心脏性晕厥或猝死的若干高危心电表现

目的 探讨快速性心律失常所致心脏性晕厥或猝死的高危心电图表现。方法 分析入院时或入院后至少发生1次心脏性晕厥或猝死的33例患者发作时与发作前后的常规12导联心电图或持续心电监护心电图。结果 引起心脏性晕厥或猝死的若干高危心电图表现：①长Q—T间期综合征，②Brugada综合征，③异常J波，④复杂性室性期前收缩，⑤冠心病急性心肌梗死呈广泛前壁心肌梗死伴新出现的右束支传导阻滞及弓背抬高的ST段持续不降，或伴ST—T电交替；或广泛前壁心肌梗死伴墓碑样ST段抬高，⑥扩张型心肌病伴进展性QRS波群低电压。结论 心脏性晕厥或猝死存在多种高危心电图表现。     

动态心电图对诊断心源性晕厥的临床意义

目的 探讨心源性晕厥或猝死发作相关的心电图特征.方法 对120例疑为心源性晕厥者行24h12导联动态心电图(DCG)检查.结果 120例中55例(45.8%)出现严重心律失常,检出晕厥发作或猝死共27例;其中21例(17.5%)晕厥发作和3例(2.5%)猝死与严重心律失常有关.尤其与心室停搏(R-R间距)>3.0s及快速室性心律失常有一定的相关性.另外3例晕厥时未记录到任何心律失常.结论 12导联DCG检查可为心源性晕厥或猝死者获得可靠的病因诊断.     

先天性QT延长综合征1例

患者,女,30岁。间断头晕、心悸9年,近1年晕厥3次,多在恐惧、精神紧张时发作。家族史:患者父亲45岁不明原因猝死;其兄曾有一次晕厥发作,原因不明;其子女尚无临床症状发作。入院体检:BP120/80mmHg(1mmHg=0·133kPa),双肺呼吸音清晰,心界不大,HR76次/min,律齐,无杂音。神经系统检查:腱反射正常,病理征阴性。心电图示窦性心律,长QT间期(0·64s),QTc0·71s(见图1)。超声心动图示心脏结构及血流正常。化验:血清电解质正常。其临床和心电图特征符合先天性QT延长综合征(CLQTs)的诊断。入院第2天,再次发作心悸、头晕,心电图示频发室性期前收缩…     

Brugada综合征2例报告

1992年西班牙ＢｒｕｇａｄａＰ和ＢｒｕｇａｄａＪ两位学者等首先发现在心脏结构正常 ,心电图以右束支阻滞伴ＳＴＶ1～Ｖ3抬高为特征 ,伴有晕厥或猝死发作的新的综合征 ,命名为Ｂｒｕｇａｄａ综合征[1] 。该综合征在全世界普遍存在 ,其发病率尚难以估计 ,是年轻人中最常见的死亡原因 ,每年心脏正常的猝死患者中约 5 0 %是由于该综合征引起的[2 ] 。故应引起临床医生的警惕和关注 ,现将我们收治的 2例患者报道如下。　　例 1.患者男 ,35岁 ,因反复心悸、胸闷 2年余 ,伴多次晕厥或先兆晕厥发作于 1998- 0 5入院。既往无心脏病史。体检 :神志清…     

恶性快速性室性心律失常致心脏骤停的临床观察

目的探讨恶性快速性室性心律失常致心脏骤停的原因与高危心电表现。方法分析45例在入院时或入院后至少发生1次心脏骤停患者的原因及其发作时与发作前后的常规12导联心电图或持续心电监视心电图形。结果45例恶性快速性心律失常致心脏骤停最常见的基本原因为冠心病急性或陈旧性心肌梗死,次为特发性及继发性巨大异常J波、扩张型心肌病;低钾血症是最常见的诱因;最常见的恶性快速性室性心律失常类型是心室颤动。其高危心电图表现:①复杂性室性早搏;②异常J波;③继发性长Q-T间期综合征;④Brugada综合征;⑤广泛前壁心肌梗死伴墓碑样ST段抬高。上述各种原因心脏骤停者有各自不同的临床及心电学特征。结论恶性快速性室性心律失常所致心脏骤停存在多种原因及高危心电图表现。     

Brugada综合征的临床研究新进展

Brugada综合征是以心电图上表现右束支传导阻滞和V1-V3导联ST段抬高,QT间期正常,多形性室速或室颤发作,临床上反复发作心源性晕厥或猝死,经心脏超声、心室造影和心肌活检等检查无异常发现为特征的临床综合征。本文对Bmgada综合征的流行病学、临床特点、发病机制、诊断标准、治疗方法、预后及展望作一综述。     

动态心电图确诊心源性晕厥五例

对5例有晕厥的患者进行动态心电图检查。结果5例晕厥发作时,动态心电图记录发现3例发生了3.0s以上的窦性停搏,2例发生了持续性室性心动过速,均确诊为缓慢性心律失常或室性快速性心律失常引起的心源性晕厥,植入了人工心脏起搏器或除颤器,防止了阿-斯综合征和猝死的发生。     

Brugada 综合征一例

临床资料 患者男性,38岁,因反复晕厥9个月于2001年6月27日入院。发作前无明显诱因,晕厥时伴抽搐,持续数秒至5min不等,能自行缓解,数天至数周发作1次,平素无胸闷、胸痛等不适。期间在广州某医院住院时发作过1次晕厥,当时心电监护示心室颤动（图1）,经心肺复苏等抢救,恢复为窦性心律。家族史:其父有多次晕厥史,于67岁猝死,其弟于27岁猝死。体格检查:体温36.7℃,呼吸20次/min,血压100/70mmHg（1 mmHg=0.133kPa）,双肺及腹部无异常,心率100次/min,心律齐,无杂音,化验血、尿、大便常规、肝肾功能、血糖、心肌酶谱、电解质均正常,X线心脏片、彩色超声心动图未见异常。心电图（图2）:图2为入院第1d的心电图,即晕厥发作后第2d的心电图,示窦性心律,V1～V3ST段下斜型抬高,T波倒置,QRS波呈rsd’,酷似完全性右束支阻滞,QT间期正常。患者入院后未经治疗,亦无晕厥发作。结合临床表现及家族史诊断为Brugada综合征。     

异常J波、Brugada综合征与特发性Brugada心电图征的临床与心电图特征

对比分析异常J波 2 1例、Brugada综合征 8例与特发性Brugada心电图征 11例的临床及心电学特点。结果 :①特发性异常J波在肢导联或 (和 )胸导联可见正向异常J波 [除aVR(部分患者aVL)外 ],其波幅较低而分布较广 ,一般V1～V2 导联不出现J波 ,若出现则JV1 ～V2R ,TV1 ～V2 (V3) 倒置或直立 ,前者常出现恶性快速性室性心律失常而发生晕厥或猝死 ,后者则无晕厥或猝死及恶性心律失常发作。结论 :异常J波和Brugada综合征及特发性Brugada心电图征是具有不同临床及心电学特点的临床实体。     

短QT综合征一例

1例女性患者,47岁,因发作性晕厥入院,心电图检查发现QT间期短,为0.28~0.32s,体格检查未发现其他异常。其有猝死家族史。诊断为短QT综合征,安置埋藏式心脏转复除颤器治疗,术后随访未见晕厥发生。     

Brugada or not-Brugada: misdiagnosis of recorder-induced artifact

The Brugada-Brugada syndrome is a life threatening cardiac arrhythmia that features syncopal events or aborted sudden death in combination with electrocardiographic characteristics (ST-segment elevation of V(1)-V(3) and right bundle branch block). Typical ECG alterations were recorded in a young man who was admitted to our hospital after syncope and a Brugada-Brugada syndrome was suspected. The following days similar pathological ECG recordings of other patients were noticed. The electrocardiographic artifact was diagnosed as being caused by incorrect handling of the ECG recorder.     

Cardiac asystole: a manifestation of neurally mediated hypotension-bradycardia

It has been proposed that prolonged cardiac asystole mimicking an episode of sudden cardiac death may occur as a manifestation of neurally mediated hypotension-bradycardia syndrome. To assess this possibility, electrocardiographic and hemodynamic findings during upright tilt testing were evaluated in six survivors of suspected asystolic sudden cardiac arrest with normal conventional electrophysiologic evaluation (Group I). These observations were compared with findings in two control groups: six patients with syncope but without evident asystole and with normal conventional electrophysiologic evaluation but demonstrable neurally mediated hypotension-bradycardia (Group II), and six patients with syncope in whom conventional electrophysiologic evaluation provided a presumptive diagnosis (Group III). Patients in all three groups ranged in age from 16 to 59 years. During head-up tilt testing (either alone or with isoproterenol infusion), patients in both Groups I and II developed syncope in less than or equal to 5 min, whereas patients in Group III remained asymptomatic. Patients in Groups I and II exhibited a similar tilt-induced decrease in mean arterial pressure (-46 +/- 9 and -40 +/- 9 mm Hg, respectively, p = NS) and heart rate (-44 +/- 28 and -49 +/- 12 beats/min, respectively, p = NS). In contrast, patients in Group III manifested only a moderate decrease in mean arterial pressure (-14 +/- 5 mm Hg) and had an increase in heart rate (+14 +/- 8 beats/min). Both mean arterial pressure and heart rate changes in Group I and Group II patients differed significantly (p less than 0.001) from values in Group III patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of Genetic Causes of Cardiac Arrest

Unexplained cardiac arrest is defined as a cardiac arrest in the absence of coronary artery disease and overt structural heart disease, present in 5%-10% of cardiac arrest survivors. A genetic contribution to cardiac arrest is more common in this population, most commonly attributed to an inherited ion channel abnormality leading to familial syncope and sudden death. The common causes are Long QT and Brugada syndrome, catecholaminergic ventricular tachycardia, idiopathic ventricular fibrillation, and early repolarization syndrome. Latent structural causes include inherited cardiomyopathy such as arrhythmogenic right ventricular cardiomyopathy. We review these causes in detail and a structured approach to the investigation of these patients, which provides a diagnosis in approximately half of these patients. This allows for the initiation of disease-specific treatments and enables family screening.     

Cardiac arrest and sudden death in patients treated with amiodarone for sustained ventricular tachycardia or ventricular fibrillation: risk stratification based on clinical variables

Multivariate analysis of 11 clinical variables was performed in 104 patients with sustained, symptomatic ventricular tachycardia (VT) or ventricular fibrillation treated with amiodarone to determine variables predictive of subsequent cardiac arrest or sudden death. Twenty-five patients (24%) had fatal or nonfatal cardiac arrest after 7.3 +/- 6.2 months (mean +/- standard deviation) of therapy. Multivariate analysis identified an ejection fraction of less than 0.40, syncope or cardiac arrest before amiodarone therapy, and VT (3 or more consecutive ventricular premature complexes) during predischarge ambulatory electrocardiographic monitoring as variables associated with a high risk of subsequent fatal or nonfatal cardiac arrest (p less than 0.03). Patients who had these 3 clinical variables had a much higher predicted incidence of cardiac arrest at 6 months (62%) and 12 months (76%) than did patients with an ejection fraction greater than 0.40, without syncope or cardiac arrest before amiodarone therapy, and without VT during predischarge ambulatory electrocardiographic monitoring (2% and 5%, respectively) (p less than 0.02). Risk stratification using clinical variables can predict which patients are at high risk of recurrent cardiac arrest or sudden death during amiodarone therapy.     

Driving Guidelines and Restrictions in Patients With a History of Cardiac Arrhythmias,Syncope,or Implantable Devices

The need to drive is universal in many countries. Patients with syncope, cardiac arrhythmias, or implantable cardioverter–defibrillators (ICDs) have an ongoing risk of sudden incapacitation that may cause harm to themselves and/or others when driving. Restrictions on driving and driving guidelines have been developed with the intent to reduce and prevent motor vehicle accidents, thereby improving personal and public safety. Several guidelines and consensus statements recently were updated. This review focuses on the syncope-related driving guidelines and restrictions. Driving issues related to other causes of loss of consciousness, such as drug or alcohol intoxication, epilepsy, or metabolic disorders, are not included in this review. Approximately 1% to 3% of all motor vehicle accidents are caused by the driver’s sudden incapacitation; of these accidents, 5% to 10% are related to cardiac causes, with or without syncope. Major cardiac causes of syncope are neurally mediated mechanisms, bradycardia, and tachycardia. When the cause of syncope is determined and adequately treated, no driving restrictions are usually required after treatment is implemented. Patients who receive ICD therapy for primary or secondary sudden cardiac death prevention are at risk for future device discharges and sudden incapacitation whether or not they are driving. When the cause of syncope is unknown, the response to treatment is uncertain (such as treating the neurocardiogenic/vasovagal syncope), or ICD discharge is possible, driving recommendations are based on the estimation of “risk of harm while driving” and the general consensus on the threshold of “acceptable risk of harm.” The annual risk of harm while driving can be estimated by the following formula: driving time (%) × vehicle type (commercial to private) × annual risk of syncope or incapacitation × probability of injury or accident.     

Congenital long QT syndrome: A case report

The congenital long QT syndrome (LQTS) is characterized by abnormally prolonged ventricular repolarization due to inherited defects in cardiac sodium and potassium channels, which predispose the patients to syncope, seizure like activity, ventricular arrhythmias, and sudden cardiac death. Early diagnosis and preventive treatment are instrumental in preventing sudden cardiac deaths in patients with the congenital LQTS. The diagnostic criteria for congenital LQTS are based on certain electrocardiographic findings, clinical findings and findings of epinephrine stress test. Recently genotype specific electrocardiographic pattern in the congenital LQTS has also been described. Recent studies suggest feasibility of genotype specific treatment of LQTS and, in near future, mutation specific treatment will probably become a novel approach to this potentially fatal syndrome. We describe one case that fulfilled the electrocardiographic, historical diagnostic criteria and epinephrine stress test suggestive of LQT syndrome.     

Sudden death in patients and relatives with the syndrome of right bundle branch block, ST segment elevation in the precordial leads V(1)to V(3)and sudden death.

BACKGROUND: The syndrome with an electrocardiographic pattern of right bundle branch block, ST segment elevation in leads V(1)to V(3)and sudden death is genetically determined and caused by mutations in the cardiac sodium channel. The inheritance of the disease is autosomal dominant. Sudden death may, however, occur from a variety of causes in relatives and patients with this syndrome. PATIENTS AND METHODS: Twenty-five Flemish families with this syndrome with a total of 334 members were studied. Affected members were recognized by means of a typical electrocardiogram either occurring spontaneously or after the intravenous administration of antiarrhythmic drugs. Sudden deaths in these families were classified as related or not to the syndrome by analysis of the data at the time of the event, mode of inheritance of the disease, and data provided by survivors.Results Of the 25 families with the syndrome, 18 were symptomatic (at least one sudden death related to the syndrome) and seven were asymptomatic (no sudden deaths related to the syndrome). In total, there were 42 sudden cardiac deaths (12% incidence). Twenty-four sudden deaths were related to the syndrome and all occurred in symptomatic families. Eighteen sudden deaths (43% of total sudden deaths) were not related to the syndrome (nine cases) or were of unclear cause (nine cases). Three of them occurred in two asymptomatic families and the remaining 15 in five symptomatic families. Twenty-four of the 50 affected members (47%) suffered (aborted) sudden death and 18 of the 284 unaffected members (6%). This difference in the incidence of sudden death was statistically significant (P<0.0001). Patients with (aborted) sudden death caused by the syndrome were younger than patients with sudden death of other or unclear causes (38+/-4 years vs 59+/-3 years respectively, P=0.0003). CONCLUSIONS: In families at high risk of sudden death because of genetically determined diseases, the main cause of sudden death remains the disease. However, almost the half of sudden deaths are caused by unrelated diseases or are of unclear cause. Accurate classification of the causes of sudden death is mandatory for appropriate analysis of the causes of death when designing preventive treatments.     

Clinical Aspects of the Early Repolarization Syndrome: A 2011 Update

Recent studies suggest that the electrocardiographic (ECG) finding of J‐point ST‐elevation, the early repolarization syndrome, is not as benign as earlier believed. Three important articles published in 2008/2009 suggest that this finding in the inferolateral leads of the ECG may be representing a risk for subsequent ventricular fibrillation. Although these retrospective studies do justify a careful evaluation of persons with this electrocardiographic pattern, especially of those with syncope or ventricular arrhythmias and/or family history of sudden cardiac death, it seems to be unjustified to consider it today to be a marker for high risk for sudden cardiac deaths in a general population. Even in athletes, early repolarization was found to increase only minimally their arrhythmic risk. In spite of certain similarities with the Brugada syndrome, their association is far from being proved. Prospective studies and further electrophysiological and genetic information will help to clarify the clinical significance of this syndrome. Ann Noninvasive Electrocardiol 2011;16(2):192–195     

ST segment elevation, right bundle branch block and sudden death: Brugada's syndrome

Brugada's syndrome is one of the main causes of sudden death in young adults without a structural heart disease. This is an electrical cardiac illness secondary to a mutation of SCN5A gene of chromosome 3 that has a dominant autosomic transmission pattern. This mutation implies the dysfunction of the sodium channel that increases the Ito, loosing the dome of the epicardiac action potential phase two. An "all or none" repolarization pattern ensues and gives rise to a phase two reentry. This kind of reentry is responsible for the initiation and perpetuation of malignant ventricular arrhythmias among these patients. The clinical characteristics of the syndrome are the right bundle branch block, ST segment elevation from V1 to V3 leads and sudden death or syncope. In some patients, a pharmacological test must be done with ajmaline or procainamide to unmask the electrocardiographic changes. At present, the only effective treatment is the implantable cardioverter defibrillator (ICD). This device has the capability to reduce mortality from 40% annually to 0% at ten years. Pharmacological treatment is not useful.     

Evaluation and outcome of patients with syncope

We studied 433 patients with syncope to derive insights into the diagnostic evaluation and outcome of patients with this common problem. This study shows that the etiology of syncope was not found in approximately 41% of patients. When a cause of syncope was determined, it was most frequently established on the basis of initial history, physical examination and an electrocardiogram (EKG). Furthermore, many of the other entities (e.g., aortic stenosis, subclavian steal) were suggested by findings on the history and physical examinations that required directed diagnostic testing. Initial EKG was abnormal in 50% of patients but led to a cause of syncope infrequently (less than 7%). Prolonged electrocardiographic monitoring, which has assumed a central role in the evaluation of syncope, led to a specific cause in only 22% of patients. Other tests were less often helpful in assigning a cause of syncope. At 5 years, the mortality of 50.5% in patients with a cardiac cause of syncope was significantly higher than the 30% mortality in patients with a noncardiac cause or 24.1% in patients with an unknown cause. At 5 years, a mortality of 50.5% in patients with a cardiac cause of syncope was noted. There were 54 actual deaths in this group as compared to 10.7 expected deaths based on 1980-86 mortality data from Allegheny County, PA (standardized mortality ratio = 5.02). At 5 years, a 33.1% incidence of sudden death was noted in patients with cardiac cause of syncope, as compared with 4.9% in patients with a noncardiac cause and 8.5% in patients with an unknown cause. Mortality and sudden death remained significant for the first 3 years after which the survival curves were parallel. A cardiac cause of syncope was an independent predictor of sudden death and mortality. Recurrences were common but were not associated with an increased risk of mortality or sudden death. Major vascular events were also more frequent in patients with cardiac causes of syncope. The results of this study will be helpful in designing future studies to evaluate the usefulness of newer diagnostic techniques. Furthermore, short- and long-term outcome data will be useful in planning intervention strategies in these patients.