patients with unexplained syncope who underwent an ILR implantation. Between November 1997 and December 2002, a total of 2052 patients with syncope were evaluated (referral population of 590000 inhabitants). The diagnosis remained unexplained in 371 (18%). Of these, 103 patients (5% of total, 28% of unexplained syncope) received an ILR. SHD was present in 38 (37%), and absent in 65 (63%). During a median follow-up of 13 months, syncope was recorded in 52 patients. While patients with and without SHD had similar incidence of syncope recurrence, its mechanism was different. Patients with SHD more frequently had paroxysmal AV block and tachyarrhythmias and patients without SHD more frequently had sinus bradycardia/sinus arrest or no arrhythmia. More patients with SHD finally received an ILR-guided therapy. Sudden death occurred in one patient with SHD. Five syncope-related injuries were noted in 3 patients. CONCLUSION: The mechanism of syncope is different in patients with and without SHD; diagnostic yield and safety are similar in both groups. About 28% of patients with unexplained syncope have an indication to ILR implantation. The need for ILR implantation in the general population is 34 implants/million inhabitants/year.     

Utility of implantable loop recorder (Reveal Plus) in the diagnosis of unexplained syncope.

AIMS: In about 30% of patients with syncope, the responsible mechanisms remain unrecognised. Nevertheless, the possibility of an arrhythmic aetiology remains, however, difficult to rule out. METHODS: We therefore monitored with an implantable loop recorder (ILR, Reveal Plus, Medtronic) 34 subjects (60+/-15 years) with at least two unexplained syncopal episodes and negative neurological and cardiovascular work-up. RESULTS: During a follow-up of 7+/-4 months, syncope occurred in 11 subjects. In nine of them the mechanisms responsible for these events were identified by ILR monitoring: marked bradycardia or asystole (n=6), atrial fibrillation with wide QRS tachycardia (n=1) and sinus rhythm with fine artifacts likely to be due to muscle contractions (n=2). Pre-syncope occurred in seven patients: advanced atrioventricular block (n=3), sinus tachycardia (n=1), and wide QRS tachycardia (n=1) were documented. Thus, when considering all 18 patients with recurrences, a diagnosis was achieved in 53% of subjects. Recognition of the rhythm disorder in seven patients with syncope and four patients with pre-syncope guided patient management. CONCLUSIONS: These data indicate that ILR monitoring facilitates the identification of mechanisms responsible for recurrences and therapeutic management in subjects with syncope or pre-syncope and negative traditional neurological and cardiovascular work-up.     

Cardioinhibitory carotid sinus hypersensitivity predicts an asystolic mechanism of spontaneous neurally mediated syncope.

AIMS: We correlated the finding of cardioinhibitory carotid sinus hypersensitivity (CSH) with that observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR). METHODS AND RESULTS: We included 18 consecutive patients with suspected recurrent neurally mediated syncope and positive cardioinhibitory response during carotid sinus massage (max pause 5.5 +/- 1.6 s) who had subsequent documentation of a spontaneous syncope by means of an ILR. They were compared with a 2:1 age- and sex-matched group of 36 patients with a clinical diagnosis of recurrent neurally mediated syncope and negative response to carotid sinus massage, tilt testing and ATP test. Asystole >3 s was observed at the time of the spontaneous syncope in 16 (89%) of CSH patients and in 18 (50%) of the control group (P = 0.007). Sinus arrest was the most frequent finding among CSH patients but not among controls (72 vs. 28%, P = 0.003). After ILR documentation, 14 CSH patients with asystole received dual-chamber pacemaker implantation; during 35 +/- 22 months of follow-up, 2 syncopal episodes recurred in 2 patients (14%), and pre-syncope occurred in another 2 patients (14%). Syncope burden decreased from 1.68 (95% confidence interval 1.66 - 1.70) episodes per patient per year before to 0.04 (0.038-0.042) after pacemaker implant (98% relative risk reduction). CONCLUSIONS: In patients with suspected neurally mediated syncope, the finding of cardioinhibitory CSH predicts an asystolic mechanism at the time of spontaneous syncope and, consequently, suggests a possible benefit of cardiac pacing therapy.