RESUMO
BACKGROUND: Non-vitamin K oral anticoagulants have become the standard therapy for preventing stroke and ischemic thromboembolism in most patients with atrial fibrillation (AF). The effectiveness and safety of non-vitamin K oral anticoagulants in patients on hemodialysis is not well known. METHODS: From June 2017 through May 2022, AXADIA-AFNET 8 (Compare Apixaban and Vitamin K Antagonists in Patients With Atrial Fibrillation and End-Stage Kidney Disease), an investigator-initiated PROBE (prospective randomized open blinded end point) outcome assessment trial, randomized patients with AF on chronic hemodialysis to either apixaban (2.5 mg BID) or the vitamin K antagonist (VKA) phenprocoumon (international normalized ratio, 2.0 to 3.0). The composite primary safety outcome was defined by a first event of major bleeding, clinically relevant nonmajor bleeding, or all-cause death. The primary efficacy outcome was a composite of ischemic stroke, all-cause death, myocardial infarction, and deep vein thrombosis or pulmonary embolism. Our hypothesis was that apixaban is noninferior to VKA. RESULTS: Thirty-nine sites randomized 97 patients (30% women; mean age 75 years; mean CHA2DS2-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, female sex] score, 4.5; baseline characteristics balanced between groups): 48 to apixaban and 49 to VKA. The median follow-up time was 429 days (range, 37 to 1370) versus 506 days (range, 101 to 1379), respectively. Adherence to apixaban was >80% in 44 of 48 patients; the median time in therapeutic range on VKA was 50.7%. Composite primary safety outcome events occurred in 22 patients (45.8%) on apixaban and in 25 patients (51.0%) on VKA (hazard ratio, 0.93 [95% CI, 0.53-1.65]; Pnoninferiority=0.157). Composite primary efficacy outcome events occurred in 10 patients (20.8%) on apixaban and in 15 patients (30.6%) on VKA (P=0.51; log rank). There were no significant differences regarding individual outcomes (all-cause mortality, 18.8% versus 24.5%; major bleeding, 10.4% versus 12.2%; and myocardial infarction, 4.2% versus 6.1%, respectively). CONCLUSIONS: In this randomized trial comparing apixaban and VKA in patients with AF on hemodialysis with long follow-up, no differences were observed in safety or efficacy outcomes. Even on oral anticoagulation, patients with AF on hemodialysis remain at high risk of cardiovascular events. Larger randomized trials are needed to determine the optimal anticoagulation regimen for patients with AF on hemodialysis. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02933697.
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Fibrilação Atrial , Infarto do Miocárdio , Acidente Vascular Cerebral , Humanos , Feminino , Idoso , Masculino , Femprocumona/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Estudos Prospectivos , Anticoagulantes/efeitos adversos , Acidente Vascular Cerebral/prevenção & controle , Hemorragia/induzido quimicamente , Piridonas/efeitos adversos , Diálise Renal/efeitos adversos , Infarto do Miocárdio/tratamento farmacológico , Resultado do TratamentoRESUMO
BACKGROUND: Treatment with ivabradine became a new therapeutic alternative for patients with inappropriate sinus tachycardia (IST). The aim was to determine a relation between intrinsic heart rate (IHR) and response to ivabradine treatment. METHODS: Twenty-seven patients (mean age 37 ± 11; 23 women) with symptomatic IST despite medical treatment were recruited into the study. Resting ECG, 24-hr ECG monitoring (24hECG), exercise treadmill test, and symptoms evaluation were performed initially and after 60 days on ivabradine. IHR was acquired at baseline after pharmacological autonomic blockade. RESULTS: Nineteen patients (70%) were classified as abnormal IHR group (AIHR) while eight showed normal IHR (NIHR). No significant differences in ECG parameters were found between NIHR and AIHR subgroups, while baseline exercise capacity was higher in AIHR patients (10.9 vs. 9.5 METs, p < .05). Ivabradine treatment resulted in significant reduction in resting heart rate, average 24hECG heart rate, improvement in exercise capacity and reduction of symptoms in both subgroups. Nevertheless, favorable influence of ivabradine was significantly more exaggerated in AIHR subgroup (HR 116 vs. 90 bpm, av. HR 98 vs. 79 bpm, 10.9 vs. 13.6 METS, EHRA score 3.1 vs. 1.1, p < .001 for all) than in NIHR patients (HR 112 vs. 98 bpm, av. HR 97 vs. 88 bpm, 9.5 vs. 11.1 METs, EHRA score 3.1 vs. 1.9; p < .05 for all). CONCLUSIONS: Intrinsic heart rate may be useful in predicting response to ivabradine in patients with IST. More intense response to ivabradine in patients with AIHR may be attributed to different pathophysiological mechanisms underlying IST in AIHR and NIHR groups.
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Fármacos Cardiovasculares/uso terapêutico , Eletrocardiografia/métodos , Frequência Cardíaca/efeitos dos fármacos , Ivabradina/uso terapêutico , Taquicardia Sinusal/diagnóstico , Taquicardia Sinusal/tratamento farmacológico , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto JovemRESUMO
Microvolt-level T-wave alternans (TWA) assessed by spectral method during an exercise stress test has been widely studied for risk stratification. Several studies have documented the association of a positive TWA with total mortality and arrhythmic events. Nevertheless, the need to achieve an elevated and stabilized heart rate resulting in a considerable proportion of indeterminate test results constitutes one of the main limitations of this method. It is well recognized that arrhythmic events may be triggered not only by physical but also by mental stress and are not necessarily associated with exercise. Detection of TWA in ambulatory electrocardiogram recordings during daily activities might be a valuable option in risk stratification. This review describes the modified moving average (MMA) technique for detection of TWA and summarizes the results of clinical studies on the prognostic value of MMA-TWA. So far, MMA-TWA has been studied in over 5000 patients including those evaluated during exercise as well as during daily activities with ambulatory ECG recordings. The results of these studies indicate that increased MMA-TWA is associated with higher risk of cardiac mortality and arrhythmic events.
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Potenciais de Ação , Arritmias Cardíacas/diagnóstico , Eletrocardiografia Ambulatorial , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Atividades Cotidianas , Arritmias Cardíacas/complicações , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/fisiopatologia , Teste de Esforço , Humanos , Valor Preditivo dos Testes , Prognóstico , Medição de Risco , Fatores de Risco , Processamento de Sinais Assistido por ComputadorRESUMO
BACKGROUND: Modulation of cardiac repolarization by sexual hormones is controversial and hormonal effects on ion channels remain largely unknown. In the present translational study, we therefore assessed the relationship between QTc duration and gonadal hormones and studied underlying mechanisms. METHODS AND RESULTS: We measured hormone levels and QTc intervals in women during clomiphene stimulation for infertility and women before, during, and after pregnancy. Three heterozygous LQT-2 patients (KCNH2-p.Arg752Pro missense mutation) and two unaffected family members additionally were studied during their menstrual cycles. A comprehensive cellular and molecular analysis was done to identify the mechanisms of hormonal QT-interval regulation. High estradiol levels, but neither progesterone nor estradiol/progesterone ratio, inversely correlated with QTc. Consistent with clinical data, in vitro estradiol stimulation (60 pmol/L, 48 h) enhanced IKCNH2. This increase was mediated by estradiol receptor-α-dependent promotion of KCNH2-channel trafficking to the cell membrane. To study the underlying mechanism, we focused on heat-shock proteins. The heat-shock protein-90 (Hsp90) inhibitor geldanamycin abolished estradiol-induced increase in IKCNH2. Geldanamycin had no effect on KCNH2 transcription or translation; nor did it affect expression of estradiol receptors and chaperones. Estradiol enhanced the physical interaction of KCNH2-channel subunits with heat-shock proteins and augmented ion-channel trafficking to the membrane. CONCLUSION: Elevated estradiol levels were associated with shorter QTc intervals in healthy women and female LQT-2 patients. Estradiol acts on KCNH2 channels via enhanced estradiol-receptor-α-mediated Hsp90 interaction, augments membrane trafficking and thereby increases repolarizing current. These results provide mechanistic insights into hormonal control of human ventricular repolarization and open novel therapeutic avenues.
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Canal de Potássio ERG1/metabolismo , Estradiol/fisiologia , Adulto , Benzoquinonas/farmacologia , Clomifeno/uso terapêutico , Canal de Potássio ERG1/genética , Eletrocardiografia , Inibidores Enzimáticos/farmacologia , Estradiol/metabolismo , Feminino , Fármacos para a Fertilidade Feminina/uso terapêutico , Voluntários Saudáveis , Sistema de Condução Cardíaco/efeitos dos fármacos , Heterozigoto , Humanos , Infertilidade Feminina/genética , Lactamas Macrocíclicas/farmacologia , Síndrome do QT Longo/genética , Ciclo Menstrual , Mutação de Sentido Incorreto/genética , Gravidez , Complicações Cardiovasculares na Gravidez/genética , Estudos Prospectivos , Transporte Proteico/genéticaRESUMO
BACKGROUND: As telemedical structures continues to be developed in the German healthcare system, remote monitoring is becoming increasingly important to ensure comprehensive, outpatient, and tailored care. The national quality assurance measure "DOQUVIDE-Documentation of quality in the assessment of vital parameters by implanted devices" is used to provide insight into everyday care for patients with telemedicine-enabled devices in Germany. METHODS: DOQUVIDE is a measuring instrument for recording outpatient remote monitoring for patients with implanted pacemaker, implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy with a pacemaker (CRT-P), CRT defibrillator (CRT-D) devices and event recorder. DOQUVIDE records telemedically measured vital signs as well as cardiac events and the associated procedures initiated by cardiologists using standardized forms. RESULTS: In 74 practices/clinics in 14 federal states, 6687 patients received telemedical care in 2022; 937 were newly enrolled. These (60% male) were on average 77.8 years old, mainly with New York Heart Association (NYHA) class II (62.6%). A total of 5801 electronic records were generated as a result of telecardiology events, of which 3590 were due to pathological atrial fibrillation and 1812 due to ventricular high-frequency episodes. 295 events were triggered by event recorders and 95 by device therapies. The main measures taken were telephone contacts or outpatient visits. CONCLUSION: Remote monitoring has become a reality in German healthcare. Standardized processes and the establishment of quality assurance measures enable the definition of common quality standards and the identification of the potential for further development and simplify implementation in day-to-day care for practices.
Assuntos
Desfibriladores Implantáveis , Telemedicina , Humanos , Alemanha , Idoso , Masculino , Feminino , Marca-Passo Artificial , Idoso de 80 Anos ou mais , Garantia da Qualidade dos Cuidados de Saúde , Pessoa de Meia-IdadeRESUMO
AIMS: Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional increasing HR during exercise. The treatment of IST symptoms using beta-blockers or calcium channel-blockers is often non-effective or not well tolerated. Ivabradine is a new agent inhibiting sinus node I(f) current, resulting in a decrease of HR without haemodynamic compromise. METHODS AND RESULTS: We enrolled 20 patients (36 ± 10 years; 14 women) affected by IST and resistant to previous administered therapy by using beta-blockers or verapamil. After 4 weeks of treatment with metoprolol succinate (up to 190 mg once a day) the therapy was switched to ivabradine up to 7.5 mg twice daily. Holter monitoring and treadmill stress test were performed after 1 and 2 months following start of the study. We observed a significant reduction of resting HR both for metoprolol and for ivabradine compared with baseline (92.8 vs. 90.2 vs. 114.3 b.p.m.; P< 0.001). During daily activity there was an even larger decrease of HR on ivabradine (mean daytime HR 94.6 vs. 87.1 vs. 107.3 b.p.m.; P< 0.001). Ivabradine was very well tolerated whereas in 10 patients on metoprolol we observed hypotension or bradycardia requiring dose reduction. Significantly lower incidence of IST-related symptoms were registered on ivabradine therapy than on metoprolol. Fourteen patients (70%) treated with I(f) blocker were free of IST-related complaints. CONCLUSIONS: Metoprolol and ivabradine exert a similar effect on resting HR in patients with IST. Ivabradine seems to be more effective to relieve symptoms during exercise or daily activity.
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Benzazepinas/uso terapêutico , Metoprolol/análogos & derivados , Taquicardia Sinusal/diagnóstico , Taquicardia Sinusal/tratamento farmacológico , Antagonistas Adrenérgicos beta/uso terapêutico , Adulto , Antiarrítmicos/uso terapêutico , Feminino , Humanos , Ivabradina , Masculino , Metoprolol/uso terapêutico , Falha de Tratamento , Resultado do TratamentoRESUMO
BACKGROUND: Inappropriate sinus tachycardia (IST) occurs relatively common after catheter ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia. The treatment of IST symptoms using ß-blockers or calcium channel-blockers are often noneffective or not well tolerated. Ivabradine is a new heart rate (HR)-decreasing agent inhibiting sinus node If current. The purpose of the study was to evaluate the efficacy and safety of ivabradine in patients with persistent and ß-blocker-resistant IST after successful radiofrequency (RF) ablation of atrioventricular node slow pathway. METHODS: We enrolled 14 patients (42 ± 11 years; 10 women) affected by IST after RF ablation. Holter monitoring, treadmill stress test, and IST symptoms assessment were performed at baseline and after first, and second month of the study. RESULTS: We observed significant reduction of mean resting HR after 30 and 60 days of ivabradine treatment compared to baseline (P < 0.001). 24-hour Holter monitoring showed a significant reduction of mean HR and mean HR during daily activity (P < 0.001). The study revealed significant improvement in exercise capacity during treadmill exercise test on ivabradine therapy (P < 0.001). Significantly lower incidence of IST-related symptoms were registered after administration of If current inhibitor. After 2 months of treatment no patients reported severe complaints assessed by means of European Heart Rhythm Association score. We did not observe severe side effects during therapy. CONCLUSION: Ivabradine is an effective treatment option to reduce HR and symptoms in patients with IST after RF ablation of atrioventricular node slow pathway. The therapy with ivabradine is well tolerated even with maximum daily dose.
Assuntos
Benzazepinas/uso terapêutico , Ablação por Cateter/efeitos adversos , Sistema de Condução Cardíaco/anormalidades , Sistema de Condução Cardíaco/cirurgia , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Taquicardia Sinusal/tratamento farmacológico , Taquicardia Sinusal/etiologia , Adulto , Feminino , Humanos , Ivabradina , Masculino , Taquicardia por Reentrada no Nó Atrioventricular/complicações , Resultado do TratamentoRESUMO
Patients with highly symptomatic tachycardia may suffer significantly; in addition to a standardized rule-out of structural heart disease, secondary causes need to be excluded. Disorders such as inappropriate sinus tachycardia and postural tachycardia syndrome are caused by cardiac autonomic dysregulation which may be part of a rare underlying noncardiac disease.
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Síndrome da Taquicardia Postural Ortostática , Adolescente , Humanos , Síndrome da Taquicardia Postural Ortostática/diagnóstico , Síndrome da Taquicardia Postural Ortostática/terapia , Síncope/diagnóstico , Síncope/etiologia , TaquicardiaRESUMO
Patients with primary neurogenic disorders such as pure autonomic failure or multiple system atrophy may initially present with cardiocirculatory symptoms such as orthostatic intolerance or fluctuations in heart rate with symptomatic tachycardia. It is therefore clinically important to identify such patients since circulatory manifestations are only one of a series of symptoms resulting from autonomic dysfunction in various organ systems. These patients require a multimodal diagnostic and therapeutic approach and should undergo extensive evaluation in a specialized autonomic nervous system (ANS) outpatient unit. Based on a clinical case presentation, the current review summarizes the diagnostic and therapeutic approach to key cardiovascular symptoms of primary autonomic disorders and their neurological work-up in a specialized autonomic function laboratory.
Assuntos
Doenças do Sistema Nervoso Autônomo , Cardiologia , Hipotensão Ortostática , Neurologia , Intolerância Ortostática , Doenças do Sistema Nervoso Autônomo/diagnóstico , Doenças do Sistema Nervoso Autônomo/terapia , HumanosRESUMO
INTRODUCTION: Vasovagal syncope is common, often recurrent, and reduces quality of life. No therapies have proven useful to improve quality of life in adequately designed randomized clinical trials. Beta-blockers have mixed evidence for effectiveness in preventing syncope. METHODS: The Prevention of Syncope Trial was a randomized, placebo-controlled, double-blind, multinational, clinical trial that tested the hypothesis that metoprolol improves quality of life in adult patients with vasovagal syncope in a 1-year observation period. Randomization was stratified in strata of patients <42 and > or =42 years old. The quality of life questionnaires Short Form-36 (SF-36) and Euroqol EQ-5D were completed at baseline and after 6 and 12 months of treatment by 204, 132, and 121 patients, respectively. RESULTS: There were 208 patients, mean age 42 +/- 18, of whom 134 (64%) were females. All had positive tilt tests. There was no improvement in quality of life during the trial in the entire group or in either treatment arm. Patients in the metoprolol treatment arm did not have improved quality of life compared to the patients in the placebo arm using either the SF-36 or EQ5D after either 6 or 12 months. Finally, there was no improvement in quality of life associated with metoprolol use in patients either <42 or > or =42 years of age. CONCLUSION: Metoprolol does not improve quality of life in patients with recurrent vasovagal syncope and a positive tilt test.
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Qualidade de Vida , Síncope Vasovagal/epidemiologia , Síncope Vasovagal/prevenção & controle , Adulto , Método Duplo-Cego , Feminino , Humanos , Internacionalidade , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prevalência , Medição de Risco , Fatores de Risco , Inquéritos e Questionários , Síncope Vasovagal/diagnóstico , Resultado do TratamentoRESUMO
INTRODUCTION: Vasovagal syncope is common and distressing. One important symptom is presyncope, but there are no clinimetric measures of this. We developed the Calgary Presyncope Form (CPF) and used it to test whether metoprolol reduces presyncope in a randomized trial. METHODS: The CPF captures the frequency, duration, and severity of presyncope. We administered it to participants in the Prevention of Syncope Trial (POST), a randomized clinical trial that tested the hypothesis that metoprolol reduces syncope and presyncope in adult patients with vasovagal syncope. RESULTS: The CPF was completed by 44 patients on metoprolol and 39 patients on placebo, of a total of 208 subjects. Completion of the CPF for each of the threedimensions was 84-87% in the 83 respondents. Results were centrally distributed in duration and severity dimensions, but not in frequency. Patients had a median of 1.2 presyncopal spells per day, with a median moderate severity, lasting a median 10 minutes. The 3 scales were statistically independent of each other. These results were independent of subject age, and results in all 3 dimensions were stable over the observation period. There was no significant difference between patients on metoprolol and placebo in any dimension. CONCLUSION: The 3-dimensional CPF is simple, easy to use, stable over time, measures 3 independent variables, and documents that metoprolol does not reduce presyncope.
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Projetos de Pesquisa/normas , Síncope/diagnóstico , Síncope/fisiopatologia , Pesos e Medidas/normas , Adulto , Método Duplo-Cego , Estudos de Avaliação como Assunto , Feminino , Seguimentos , Humanos , Masculino , Metoprolol/uso terapêutico , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Síncope/tratamento farmacológico , Adulto JovemRESUMO
BACKGROUND: Microvolt T-wave alternans (MTWA) has been used for arrhythmogenic risk stratification in cardiac disease conditions associated with increased risk of sudden cardiac death. Macroscopic T-wave alternans has been observed in patients with congenital long-QT syndrome (LQTS). The role of MTWA testing in patients with LQTS has not been established. OBJECTIVE: To determine the diagnostic value of MTWA testing in high-risk patients with LQTS. METHODS AND RESULTS: We assessed MTWA in 10 consecutive LQTS index patients who survived cardiac arrest or had documented torsade de pointes tachycardia and 6 first-degree family members with congenital LQTS which had been genotyped in 13 of 16 subjects (7 index patients, 6 family members). No LQTS-causing mutation was identified in 3 index patients with overt QT prolongation. MTWA was assessed during standardized bicycle exercise testing using the spectral method and yielded negative (n = 8) or indeterminate (n = 2) results in index patients, respectively. Similarly, all first-degree family members tested MTWA negative except for one indeterminate result. Two genotype positive family members could not be tested (two children-4 and 9 years of age). CONCLUSION: In patients with congenital LQTS, free from structural heart disease and with a history of life-threatening cardiac arrhythmias, assessment of MTWA does not yield diagnostic value. Hence, determination of MTWA in lower risk LQTS patients without spontaneous arrhythmic events is likely not to be useful for arrhythmia risk stratification.
Assuntos
Arritmias Cardíacas/diagnóstico , Síndrome do QT Longo/fisiopatologia , Adolescente , Adulto , Idoso , Arritmias Cardíacas/genética , Arritmias Cardíacas/fisiopatologia , Morte Súbita Cardíaca , Teste de Esforço/métodos , Teste de Esforço/estatística & dados numéricos , Feminino , Predisposição Genética para Doença/genética , Parada Cardíaca/genética , Parada Cardíaca/fisiopatologia , Humanos , Síndrome do QT Longo/genética , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Taquicardia Ventricular/genética , Taquicardia Ventricular/fisiopatologia , Torsades de Pointes/genética , Torsades de Pointes/fisiopatologiaRESUMO
Initiation of antiarrhythmic drug therapy (AADx) for atrial fibrillation (AF) on an outpatient basis requires intensive ECG monitoring in order to assess antiarrhythmic efficacy as well as ECG signals of potential proarrhythmia. Dronedarone (DRO) reduces cardiovascular endpoints in AF patients fulfilling criteria of the ATHENA trial [1]. In the present study transtelephonic ECG monitoring was used to guide initiation of AADx in AF patients fulfilling the ATHENA criteria. In 19 consecutive patients (37% female; age 65+10 years; LVEF 62+7%; mean CHA2DS2-VASc score 2.9 + 1.6 (median=2), with symptomatic non-permanent AF and additional cardiovascular risk factors, DRO was prescribed as AADx of first choice. Initiation of therapy and follow-up were monitored by transtelephonic ECG recordings (VITAPHONE™100 IR; Vitaphone GmbH; Germany). In patients with persistent AF, electrical cardioversion was performed on an outpatient basis when DRO was started. Patients were followed for changes in QT intervals as well as AF recurrency. ECGs were transmitted according to a scheduled FU form as well as any time in case of pts symptoms. Patients in whom DRO did not prevent AF recurrence were switched to alternative AADx, or to pulmonary vein isolation (PVI), respectively. At the end of long-term follow-up, DRO alone was successful in preventing AF recurrence in 5 of 19 patients (26%). When pts who responded to AADx of second or third choice or who underwent PVI were included, SR could be maintained in 17/19 pts (89%). No patient required discontinuation of AADx due to ventricular depolarization abnormalities, symptomatic bradycardia or pathologic QT prolongation. In conclusion, transtelephonic ECG transmission is useful for close rhythm monitoring during initiation and follow-up of AADx, also during change from DRO to other AADx. DRO was effective to prevent AF recurrence in 26% of patients during a mean long-term follow-up of more than 30 months - which is well in line with data from the literature.
RESUMO
AIMS: We hypothesize that the neural component (NC) of the baroreflex sensitivity (BRS) is a better risk stratifier for ventricular tachycardia/fibrillation (VT/VF) than conventional BRS itself, because it is both independent of vessel wall stiffness and can be measured non-invasively. METHODS AND RESULTS: NC was determined by correlating spontaneous carotid artery diameter variations with R-R interval variations using spectral analyses. In consecutive outpatient populations with chronic coronary artery disease the ability of the NC to distinguish post-myocardial infarction (MI) patients at risk for VT/VF (post-MI(HIGH RISK)) from post-MI less prone to arrhythmias (post-MI(LOW RISK)) was compared with the pressure-derived BRS(phenyl) and BRS(spectral) method. Ninety-six patients, i.e. 28 post-MI(LOW RISK), 28 post-MI(HIGH RISK) [a LVEF(left ventricular ejection fraction) <30% and/or history of VT/VF] and 40 healthy controls were enrolled. With NC, rather than with BRS methods, median values for post-MI(HIGH RISK) were smaller than for post-MI(LOW RISK) patients (NC, P = 0.03; BRS(spectral), P = 0.35; BRS(phenyl), P = 0.63). Variability of R-R interval (LF = 0.04-0.15 Hz) was significantly larger in the control group than in the post-MI(HIGH RISK) and post-MI(LOW RISK) group (P < 0.01 and P < 0.01). To separate post-MI(HIGH RISK) from post-MI(LOW RISK) patients, a linear combination of age and the logarithm of the NC measurement was constructed as a risk index. By optimizing the intercept of this line, an optimal sensitivity and specificity pair was determined. The sum of optimal specificity and sensitivity was higher for NC (155) than for BRS(spectral) (133) and BRS(phenyl) method (132). With all methods, values for post-MI patients were significantly smaller than for controls. CONCLUSION: NC may be superior to conventional BRS measures in identifying post-MI patients at high risk for VT/VF.
Assuntos
Barorreflexo/fisiologia , Infarto do Miocárdio/complicações , Infarto do Miocárdio/fisiopatologia , Taquicardia Ventricular/etiologia , Fibrilação Ventricular/etiologia , Pressão Sanguínea/fisiologia , Artérias Carótidas/fisiopatologia , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Valor Preditivo dos Testes , Estudos Retrospectivos , Medição de RiscoRESUMO
BACKGROUND: Noninvasive arrhythmia risk stratification in patients with nonischemic dilated cardiomyopathy (DCM) using autonomic markers have yielded disappointing results. Heart rate turbulence is a new method to assess cardiac autonomic function. AIM: The aim of the study was to compare the predictive value of heart rate turbulence with those of conventional autonomic risk markers for ventricular tachyarrhythmic events in patients with DCM. METHODS: The predictive value of heart rate turbulence, baroreflex sensitivity (phenylephrine method), and heart rate variability was assessed in patients with symptomatic congestive heart failure due to DCM who were in sinus rhythm and had a 24-hour Holter recording. Patients were followed for a combined end point of ventricular tachyarrhythmic events. RESULTS: A total of 114 patients (mean left ventricular ejection fraction, 28 +/- 11%), included in the Frankfurt DCM database between 1996 and 2000, fulfilled the criteria for inclusion in this study. Determinate test results were obtained for heart rate variability in 98%, for baroreflex sensitivity in 90%, and for heart rate turbulence in 75% of patients (P = .008). Correlation between the different autonomic markers were only modest (r values, 0.36-0.43). During a follow-up of 22 +/- 17 months, an end point event occurred in 15 patients. On univariate analysis, left ventricular ejection fraction and baroreflex sensitivity were significant predictors of arrhythmic events. On multivariate analysis, only baroreflex sensitivity remained an independent predictor (chi(2) = 3.17; P = .07). CONCLUSION: Reliable analysis of heart rate turbulence is possible in approximately 75% of eligible patients with DCM. Whereas blunted baroreflex sensitivity is a predictor of arrhythmic events, heart rate variability and turbulence do not yield predictive power in these patients.
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Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/epidemiologia , Doenças do Sistema Nervoso Autônomo/diagnóstico , Doenças do Sistema Nervoso Autônomo/epidemiologia , Cardiomiopatia Dilatada/diagnóstico , Cardiomiopatia Dilatada/epidemiologia , Medição de Risco/métodos , Comorbidade , Eletrocardiografia/estatística & dados numéricos , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Previous studies that assessed the effects of beta-blockers in preventing vasovagal syncope provided mixed results. Our goal was to determine whether treatment with metoprolol reduces the risk of syncope in patients with vasovagal syncope. METHODS AND RESULTS: The multicenter Prevention of Syncope Trial (POST) was a randomized, placebo-controlled, double-blind, trial designed to assess the effects of metoprolol in vasovagal syncope over a 1-year treatment period. Two prespecified analyses included the relationships of age and initial tilt-test results to any benefit from metoprolol. All patients had >2 syncopal spells and a positive tilt test. Randomization was stratified according to ages <42 and > or =42 years. Patients received either metoprolol or matching placebo at highest-tolerated doses from 25 to 200 mg daily. The main outcome measure was the first recurrence of syncope. A total of 208 patients (mean age 42+/-18 years) with a median of 9 syncopal spells over a median of 11 years were randomized, 108 to receive metoprolol and 100 to the placebo group. There were 75 patients with > or =1 recurrence of syncope. The likelihood of recurrent syncope was not significantly different between groups. Neither the age of the patient nor the need for isoproterenol to produce a positive tilt test predicted subsequent significant benefit from metoprolol. CONCLUSIONS: Metoprolol was not effective in preventing vasovagal syncope in the study population.
Assuntos
Metoprolol/administração & dosagem , Síncope Vasovagal/prevenção & controle , Antagonistas Adrenérgicos beta/uso terapêutico , Adulto , Fatores Etários , Método Duplo-Cego , Feminino , Humanos , Incidência , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Placebos , Recidiva , Síncope Vasovagal/tratamento farmacológico , Teste da Mesa Inclinada , Falha de TratamentoRESUMO
INTRODUCTION: Much of the natural history of vasovagal syncope is unknown. We determined whether patients presenting for care have had a recently worsened syncope frequency. METHODS AND RESULTS: We compared 208 subjects in the referral-based Prevention of Syncope Trial (POST) and 122 subjects who fainted > or =1 in a community survey study. Their mean ages and gender proportions were similar. The POST population had a higher median lifetime syncope frequency (1.16 vs 0.12 spells/year, P < 0.0001) and more subjects began fainting at age > or =35 years (26% vs 6%, P < 0.0001). In POST, the median frequency of syncopal spells in the preceding year was higher than in all previous years (3 vs 0.57, P < 0.0001). POST subjects presented sooner after their first spell (median 11.0 vs 16.8 years, P = 0.0002), and after their last spell (median 0.3 vs 7.4 years, P < 0.0001). POST subjects > or =35 years old had a shorter history than similar community-survey subjects (2.8 vs 14.9 y, P < 0.0001) and presented earlier after their first syncopal spell than POST subjects with a younger onset of syncope (median 2.8 vs 14.7 y, P < 0.0001), despite having fewer faints (median 6 vs 10, P = 0.0002). CONCLUSIONS: Many syncope patients present for care after a recent worsening of their frequency of syncope.
Assuntos
Encaminhamento e Consulta/estatística & dados numéricos , Medição de Risco/métodos , Síncope Vasovagal/epidemiologia , Síncope Vasovagal/prevenção & controle , Adulto , Idade de Início , Canadá/epidemiologia , Progressão da Doença , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Índice de Gravidade de Doença , Síncope Vasovagal/diagnóstico , Resultado do TratamentoRESUMO
Various disorders of autonomic circulatory control are characterized by symptoms of orthostatic intolerance and syncope. Since the introduction of tilt-table testing as a cardiac diagnostic tool by Kenny et al., definition of these disorders has changed significantly. This review summarizes the current knowledge of diagnosis and treatment of the syndromes of orthostatic intolerance.
Assuntos
Síndrome de Shy-Drager/diagnóstico , Sistema Nervoso Autônomo/fisiopatologia , Diagnóstico Diferencial , Humanos , Síndrome de Shy-Drager/terapia , Síncope/etiologia , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/terapia , Taquicardia/diagnóstico , Taquicardia/terapia , Teste da Mesa InclinadaRESUMO
BACKGROUND: There is limited evidence whether being on fludrocortisone prevents vasovagal syncope. OBJECTIVES: The authors sought to determine whether treatment with fludrocortisone reduces the proportion of patients with recurrent vasovagal syncope by at least 40%, representing a pre-specified minimal clinically important relative risk reduction. METHODS: The multicenter POST 2 (Prevention of Syncope Trial 2) was a randomized, placebo-controlled, double-blind trial that assessed the effects of fludrocortisone in vasovagal syncope over a 1-year treatment period. All patients had >2 syncopal spells and a Calgary Syncope Symptom Score >-3. Patients received either fludrocortisone or matching placebo at highest tolerated doses from 0.05 mg to 0.2 mg daily. The main outcome measure was the first recurrence of syncope. RESULTS: The authors randomized 210 patients (71% female, median age 30 years) with a median 15 syncopal spells over a median of 9 years equally to fludrocortisone or placebo. Of these, 96 patients had ≥1 syncope recurrences, and only 14 patients were lost to follow-up before syncope recurrence. There was a marginally nonsignificant reduction in syncope in the fludrocortisone group (hazard ratio [HR]: 0.69: 95% confidence interval [CI]: 0.46 to 1.03; p = 0.069). In a multivariable model, fludrocortisone significantly reduced the likelihood of syncope (HR: 0.63; 95% CI: 0.42 to 0.94; p = 0.024). When the analysis was restricted to outcomes after 2 weeks of dose stabilization, there was a significant benefit due to fludrocortisone (HR: 0.51; 95% CI: 0.28 to 0.89; p = 0.019). CONCLUSIONS: The study did not meet its primary objective of demonstrating that fludrocortisone reduced the likelihood of vasovagal syncope by the specified risk reduction of 40%. The study demonstrated a significant effect after dose stabilization, and there were significant findings in post hoc multivariable and on-treatment analyses. (A randomised clinical trial of fludrocortisone for the prevention of vasovagal syncope; ISRCTN51802652; Prevention of Syncope Trial 2 [POST 2]; NCT00118482).