RESUMO
INTRODUCTION: Mitral valve surgery employing a superior transseptal approach (STA) is associated with arrhythmogenicity and intra-atrial conduction delay, despite being optimal for visualization of the surgical field. It is sometimes difficult to treat atrial tachycardias (AT) that arise after STA. To investigate AT circuits that arise after STA in detail in order to identify the optimal ablation line, using ultra-high-resolution mapping (UHRM). METHODS: We retrospectively analyzed 12 AT from 10 patients (median age 70 years, nine males) who had undergone STA surgery. The tachycardias were mapped using the Rhythmia mapping system (Boston Scientific, Natick, Massachusetts). RESULTS: The 12 STA-related AT (STA-AT) circuits were classifiable as follows according to location of the optimal ablation line: (1) peri-septal incision STA-AT (n = 3), (2) cavotricuspid isthmus (CTI) dependent STA-AT (n = 7), and (3) biatrial tachycardia (n = 2). Radiofrequency (RF) application terminated 11 of the 12 STA-AT. We found that difference in STA-AT circuit type was due to characteristics of the septal incision line made for STA. UHRM was important in identifying optimal ablation sites that did not create additional conduction disturbances in the right atrium (RA). CONCLUSIONS: ATs after STA involve complex arrhythmia circuits due to multiple and long incision lines in the RA. Accurate understanding of the arrhythmia circuit and sinus conduction in the RA after STA is recommended for treating post-surgical tachycardia in a minimally invasive manner.
Assuntos
Bloqueio Atrioventricular , Ablação por Cateter , Taquicardia Supraventricular , Idoso , Arritmias Cardíacas/cirurgia , Bloqueio Atrioventricular/cirurgia , Técnicas Eletrofisiológicas Cardíacas , Humanos , Masculino , Valva Mitral/cirurgia , Estudos Retrospectivos , Taquicardia , Taquicardia Supraventricular/etiologia , Taquicardia Supraventricular/prevenção & controle , Taquicardia Supraventricular/cirurgia , Resultado do TratamentoAssuntos
Bloqueio Atrioventricular/diagnóstico , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Adenosina/administração & dosagem , Idoso de 80 Anos ou mais , Antiarrítmicos/administração & dosagem , Bloqueio Atrioventricular/cirurgia , Ablação por Cateter , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Humanos , Masculino , Taquicardia por Reentrada no Nó Atrioventricular/cirurgiaRESUMO
Background: The biological behaviour and clinical significance of mercury toxicity vary according to its chemical structure. Mercury differs in its degree of toxicity and in its effects on the nervous, digestive and immune systems as well as on organs such as the lungs, kidneys, skin, eyes and heart. Human exposure occurs mainly through inhalation of elemental mercury vapours during industrial and artisanal processes such as artisanal and small-scale gold mining. Case presentation: A 52-years-old female, housewife, with a body mass index of 25.3 kg/cm², without smoking or alcohol habits or any important clinical or chronic cardiovascular history, was admitted to the emergency room due to probable accidental poisoning by butane gas. Clinical manifestations with a headache, dizziness, cough, and dyspnoea of medium to small efforts. An initial physical exploration with Glasgow scored at 15, with arrhythmic heart sounds, pulmonary fields with bilateral subcrepitant rales and right basal predominance. Electrocardiographic findings were as follows: a cardiac frequency of 50 beats per minute and atrioventricular dissociation. Laboratory parameters were: white blood cells at 15.8 × 108/L; aspartate aminotransferase at 38 U/L; lactate dehydrogenase at 1288 U/L; creatine-kinase at 115 U/L; CK-MB fraction at 28 U/L; and other biochemical parameters were within the reference values. A radiographic evaluation showed flow cephalization, diffuse bilateral infiltrates with right basal predominance. In addition, the patient presented data of low secondary expenditure to third-degree atrioventricular (AV) block for which the placement of a transvenous pacemaker was decided, substantially improving the haemodynamic parameters. Subsequently, after a family interrogation, the diagnosis of mercury inhalation poisoning was established. An initial detection of mercury concentration (Hg(0)) was carried out, reporting 243.5 µg/L. In view of this new evidence, mercury chelation therapy with intravenous calcium disodium ethylenediamine tetraacetic acid (CaNa2·EDTA) was initiated. After 8-days of hospital stay, she presented a favourable evolution with both clinical and radiological improvements, so that the mechanical ventilation progressed to extubating. Subsequently, she was referred for cardiology because of her persistent 3rd-degree atrioventricular block, deciding to place a definitive bicameral pacemaker. The patient was discharged from the hospital 14 days after admission due to clinical improvements with mercury plasma levels at 5 µmol/L and a heart rhythm from the pacemaker. Conclusions: We show evidence that acute exposure to elemental mercury can affect the heart rhythm, including a complete atrioventricular blockage.
Assuntos
Bloqueio Atrioventricular/etiologia , Intoxicação por Mercúrio/complicações , Bloqueio Atrioventricular/cirurgia , Feminino , Humanos , Mercúrio/análise , Pessoa de Meia-Idade , Marca-Passo ArtificialRESUMO
In patients with unexplained cardiomyopathy, electroanatomical mapping can identify abnormal tissue to target during electrophysiology-guided endomyocardial biopsy (EP-guided EMB). The objective of this study is to determine whether catheter ablation performed in the same setting as EP-guided EMB increases procedural risk. Sixty-seven patients (mean age 54.4 ± 13.8, 57% male) undergoing EP-guided EMB were included. Radiofrequency catheter ablation was performed in 17 patients (25%) for ventricular arrhythmias and in 2 (3%) for typical atrial flutter. Femoral arterial access was obtained in 90% ablation patients and 40% biopsy-only patients; vascular access complications were more common in the ablation group than in the EMB-only group (p = 0.02). There were no significant differences in rate of tricuspid regurgitation, thromboembolism, or pericardial effusion, whether procedural anticoagulation was used. In conclusion, catheter ablation and procedural anticoagulation can be combined with EP-guided EMB with an increased risk of vascular access complications, but no significant increase in intracardiac complications.
Assuntos
Arritmias Cardíacas/patologia , Biópsia/métodos , Cardiomiopatias/patologia , Ablação por Cateter/métodos , Endocárdio/patologia , Miocardite/patologia , Miocárdio/patologia , Sarcoidose/patologia , Adulto , Idoso , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/cirurgia , Flutter Atrial/etiologia , Flutter Atrial/patologia , Flutter Atrial/cirurgia , Bloqueio Atrioventricular/patologia , Bloqueio Atrioventricular/cirurgia , Cardiomiopatias/complicações , Técnicas Eletrofisiológicas Cardíacas , Endocárdio/cirurgia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miocardite/complicações , Complicações Pós-Operatórias/epidemiologia , Sarcoidose/complicações , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/patologia , Taquicardia Ventricular/cirurgia , Complexos Ventriculares Prematuros/etiologia , Complexos Ventriculares Prematuros/patologia , Complexos Ventriculares Prematuros/cirurgiaAssuntos
Feixe Acessório Atrioventricular , Potenciais de Ação , Bloqueio Atrioventricular/fisiopatologia , Bloqueio Cardíaco/congênito , Frequência Cardíaca , Taquicardia Supraventricular/fisiopatologia , Técnicas de Ablação , Bloqueio Atrioventricular/diagnóstico por imagem , Bloqueio Atrioventricular/cirurgia , Estimulação Cardíaca Artificial , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Feminino , Bloqueio Cardíaco/diagnóstico , Bloqueio Cardíaco/fisiopatologia , Bloqueio Cardíaco/cirurgia , Humanos , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/cirurgia , Fatores de Tempo , Adulto JovemRESUMO
BACKGROUND: Although multiple approaches have been used to create biological pacemakers in animal models, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) have not been investigated for this purpose. We now report pacemaker function of iPSC-CMs in a canine model. METHODS AND RESULTS: Embryoid bodies were derived from human keratinocytes, their action potential characteristics determined, and their gene expression profiles and markers of differentiation identified. Atrioventricular blocked dogs were immunosuppressed, instrumented with VVI pacemakers, and injected subepicardially into the anterobasal left ventricle with 40 to 75 rhythmically contracting embryoid bodies (totaling 1.3-2×106 cells). ECG and 24-hour Holter monitoring were performed biweekly. After 4 to 13 weeks, epinephrine (1 µg kg-1 min-1) was infused, and the heart removed for histological or electrophysiological study. iPSC-CMs largely lost the markers of pluripotency, became positive for cardiac-specific markers. and manifested If-dependent automaticity. Epicardial pacing of the injection site identified matching beats arising from that site by week 1 after implantation. By week 4, 20% of beats were electronically paced, 60% to 80% of beats were matching, and mean and maximal biological pacemaker rates were 45 and 75 beats per minute. Maximum night and day rates of matching beats were 53±6.9 and 69±10.4 beats per minute, respectively, at 4 weeks. Epinephrine increased rate of matching beats from 35±4.3 to 65±4.0 beats per minute. Incubation of embryoid bodies with the vital dye, Dil, revealed the persistence of injected cells at the site of administration. CONCLUSIONS: iPSC-CMs can integrate into host myocardium and create a biological pacemaker. Although this is a promising development, rate and rhythm of the iPSC-CMs pacemakers remain to be optimized.
Assuntos
Bloqueio Atrioventricular/cirurgia , Relógios Biológicos , Diferenciação Celular , Frequência Cardíaca , Células-Tronco Pluripotentes Induzidas/transplante , Miócitos Cardíacos/transplante , Transplante de Células-Tronco , Potenciais de Ação , Animais , Bloqueio Atrioventricular/metabolismo , Bloqueio Atrioventricular/fisiopatologia , Estimulação Cardíaca Artificial , Linhagem Celular , Modelos Animais de Doenças , Cães , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Perfilação da Expressão Gênica/métodos , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Miócitos Cardíacos/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Recuperação de Função Fisiológica , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Fatores de Tempo , Transcriptoma , TransfecçãoRESUMO
AIMS: In patients with severe neurally mediated syncope (NMS), radiofrequency catheter ablation (RFA) of ganglionic plexi (GP) has been proposed as a new therapeutic approach. Cardio-inhibitory response during NMS is usually related to the sinoatrial (SA) and less frequently to atrioventricular (AV) node. Differential effect of GP ablation on SA and AV node is poorly understood. METHODS AND RESULTS: We report a case of a 35-year-old female with frequent symptomatic episodes of advanced AV block treated by anatomically guided RFA at empirical sites of GPs. After RFA at the septal portion of the right atrium-superior vena cava junction, heart rate accelerated from 62 to 91 beats/min and PR interval prolonged from 213 to 344 ms. Sustained first-degree AV block allowed to observe directly the effects of subsequent RFA on the AV nodal properties. Subsequent RFA at right- and left-sided aspects of the inter-atrial septum had no further effect on heart rate and PR interval. Ablation at the inferior left GP was critical for restoration of normal AV conduction (final PR interval of 187 ms). No bradycardia episodes were observed by implantable loop recorder during the follow-up of 10 months and the patient was symptomatically improved. CONCLUSION: This is the first clinical case showing the differential effect of GP ablation on SA and AV nodal function, and critical importance of targeting the GP at the postero-inferior left atrium. The successful procedure corroborates clinical utility of ablation treatment instead of pacemaker implantation in selected patients with cardio-inhibitory NMS.
Assuntos
Bloqueio Atrioventricular/cirurgia , Nó Atrioventricular/fisiopatologia , Denervação Autônoma/métodos , Ablação por Cateter , Gânglios Autônomos/cirurgia , Nó Sinoatrial/fisiopatologia , Síncope Vasovagal/cirurgia , Potenciais de Ação , Adulto , Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/fisiopatologia , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Feminino , Gânglios Autônomos/fisiopatologia , Frequência Cardíaca , Humanos , Recidiva , Índice de Gravidade de Doença , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/fisiopatologia , Fatores de Tempo , Resultado do TratamentoRESUMO
AIMS: Asymptomatic nocturnal long ventricular pauses are usually detected accidentally and it has been suggested that they may lead to sudden death. Identification of predisposing factors could prevent cardiovascular events. METHODS AND RESULTS: We report the case of a patient with frequent asymptomatic nocturnal ventricular pauses of 3-11 s, characteristic of a vagally mediated atrioventricular (AV) block. Echocardiography, treadmill test, thyroid function test levels, and polysomnogram were normal. In an attempt to reduce the risk, it was decided that an atrial vagal denervation induced by radiofrequency (RF) ablation (cardioneuroablation) could be useful. Spectral mapping was used to localize endocardial vagal innervation in the right and left aspects of the inter-atrial septum, responsible for the sinus node and AV node modulation, and RF pulses were applied in those sites only. After finishing the procedure, significant changes were observed in the heart rate (66-90 b.p.m.), atrial-His interval (115-74 ms), Wenckebach cycle length (820-570 ms), and sinus node recovery time (1100-760 ms). Follow-up Holter recording demonstrated that the number of ventricular pauses had reduced from 438 to 0. Heart rate and time domain characteristics were compatible with vagal denervation. CONCLUSION: Ablation of the endocardial vagal innervation sites seems to be safe and efficient in reducing the frequency and the length of the ventricular pauses. It was possible by identifying certain spectral components of the atrial electrogram, resulting in a conservative approach.
Assuntos
Bloqueio Atrioventricular/cirurgia , Ablação por Cateter , Técnicas Eletrofisiológicas Cardíacas , Endocárdio/inervação , Átrios do Coração/inervação , Processamento de Sinais Assistido por Computador , Vagotomia/métodos , Nervo Vago/cirurgia , Potenciais de Ação , Adulto , Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/fisiopatologia , Eletrocardiografia Ambulatorial , Frequência Cardíaca , Humanos , Masculino , Valor Preditivo dos Testes , Fatores de Tempo , Resultado do Tratamento , Nervo Vago/fisiopatologiaRESUMO
BACKGROUND: For patients presenting with syncope and bundle branch block (BBB), results during electrophysiological studies (EPS) might depend on the electrocardiographic pattern of conduction disturbances. We sought to identify predictors of advanced His-Purkinje conduction disturbances (HPCDs) in these patients. METHODS: In this retrospective multicentre study, patients were included who: (1) presented with unexplained syncope; (2) had BBB (QRS duration ≥ 120 ms); and (3) were investigated with EPS. HPCD was diagnosed if the baseline His-ventricular interval was ≥ 70 ms or if second- or third-degree His-Purkinje block was observed during atrial pacing or pharmacological challenge. RESULTS: Of the 171 patients studied (72 ± 13 years, 64% male sex, mean left ventricular ejection fraction 57 ± 9%), advanced HPCD was found in 73 patients (43%). The following electrocardiographic features were associated with HPCD (P = 0.01): isolated right BBB (34.4%), right BBB with left anterior fascicular block (36.4%), left BBB (46.2%), and right BBB with left posterior fascicular block (LPFB, 78.6%). Multivariate analysis identified first-degree atrioventricular block (odds ratio, 2.4; 95% confidence interval, 1.2-4.7; P = 0.01) and LPFB (odds ratio, 4.8; 95% confidence interval, 1.3-18.5; P = 0.02) as the only 2 independent predictors of advanced HPCD. CONCLUSIONS: For patients presenting with syncope and BBB, first-degree atrioventricular block and LPFB increased the likelihood of finding HPCDs during EPS. However, no single electrocardiographic feature could consistently predict the outcome of EPS, so this investigation is still necessary in assessing the need for pacemaker implantation, irrespective of the precise appearance of abnormalities on ECG.
Assuntos
Fascículo Atrioventricular/fisiopatologia , Bloqueio de Ramo/fisiopatologia , Técnicas Eletrofisiológicas Cardíacas , Ramos Subendocárdicos/fisiopatologia , Síncope/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Bloqueio Atrioventricular/classificação , Bloqueio Atrioventricular/fisiopatologia , Bloqueio Atrioventricular/cirurgia , Bloqueio de Ramo/diagnóstico , Bloqueio de Ramo/cirurgia , Desfibriladores Implantáveis , Eletrocardiografia , Feminino , Humanos , Masculino , Análise Multivariada , Marca-Passo Artificial , Estudos Retrospectivos , Volume Sistólico/fisiologiaAssuntos
Bloqueio Atrioventricular/cirurgia , Ablação por Cateter , Sistema de Condução Cardíaco/cirurgia , Complexos Ventriculares Prematuros/cirurgia , Idoso , Bloqueio Atrioventricular/diagnóstico , Bloqueio Atrioventricular/fisiopatologia , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Humanos , Resultado do Tratamento , Complexos Ventriculares Prematuros/diagnóstico , Complexos Ventriculares Prematuros/fisiopatologiaRESUMO
BACKGROUND: To identify and understand clinically encountered pitfalls in the assessment of transmitral conduction block using differential coronary sinus and left atrial appendage pacing techniques in patients with left mitral isthmus linear ablation. METHODS AND RESULTS: All the available assessments of mitral isthmus block were thoroughly reviewed in 271 mitral isthmus ablation procedures undertaken among 236 patients from October 2008 to April 2011. Bidirectional block was established in 186 of 271 (69%) procedures. Careful evaluation of electrograms recorded on the multipolar coronary sinus and ablation catheters was undertaken to identify and understand the characteristics of pitfall, if any. Pitfall was encountered in 55 of 271 (20%) procedures among 51 patients and categorized into 6 types (types 1, 3, 4, and 5 led to spurious diagnosis of block; types 2 and 6 led to erroneous diagnosis of absence of block). There were 14, 10, 17, 2, 15, and 3 (total=61) cases of pitfall types 1 through 6, respectively. Operator recognized 42 of 61 (69%) pitfalls intraprocedurally. Recognition of types 1 and 5 was difficult because of indiscernible electrograms at usual amplifier settings or presence of slow conduction mimicking block. CONCLUSIONS: Every fifth assessment of bidirectional block across mitral isthmus linear lesion using differential coronary sinus and left atrial appendage pacing techniques encounters a pitfall, which can lead to erroneous clinical diagnosis of block or absence of block. Recognition of pitfall during the procedure is feasible and necessitates careful distinction of far-field left atrium from the local coronary sinus electrograms besides appropriate adjustments in catheter position and pacing outputs.