RESUMO
AIMS: The implantation of an implantable loop recorder (ILR) leads to the diagnosis in about 35% of patients with syncope of unknown origin. Information on outcome of patients in whom a diagnosis is not reached during the lifetime of the device is scarce. The aim of our study is to determine the outcome of these patients in terms of syncope recurrence and survival. METHODS AND RESULTS: An ILR was implanted to 97 patients with syncope of unknown origin. Patients were classified in groups A and B depending on their high or low risk, respectively, of having arrhythmic syncope. Diagnosis had not been reached in 60 patients (62%) when the ILR battery reached end operational life. Five patients were lost to follow up. During a median follow-up of 48 months after ILR explantation (interquartile range 36-56), 22 patients (40%) had recurrence of syncope (32% in group A vs. 48% in group B, P = 0.3). Syncopes with no neurally mediated profile were more frequent in group A (18 vs. 0%, P = 0.05) and neurally mediated profile syncopes were more frequent in group B (44 vs. 11%, P = 0.007). Five patients died, four of them in group A and 1 in group B (P = 0.4). No sudden or cardiac deaths were detected during follow-up. All deaths were due to non-cardiac causes. CONCLUSION: Recurrent syncope is common in patients in whom a diagnosis is not established after the full battery life of an ILR. The prognosis of these patients seems to be good, without observed sudden or cardiac death.
Assuntos
Morte Súbita Cardíaca/epidemiologia , Eletrocardiografia Ambulatorial/estatística & dados numéricos , Síncope/diagnóstico , Síncope/mortalidade , Eletrocardiografia Ambulatorial/métodos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prognóstico , Recidiva , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade , Espanha/epidemiologia , Análise de Sobrevida , Taxa de SobrevidaRESUMO
AIMS: Electrical storm (ES) is a life-threatening condition that predicts bad prognosis. Treatment includes antiarrhythmic drugs (AAD) and catheter ablation (CA). The present study aims to retrospectively compare prognosis in terms of survival and ES recurrence in 52 consecutive patients experiencing a first ES episode. METHODS AND RESULTS: Patients were admitted from 1995 to 2011 and treated for ES by conservative therapy (pharmacological, 29 patients) or by CA (23 patients), according to the physician's preference and time of occurrence, i.e. conservative treatments were more frequently administered during the first years of the study, as catheter ablation became more frequent as the years passed by. After a median follow-up of 28 months, no differences either in survival (32% vs. 29% P = 0.8) or in ES recurrence (38% in ablated vs. 57% in non-ablated patients, P = 0.29) were observed between groups. Low left ventricle ejection fraction (LVEF) was the only variable associated with ES recurrence in ablated patients. When including patients with LVEF > 25%, ES recurrence was significantly lower in ablated patients (24 months estimated risk of ES recurrence was 21% vs. 62% in ablated and non-ablated patients, respectively); however, no benefit in survival was observed. CONCLUSION: Our data suggest that in most patients, especially those with an LVEF > 25%, catheter ablation following a first ES episode, decreases the risk of ES recurrence, without increasing survival.
Assuntos
Antiarrítmicos/uso terapêutico , Ablação por Cateter/métodos , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/terapia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
AIMS: Fluoroscopy is the standard and almost unique tool used for cardiac imaging during permanent pacemaker implantation, and its use implies exposure of patients and operators to radiation. The usefulness for this purpose of electroanatomic systems not based on fluoroscopy is unknown. Our aim was to study the feasibility of implanting single-lead VDD pacemakers without the use of fluoroscopy. METHODS AND RESULTS: EnSite NavX, a catheter navigation tool based on the creation of a voltage gradient across the thorax of the patient, was used as an exclusive imaging tool during the implantation of single-lead atrioventricular (VDD) permanent pacemakers in 15 consecutive patients with atrioventricular block and normal sinus node function. A retrospective series of 15 consecutive patients in whom VDD pacemakers were implanted under fluoroscopic guidance was used as a control group. The pacemaker could be implanted in all patients. Time spent to obtain the right ventricle anatomy was 10.1 +/- 5.4 min and time to place the lead in an adequate position was 10.1 +/- 7.8 min. Total implant time was 59.3 +/- 15.6 min (51.5 +/- 12.3 min in the control group; P = 0.14). In one patient, a short pulse of radioscopy was needed for a correct catheterization of the subclavian vein. No complications were observed during the procedure. One lead dislodgement that required re-operation was detected 24 h after implantation. At 3 months follow-up, all pacemakers were functioning properly, with adequate pacing and sensing thresholds. CONCLUSION: Electroanatomic navigation systems such as NavX can be used for cardiac imaging during single-lead atrioventricular pacemaker implantation as a reliable and safe alternative to fluoroscopy.
Assuntos
Nó Atrioventricular/cirurgia , Eletrodos Implantados , Marca-Passo Artificial , Pletismografia de Impedância/instrumentação , Pletismografia de Impedância/métodos , Implantação de Prótese/métodos , Idoso , Idoso de 80 Anos ou mais , Nó Atrioventricular/patologia , Feminino , Fluoroscopia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The occurrence of ventricular tachyarrhythmias seems to follow circadian, daily, and seasonal distributions. Our aim is to identify potential temporal patterns of electrical storm (ES), in which a cluster of ventricular tachycardias or ventricular fibrillation, negatively affects short- and long-term survival. METHODS AND RESULTS: The TEMPEST study (Circannual Pattern and Temperature-Related Incidence of Electrical Storm) is a patient-level, pooled analysis of previously published data sets. Study selection criteria included diagnosis of ES, absence of acute coronary syndrome as the arrhythmic trigger, and ≥10 patients included. At the end of the selection and collection processes, 5 centers had the data set from their article pooled into the present registry. Temperature data and sunrise and sunset hours were retrieved from Weather Underground, the largest weather database available online. Total sample included 246 patients presenting with ES (221 men; age: 65±9 years). Each ES episode included a median of 7 ventricular tachycardia/ventricular fibrillation episodes. Fifty-nine percent of patients experienced ES during daytime hours (P<0.001). The prevalence of ES was significantly higher during workdays, with Saturdays and Sundays registering the lowest rates of ES (10.4% and 7.2%, respectively, versus 16.5% daily mean from Monday to Friday; P<0.001). ES occurrence was significantly associated with increased monthly temperature range when compared with the month before (P=0.003). CONCLUSIONS: ES incidence is not homogenous over time but seems to have a clustered pattern, with a higher incidence during daytime hours and working days. ES is associated with an increase in monthly temperature variation. CLINICAL TRIAL REGISTRATION: https://www.crd.york.ac.uk. Unique identifier: CRD42013003744.
Assuntos
Eletrocardiografia , Estações do Ano , Taquicardia Ventricular/epidemiologia , Fibrilação Ventricular/epidemiologia , Idoso , Antiarrítmicos/uso terapêutico , Ritmo Circadiano , Análise por Conglomerados , Comorbidade , Bases de Dados Factuais , Desfibriladores Implantáveis , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prognóstico , Medição de Risco , Estudos de Amostragem , Índice de Gravidade de Doença , Taxa de Sobrevida , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/terapia , Temperatura , Fibrilação Ventricular/diagnóstico , Fibrilação Ventricular/terapiaRESUMO
INTRODUCTION AND OBJECTIVES: The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. METHODS: Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. RESULTS: Linear regression analysis showed that there was a good correlation between the dominant frequency obtained using the two signal analysis methods: frequency (spectral analysis) = 1.01 x frequency (time-frequency analysis) -- 0.4 (r=0.9; P< .0001; standard error of the estimate, 2.2 Hz). In all cases except one, the dominant frequency exhibited a significant temporal variation on a short timescale (time-frequency analysis); the coefficient of variation was between 0.19 (0.06) and 0.24 (0.07) (NS). In all cases, there were significant differences between regions. The location at which the frequency was highest varied according to the timepoint considered, though it was predominantly in the apical or anterior zone. CONCLUSIONS: In the absence of external modulating factors, the frequency of ventricular fibrillation exhibits temporal and spatial variations which can be observed at short timescales. In the free wall of the left ventricle, the dominant frequency is highest in the apical and anterior zones, and the maximum frequencies are most often found in these zones.
Assuntos
Coração/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Animais , Modelos Animais de Doenças , Eletrocardiografia , Eletrofisiologia , Coelhos , Fatores de Tempo , Fibrilação Ventricular/diagnósticoRESUMO
INTRODUCTION AND OBJECTIVES: The best therapeutic approach for persistent atrial fibrillation has yet to be defined. Our aim was to investigate the effects of cardioversion in unselected patients with persistent atrial fibrillation who were treated according to a strict protocol involving pretreatment, cardioversion, and follow-up. METHODS: Consecutive patients with persistent atrial fibrillation of at least 1 months' duration were included prospectively in a cardioversion protocol that involved standard antiarrhythmic pretreatment, with amiodarone being offered first, and follow-up. RESULTS: The study included 295 patients, 87.5% of whom were taking the antiarrhythmic drug amiodarone. Sinus rhythm was restored in 92.5%, with pharmacologic cardioversion occurring in 9.5%. The recurrence rate was 33.5% in the first month and 54.9% by month 12. Antiarrhythmic treatment had to be modified in 10.8% of patients. Independent risk factors for recurrence during the first year after cardioversion were an atrial fibrillation duration greater than one year, previous cardioversion, and left ventricular dilatation. A simple risk scoring system was able to differentiate between subgroups of patients with a low, intermediate or high risk of recurrence in the first year after cardioversion. CONCLUSIONS: Sinus rhythm was maintained for 1 year after effective cardioversion in 45.1% of patients who received homogeneous antiarrhythmic pretreatment. There were few side effects. Recurrence can be predicted using clinical variables such as left ventricular dilatation, arrhythmia duration, and previous cardioversion.
Assuntos
Fibrilação Atrial/terapia , Cardioversão Elétrica , Idoso , Amiodarona/administração & dosagem , Amiodarona/efeitos adversos , Amiodarona/uso terapêutico , Antiarrítmicos/administração & dosagem , Antiarrítmicos/efeitos adversos , Antiarrítmicos/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/mortalidade , Protocolos Clínicos , Interpretação Estatística de Dados , Cardioversão Elétrica/efeitos adversos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Medição de Risco , Fatores de Risco , Análise de Sobrevida , Fatores de TempoRESUMO
INTRODUCTION AND OBJECTIVES: Cardiovascular disease is the main cause of death in patients with kidney failure. Moreover, the presence of impaired renal function is an important prognostic factor in patients with heart disease, and is a determinant of outcome during follow-up. The main aim was to investigate the relationship between kidney failure at admission and one-year mortality in patients with non-ST-elevation acute coronary syndrome. PATIENTS AND METHOD: We studied 1029 consecutive patients admitted to our institution. The serum creatinine level and glomerular filtration rate were determined at admission, and classical risk factors and biochemical markers were assessed. The primary endpoint was all-cause mortality at one year. RESULTS: Patients who died were older, more frequently had a history of diabetes or coronary artery disease, were more likely to have heart failure at admission, had higher troponin-I, myoglobin and creatinine levels, and were less likely to have dyslipidemia or to be a smoker. Multivariate analysis showed that the independent predictors of all-cause mortality at one year were age, diabetes, troponin-I level, Killip class > 1, male gender, creatinine level, and glomerular filtration rate. There was a linear correlation between increased risk and creatinine level. CONCLUSIONS: Creatinine level at admission is one of the most important covariates in early prognostic stratification in these patients. A high serum creatinine level (or a low glomerular filtration rate) increases the probability of death due to all causes. The serum creatinine level is, moreover, an inexpensive, easy-to-use, and widely available prognostic marker.
Assuntos
Creatinina/sangue , Isquemia Miocárdica/mortalidade , Insuficiência Renal/diagnóstico , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Interpretação Estatística de Dados , Eletrocardiografia , Feminino , Seguimentos , Taxa de Filtração Glomerular , Humanos , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/sangue , Isquemia Miocárdica/complicações , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/fisiopatologia , Valor Preditivo dos Testes , Prognóstico , Insuficiência Renal/complicações , Fatores de Risco , Fatores Sexuais , Fatores de TempoRESUMO
BACKGROUND: Management of acute chest pain in the emergency room constitutes a challenge. METHODS: Seven hundred and one consecutive patients were evaluated by clinical history (chest pain score and risk factors), ECG, troponin I and early (<24 h) exercise testing in low risk patients (n=165). A composite end-point (recurrent unstable angina, acute myocardial infarction or cardiac death) was recorded during hospital stay or in ambulatory care settings for patients discharged after early exercise testing. RESULTS: The end-point occurred in 122 patients (17%). Multivariate analysis identified the following predictors: chest pain score > or =11 points (OR=1.8, 2-2.8, 95% CI, P=0.007), age > or =68 (OR 1.6, 1.1-2.4 CI 95%, P=0.03), insulin-dependent diabetes mellitus (OR 1.9, 1.1-3.4 CI 95%, P=0.02), a history of coronary surgery (OR 3.3, 1.5-7.2 CI 95%, P=0.003), ST-segment depression (OR 1.9, 1.2-3.0 CI 95%, P=0.009) and troponin I elevation (OR 1.6, 1.1-2.5, CI 95%, P=0.05). ST-segment depression produced a high end-point increase (31 vs. 13%, P=0.0001). Troponin I elevation increased the risk in the subgroup without ST-segment depression (20 vs. 11%, P=0.006) but did not further modify the risk in the subgroup with ST depression (31 vs. 28%, ns). Nevertheless, the negative ECG and troponin I subgroup showed a non-negligible end-point rate (16% when pain score > or =11 or 7% when pain score <11, P=0.004). Finally, no patient with a negative exercise test presented events compared to 7% of those with a non-negative test (RR=2.5, 2.1-3.1 95% CI, P=0.01). CONCLUSIONS: Emergency room evaluation of chest pain should not focus on a single parameter; on the contrary, the clinical history, ECG, troponin and early exercise testing must be globally analysed.
Assuntos
Dor no Peito/diagnóstico , Eletrocardiografia , Doença Aguda , Idoso , Dor no Peito/epidemiologia , Serviço Hospitalar de Emergência , Teste de Esforço , Feminino , Humanos , Masculino , Análise Multivariada , Fatores de Risco , Troponina I/sangueRESUMO
INTRODUCTION AND OBJECTIVES: The aim of this study was to analyze the effects of myocardial stretching on excitation frequencies, as determined by spectral analysis, during ventricular fibrillation. METHODS: In 12 isolated rabbit heart preparations, ventricular activation during ventricular fibrillation was recorded with multiple electrodes. Recordings were obtained before, during and after ventricular dilatation produced with an intraventricular balloon. The dominant frequency of the signals obtained with each of the electrodes was determined by spectral analysis. RESULTS: During the control phase, the mean, minimum and maximum dominant frequencies were, respectively, 14.3 1.7, 12.5 1.7, and 16.2 1.4 Hz, and the average difference between the maximum and minimum frequencies was 3.6 2.1 Hz. This difference was over 4 Hz in four cases, and in no case did it exceed 8 Hz. During ventricular stretching, the mean dominant frequency increased significantly (21.1 6.1 Hz; p < 0.0001), as did the minimum values (14 2.6 Hz; p < 0.05) and especially the maximum values (26.6 7.7 Hz; p < 0.0001). The difference between the maximum and minimum frequencies (12.6 6.4 Hz; p < 0.001) was over 4 Hz in all cases except one, and over 8 Hz in 9 cases. The maximum values were distributed heterogeneously during ventricular stretching. Upon suppressing ventricular stretching, the dominant frequency did not differ from controls. CONCLUSIONS: Myocardial frequency maps during ventricular fibrillation show limited variations in the dominant frequency of the signals recorded in the lateral wall of the left ventricle. During stretching, the patterns were heterogeneous, due mainly to the marked increase in the maximum dominant frequency. In the experimental model used, the effects of stretching remitted after suppressing ventricular dilatation.
Assuntos
Coração/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Animais , Eletrofisiologia , Técnicas In Vitro , Miocárdio , CoelhosRESUMO
OBJECTIVE: The recommendations for complete lead extraction because of local complications at the site of implantable devices have changed in the last 10 years. We analyze the outcome of patients who required an intervention because of a local complication between 2002 and 2010, in our Hospital. METHODS: We retrospectively studied 83 patients with a local complication that was classified according to skin integrity: 1. Integrity, and 2. Open skin. We analyzed the type of intervention: 1. Conservative approach, 2. Incomplete extraction, 3. Complete extraction. The endpoints were the needing a later intervention and a complete removal during follow up. RESULTS: The group of patients with complete system extraction showed a lower rate of re-intervention during an average follow up of 1000 days, when compared to other two groups (6.7% vs. 57.7 and 43.8%, P<.01). Incomplete extraction and conservative approach had a similar outcome, needing a complete extraction 25% and 37.5%, respectively. The skin integrity did not seem to be relevant for outcome in these two groups. An 8.4% incidence of endocarditis was observed; all of them had a previous history of incomplete extraction or conservative approach. CONCLUSIONS: Local complications treated with either a conservative approach or incomplete extraction are associated with a high rate of re-interventions, regardless of skin integrity, frequently needing final complete extraction and are associated to endocarditis.
Assuntos
Desfibriladores Implantáveis/efeitos adversos , Marca-Passo Artificial/efeitos adversos , Humanos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos RetrospectivosRESUMO
BACKGROUND: Infarct size (IS) determined by cardiac magnetic resonance (CMR) has proven an additional value, on top of left ventricular ejection fraction (LVEF), in prediction of adverse arrhythmic cardiac events (AACEs) in chronic ischemic heart disease. Its value soon after an acute ST-segment-elevation myocardial infarction remains unknown. Our aim was to determine whether early CMR can improve AACE risk prediction after acute ST-segment-elevation myocardial infarction. METHODS AND RESULTS: Patients admitted for a first noncomplicated ST-segment-elevation myocardial infarction were prospectively followed up. A total of 440 patients were included. All of them underwent CMR 1 week after admission. CMR-derived LVEF and IS (grams per meter squared) were quantified. AACEs included postdischarge sudden death, sustained ventricular tachycardia, and ventricular fibrillation either documented on ECG or recorded via an implantable cardioverter-defibrillator. Within a median follow-up of 2 years, 11 AACEs (2.5%) were detected: 5 sudden deaths (1.1%) and 6 spontaneous ventricular tachycardia/ventricular fibrillation. In the whole group, AACEs associated with more depressed LVEF (adjusted hazard ratio [95% confidence interval], 0.90 [0.83-0.97]; P<0.01) and larger IS (adjusted hazard ratio [95% confidence interval], 1.06 [1.01-1.12]; P=0.01). According to the corresponding area under the receiver operating characteristic curve, LVEF ≤36% and IS ≥23.5 g/m(2) best predicted AACEs. The vast majority of AACEs (10/11) occurred in patients with simultaneous depressed LVEF ≤36% and IS ≥23.5 g/m(2) (n=39). CONCLUSIONS: In the era of reperfusion therapies, occurrence of AACEs in patients with an in-hospital noncomplicated first ST-segment-elevation myocardial infarction is low. In this setting, assessment of an early CMR-derived IS could be useful for further optimization of AACE risk prediction.
Assuntos
Arritmias Cardíacas/etiologia , Imagem Cinética por Ressonância Magnética , Infarto do Miocárdio/diagnóstico , Miocárdio/patologia , Idoso , Área Sob a Curva , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/terapia , Distribuição de Qui-Quadrado , Morte Súbita Cardíaca/etiologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Infarto do Miocárdio/complicações , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/terapia , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Curva ROC , Medição de Risco , Fatores de Risco , Volume Sistólico , Fatores de Tempo , Função Ventricular EsquerdaRESUMO
INTRODUCTION AND OBJECTIVES: The objective of this study was to determine the diagnostic yield of a stepped protocol involving an electrophysiologic study (EPS) and implantable loop recorders (ILR) in patients with syncope and bundle branch block (BBB). METHODS: Eighty-five consecutive patients referred for syncope and BBB after initial non-diagnostic assessment underwent EPS including a pharmacological challenge with procainamide. Those patients without indication for defibrillator implantation received ILRs. Follow-up continued until diagnosis or end of battery life. RESULTS: The EPS was diagnostic in 36 patients (42%). The most frequent diagnoses were paroxysmal atrioventricular block (AVB) (n=27), followed by ventricular tachycardia (VT) (n=6). All patients with VT had structural heart disease; left BBB was more prevalent in this group. Thirty-eight patients received ILRs and diagnosis was achieved in 13 (34%) of them; paroxysmal AVB (n=10) was the most frequent diagnosis. Median follow-up to diagnosis of paroxysmal AVB was 97 days (interquartile range 60-117 days). Paroxysmal AVB was more frequent in patients with right BBB and prolonged PR interval and/or axis deviation. We found no occurrence of VT or arrhythmic death during follow-up. CONCLUSIONS: The most common etiology of syncope in patients with BBB was paroxysmal AVB, followed by VT. The stepped use of EPS and ILR in negative patients enables us to safely achieve a high diagnostic yield, given that VT is usually diagnosed during EPS.
Assuntos
Bloqueio de Ramo/diagnóstico , Síncope/diagnóstico , Idoso , Técnicas Eletrofisiológicas Cardíacas/instrumentação , Feminino , Humanos , MasculinoRESUMO
Introducción: la ablación de la fibrilación auricular es uno de los procedimientos más frecuentemente realizados en las unidades de arritmias. La información de los resultados proviene de estudios prospectivos, registros multicéntricos y registros nacionales. Objetivo: evaluar la situación de la ablación de la fibrilación auricular en España a través de los datos recogidos en el Registro Español de Ablación, auspiciado por la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología. Métodos: los datos analizados provienen de los formularios remitidos, de forma voluntaria y anónima, por los diferentes centros hospitalarios, tanto de financiación pública como privada, durante el período 2008-2013. Cada centro fue analizado, año a año, de forma independiente. Analizamos los recursos humanos y materiales de los centros que realizaron procedimientos de ablación de fibrilación auricular durante ese período de tiempo. Asimismo, analizamos la técnica utilizada, el tipo de energía, complicaciones, etcétera. Comparamos todas las variables de forma evolutiva, año a año. Dividimos a los centros en función del número de procedimientos de ablación realizados cada año: 1-49, grupo A; 50-99, grupo B, y 100 o más, grupo C. Resultados: trescientos noventa y un centros (n=391) y 8.926 procedimientos de ablación fueron analizados. Año a año ha aumentado el número de centros que realizan ablación de fibrilación auricular y el número de procedimientos que realiza cada centro. El porcentaje de complicaciones se ha mantenido estable reduciéndose ligeramente la mortalidad. Los centros con mayor volumen tienen mayor dotación de recursos humanos y materiales. Realizan ablación de fibrilación auricular persistente con mayor frecuencia y realizan crioablación con menor frecuencia. Asimismo, estos centros tienen una menor incidencia de complicaciones. Conclusiones: la ablación de fibrilación auricular en España ha aumentado en los últimos años y presenta resultados similares a los recogidos en otros registros nacionales y multinacionales.
RESUMO
Objetivo: Las recomendaciones para la extracción completa de la bolsa de dispositivos implantables por problemas locales han cambiado. Analizamos la evolución entre 2002 y 2010 de los pacientes que requirieron una intervención por una complicación local en nuestro centro. Métodos: Ochenta y tres pacientes tuvieron un problema local de la bolsa que se clasificó según integridad de la piel: 1. Íntegra y 2. Abierta, y el tipo de intervención realizada: 1. Conservadora, 2. Extracción parcial y 3. Extracción completa. El objetivo primario fue la necesidad de reintervención posterior y la de extracción total durante el seguimiento. Resultados: El grupo de pacientes con extracción completa presentó una menor tasa de reintervención durante el seguimiento medio de 1,000 días comparado con los otros 2 grupos (6.7 vs. 57.7 y 43.8%, p < 0.01). La extracción parcial y la actitud conservadora mostraron una evolución parecida con una tasa de extracción completa final del 25% y del 37.5%. Se observó una incidencia de endocarditis del 8.4%; todos con antecedente de extracción parcial o actitud conservadora. Conclusiones: Las complicaciones de la bolsa, independientemente de la integridad de la piel, tratadas conservadoramente o con extracción parcial se asocian a alta tasa de reintervenciones, necesidad de extracción completa y evolución a endocarditis.
Objective: The recommendations for complete lead extraction because of local complications at the site of implantable devices have changed in the last 10 years. We analyze the outcome of patients who required an intervention because of a local complication between 2002 and 2010, in our Hospital. Methods: We retrospectively studied 83 patients with a local complication that was classified according to skin integrity: 1. Integrity, and 2. Open skin. We analyzed the type of intervention: 1. Conservative approach, 2. Incomplete extraction, 3. Complete extraction. The endpoints were the needing a later intervention and a complete removal during follow up. Results: The group of patients with complete system extraction showed a lower rate of reintervention during an average follow up of 1000 days, when compared to other two groups (6.7% vs. 57.7 and 43.8%, P<.01). Incomplete extraction and conservative approach had a similar outcome, needing a complete extraction 25% and 37.5%, respectively. The skin integrity did not seem to be relevant for outcome in these two groups. An 8.4% incidence of endocarditis was observed; all of them had a previous history of incomplete extraction or conservative approach. Conclusions: Local complications treated with either a conservative approach or incomplete extraction are associated with a high rate of re-interventions, regardless of skin integrity, frequently needing final complete extraction and are associated to endocarditis.
Assuntos
Humanos , Desfibriladores Implantáveis/efeitos adversos , Marca-Passo Artificial/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos RetrospectivosRESUMO
INTRODUCTION AND OBJECTIVES: Although electro- physiological databases contain information about changes in the time domain in lesions produced by radiofrequency ablation, very few data on changes in the frequency domain are available. The aim of this study was to investigate changes in the spectral characteristics of ventricular fibrillation in zones with radiofrequency lesions. METHODS: Recordings of ventricular fibrillation were obtained in 11 isolated perfused rabbit heart preparations using a multiple epicardial electrode located on the left ventricular free wall. Spectral parameters derived by Fourier analysis before and after the creation of transmural radiofrequency lesions were compared. RESULTS: In the ablated zones, significant reductions were observed in the spectral density of the dominant (0.168+/-0.113 mV(2)/Hz vs 0.025+/-0.018 mV(2)/Hz; P< .001) and mean frequencies (0.053+/-0.057 mV(2)/Hz vs 0.012+/-0.016 mV(2)/Hz; P< .001), the normalized energy around the dominant frequency (0.860+/-0.570 vs 0.128+/-0.091; P< .001), and the standard deviation of the power spectrum (0.031+/-0.020 mV(2)/Hz vs 0.004+/-0.001 mV(2)/Hz; P< .001). There was no significant change in the dominant (16.2+/-5.6 vs 14.8+/-1.8 Hz) or mean frequency (17.7+/-3.4 vs 16.6+/-1.3 Hz). The spectral parameters that could be used in a multivariate model to identify the lesion were the standard deviation of the power spectrum and the spectral density of the mean frequency. CONCLUSIONS: During ventricular fibrillation, the spectral parameters associated with spectral power and spectral energy were significantly altered in zones with radiofrequency lesions and could be used to identify those zones. There was no significant change in either the dominant or mean frequency in these zones.
Assuntos
Ablação por Cateter/efeitos adversos , Ventrículos do Coração/lesões , Ventrículos do Coração/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Fibrilação Ventricular/cirurgia , Animais , Técnicas In Vitro , CoelhosRESUMO
It is known that the effect of flecainide on longitudinal and transverse ventricular conduction velocities depends on the coupling interval. If this is so, whether the longitudinal or transverse direction is predominantly affected could depend on the magnitude of the coupling interval. In order to investigate this hypothesis, we studied the effect of flecainide, 1 micromol/L, on conduction velocities in excised heart preparations from 11 rabbits using a basal cycle length of 250 ms and inserting two extrastimuli at a decreasing coupling interval. Flecainide significantly reduced both conduction velocities. However, the effect increased as the coupling interval decreased for only the longitudinal velocity. At long coupling intervals, flecainide produced a greater reduction in transverse than longitudinal velocity, whereas, at short intervals, both velocities were affected similarly.
Assuntos
Antiarrítmicos/farmacologia , Flecainida/farmacologia , Sistema de Condução Cardíaco/efeitos dos fármacos , Coração/efeitos dos fármacos , Coração/fisiologia , Função Ventricular/efeitos dos fármacos , Animais , CoelhosRESUMO
INTRODUCTION AND OBJECTIVES: The aim of this study was to examine the hypothesis that the recording mode (i.e., unipolar or bipolar) affects the information obtained using spectral analysis techniques during ventricular fibrillation by carrying out an experiment using epicardial electrodes. METHODS: Recordings of ventricular fibrillation were obtained in 29 isolated rabbit hearts using a multiple-electrode probe located on the left ventricular free wall. The parameter values obtained in the frequency domain (by Fourier analysis) using unipolar or bipolar electrodes, different interelectrode distances, and different orientations (i.e., horizontal, vertical or diagonal) were compared. RESULTS: Changing the recording mode (i.e., unipolar to bipolar) or the interelectrode distance significantly altered the mean frequency (P< .0001) and the normalized energy of the spectrum (+/-1 Hz) around the dominant frequency (P< .05), though the changes were small relative to the dominant frequency. Cross-spectral analysis showed that the coherence between unipolar recordings decreased as the interelectrode distance increased, while the opposite occurred with the coherence between unipolar and bipolar recordings. The two coherences were inversely correlated such that the greater the former coherence, the less the coherence between unipolar and bipolar recordings (r=0.29; P< .0001; n=348). CONCLUSIONS: The recording mode (i.e., unipolar or bipolar) used influenced the information obtained using spectral analysis techniques from epicardial recordings of ventricular fibrillation. Differences were observed in the mean frequency and in the frequency distribution, but they were very small relative to the dominant frequency.
Assuntos
Eletrocardiografia/métodos , Fibrilação Ventricular/fisiopatologia , Animais , Eletrocardiografia/instrumentação , Eletrodos Implantados , Técnicas Eletrofisiológicas Cardíacas/métodos , Ventrículos do Coração/fisiopatologia , Pericárdio/fisiopatologia , CoelhosRESUMO
BACKGROUND: Few experimental studies have analyzed the effects of selective radiofrequency (RF) lesions upon ventricular fibrillation (VF). The RF-induced isolation of selected zones would make it possible to determine whether these zones are essential for existence of the arrhythmia. METHODS: In 31 Langendorff-perfused rabbit hearts, the characteristics and inducibility of VF were analyzed before and after the induction of RF lesions comprising: (1) the posterior zone of the septum and of the walls of both ventricles (n = 10); (2) the anterior zone of the septum and of the walls of both ventricles (n = 11); and (3) the midseptal zone (n = 10). RESULTS: Complete isolation of the zone encompassed by the lesions was obtained in 5, 6, and 5 experiments of series 1, 2, and 3, respectively. In these experiments, the arrhythmia was only induced from within the zone encompassed by the lesions in one experiment belonging to series 2 (P < 0.05 with respect to baseline). In contrast, in all but one of the cases in series 2, VF could be induced from outside the isolated zone (ns vs baseline). Partial isolation was obtained in five experiments of each series. In these experiments, on pacing from within the partially isolated zone, sustained VF was not induced in any experiment (P < 0.05 with respect to baseline), while in all cases VF could be induced on pacing from the external zone (ns vs baseline). CONCLUSION: In the experimental model used, the three zones studied were not essential for maintaining VF. In most cases, their partial or total isolation avoided inducibility of the arrhythmia in those zones, though not in the remaining myocardium.
Assuntos
Mapeamento Potencial de Superfície Corporal , Ablação por Cateter , Sistema de Condução Cardíaco/fisiopatologia , Sistema de Condução Cardíaco/cirurgia , Fibrilação Ventricular/fisiopatologia , Fibrilação Ventricular/cirurgia , Animais , CoelhosRESUMO
Polymorphic ventricular tachycardia and ventricular fibrillation are the most common arrhythmias in Brugada syndrome, causing syncope or sudden death. Sustained monomorphic ventricular tachycardias are rare in this context. We report the case of a 41-year-old man with repetitive syncopal episodes and an ajmaline-induced characteristic Brugada ECG pattern, in whom episodes of monomorphic ventricular tachycardia with pleomorphism and response to ventricular pacing were documented.
Assuntos
Síndrome de Brugada/fisiopatologia , Eletrocardiografia , Marca-Passo Artificial , Síncope/fisiopatologia , Taquicardia Ventricular/fisiopatologia , Adulto , Síndrome de Brugada/complicações , Síndrome de Brugada/terapia , Humanos , Masculino , Síncope/complicações , Síncope/terapia , Taquicardia Ventricular/complicações , Taquicardia Ventricular/terapiaRESUMO
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.