Syncope in Patients With Severe Aortic Stenosis: More Than Just an Obstruction Issue.

BACKGROUND: Severe aortic stenosis (AoS) is considered a primary cause of syncope. However, other mechanisms may be present in these patients and accurate diagnosis can have important clinical implications. The aim of this study is to assess the different etiologies of syncope in patients with severe AoS and the impact on prognosis of attaining a certain or highly probable diagnosis for the syncope. METHODS: Out of a cohort of 331 patients with AoS and syncope, 61 had severe AoS and were included in the study. Main cause of syncope and adverse cardiac events were assessed. RESULTS: In 40 patients (65.6%), we reached a certain or highly probable diagnosis of the main cause of the syncope. AoS was considered the primary cause of the syncope in only 7 patients (17.5% of the patients with known etiology). Atrioventricular block (14 patients, 35.0%) and vasovagal syncope (6 patients, 15.0%) were the most frequently diagnosed causes. The presence of a known cause for syncope during the admission was not associated with a lower incidence of recurrence during follow-up (hazard ratio [HR] 0.69, 95% confidence interval [CI] 0.20-2.40). Syncope of unknown etiology was independently associated with greater mortality during 1-year follow-up (HR 5.4, 95% CI 1.3-21.6) and 3-year follow-up (HR 3.5, 95% CI 1.2-10.3). CONCLUSIONS: In a high proportion of patients with severe AoS admitted for syncope, the valvulopathy was not the main cause of the syncope. Syncope in two-thirds of this population was caused by either bradyarrhythmia or reflex causes. Syncope of unknown cause was associated with increased short- and medium-term mortality, independently from treatment of the valve disease. An exhaustive work-up should be conducted to determine the main cause for syncope.

Long-Term Mortality in Cardioinhibitory Carotid Sinus Hypersensitivity Patient Cohort / Mortalidade de uma Coorte de Portadores da Resposta Cardioinibitória à Massagem do Seio Carotídeo - Estudo Longitudinal com 11 Anos de Seguimento

Abstract Background: Cardioinhibitory carotid sinus hypersensitivity (CICSH) is defined as ventricular asystole ≥ 3 seconds in response to 5-10 seconds of carotid sinus massage (CSM). There is a common concern that a prolonged asystole episode could lead to death directly from bradycardia or as a consequence of serious trauma, brain injury or pause-dependent ventricular arrhythmias. Objective: To describe total mortality, cardiovascular mortality and trauma-related mortality of a cohort of CICSH patients, and to compare those mortalities with those found in a non-CICSH patient cohort. Methods: In 2006, 502 patients ≥ 50 years of age were submitted to CSM. Fifty-two patients (10,4%) were identified with CICSH. Survival of this cohort was compared with that of another cohort of 408 non-CICSH patients using Kaplan-Meier curves. Cox regression was used to examine the relation between CICSH and mortality. The level of statistical significance was set at 0.05. Results: After a maximum follow-up of 11.6 years, 29 of the 52 CICSH patients (55.8%) were dead. Cardiovascular mortality, trauma-related mortality and the total mortality rate of this population were not statistically different from that found in 408 patients without CICSH. (Total mortality of CICSH patients 55.8% vs. 49,3% of non-CICSH patients; p: 0.38). Conclusion: At the end of follow-up, the 52 CICSH patient cohort had total mortality, cardiovascular mortality and trauma-related mortality similar to that found in 408 patients without CICSH.

Resumo Fundamento: A resposta cardioinibitória (RCI) à massagem do seio carotídeo (MSC) caracteriza-se por assistolia ≥ 3 segundos provocada por 5 a 10 segundos de MSC. Existe uma preocupação de que pacientes com RCI e episódios prolongados de assistolia possam falecer em consequência direta de bradiarritmia, ou em decorrência de lesão cerebral, trauma grave ou arritmia ventricular pausa dependente. Objetivos: Determinar a mortalidade total, a mortalidade cardiovascular e a mortalidade relacionada ao trauma de uma coorte de pacientes com RCI à MSC e comparar essas mortalidades com as de uma coorte de pacientes sem RCI à MSC. Métodos: Em 2006, 502 pacientes com idade igual ou superior a 50 anos foram submetidos à MSC. Destes, 52 pacientes (10,4%) foram identificados com RCI. A sobrevida desta coorte foi comparada àquela observada em uma coorte de 408 pacientes sem RCI por meio de curvas de Kaplan-Meier. A regressão de Cox foi utilizada para avaliação da relação entre a RCI à MSC e a mortalidade. Variáveis com p < 0,05 foram consideradas estatisticamente significativas. Resultados: Após seguimento máximo de 11,6 anos, 29 dos 52 portadores de RCI (55,8%) faleceram. A mortalidade total, a mortalidade cardiovascular e a mortalidade relacionada ao trauma desta coorte de pacientes não foram significativamente diferentes daquelas encontradas nos 408 pacientes sem RCI (mortalidade total com RCI: 55,8% versus 49,3% sem RCI; p: 0,38). Conclusões: No fim do seguimento, a mortalidade dos 52 portadores de RCI foi semelhante à observada em uma coorte de pacientes sem RCI. A mortalidade cardiovascular e a relacionada ao trauma também foi semelhante nas duas coortes.

Structural heart disease as the cause of syncope

We described the clinical evolution of patients with structural heart disease presenting at the emergency room with syncope. Patients were stratified according to their syncope etiology and available scores for syncope prognostication. Cox proportional hazard models were used to investigate the relationship between etiology of the syncope and event-free survival. Of the 82,678 emergency visits during the study period, 160 (0.16%) patients were there due to syncope, having a previous diagnosis of structural heart disease. During the median follow-up of 33.8±13.8 months, mean age at the qualifying syncope event was 68.3 years and 40.6% of patients were male. Syncope was vasovagal in 32%, cardiogenic in 57%, orthostatic hypotension in 6%, and of unknown causes in 5% of patients. The primary composite endpoint death, readmission, and emergency visit in 30 days was 39.4% in vasovagal syncope and 60.6% cardiogenic syncope (P<0.001). Primary endpoint-free survival was lower for patients with cardiogenic syncope (HR=2.97, 95%CI=1.94-4.55; P<0.001). The scores were analyzed for diagnostic performance with area under the curve (AUC) and did not help differentiate patients with an increased risk of adverse events. The differential diagnosis of syncope causes in patients with structural heart disease is important, because vasovagal and postural hypotension have better survival and less probability of emergency room or hospital readmission. The available scores are not reliable tools for prognosis in this specific patient population.

Syncope: Outcomes and Conditions Associated with Hospitalization.

PURPOSE: Syncope is a perplexing problem for which hospital admission and readmission are contemplated but outcomes remain uncertain. Our purpose was to determine the incidence of admissions and readmissions for syncope and compare associated conditions, in-hospital outcomes, and resource utilization. METHODS: The 2005-2011 California Statewide Inpatient Database was utilized. Patients of age ≥18 years admitted under International Classification of Diseases, Ninth Revision, Clinical Modification code 780.2 ("syncope or collapse") were selected. Records with a primary discharge diagnosis of syncope were classified as primary syncope. Primary outcome was mortality and secondary outcome measures were cardiopulmonary resuscitation, mechanical ventilation, discharge disposition, length of stay, frequency of readmission and hospital charges. RESULTS: An estimated 1.52 ± 0.02% admissions every year are related to syncope. Among admissions for syncope, in 42.1%, the cause remained unknown; 23% of syncope admissions were for recurrent episodes. The top 5 associated new diagnoses were hypokalemia (0.24%), ventricular tachycardia (0.17%), atrial fibrillation (0.16%), dehydration (0.12%), and hyponatremia (0.12%). Mortality rates are lower for primary vs secondary syncope (0.2% vs 1.4%; P <.0001). Greatest risk factors for mortality in primary syncope were pulmonary hypertension (odds ratio 12.3; 95% confidence interval, 3.34-45.04) and metastatic cancer (odds ratio 7.22; 95% confidence interval, 4.50-11.58). Major adverse events showed a decreasing trend for patients with multiple syncope admissions. Older patients and defibrillators or pacemaker recipients are admitted more often but experience negligible adverse events. Over a decade, median hospital charge for a single syncope admission has increased by 1.5 times. CONCLUSIONS: Despite a good prognosis, syncope is a frequent cause for hospitalization, particularly in the elderly. Present evaluation strategies are expensive and lack diagnostic value.

Clinical Presentation and Outcomes by Sex in Arrhythmogenic Right Ventricular Cardiomyopathy: Findings from the North American ARVC Registry.

BACKGROUND: Sex differences in clinical presentation and outcomes of hereditary arrhythmias are commonly reported. We aimed to compare clinical presentation and outcomes in men and women with arrhythmogenic right ventricular cardiomyopathy (ARVC) enrolled in the North American ARVC Registry. METHODS: A total of 125 ARVC probands (55 females, mean age 38 ± 12; 70 males, mean age 41 ± 15) diagnosed, as either "affected" or "borderline" were included. Baseline clinical characteristics and time-dependent outcomes including syncope, ventricular tachycardia (VT), fast VT (>240 bpm), ventricular fibrillation (VF), and death were compared between males and females. RESULTS: The percentage of ARVC subjects diagnosed as "affected" (84% vs. 89%; P = 0.424) or "borderline" (16% vs. 11%; P = 0.424) was similar between females and males. Among the baseline characteristics, inverted T-waves in V2 trended to be more common in women (P = 0.09), whereas abnormal signal-averaged ECGs (SAECGs; P < 0.001) and inducible VT/VF (P = 0.026) were more frequent in men. During a mean follow-up of 37 ± 20 months, the probability of ICD-recorded VT/VF or death was not significantly different between men and women (P = 0.456). However, there was a trend toward lower risk of fast VT/VF or death in women compared to men (hazard ratio 0.41, 95% CI 0.151-1.113, P = 0.066). Abnormal SAECG and evidence of intramyocardial fat by cardiac MRI was associated with adverse outcomes in men (P = 0.006 and 0.02 respectively). CONCLUSION: In the North American ARVC Registry, we found similar frequency of "affected" and "borderline" subjects between men and women. Sex-related differences were observed in baseline ECG, SAECG, Holter-recorded ventricular arrhythmias, and VT inducibility. Men showed a trend toward greater risk of fast VT than women.

Preditores de internação hospitalar em pacientes com síncope atendidos em hospital cardiológico / Predictors of hospitalization in patients with syncope assisted in specialized cardiology hospital

FUNDAMENTO: No atendimento ao episódio sincopal é necessário estratificar o risco para melhor diferenciar pacientes que necessitam de internação hospitalar daqueles que podem ser liberados. Os critérios utilizados pelos médicos avaliadores desses pacientes em emergências cardiológicas em nosso meio são desconhecidos. OBJETIVOS: Analisar quais os critérios adotados para internação hospitalar, diferenciá-los dos utilizados nos pacientes liberados e compará-los com os preditores de alto risco definidos pelo escore de OESIL já validado para esse fim. MÉTODOS: Estudo transversal em pacientes diagnosticados com síncope na emergência em nossa instituição no ano de 2011. RESULTADOS: Dos 46.476 atendimentos realizados naquele ano, 216 foram descritos como síncope. Dos 216 pacientes analisados, 39% foram internados, sendo que as principais variáveis associadas à admissão foram síncope prévia, doença cardíaca conhecida, história negativa para acidente vascular encefálico no passado, ECG alterado e possuir plano de súde. Na comparação internação contra não internação, os escores OESIL 0-1 foram associados a maior chance de liberação hospitalar; os escores 2-3 apresentaram maior associação com internação. Um escore OESIL >2 demonstrou razão de chances 7,8 vezes maior de internação comparado com o escore 0 (p < 0,001; IC95%: 4,03-15,11). Aproximadamente 39% dos pacientes não tiveram definição etiológica e em 18% foi identificada uma causa cardiológica. CONCLUSÕES: Fatores como doença cardiovascular conhecida, história sincopal prévia, ausência de AVC prévio, possuir seguro de saúde e eletrocardiograma alterado foram os critérios utilizados pelos médicos em emergência para indicar internação hospitalar. Houve boa correlação entre os critérios clínicos e os critérios de risco do OESIL descritos na literatura.

BACKGROUND: Risk stratification of a syncopal episode is necessary to better differentiate patients needing hospitalization of those who can be safely set home from the emergency department. Currently there are no strict guidelines from our Brazilian medical societies to guide the cardiologist that evaluate patients in an emergency setting. OBJECTIVES: To analyze the criteria adopted for defining the need for hospitalization and compare them with the predictors of high risk for adverse outcome defined by the OESIL score that is already validated in the medical literature for assessing syncope. METHODS: A cross-sectional study of patients diagnosed with syncope during emergency department evaluation at our institution in the year 2011. RESULTS: Of the 46,476 emergency visits made in that year, 216 were due to syncope. Of the 216 patients analyzed, 39% were hospitalized. The variables associated with the need of hospital admission were - having health care insurance, previous known cardiovascular disease, no history of prior stroke, previous syncope and abnormal electrocardiograms during the presentation. In comparison with those not admitted OESIL scores of 0-1 were associated with a greater chance of emergency discharge; 2-3 scores showed greater association with the need of hospitalization. A score > 2 OESIL provided an odds ratio 7.8 times higher for hospitalization compared to score 0 (p <0.001, 95% CI:4,03-15,11). In approximately 39% no etiological cause for syncope was found and in 18% cardiac cause was identified. CONCLUSIONS: Factors such as cardiovascular disease, prior history of syncope, health insurance, no previous stroke and abnormal electrocardiograms, were the criteria used by doctors to indicate hospital admission. There was a good correlation between the clinical judgment and the OESIL criteria for high risk described in literature.

Predictors of mortality, rehospitalization for syncope, and cardiac syncope in 352 consecutive elderly patients with syncope.

OBJECTIVES: To investigate the etiologies of syncope and predictors of all-cause mortality, rehospitalization, and cardiac syncope in consecutive elderly patients presenting with syncope to our emergency department. PARTICIPANTS: Participants were 352 consecutive patients aged 65 years or older with syncope admitted to hospital from the emergency department. DESIGN: Observational retrospective study. MEASUREMENTS: Review of medical records for history, physical examination, medications, and tests to determine causes of syncope. Cox stepwise logistic regression analysis was performed to identify significant independent prognostic factors for rehospitalization with syncope, all-cause mortality, and cardiac syncope. RESULTS: Of 352 patients, mean age 78 years, the etiology of syncope was diagnosed in 243 patients (69%). Vasovagal syncope was diagnosed in 12%, volume depletion in 14%, orthostatic hypotension in 5%, cardiac syncope in 29%, carotid sinus hypersensitivity in 2%, and drug overdose/others in 7% of patients. During a mean follow-up of 24 months, 10 patients (3%) were readmitted to the hospital for syncope and 39 (11%) died. Stepwise logistic regression analysis identified history of congestive heart failure (OR 5.18; 95% CI 1.23-21.84, P = .0257) and acute coronary syndrome (OR 5.95; 95% CI 1.11-31.79, P = .037) as independent risk factors for rehospitalization. Significant independent prognostic factors for mortality were diabetes mellitus (OR 2.08; 95% CI 1.09-3.99, P = .0263), history of smoking (OR 2.23; 95% CI 1.10-4.49, P = .0255), and use of statins (OR 0.37; 95% CI 0.19-0.72, P = .0036). Independent risk factors for predicting a cardiac cause of syncope were an abnormal electrocardiogram (OR 2.58; 95% CI 1.46-4.57, P = .0012) and reduced ejection fraction (OR 2.92; 95% CI 1.70-5.02, P < .001). The San Francisco Syncope Rule and Osservatorio Epidemiologico sulla Sincope nel Lazio scores did not predict mortality or rehospitalization in our study population. CONCLUSIONS: Significant independent risk factors for rehospitalization for syncope were congestive heart failure and acute coronary syndrome. Significant independent risk factors for mortality were diabetes mellitus, history of smoking, and use of statins (inverse association).

Risk of recurrent cardiac events after onset of menopause in women with congenital long-QT syndrome types 1 and 2.

BACKGROUND: Women with congenital long-QT syndrome experience an increased risk for cardiac events after the onset of adolescence that is more pronounced among carriers of the LQT2 genotype. We hypothesized that the hormonal changes associated with menopause may affect clinical risk in this population. METHODS AND RESULTS: We used a repeated-events analysis to evaluate the risk for recurrent syncope during the menopause transition and postmenopausal periods (5 years before and after the age at onset of menopause, respectively) among 282 LQT1 (n=151) and LQT2 (n=131) women enrolled in the Long-QT Syndrome Registry. Multivariate analysis showed that the risk for recurrent syncope (n=150) among LQT2 women was significantly increased during both menopause transition (hazard ratio, 3.38; P=0.005) and the postmenopausal period (hazard ratio, 8.10; P<0.001) compared with the reproductive period. The risk increase was evident among women who did or did not receive estrogen therapy. In contrast, among LQT1 women, the onset of menopause was associated with a reduction in the risk for recurrent syncope (hazard ratio, 0.19; P=0.05; P=0.02 for genotype-by-menopause interaction). Only 22 women (8%) experienced aborted cardiac arrest or sudden cardiac death during follow-up. The frequency of aborted cardiac arrest/sudden cardiac death showed a similar genotype-specific association with the onset of menopause. CONCLUSIONS: The onset of menopause is associated with a significant increase in the risk of cardiac events (dominated by recurrent episodes of syncope) in LQT2 women, suggesting that careful follow-up and continued long-term therapy are warranted in this population.

Imaging spectrum of sudden athlete cardiac death.

Sudden athlete death (SAD) is a widely publicized and increasingly reported phenomenon. For many, the athlete population epitomize human physical endeavour and achievement and their unexpected death comes with a significant emotional impact on the public. Sudden deaths within this group are often without prior warning. Preceding symptoms of exertional syncope and chest pain do, however, occur and warrant investigation. Similarly, a positive family history of sudden death in a young person or a known family history of a condition associated with SAD necessitates further tests. Screening programmes aimed at detecting those at risk individuals also exist with the aim of reducing fatalities. In this paper we review the topic of SAD and discuss the epidemiology, aetiology, and clinical presentations. We then proceed to discuss each underlying cause, in turn discussing the pathophysiology of each condition. This is followed by a discussion of useful imaging methods with an emphasis on cardiac magnetic resonance and cardiac computed tomography and how these address the various issues raised by the pathophysiology of each entity. We conclude by proposing imaging algorithms for the investigation of patients considered at risk for these conditions and discuss the various issues raised in screening.

Etiology of syncope in patients hospitalized with syncope and predictors of mortality and rehospitalization for syncope at 27-month follow-up.

The authors investigated the etiologies of syncope and risk factors for mortality and rehospitalization for syncope at 27-month follow-up in 325 consecutive patients, mean age 66 years, hospitalized for syncope. The causes of syncope were diagnosed in 241 patients (74%). Of 325 patients, 13 (4%) were rehospitalized for syncope and 38 (12%) died. Stepwise logistic regression analysis showed that significant independent prognostic factors for rehospitalization for syncope were diabetes (odds ratio [OR], 5.7; 95% confidence interval [CI], 1.6-20.4), atrial fibrillation (OR, 4.0; 95% CI, 1.0-15.6), and smoking (OR, 4.6; 95% CI, 1.3-16.8). Stepwise Cox regression analysis showed that significant independent prognostic factors for time to mortality were diabetes (hazard ratio [HR], 2.7; 95% CI, 1.4-5.2), coronary artery bypass graft surgery (HR, 2.9; 95% CI, 1.3-6.5), malignancy history (HR, 2.5; 95% CI, 1.2-5.2), narcotics use (HR, 4.0; 95% CI, 1.7-9.8), smoking (HR, 2.8; 95% CI, 1.4-5.5), atrial fibrillation (HR, 2.4; 95% CI, 1.0-5.4), and volume depletion (HR, 2.8; 95% CI, 1.4-5.8). Copyright © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Short- and long-term prognosis of syncope, risk factors, and role of hospital admission: results from the STePS (Short-Term Prognosis of Syncope) study.

OBJECTIVE: We sought to assess short- and long-term prognosis of syncope and associated risk factors. BACKGROUND: Syncope is a common clinical event, but our knowledge of its short-term outcome is largely incomplete. Further, it is unknown whether hospital admission might positively affect a patient's syncope prognosis. METHODS: We screened 2,775 consecutive subjects who presented for syncope at 4 emergency departments between January and July 2004. Short- and long-term severe outcomes (i.e., death and major therapeutic procedures) and related risk factors were compared in all enrolled patients arrayed according to hospital admission or discharge. RESULTS: A total of 676 subjects were included in the study. Forty-one subjects (6.1%) experienced severe outcomes (5 deaths, 0.7%; 36 major therapeutic procedures, 5.4%) in the 10 days after presentation. An abnormal electrocardiogram, concomitant trauma, absence of symptoms of impending syncope, and male gender were associated with short-term unfavorable outcomes. Long-term severe outcomes were 9.3% (40 deaths, 6.0%; 22 major therapeutic procedures, 3.3%), and their occurrence was correlated with an age >65 years, history of neoplasms, cerebrovascular diseases, structural heart diseases, and ventricular arrhythmias. Short-term major therapeutic procedures were more common (p < 0.05) in subjects who had been admitted to hospital (13.3%) than in discharged (1.6%), whereas mortality was similar. One-year mortality was greater (p < 0.05) in admitted (14.7%) than in discharged (1.8%) patients. CONCLUSIONS: Risk factors for short- and long-term adverse outcomes after syncope differed. Hospital admission favorably influenced syncope short term prognosis. Instead, 1-year mortality was unaffected by hospital admission and related to comorbidity.

Recognition and management of aortic stenosis in the elderly.

Angina pectoris, syncope or near-syncope, and congestive heart failure (CHF) are the 3 cardinal manifestations of aortic stenosis (AS) in the elderly. Prolonged duration and late peaking of the aortic systolic ejection murmur best differentiate severe from mild AS. The agreement in quantitation of AS severity between Doppler echocardiography and cardiac catheterization is approximately 95%. The average survival is 3 years after the onset of angina pectoris or syncope and 1.5 to 2 years after the onset of CHF in patients with severe AS who does not undergo surgery. Indications for aortic valve replacement (AVR), for use of warfarin after AVR in patients with mechanical prostheses, and for use of aspirin or warfarin after AVR in patients with bioprostheses are listed in the article.

Arritmias na infância / Arrhthmias in childhood

Arritmias cardíacas de algum tipo ocorrem entre 10 por cento e 30 por cento nos exames de Holter nas crianças. Podem ser assintomáticas e benignas, porém em muitos casos produzem sintomas incapacitantes e risco de morte súbita. Frequentemente estão relacionadas a cardiopatias congênitas ou a cirurgias de correção, assim como à presença de feixes ou vias anômalas ou a cardiopatias adquiridas. A ablação por cateter por meio de radiofrequência mudou a história natural de muitas arritmias pediátricas, permitindo a cura definitiva na maioria dos casos. Adicionalmente, marcapassos especiais, desfibriladores e ressincronizadores estão cada vez mais estendendo seus benefícios ao pequeno paciente. Análises clínicas e laboratoriais...

Preditores eletrocardiográficos de síncope e de morte súbita em portadores de síndrome do QT longo congênito / Electrocardiographic predictors of syncope and sudden death in patients with congenital long QT syndrome

Objetivo: Definir critérios eletrocardiográficos preditores de eventos cardíacos (síncope ou morte súbita) em portadores da síndrome do QT longo congênito (SQTLc). Métodos: Foram avaliados 11 portadores de SQTLc. Os critérios de inclusão foram: alta ou intermediaria probabilidade para SQTLc. Os critérios de inclusão foram: baixa probabilidade para QTLc e uso de drogas que prolongassem o intervalo QT. As seguintes variáveis foram analisadas: frequência cardíaca basal, intevalo QT corrigido (QTc), dispersão do QT e presença de alterações da repolarização ventricular. Esses parâmetros foram obtidos a partir de ECG basal realizado no momento do diagnóstico . O período de acompanhamento médio foi de 2,2 anos. Foi utilizado o teste do qui-quadrado para análise estatística. Resultados: A idade média ao diagnóstico foi de 24 anos e 82 por cento eram do sexo feminino. Oito pacientes (73 por cento) apresentavam cíncope e 1 paciente (9,9 por cento) apresentava história de morte súbita abortada. Apenas 1 pacientes apresentava cardiopatia estrutural associada )defeito do septo AV-forma total). Os pacientes foram estratificados em dois grupos. Grupo I - em eventos cardíacos, e Grupo II - sem eventos cardíacos....

Association of painless acute aortic dissection with increased mortality.

OBJECTIVE: To evaluate the clinical characteristics and outcomes of patients with painless acute aortic dissection (AAD). PATIENTS AND METHODS: For this study conducted from 1997 to 2001, we searched the International Registry of Acute Aortic Dissection to identify patients with painless AAD (group 1). Their clinical features and in-hospital events were compared with patients who had painful AAD (group 2). RESULTS: Of the 977 patients in the database, 63 (6.4%) had painless AAD, and 914 (93.6%) had painful AAD. Patients in group 1 were older than those in group 2 (mean +/- SD age, 66.6 +/- 13.3 vs 61.9 +/- 14.1 years; P = .01). Type A dissection (involving the ascendIng aorta or the arch) was more frequent in group 1 (74.6% vs 60.9%; P = .03). Syncope (33.9% vs 11.7%; P < .001), congestive heart failure (19.7% vs 3.9%; P < .001), and stroke (11.3% vs 4.7%; P = .03) were more frequent presenting signs in group 1. Diabetes (10.2% vs 4.0%; P = .04), aortic aneurysm (29.5% vs 13.1%; P < .001), and prior cardiovascular surgery (48.1% vs 19.7%; P < .001) were also more common in group 1. In-hospital mortality was higher in group 1 (33.3% vs 23.2%; P = .05), especially due to type B dissection (limited to the descending aorta) (43.8% vs 10.4%; P < .001), and the prevalence of aortic rupture was higher among patients with type B dissection in group 1 (18.8% vs 5.9%; P = .04). CONCLUSION: Patients with painless AAD had syncope, congestive heart failure, or stroke. Compared with patients who have painful AAD, patients who have painless AAD have higher mortality, especially when AAD is type B.

O eletrocardiograma de alta resolução e suas aplicações clínicas / The signal-averaged electrocardiogram and itÝs application in clinical practice

O eletrocardiograma de alta resolução (ECGAR) é um registro obtido por meio de técnicas de amplificação de sinais elétricos de baixa amplitude e alta freqüência, permitindo a detecção de potenciais elétricos de baixa voltagem que podem ocorrer na porção terminal do QRS e que representam áreas de condução elétrica lenta e fracionada. A presença desses potenciais tem sido considerada como fator preditor de eventos arrítmicos fatais, de utilidade portanto na prevenção da morte súbita, especialmente nas cardiopatias isquêmicas, em que o seu valor diagnóstico já está bem estabelecido. Embora ainda sob investigação, o seu uso tem se estendido a cardiopatias de outras etiologias e a outras situações, como no pós-operatório de cirurgia cardíaca, após terapia trombolítica e na investigação de síncope. Esta revisão tem como objetivo uma abordagem atualizada do método, suas aplicações clínicas e limitações

Implantable cardioverter defibrillator discharge rates in patients with unexplained syncope, structural heart disease, and inducible ventricular tachycardia at electrophysiologic study.

BACKGROUND AND HYPOTHESIS: The implantable cardioverter defibrillator (ICD) is the best available strategy to protect patients from life-threatening ventricular arrhythmia. Although unproven, it is commonly utilized to treat subjects with syncope, a negative clinical workup, structural heart disease, and inducible sustained monomorphic ventricular tachycardia (VT) on programmed electrophysiologic stimulation (EPS). The purpose of this paper was to validate this approach. METHODS: We retrospectively identified 36 subjects who received primary ICD therapy for syncope in the setting of structural heart disease with inducible sustained monomorphic VT on EPS. The cohort was predominantly male (32/36) with underlying coronary artery disease (29/36). The mean left ventricular ejection fraction was 31 +/- 12%, and a third of the patients (12/36) had undergone bypass surgery. RESULTS: The study group was followed for a mean of 23 +/- 15 months (range 3-81 months) and experienced an ICD event rate of 22% at 3 months, which increased to 55% at 36 months. This event rate was comparable with the 66% event rate seen in a group of patients with primary ICD therapy for spontaneous life-threatening VT treated during the same time period. No future predictors of ICD events in the study group could be identified. CONCLUSION: Syncope patients with negative workup, structural heart disease, and sustained monomorphic VT at EPS are at high risk for future tachyarrhythmic events. Based on present evidence, primary ICD therapy in this group appears warranted and justified.

Causes and outcome of syncope.

BACKGROUND: Little is known about the frequency of patients presenting to the emergency department with syncope. Regarding mortality and predictors of outcome the literature remains inconclusive. AIMS: The aims of the study were to determine the frequency of patients presenting with syncope to an emergency department, to assess mortality among these patients and to determine potential predictors of poor outcome. METHODS: Data of all consecutive patients who were treated at our emergency department between January 1st 1994 and September 1st 1997 following syncope were collected retrospectively. The presumptive causes of syncope were classified into six categories (cardiogenic, neurogenic, autonomic dysfunction, psychiatric, toxic/alcoholic, idiopathic/unexplained). Patients were followed until December 31st, 1997. RESULTS: 701 patients (0.35% of all emergency department visits) were treated for this reason. 507 patients were eligible for the study. During follow-up 8% (n = 38) of the patients died. Three patients died within the first 28 days, all with a known severe underlying disease (congestive heart failure, malignancy, ischemic cerebral infarction). Non-survivors more frequently had a cardiogenic (34%) or neurogenic (13%) cause of syncope (p < 0.01). Age > 60 years, syncope due to neurogenic cause and abnormal ECG findings were independent predictors of increased mortality. CONCLUSIONS: Patients with syncope only comprise a small proportion of those seen at the emergency department. Mortality among these patients is 8%. Clinical history and ECG findings are major determinants of risk stratification: Age > 60 years, syncope due to neurogenic causes and abnormal ECG are independent predictors of poor outcome.

[It is not easy to examine the causes of fainting. Vasovagal syncope is mostly not dangerous, cardiac syncope is potentially life-threatening]. / Inte helt lätt att utreda orsakerna till svimning. Vasovagal svimning oftast ofarlig, kardiell potentiellt livshotande.

Of the approximately 30 per cent of the population who are afflicted with syncope at some time of life, 30 per cent will relapse. Despite extensive investigation, no specific cause is identified in about one third of cases. Although some episodes of syncope, e.g. cardiovascular syncope, are benign and self-limiting, others such as mechanical cardiac syncope and arrhythmogenic syncope are associated with considerable mortality. The article consists in a review of available data on differential diagnostic evaluation and treatment with special emphasis on case history.