Результаты поиска

Ablate and pace revisited: long term survival and predictors of permanent atrial fibrillation.

OBJECTIVE: To assess long term mortality and identify factors associated with the development of permanent atrial fibrillation after atrioventricular (AV) node ablation for drug refractory paroxysmal atrial fibrillation. DESIGN: Retrospective cohort study. SETTING: UK tertiary centre teaching hospital. PATIENTS: Patients admitted to the University Hospital Birmingham between January 1995 and December 2000. INTERVENTIONS: AV node ablation and dual chamber mode switching pacing. MAIN OUTCOME MEASURES: Long term mortality and predictors of permanent atrial fibrillation, assessed through Kapl

Time-dependent variation in the cardiac conduction system assessed in young healthy individuals at weeks' interval: implications for clinical trials.

The time-dependent physiologic variations of the cardiac conduction system were evaluated at repeated invasive studies in 10 healthy individuals. Their mean age was 28 years (range 22 to 34) and they volunteered to undergo two electrophysiologic studies at intervals of 14 to 63 days (mean 25). The coefficients of variation, repeatability and reproducibility, which should be the preferred statistics when assessing the reproducibility of continuous variables, were calculated. The mean sinus cycle length had a high reproducibility, with coefficients of variation between 2% and 6%. The mean and ma

Infants with apparent life threatening events. Cardiac rhythm and conduction.

The role of cardiac dysrhythmias in the pathogenesis of Sudden Infant Death Syndrome (SIDS) is uncertain, but there have been several reports of infants with Apparent Life Threatening Events (ALTE) due to significant dysrhythmias. To further characterize the cardiac rhythm and conduction of these "at-risk for SIDS" infants, we performed 24-hour continuous (Holter) electrocardiograms on 100 full term, healthy infants with ALTE. Sixty-two patients (62%) had one or more dysrhythmias on Holter monitor. Twenty-five patients (25%) had premature ventricular depolarizations (PVD), including five with

Histopathological correlation between the QRS axis and disposition of the atrioventricular conduction system in common atrioventricular orifice and in its related anomalies.

Serial sections of the atrioventricular (AV) conduction system were microscopically studied in 12 autopsied hearts: four with complete type common AV orifice (CAVO), two with atrial septal defect of the ostium primum type (ASD-I), two with ventricular septal defect of the persistent common AV canal type (VSD-C) and four without heart disease. The anatomic findings were semiquantitatively compared with the normal control using Feldt's method and correlated to the mean frontal QRS axis on ECG. The cases of CAVO or VSD-C with left axis devation invariably showed similar patterns regarding the loc

The Bachmann's bundle connection: from obesity and aging to atrial arrhythmia development.

In recent years, Bachmann's bundle (BB), a band of cardiac muscle that enables electrical conduction from the heart's right atrium to the left atrium, has drawn significant interest from the scientific community. It has been identified as a branch of the anterior interatrial pathways connecting the sinoatrial node to the atrioventricular node, departing at the level of the superior vena cava. It is now understood that BB serves as a preferential pathway for interatrial conduction, and structural abnormalities in BB can result in interatrial block, which is associated with the onset of atrial f…

Mitochondrial Oxidative Stress Mediates Bradyarrhythmia in Leigh Syndrome Mitochondrial Disease Mice.

Mitochondrial oxidative stress has been implicated in aging and several cardiovascular diseases, including heart failure and cardiomyopathy, ventricular tachycardia, and atrial fibrillation. The role of mitochondrial oxidative stress in bradyarrhythmia is less clear. Mice with a germline deletion of Ndufs4 subunit respiratory complex I develop severe mitochondrial encephalomyopathy resembling Leigh Syndrome (LS). Several types of cardiac bradyarrhythmia are present in LS mice, including a frequent sinus node dysfunction and episodic atrioventricular (AV) block. Treatment with the mitochondrial

ECG based assessment of circadian variation in AV-nodal conduction during AF-Influence of rate control drugs.

The heart rate during atrial fibrillation (AF) is highly dependent on the conduction properties of the atrioventricular (AV) node. These properties can be affected using β-blockers or calcium channel blockers, mainly chosen empirically. Characterization of individual AV-nodal conduction could assist in personalized treatment selection during AF. Individual AV nodal refractory periods and conduction delays were characterized based on 24-hour ambulatory ECGs from 60 patients with permanent AF. This was done by estimating model parameters from a previously created mathematical network model of th

Exome Sequencing Identifies Compound Heterozygous Mutations in SCN5A Associated with Congenital Complete Heart Block in the Thai Population.

Background. Congenital heart block is characterized by blockage of electrical impulses from the atrioventricular node (AV node) to the ventricles. This blockage can be caused by ion channel impairment that is the result of genetic variation. This study aimed to investigate the possible causative variants in a Thai family with complete heart block by using whole exome sequencing. Methods. Genomic DNA was collected from a family consisting of five family members in three generations in which one of three children in generation III had complete heart block. Whole exome sequencing was performed on…

Sickle cells and sudden death: morphologic abnormalities of the cardiac conduction system.

Sudden unexpected death has become increasingly recognized as an important clinical feature of both homozygous and heterozygous sickling syndromes, but the exact nature of its cause has remained unexplained. We have conducted special postmortem examinations of the cardiac conduction system and a coronary chemoreceptor from the hearts of two black males who had sickled erythrocytes. There were abundant foci of old and recent degeneration in the sinus node, atrioventricular node, and His bundle, as well as the coronary chemoreceptor. Many capillaries and small arteries were packed with sickled e…

Clinical and electrophysiologic course of sinus node disease: five-year follow-up study.

Thirty patients with symptomatic sinus node disease (SND) who 5 years previously had undergone a clinical investigation including intracardiac electrophysiologic studies with pharmacologic inhibition of autonomic tone were followed up with respect to development of arrhythmias and cardiac conduction abnormalities. In 17 of these patients a reinvestigation, including a second intracardiac study, was performed. Stable atrial fibrillation developed in five patients, paroxysmal supraventricular tachycardia occurred in one patient, and complete heart block appeared in another patient. Paroxysmal at

Combined verapamil and propranolol for supraventricular tachycardia.

The electrophysiologic effects of intravenous verapamil and propranolol were compared alone and in combination in 14 patients (aged 21 to 69 years) with paroxysmal supraventricular tachycardia (SVT). Ten patients had atrioventricular (AV) reentry utilizing a manifest (7 patients) or concealed (3 patients) accessory pathway. Four patients had AV nodal reentry. Electrophysiology studies were performed using standard techniques in the control state and after verapamil (0.15 mg/kg intravenous bolus and 0.005 mg/kg/min). The next day, studies were repeated after propranolol (0.1 mg/kg) and a combin

[Hemodynamic and electrophysiologic effects of the new calcium antagonist Ro 11-1781 (author's transl)].

In a 3-part study the new calcium-antagonist Ro 11-1781 was investigated in respect to hemodynamic, electrophysiologic and antiarrhythmic effects. In the first part of the investigation, systolic time intervals were determined as an indicator of left ventricular performance in 10 patients without cardiac disease before and 5 min after i.v. injection of Ro 11-1781 (1 mg/kg/body weight). At the same time blood pressure was measured. There was a significant decrease in systolic and diastolic blood pressure (p < 0.01). Due to the resulting activation of the sympathetic nervous system by baroreflex

Impact of Age and Polytherapy on Fingolimod Induced Bradycardia: a Preclinical Study.

Fingolimod is a an oral disease modifying drug for relapsing remitting multiple sclerosis (MS) preventing egress of B and T cells from lymph nodes. Relevant first dose adverse events include bradycardia and atrioventricular conduction slowing. Cardiac side effects of fingolimod and combinational pharmacotherapy including duloxetine and tolterodine were monitored in mice of different age using implantable ECG telemetric systems. Cardiac tissue was assessed for S1P-receptor subtype (1 and 3), and for GIRK1 expression. Fingolimod led to a significant heart rate reduction within 60 min, which retu

Epinephrine-induced reversal of verapamil's electrophysiologic and therapeutic effects in patients with paroxysmal supraventricular tachycardia.

The purpose of our study was to determine whether an infusion of epinephrine reverses the electrophysiologic effects of verapamil and whethe … mil significantly slowed atrioventricular conduction and prolonged refractoriness in the atrium and atrioventricular node. The effects of the two infusion rates of epinephrine were generally similar in magnitude and, therefore, the results were pooled. Epinephrine partially or completely reversed all of verapamil's electrophysiologic effects. Verapamil suppressed the i …

Theoretical evaluation of the Rosenblueth hypothesis.

Rosenblueth's hypothesis states that atrioventricular (AV) nodal conduction delay and Wenckebach periodicity of AV transmission are not due to overall decremental conduction within the AV node but are due to a single step delay which is caused by a special element or layer of the AV nodal tissue. This paper discusses some theoretical considerations which allow detailed evaluation of the original hypothesis. Two artificial conduction structures which incorporate the Rosenblueth phenomenon are presented and tested by theoretical experiments that consider the potential of these structures to prod

Time dependent changes in the functional properties of the atrioventricular conduction system in man.

Time dependent changes in the electrophysiological properties of the atrioventricular conducting system (AVCS) were determined at two or more cycle lengths (CL) in 22 patients using bundle of His (H) electrograms, incremental atrial pacing and atrial extrastimulus method. The atrioventricular (A-H interval) and intraventricular (H-V interval) conduction times and refractory periods (RP) of the atrium, the A-V node (AVN) and His-Purkinje system (HPS) were measured during the control period, and repeat measurements were made after a 30 minute interval in eight patients (group A), after a 60 minu

[Use of transesophageal left atrial cardiac pacing for assessment of cordarone effectiveness in patients with atrioventricular tachycardia].

AIM: To assess by means of transesophageal left atrial pacing the effectiveness of cordarone treatment for arrhythmias caused by re-entry mechanism. MATERIALS AND METHODS: Effectiveness of cordarone treatment was estimated in 25 patients with atrioventricular nodal tachycardia (AVNT) and in 33 patients with WPW syndrome and reciprocal atrioventricular tachycardia (RAVT) with frequent paroxysms of tachycardia 1-5 times per week. Transesophageal left atrial pacing (TELAP) was performed before antiarrhythmic treatment and on cordarone treatment day 14-18. Cordarone was given for two months in co

Bradyarrhythmias Associated with Oncologic Treatment-An Updated Review.

Background/Objectives: Bradyarrhythmias are an under-recognized component of cancer therapy-related cardiovascular toxicity. As survivorship improves and exposure to targeted and immune therapies increases, clinicians increasingly face clinically relevant sinus node dysfunction and atrioventricular (AV) conduction disease that may interrupt otherwise effective oncologic treatment. We aimed to synthesize evidence on the incidence, phenotype, mechanisms, and management of bradyarrhythmias across major anticancer drug classes. Methods: We performed a narrative review of PubMed and major clinical

Совпадение в полном тексте источника
… node, the atrioventricular bundle, and both bundle branches [ 189 ]. … However, clinically validated methods for selecting patients who would benefit from dedicated conduction-system-sparing approaches, as well as specific dose constraints for the sinoatrial and atrioventricular nodes, remain to be established. 3.21. …

Alternating bundle branch block and infra-Hisian Mobitz II block: an educational case of rapidly progressive His-Purkinje disease.

BACKGROUND: Disease of the cardiac conduction system may arise in the atrioventricular node or distal His-Purkinje network, with important differences in mechanism, prognosis, and management. Alternating bundle branch block (ABBB) is a rare, high-risk electrocardiographic finding reflecting advanced bilateral His-Purkinje involvement, particularly when accompanied by atrioventricular block. Full serial documentation of its progression with intracardiac confirmation during the same clinical course appears exceptionally uncommon. CASE SUMMARY: We present an educational case of rapidly progressi…

Influence of percutaneous transcatheter closure of an atrial septal defect on the atrioventricular conduction.

OBJECTIVE: This study aimed at determining the effect of percutaneous ASD closure on the AV conduction. Percutaneous closure of ostium secundum atrial septal defects (ASDs) has been widely accepted and has become the standard treatment of this malformation. However, some complications have been reported. Because of the close proximity between the discs of the device and the atrioventricular (AV) node, atrioventricular conduction disturbances (AVCD) are a likely complication. METHODS AND RESULTS: From the database of congenital heart disease, 46 patients (mean age 54 +/- 12 y) who underwent pe