Objetivo. Verificar se as características espectrais dos eletrogramas atriais (EgA) em ritmo sinusal (RS) se correlacionam com a presença de gânglios parassimpáticos cardíacos. Materiais e Resultados. Treze pacientes encaminhados para submeter-se a ablação de fibrilação atrial (FA) foram incluídos de forma prospectiva. Previamente ao início da ablação, realizou-se o registro de EgA em RS em uma série de regiões anatômicas pré-determinadas, seguindo-se uma ordem sequencial. Em seguida, aplicou-se estímulos elétricos de alta frequência (20 Hz de frequência, amplitude de 100 V e duração de pulso de 4 ms), nos mesmos locais. Uma resposta vagal evocada foi definida como um súbito aumento no intervalo RR ou a indução de bloqueio na condução átrio-ventricular imediatamente após a aplicação do estímulo de alta-frequência (EAF). Procedeu-se à análise espectral dos sinais atriais em RS registrados, com amostragem de 1000 Hz, janela Hanning. No total, 1488 EgA oriundos de 186 locais anatômicos foram registrados, sendo 129 de regiões com resposta vagal negativa e 57 correspondentes a regiões de resposta vagal positiva. A duração do eletrograma e o número de deflecções foram similares nos pontos com resposta vagal positiva e negativa. A densidade de potência espectral em locais de resposta vagal positiva, no entanto, foi menor entre 26 e 83 Hz, e maior entre 107 e 200 Hz, comparados com os locais de resposta negativa. A área sobre a curva entre 120 e 170 Hz normalizada para a área total do espectro foi testada como um novo parâmetro diagnóstico. A análise de curva ROC demonstrou que o valor area 120-170 / area total > 0,14 foi capaz de identificar locais de inervação vagal com sensibilidade de 70,9% e especificidade de 72,1%. Conclusão. A análise espectral de sinais atriais durante RS é um método factível e simples de mapear os locais de inervação parassimpática cardíaca, sem a necessidade de qualquer tipo de estimulação / Objective. To verify whether spectral components of atrial electrograms (AE) during sinus rhythm (SR) correlate with cardiac ganglionated plexus (GP) sites. Methods and Results. Thirteen patients undergoing atrial fibrillation (AF) ablation were prospectively enrolled. Prior to radio frequency application, endocardial AE were recorded with a sequential point-by-point approach. Electrical stimuli were delivered at 20 Hz, amplitude 100 V, and pulse width of 4 msec. A vagal response was defined as a high-frequency stimulation (HFS) evoked AV block or a prolongation of RR interval. Spectral analysis was performed on single AE during SR, sampling rate of 1000 Hz, Hanning window. Overall, 1488 SR electrograms were analyzed from 186 different left atrium sites, 129 of them corresponding to negative vagal response sites and 57 to positive response sites. The electrogram duration and the number of deflections were similar in positive and negative response sites. Spectral power density of sites with vagal response was lower between 26 and 83 Hz and higher between 107 and 200 Hz compared with negative response sites. The area between 120 and 170 Hz normalized to the total spectrum area was tested as a diagnostic parameter. ROC curve analysis demonstrated that an area 120-170 / area total value > 0,14 identified vagal sites with 70,9% sensitivity and 72,1% specificity. Conclusions. Spectral analysis of AE during SR is feasible and simple method of mapping the cardiac autonomic nervous system (ANS), with no stimulation required

A fibrilação atrial (FA) é a arritmia mais comum no pós-operatório de cirurgia cardíaca. Apesar de estar relacionada a alterações estruturais, alguns pacientes, mesmo que sem tais condições, ainda assim, cursam com fibrilação atrial no pós-operatório (FAPO) causando aumento no tempo de internação e custos. Estudos recentes vem ampliando o conhecimento sobre pequenos fragmentos de RNA, chamados de microRNAs (miRNAs) que podem interferir diretamente no aparecimento de algumas doenças na área cardiovascular. O objetivo do presente estudo é: 1) comparar a expressão dos miRNAs 1, 23 e 26 entre pacientes com e sem FAPO; 2) comparar nos grupos a expressão destes miRNAs entre os período pré e pós-cirúrgico; 3)comparar a expressão dos genes GJA1, KCNJ2, CACNB1, CACNA1C e KCNN3 entre os tempos pré e pós-cirúrgico no grupo FAPO; 4) comparar estes últimos genes no tecido atrial; 5) comparar os genes relacionados à produção de interleucinas (IL)-1, 6 e fator de necrose tumoral alfa (TNF?) entre os grupos e entre os tempos pré e pós-cirúrgico; 6)avaliar as características clínicas e evolutivas da população estudada. Pacientes submetidos à cirurgia de revascularização miocárdica foram submetidos à coleta de 20ml de sangue pré e pós-cirurgia bem como fragmento de tecido atrial. Um total de 143 pacientes compuseram os grupos: FAPO (24 pacientes), controle genético (24 pacientes) e controle total (97 pacientes + 24 grupo controle genético). Do ponto de vista clínico observou-se maior idade, tempo de anóxia, tempo de internação em terapia intensiva e hospitalar no grupo FAPO. A análise genética revelou menor expressão do miRNA-23 no grupo FAPO (p=0,02). A comparação entre os períodos pré e pós-cirúrgico revelou redução dos três miRNAs no tempo pós-cirúrgico (p<0,05) e dos genes relacionados às proteínas de canal (p<0,05). A comparação no tecido não evidenciou alterações entre os grupos. Os genes relacionados ás citocinas revelaram redução no período pós-cirúrgico (p<0,05) em ambos os grupos. Concluiu-se que o miRNA-23 pode ter implicação no surgimento da FAPO e outros miRNAs não estudados devem estar envolvidos neste processo uma vez que houve redução de outros genes de canais relacionados ao aparecimento de FAPO. / Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery. AF is related to cardiac structural changes although a group of patients still remains developing post-operative atrial fibrillation (FAPO) even without those changes, leading to more days in the hospital and costs. Recent studies showed that short fragments of RNA, called microRNA (miRNA) can contribute to the development of several diseases in the cardiovascular area. The aim of this study is to 1) compare the expression of miRNA-1, 23 and 26 between the group with and without FAPO; 2) compare, in the FAPO group, the expression of these miRNAs in the pre and post-surgery periods; 3) compare the expression of GJA1, KCNJ2, CACNB1, CACNA1C e KCNN3 genes between the pre and post-surgery periods; 4) compare this genes in atrial tissue; 5) compare the genes related to inflammation cytokines as interleukin(IL)-1, 6 and alpha tumoral necrosis factor between the groups in the pre and post-surgery periods; 6) evaluate clinical and evaluative patterns of the study population. Twenty milliliters of blood samples in the pre and post-operative periods and an atrial fragment were extracted from patients submitted to coronary artery bypass graft surgery. A total of 143 patients were divided in the FAPO group (24 patients), genetic control group (24 patients) and a total control (97 + 24 genetic control patients). The clinical analysis showed bigger age and clamp-time, more days in the intensive care unit and hospital in the FAPO group. The genetic analysis revealed less expression of miRNA-23 in the FAPO group (p=0.02). The comparison between the pre and post-surgery periods showed reduction in the three studied miRNAs (p<0.05) and reduction in the genes related to the production of the membrane protein channel sites. The comparisons in the atrial tissue didn´t show any difference in the study groups. The cytokines showed post-surgery reduction (p<0.05) in both groups. The conclusion is that miRNA-23 can be implicated in FAPO as others miRNAs not studied can also be, once there was a significative reduction in the genes related to FAPO development.

Introdução: A miocardiopatia hipertrófica é a mais frequente doença cardiovascular de origem genética e está associada a arritmias e morte cardiovascular. O aumento do átrio esquerdo e a fibrilação atrial são considerados marcadores de morte por insuficiência cardíaca em pacientes com miocardiopatia hipertrófica. A apneia obstrutiva do sono é o distúrbio respiratório do sono mais comum, caracterizando-se por episódios recorrentes de colapso parcial ou total das vias aéreas superiores durante o sono. A apneia obstrutiva do sono é muito prevalente entre as populações com doença cardiovascular, como hipertensão arterial e insuficiência cardíaca, e está associada a remodelamento cardíaco e arritmias. Objetivos: O objetivo deste estudo foi determinar a prevalência dos distúrbios respiratórios do sono em pacientes com miocardiopatia hipertrófica e avaliar a associação da apneia obstrutiva do sono com o remodelamento cardíaco (ventricular e atrial) e fibrilação atrial em pacientes com miocardiopatia hipertrófica. Métodos: Foram estudados pacientes consecutivos estáveis clinicamente, com um diagnóstico confirmado de miocardiopatia hipertrófica acompanhados no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Os pacientes foram submetidos à avaliação clínica, questionário de sonolência, bioquímica sanguínea, ecocardiograma e monitorização respiratória noturna com poligrafia portátil. Foi utilizado um valor de corte de 15 e 30 apneias e hipopneias por hora de registro para o diagnóstico de apneia obstrutiva do sono e apneia obstrutiva do sono grave, respectivamente. Resultados: Foram avaliados 80 pacientes consecutivos com miocardiopatia hipertrófica. Apneia obstrutiva do sono foi diagnosticada em 32 pacientes (40%). Apneia obstrutiva do sono grave esteve presente em 17 pacientes (21%). Pacientes com apneia obstrutiva do sono foram significativamente mais velhos (56 [41-64] vs. 39 [30-53] anos, p < 0,001), apresentaram maior índice de massa corporal (28,2 ± 3,5 vs. 25,2 ± 5,2 Kg/m2, p < 0,01), maior dimensão do átrio esquerdo (45 [42-53] vs. 41 [39-47] mm, p = 0.01) e maior diâmetro da aorta (34 [30-37] vs. 29 [28-32] mm, p < 0,001) em comparação com pacientes sem apneia obstrutiva do sono. Dois modelos de regressão linear múltipla para identificar os fatores associados ao aumento do átrio esquerdo e da aorta ascendente mostraram que o índice de apneia e hipopneia foi a única variável associada ao aumento atrial (p = 0,05) e da aorta (p = 0,01), respectivamente. A fibrilação atrial permanente esteve presente em 31% vs. 6% dos pacientes com e sem apneia obstrutiva do sono, respectivamente (p < 0,01). A apneia obstrutiva do sono (p = 0,03) e o diâmetro do átrio esquerdo (p = 0,03) foram os únicos fatores independentemente associados à fibrilação atrial em um modelo multivariado. Conclusão: A apneia obstrutiva do sono é muito prevalente em pacientes com miocardiopatia hipertrófica e está associada com aumento do átrio esquerdo e da aorta ascendente. A apneia obstrutiva do sono está independentemente associada à fibrilação atrial, um fator de risco para óbito cardiovascular nesta população / Background: Hypertrophic cardiomyopathy is the most common genetic cardiovascular disease and is associated with arrhythmias and cardiovascular death. Left atrial enlargement and atrial fibrillation are considered markers for death due to heart failure in patients with hypertrophic cardiomyopathy. Obstructive sleep apnea is the most common sleep disordered breathing and is characterized by recurrent episodes of partial or complete collapse of the upper airway during sleep. Obstructive sleep apnea is extremely prevalent among populations with cardiovascular disease, such as systemic hypertension and heart failure and is independently associated with heart remodelling and arrhythmias. Objectives: The aim of this study was to determine the prevalence of sleep disordered breathing in consecutive patients with hypertrophic cardiomyopathy and evaluate the association of obstructive sleep apnea with heart remodelling (ventricular and atrial) and with atrial fibrillation in patients with hypertrophic cardiomyopathy. Methods: We studied consecutive clinically stable patients with a confirmed diagnosis of hypertrophic cardiomyopathy followed in the Heart Institute Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, by clinical evaluation, sleep questionnaire, biochemical blood analysis, echocardiography and sleep study (overnight portable respiratory monitoring). We used a cut-off value of 15 and 30 apneas and hypopneas per hour of recording in the sleep study for the diagnosis of obstructive sleep apnea and severe obstructive sleep apnea, respectively. Results: We evaluated 80 consecutive patients with hypertrophic cardiomyopathy. Obstructive sleep apnea was present in 32 patients (40%). Severe obstructive sleep apnea was present in 17 patients (21%). Patients with obstructive sleep apnea were significantly older (56 [41-64] vs. 39 [30-53] years, p < 0.001), presented higher body mass index (28.2 ± 3.5 vs. 25.2 ± 5.2 Kg/m2, p < 0.01), increased left atrial diameter (45 [42-53] vs. 41 [39-47] mm, p = 0.01) and aorta diameter (34 [30-37] vs. 29 [28-32] mm, p < 0.001) compared with patients without obstructive sleep apnea. Two models of stepwise multiple linear regression to identify variables associated with left atrial and ascending aorta enlargement showed that apnea-hypopnea index was the only variable associated with left atrial enlargement (p = 0.05) and aorta diameter (p = 0.01), respectively. Permanent atrial fibrillation was present in 31% vs. 6% in patients with and without obstructive sleep apnea, respectively (p < 0.01). Obstructive sleep apnea (p = 0.03) and left atrial diameter (p = 0.03) were the only factors independently associated with atrial fibrillation in a multivariate model. Conclusions: Obstructive sleep apnea is highly prevalent in patients with hypertrophic cardiomyopathy and it is associated with left atrial and ascending aorta enlargement. Obstructive sleep apnea is independently associated with atrial fibrillation, a risk factor for cardiovascular death in this population

<p>Atrial fibrillation is a common disease. With pharmacological therapy most patients with atrial fibrillation have moderate or little symptoms, but a number of patients have severely symptomatic disease. This study evaluates two new non-pharmacological therapies for atrial fibrillation, the Maze procedure and atrial overdrive pacing.</p><p>In the patients planned for Maze surgery the quality of life, assessed with the SF-36 questionnaire, was very low before the operation. The quality of life was markedly improved 6 and 12 months after the Maze operation, and was comparable to values of the general Swedish population.</p><p>In the patients with sinus rhythm before surgery, the atrial size and transport function was assessed with echocardiography, and the autonomic balance was assessed with heart rate variability (HRV). The sizes of both atria were reduced and the transmitral early filling / atrial filling (E/A) ratio was increased at 6 months after the operation compared to before. A progressive increase of the E/A ratio was seen during the 24 months follow-up period, indicating a progressive decline of the left atrial transport function.</p><p>All components of HRV, including the parameters expressing sympathetic and parasympathetic modulation, were markedly decreased early after the Maze procedure compared to before. Late after the operation all components of HRV were still markedly depressed. This is interpreted as a partial autonomic denervation of the heart</p><p>Single-site right atrial overdrive pacing with two different levels of overdriving was compared with no pacing in patients with paroxysmal atrial fibrillation in a cross-over study. Overdrive pacing reduced the median number of episodes of atrial fibrillation with 50% compared to no pacing. There was no difference between medium rate overdrive pacing and high rate overdrive pacing.</p>

Atrial fibrillation is a common disease. With pharmacological therapy most patients with atrial fibrillation have moderate or little symptoms, but a number of patients have severely symptomatic disease. This study evaluates two new non-pharmacological therapies for atrial fibrillation, the Maze procedure and atrial overdrive pacing. In the patients planned for Maze surgery the quality of life, assessed with the SF-36 questionnaire, was very low before the operation. The quality of life was markedly improved 6 and 12 months after the Maze operation, and was comparable to values of the general Swedish population. In the patients with sinus rhythm before surgery, the atrial size and transport function was assessed with echocardiography, and the autonomic balance was assessed with heart rate variability (HRV). The sizes of both atria were reduced and the transmitral early filling / atrial filling (E/A) ratio was increased at 6 months after the operation compared to before. A progressive increase of the E/A ratio was seen during the 24 months follow-up period, indicating a progressive decline of the left atrial transport function. All components of HRV, including the parameters expressing sympathetic and parasympathetic modulation, were markedly decreased early after the Maze procedure compared to before. Late after the operation all components of HRV were still markedly depressed. This is interpreted as a partial autonomic denervation of the heart Single-site right atrial overdrive pacing with two different levels of overdriving was compared with no pacing in patients with paroxysmal atrial fibrillation in a cross-over study. Overdrive pacing reduced the median number of episodes of atrial fibrillation with 50% compared to no pacing. There was no difference between medium rate overdrive pacing and high rate overdrive pacing.

Background: Despite the recent improvements in surgical techniques and postoperative patient care, atrial fibrillation (AF) remains the most frequent complication after cardiac surgery. Although postoperative AF is often regarded as a benign clinical condition, this arrhythmia has significant adverse effects on patient recovery and postoperative survival. Its exact pathophysiology has not yet been elucidated. The present thesis aims to analyze AF risk factors and their interaction, pre-existing histological explanatory alterations of the atrium, the AF impact on postoperative survival and the compliance of a prophylactic drug regimen. Methods: During a 10-year period, consecutive cardiac surgery cases with complete data on AF occurrence and postoperative survival were extracted. All patients were operated on for coronary or valvular surgery, with cardiopulmonary bypass (CPB). Hospital and long-term survival data were obtained from Swedish population registry. Study I) Isolated coronary artery bypass grafting (CABG, n=7056), aortic valve replacement (n=690) and their combination (n=688) were considered. Independent AF risk factors and AF effects on early and 1 year mortality were investigated. Study II) Patients affected by postoperative AF among isolated CABG patients (n=7621), valvular surgeries (n=995) and their combination (n=879) were studied. Long-term survival was obtained and prognostic factors identified. Study III) Seventy patients were randomized to on-pump (n=35) or off-pump (n=35) CABG. Samples from the right atrial appendage were collected and histology was evaluated by means of light and electronic microscopy with reference to preexistent alterations related to postoperative AF. Study IV) Cardiac surgery patients with complete data on smoking status (n=3245) were reviewed. Effects of smoking on AF development and interaction among variables were explored. Study V) CABG patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium were prospectively enrolled (n = 49) and compared with a matched contemporary control CABG group (n = 844). The clinical compliance to the AF prophylactic drug regimen was tested. Results: The overall AF incidence was around 26%, subdivided into 23%, 40% and 45% for isolated CABG, valve procedures and their combined surgeries, respectively. Age was the strongest predictor of postoperative AF. Coronary disease superimposed risk factors with reference to myocardial conditions at CPB weaning. Considering the preoperative smoking condition, smokers demonstrated a reduced AF incidence compared to non-smokers (20% versus 27%, p&lt;0.001). An interaction between smoking status and inotropic support was observed: without this interaction smoking conferred a 46% risk reduction of AF (p=0.011). At the histological level, myocyte vacuolization and nuclear derangement represented anatomical independent AF predictors (p=0.002 and p=0.016, respectively). CPB exposure was not associated to postoperative AF nor histological changes. Although, postoperative AF increases the length of hospitalization in all patient groups, it did not affect the hospital survival. However, AF independently impaired the late survival, a phenomenon seen in the CABG group only. With reference to the tested sotalolmagnesium drug regimen, only 55% of CABG patients were compliant to the treatment, with marginal effects on AF occurrence. Conclusions: In addition to age, details at the CPB weaning period, pre-existing histopathological changes, the hyperadrenergic state and catecholamines are key mechanisms in the pathophysiology of postoperative AF. In particular, the CPB period hides valuable information for timely AF prophylactic stratifications. Further, compliance effects due to patient selection should also be considered in a prophylactic therapy model. Postoperative AF increases late mortality after isolated CABG surgery, but not after valvular procedures. Although the mechanisms are unclear, our results draw the attention to possible AF recurrence after hospital discharge, indicating a strict postoperative surveillance.

A finite-element model of a two-dimensional slice of human atrial tissue for the study of the electrograms and propagation of action potentials is presented. Action potential propagation is described by a reaction-diffusion model coupled with the complex Courtemanche et al. atrial cell model. The effects of recording electrode size and location on electrograms are presented. Action potential propagation as a result of atrial fibrillation ablation therapy is also modeled by defining a lesion area with decreased electrical conductivity. The effect of electrical conductivity and geometry of the lesion was also studied. It is shown that the success rate of atrial fibrillation ablation therapy is primarily correlated with the creation of continuous ablation lines and also the formation of fibrous tissue.

EINLEITUNG Vorhofflimmern und orale Antikoagulation Vorhofflimmern stellt ein Grundproblem der modernen Gesellschaft dar und fordert zunehmend den Einsatz medizinischer Ressourcen. Es ist die Folge eines komplexen Prozesses aus Triggern, elektrophysiologischen und später auch strukturellen Umbauprozessen im Vorhofmyokard. Man unterscheidet paroxysmales von persistierenden und permanenten Vorhofflimmern. Zusätzlich muss man symptomatische Episoden von asymptomatischen trennen, wobei der Anteil letzterer mit bis zu 70% beschrieben wird. Asymptomatisches Vorhofflimmern wird als eine häufige Ursache eines kryptogenen Schlaganfalls vermutet. Bislang konnte gezeigt werden, dass längere Überwachungszeiträume des Herzrhythmus häufiger Vorhofflimmern bei dieser Patientengruppe erfassen können. Somit hat hier der Nachweis von Vorhofflimmern einen entscheidenden Einfluss auf die Therapie durch entsprechende Senkung des thrombembolischen Risikos. Bei Patienten mit bekanntem Vorhofflimmern dagegen besteht die Gefahr einen Therapieerfolg aufgrund asymptomatischer Episoden zu überschätzen und die Vorhofflimmerlast, den sogenannten AF Burden zu unterschätzen. Entsprechend waren und sind mit dem subjektiven Therapieerfolg medizinische Entscheidungen verbunden, welche in Bezug auf das Auftreten thrombembolischer Ereignisse eine gewisse Rolle spielen. Statistisch gesehen wird das thrombembolische Risiko nach dem CHADS2 oder CHA2DS2 VASc Score berechnet und danach zwischen einer Plättchenhemmung, einer oralen Antikoagulation, direkten Thrombin-, Faktor Xa Inhibitoren oder keiner weiteren Therapie entschieden. Patienten mit Vorhofflimmern können auf zwei Arten behandelt werden. Bei der sogenannten Frequenzkontrolle erfolgt kein direkter Angriff auf die Rhythmusstörung, nur auf die Geschwindigkeit der Herzfrequenz und deren Symptome. Demgegenüber steht die Rhythmuskontrolle mit vordergründigem Erhalt des Sinusrhythmus, sowohl elektrisch, als auch medikamentös oder interventionell. Die Erfassung des Herzrhythmus und der implantierbare kardiale Monitor Ob ein Sinusrhythmus oder Vorhofflimmern vorliegt kann nur anhand eines EKGs geklärt werden. Zur Überwachung eines längeren Zeitraums kommen sogenannte Holter-EKGs mit einer Aufzeichnungsdauer von mindestens 24 Stunden, maximal 7 Tagen in Frage. Aufgrund von seltenen, wahrscheinlich rhythmogen bedingten Symptomen wie zum Beispiel Synkopen, wurde eine Weiterentwicklung mit noch längeren Aufzeichnungskapazitäten notwendig. Dem externen Event- und Loop-Recorder folgte der implantierbare kardiale Monitor. Der Reveal XT 9529 (Medtronic Inc, Minneapolis), ein implantierbarer kardialen Monitor mit einem speziellen Detektionsalgorithmus für Vorhofflimmern ist dabei Gegenstand dieser Untersuchung. ZIEL DER ARBEIT Evaluierung des REVEAL XT 9529 (Medtronic Inc, Minneapolis) bei einer Patientenpopulation mit Vorhofflimmern im klinischen Alltag. METHODEN Der automatische Detektion von Vorhofflimmern durch einen implantierten kardialen Monitor unterliegt eine Analyse des R-Zacken Abstandes innerhalb von zwei Minuten. Kommt es hier zu Unregelmäßigen erfolgt automatisch eine Einordnung des Herzrhythmus in den Bereich Vorhofflimmern (AF). Die Episoden können in der Regel manuell mit einem Frequenzplot und einer EKG-Ableitung (EGM) überprüft werden. Analysiert wurde eine Gruppe von 92 Patienten, welche vorrangig an Vorhofflimmern litten. Zusätzliche Daten wie Alter, Geschlecht, linksventrikuläre Pumpfunktion, kardiale Begleiterkrankungen und medikamentöse Therapie wurden ebenfalls erfasst. 88% der mit dem implantierbaren kardialen Monitor versorgten Patienten wurden aufgrund des Vorhofflimmerns vorbehandelt, bei 82% stand ein neuerlicher Therapieversuch bevor. Die Implantation des kardialen Monitors fand unter sterilen Operationsbedingungen statt, nachfolgend wurden die Patienten in die Funktion eingewiesen. Die Termine zur Nachsorge wurden im Rahmen der klinischen Routine vergeben und umfassten eine Überprüfung und Wertung der automatisch detektierten Rhythmusereignisse. Bei einer Untergruppe von 62 Patienten erfolgte parallel die Anlage von 7 Tage Langzeit-EKGs und eine Wertung der Ergebnisse im Vergleich. Die statistische Datenanalyse erfolgte mit Microsoft Office Excel 2007 und SPSS, Version 11.5.1. Mittelwerte werden mit Standardabweichung angegeben, im Falle des Medians zusätzlich Minimum und Maximum. Prozentuelle Angaben erfolgen bei Zahlen. Für statistisch abhängige Stichproben erfolgte die Anwendung des McNemar Tests, für unabhängige Werte der Chi-Quadrat Test. Es gilt das allgemein übliche Signifikanzniveau von p < 0,05. ERGEBNISSE Die Ergebnisse der manuellen Überprüfung wurden in folgende Kategorien eingeteilt: 1. Kein Vorhofflimmern unter Einsicht sämtlicher EGMs. 2. Sicheres Vorhofflimmern mit eindeutigem Nachweis in den gespeicherten EGMs. 3. Mögliches Vorhofflimmern, aber ohne diagnostische Sicherheit, da ein EGM nicht vorliegt. Davon ausgehend erfolgte die weitere Unterteilung in: - Regelrechten Sinusrhythmus ohne Nachweis von Artefakten. - Regelrechten Sinusrhythmus, aber Aufzeichnung von Artefakten im Sinne einer Fehlklassifikation. - Regelrechten Nachweis von Vorhofflimmern und Fehlklassifikation von Sinusrhythmus bei Artefakten. - Fehlklassifikation von Sinusrhythmus bei Artefakten, zusätzlich diagnostische Unsicherheit ob Vorhofflimmern aufgetreten ist, da nicht alle EGMs einsehbar. Vor dem Softwareupgrade wurden 287 Abfragen von 92 Patienten analysiert. Im Durchschnitt wurden 1078 (± 4851) Episoden registriert, im Median lag diese Zahl bei 58 (0 – 67099). Bezogen auf das Auftreten von Vorhofflimmern blieben 55 (19%) der Abfragen ohne Episoden. Ein komplett einsehbarer EGM Speicher war bei 140 (49%) der Abfragen zu finden, bei 147 (51%) waren dagegen EGMs schon wieder überschrieben und damit nicht mehr überprüfbar. Unter diesen Patienten zeigten 53 (19%) reines Vorhofflimmern im Speicher, 21 (7%) Vorhofflimmern mit Artefakten und weitere 73 (25%) nur Sinusrhythmus mit Artefakten. Gerade bei dieser letzten Gruppe kann keine sichere Aussage über das reelle Auftreten oder Fehlen von Vorhofflimmern gemacht werden. Auf sämtliche Abfragen vor dem Softwareupgrade gesehen waren Muskelpotentiale, welche bei 134 (47%) von 287 Abfragen auftraten das Hauptproblem unter den Artefakten und Ursache für die automatische Fehlklassifikation. Weitere Fehlklassifikationen betrafen Undersensing, die Einordnung von Vorhofflimmern in den Bereich einer ventrikulären Tachykardie, ventrikuläre und supraventrikuläre Extrasystolen, den AT-Algorithmus und T-Wave Oversensing. In den verbleibenden 65 Patienten nach dem Softwareupgrade wurden 116 analysierbare Abfragen erhoben. Bezogen auf das Auftreten von Vorhofflimmern blieben 41 (35%) der Abfragen ohne Episoden. Ein komplett einsehbarer EGM Speicher war bei 78 (67%) der Abfragen zu finden. Unter den Patienten mit bereits überschriebenen EGM zeigten 17 (15%) reines Vorhofflimmern im Speicher, 9 (8%) Vorhofflimmern mit Artefakten und weitere 12 (10%) nur Sinusrhythmus mit Artefakten. Ein direkter Vergleich der Ergebnisse zeigte eine signifikante Reduktion der beschriebenen Fehlklassifikation von Vorhofflimmern aufgrund von Myopotentialen, Undersensing und des AT-Algorithmus. Für 62 der Patienten liegen im Mittel 502 (± 156), im Median 508 (51 – 677) Stunden an Langzeit-EKG Aufzeichnung vor. Vorhofflimmern kann 48% im Langzeit-EKG registriert werden, im Reveal XT 9529 (Medtronic Inc, Minneapolis) nach manueller Überprüfung der Episoden dagegen bei 81%. Das Signifikanzniveau liegt bei p < 0,001. DISKUSSION Nach den vorliegenden Ergebnissen dieser Arbeit zeigt sich, dass die grundlegende Forderung nach einer kontinuierlichen EKG-Überwachung nur eingeschränkt mit dem Reveal XT 9529 (Medtronic Inc, Minneapolis) zu erreichen ist. Es traten zahlreiche Probleme mit Artefakten durch das beschriebene Oversensing und aufgrund der Speicherkapazität auf. Lösungsansätze sind hier die stärkere Einbeziehung des “Patient Assistant“ beziehungsweise ein Remote-Follow-Up. Bereits initiiert wurde ein Softwareupgrade welches durch Ausweitung des “Noise“ die Artefaktanfälligkeit deutlich senken konnte. Zusätzlich stehen die direkte Anpassung der Programmierung und die Anpassung der Sensitivität zur Verfügung. Diskutiert werden sollte weiterhin eine Veränderung des Erkennungsalgorithmus mit 2-dimensionaler Auswertung der RR-Intervalle und der RR-Differenz. Zusätzlich muss der Einfluss des Patienten auf die Handhabung des Systems im Blick behalten werden. Grundsätzlich sind zum einen das technische Verständnis, zum anderen die Compliance, welche durch verschiedene Faktoren geprägt wird. Der Einfluss eines kontinuierlichen EKG-Monitorings auf das Management der oralen Antikoagulation und Rezidive von Vorhofflimmern birgt ein enormes Potential wie Daten bei Schrittmacher- und ICD-Patienten zeigen. Trotzdem sind hier viele wichtige Studien zum aktuellen Zeitpunkt ausstehend. Festzuhalten bleibt, dass Studien im allgemeinen und speziellen durch den Einsatz eines implantierbaren kardialen Monitors effektiver gestaltet, Rezidive der Rhythmusstörung sicherer erfasst werden würden und auch eine Anpassung der oralen Antikoagulation denkbar ist. Weiterhin wären im Bereich des kryptogenen Schlaganfalls höhere Aufklärungsraten anzunehmen. Im Vergleich mit einem 7 Tage Langzeit-EKG zeigt ein implantierbarer kardialer Monitor eine vermehrte Erfassung von Vorhofflimmern trotz der beschriebenen Probleme. Zu diskutieren bleiben die Invasivität des Verfahrens und die endgültigen Kosten. LIMITATIONEN Das vorgestellte Patientenkollektiv wurde nicht prospektiv untersucht, sondern im Rahmen einer Observationsstudie retrospektiv analysiert. Zusätzlich handelt es sich um eine selektionierte Gruppe von Patienten, zumeist mit dem Ziel einer invasiven Ablationsbehandlung und dadurch vorgegeben, einigen Besonderheiten. Zu beachten ist außerdem, dass einzig die Problematik in Bezug auf Vorhofflimmern untersucht, andere messbare Rhythmusstörungen im Rahmen dieser Analyse ausgeschlossen wurden. AUSBLICK Vorhofflimmern und seine Therapie wird ein relevanter Faktor in der Zukunft vieler betroffener Patienten bleiben, die Forderung nach einer kontinuierlichen EKG-Überwachung für verlässliche Aussagen sich entsprechend verstärken. Die erste Generation der implantierbaren kardialen Monitore stellt einen vielversprechenden Anfang dar. Weitere Entwicklungen mit Verbesserung der Artefaktanfälligkeit und Speicherkapazität, sowie der Telemedizin sind notwendig. Gerade mit Blick auf asymptomatisches Vorhofflimmern sind viele Fragen offen und können nur mit einer lückenlosen, sensitiven und spezifischen EKG-Dokumentation beantwortet werden.

Plautines venas, kaip ir širdies miokardą, kontroliuoja širdies nervinė sistema. Nors žmogaus epikardinis nervinis rezginys šiuo metu yra nemažai tyrinėtas, plautinių venų inervacija į tyrėjų akiratį pateko tik po darbų, įrodančių žmogaus plautinių venų ir kairiojo prieširdžio anatominių struktūrų, tarp jų ir intramuralinių nervinių mazgų ir nervinių kelių, svarbų vaidmenį širdies aritmijų genezėje. Šio tyrimo tikslas buvo vizualizuoti plautinių venų nervines struktūras totaliuose žmogaus kairiojo prieširdžio–plautinių venų preparatuose, parodant žmogaus plautinių venų nervų ir nervinių mazgų ryšį su širdies nervine sistema. Mokslinio tyrimo metu spręsti šie uždaviniai: 1) nustatyti inervacijos kelius, kuriais nervai plinta žmogaus plautinėse venose bei įvertinti sritis, išsiskiriančias nervinių struktūrų gausa, 2) ištirti žmogaus plautinių venų žiočių ir jų sienos sluoksnių nervinius komponentus bei jų pasiskirstymo ypatybes, 3) nustatyti parasimpatinei, simpatinei ir aferentinei nervų sistemai priskiriamų žymenų, atitinkamai cholinacetiltansferazės, tirozinhidroksilazės, su kalcitonino genu susijusio peptido ir substancijos P, lokalizaciją ir pasiskirstymo ypatumus žmogaus plautinėse venose. Šiame darbe atliktuose neuromorfologiniuose tyrimuose buvo panaudotos žmogaus vaisių ir suaugusių žmonių širdys, paimtos autopsijų metu. Plautinių venų nervinis rezginys išryškintas, taikant histocheminį acetilcholinesterazės metodą ir imunohistochemines reakcijas. Remiantis tyrimo... [toliau žr. visą tekstą] / Although the crucial role in a spontaneous atrial fibrillation falls on cardiomyocytes of the human pulmonary veins, the autonomic nervous system is not considered only as the strong regulator of atrial electrophysiology but it is also the major initiator of atrial fibrillation due to a disordered interaction between the atrial autonomic nerves and the cardiomyocytes of the pulmonary vein. The aim of the present study was to investigate the intrinsic neural plexus on whole (non–sectioned) human pulmonary veins. The objectives of the study was: 1) to determine the sources and morphology of nerve routes by which intrinsic nerves supply the human pulmonary veins, 2) to examine the neural structures located within distinct wall layers of the human pulmonary veins, 3) to identify the distribution and expression of tyrosine hydroxylase, choline acetyltransferase, calcitonin gene related peptide and substance P positive nerve structures on the human pulmonary veins as corresponding markers for sympathetic, parasympathetic and sensory nerve cells and fibers. Twenty–two hearts of the human fetuses and thirty five hearts of the adult humans containing the full set of pulmonary veins were investigated applying a histochemical methods for acetylcholinesterase to stain intrinsic neural structures with their subsequent stereomicroscopic examination. ChAT, TH, substantia P and CGRP immunoreactive nerves structures were also studied in the pulmonary veins sections, obtained from the six... [to full text]

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 2003</p> / digitalisering@umu