TREAT AF (Transcutaneous Electrical Vagus Nerve Stimulation to Suppress Atrial Fibrillation): A Randomized Clinical Trial.

Objectives: This study was a sham-controlled, double-blind, randomized clinical trial to examine the effect of chronic low level tragus stimulation (LLTS) in patients with paroxysmal AF.

Background: Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve at the tragus (LLTS) acutely suppresses atrial fibrillation (AF) in humans, but the chronic effect remains unknown.

Methods: LLTS (20 Hz, 1 mA below the discomfort threshold) was delivered using an ear clip attached to the tragus (active arm) (n = 26) or the ear lobe (sham control arm) (n = 27) for 1 h daily over 6 months.

Mitral regurgitation after atrioventricular node catheter ablation for atrial fibrillation and heart failure: acute hemodynamic features.

Background: Radiofrequency catheter ablation of the atrioventricular node and pacemaker insertion have been associated with occasional development of mitral regurgitation (MR). Ventricular pacing might result in MR if (1) left ventricular (LV) compliance is decreased and/or (2) mitral valve leaflet apposition is disturbed. We studied acute hemodynamic changes resulting from initiation of ventricular pacing in patients undergoing ablation.

Predictors of outcome after radiofrequency catheter ablation of the atrioventricular node for atrial fibrillation and congestive heart failure.

Background: Although radiofrequency catheter ablation of the atrioventricular (AV) node is an established treatment for atrial fibrillation (AF) with uncontrolled ventricular response, factors that predict clinical outcome in patients with associated congestive heart failure (CHF) are unknown.

Methods And Results: AV node ablation and permanent pacemaker implantation was performed in 44 consecutive patients (mean age 71+/-10 years) with CHF and AF associated with uncontrolled ventricular response. Immediately before ablation, mean left ventricular ejection fraction (EF) measured by 2-dimensional echocardiogram was 34.

Comparison of the effects of AV nodal ablation versus AV nodal modification in patients with congestive heart failure and uncontrolled atrial fibrillation.

Radiofrequency (RF) catheter ablation of the atrioventricular node (AVN) and implantation of a ventricular pacemaker can improve cardiac performance in patients with congestive heart failure (CHF) and uncontrolled atrial fibrillation (AF). Alternatively, RF catheter modification of the AVN has been proposed to slow ventricular response during AF without requirement for permanent pacing. Among 44 consecutive patients (mean age 69.

Comparative haemodynamic effects of verapamil, flecainide, amiodarone and sotalol in the conscious rabbit.

1. The effect of intravenous boluses of verapamil (0.15 mg/kg), flecainide (2 mg/kg), amiodarone (5 mg/kg), and sotalol (1.

Acute results and long-term outcome of transluminal extraction catheter atherectomy for saphenous vein graft stenoses.

Distal embolization of atheroma and thrombus is a major concern when performing balloon angioplasty in coronary saphenous vein grafts (SVGs). The transluminal extraction catheter (TEC) is designed to remove this material and may improve the safety of percutaneous treatment of SVG disease. We assessed the acute results and long-term outcome of 67 patients (mean age 65.

Late potentials are unaffected by radiofrequency catheter ablation in patients with ventricular tachycardia.

Reentrant ventricular tachycardia is dependent on an area of myofibers, embedded in scar tissue, which exhibit slow conduction. Late potentials recorded by signal-averaged electrocardiography appear to correspond to these zones of slow conduction and frequently are present in patients with VT. We hypothesized that elimination of inducible VT by catheter-mediated ablation of critical areas of slow conduction would alter late potentials.

Comparative hemodynamic effects of amiodarone, sotalol, and d-sotalol.

The effects of intravenous boluses of amiodarone (5 mg/kg), racemic sotalol (enantiomeric ratio d/l-sotalol 1:1;1.5 mg/kg), and d-sotalol (0.75 mg/kg) on mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR), left ventricular end-diastolic pressure (LVEDP), and peak rate of change of left ventricular pressure (LV dp/dt) were assessed in conscious rabbits.

Atrial natriuretic factor release during rapid ventricular pacing: interplay between autonomic and hemodynamic stimulants.

Plasma levels of atrial natriuretic factor (ANF) and norepinephrine are markedly elevated during episodes of ventricular tachycardia. Although atrial distention appears to be the major stimulus for ANF release, reflex changes in autonomic tone might also contribute. Plasma ANF and norepinephrine levels, sinus node cycle length, systolic blood pressure, and mean right atrial pressure were therefore assessed during rapid right ventricular pacing at 150 beats/min for 10 minutes.

Effects on cardiac performance of atrioventricular node catheter ablation using radiofrequency current for drug-refractory atrial arrhythmias.

Patients with atrial fibrillation or atrial flutter (AF) are candidates for radiofrequency (RF) catheter ablation of the atrioventricular (AV) node with the aim being to control heart rate. As patients with AF can have markedly impaired ventricular function, information concerning the hemodynamic effects of AV node ablation using RF current would be valuable. Fourteen consecutive patients (mean age 65 +/- 3 years) with drug-resistant AF underwent AV node catheter ablation with RF current and had permanent pacemaker implantation.

Treatment of supraventricular tachycardia due to atrioventricular nodal reentry by radiofrequency catheter ablation of slow-pathway conduction.

Background: Atrioventricular nodal reentrant tachycardia (AVNRT), the most common form of supraventricular tachycardia, results from conduction through a reentrant circuit comprising fast and slow atrioventricular nodal pathways. Antiarrhythmic-drug therapy is not consistently successful in controlling this rhythm disturbance. Catheter ablation of the fast pathway with radiofrequency current eliminates AVNRT, but it can produce heart block.

Factors associated with recurrence of accessory pathway conduction after radiofrequency catheter ablation.

Catheter ablation of 215 accessory pathways (APs) using radiofrequency current (RF) was attempted in 204 consecutive patients. Two hundred twelve of the 215 (99%) APs were successfully ablated. After a minimum of follow-up period of 1 month (mean 8.

Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current.

Background: Surgical or catheter ablation of accessory pathways by means of high-energy shocks serves as definitive therapy for patients with Wolff-Parkinson-White syndrome but has substantial associated morbidity and mortality. Radiofrequency current, an alternative energy source for ablation, produces smaller lesions without adverse effects remote from the site where current is delivered. We conducted this study to develop catheter techniques for delivering radiofrequency current to reduce morbidity and mortality associated with accessory-pathway ablation.

Concentrations of plasma atrial natriuretic factor during and after reversion of ventricular tachycardia.

Plasma concentrations of immunoreactive atrial natriuretic factor were considerably increased (mean 745 (376) pg/ml) in 15 patients during spontaneous ventricular tachycardia. There was no significant relation, however, between concentrations of plasma atrial natriuretic factor and systolic arterial blood pressure during tachycardia. Samples taken 30 minutes and 24 hours after reversion of ventricular tachycardia to sinus rhythm showed that, although plasma concentrations of atrial natriuretic factor had fallen significantly, they were still raised after 24 hours.

Echocardiographic study of U wave inversion in the electrocardiograms of hypertensive patients.

The prevalence of U wave inversion was evaluated in 58 adult patients with hypertension, and a possible mechanism for it was examined using M-mode echocardiographic indices. U wave inversion was the most common electrocardiographic abnormality, occurring in 34% of patients; voltage criteria for left ventricular hypertrophy were present in only 14% of patients, and ventricular strain pattern was not detected in any patient. Nonetheless, on echocardiography left ventricular posterior wall thickness was increased in 58% of patients.

Hemorrhagic myocardial infarction complicated by free wall-rupture: a case associated with unusual clinical features following intravenous thrombolytic therapy.

A patient is described who developed a systolic murmur soon after she was administered intravenous thrombolytic therapy for acute myocardial infarction. She died and autopsy revealed extensive hemorrhagic myocardial infarction and a free-wall rupture. A review of the literature suggests that this may be an unusual complication of thrombolytic therapy.

Results of cardiopulmonary resuscitation in adult patients managed in a teaching hospital: clinical outcome and implications.

Objective: To assess the impact and clinical implications of therapeutic strategies for managing sudden cardiac arrest in a teaching hospital.

Method: A prospective audit of the results of out-of-hospital and in-hospital cardiac arrest.

Results: Compared with other studies, our results for resuscitation of out-of-hospital cardiac arrest were poor, only 5% of patients being discharged.

Transesophageal electrocardiography and atrial pacing in acute cardiac care: diagnostic and therapeutic value.

The utility of transesophageal electrocardiography using a bipolar 'pill electrode' was assessed in 17 consecutive patients with tachycardia presenting to our casualty department. Standard 12-lead electrocardiography showed regular narrow QRS tachycardia in 12 patients, and five patients had wide QRS tachycardia. Esophageal atrial electrogram recordings were obtained in 14 patients (82%), and these were helpful in determining the mechanism of tachycardia in 11 patients (78%).

Clinical implications of electrophysiology study findings in patients with chronic bifascicular block and syncope.

Electrophysiology study was performed in 93 patients with bifascicular block and unexplained syncope. Clinical evidence of organic heart disease was present in 33 (35%). Electrophysiological abnormalities were detected in 45 patients (48%).

Computer algorithm for modeling transmission over one or two conduction pathways through AV node.

The goal of this study was to develop and test models of conduction through the atrioventricular node, particularly to encompass possible transmission over multiple pathways. Output from the atrioventricular node was related to its input, the variable coupling interval of a single extrastimulus introduced to scan diastole during programmed atrial stimulation. Trials were performed three times in 15 patients after pacing for eight beats at 100 beats/min.

Direct identification of parameters in a mathematical model describing conduction through the atrioventricular node.

Function of the atrioventricular node is assessed during intracardiac electrophysiology study by relating the output intervals A2H2 and H1H2 to the input A1A2, where A and H are, respectively, atrial and His bundle electrograms recorded by catheter. The H1H2 curves have been previously deduced from a model describing the A2H2 curves. Because of presence in a few cases of different behaviour of A2H2 and H1H2, this study aimed to establish a more suitable model of H1H2 independently of A2H2 for the particular case of a single transmission pathway.

Procainamide administration during electrophysiology study--utility as a provocative test for intermittent atrioventricular block.

The utility of procainamide, up to 10 mg/kg IV, as a provocative test for intermittent high degree atrioventricular (AV) block was evaluated in a total of 89 patients. Forty two patients had resting 1:1 AV conduction but had bifascicular block and a history of syncope. High degree AV block had not been documented in anyone.

Programmed stimulation after anterior myocardial infarction complicated by bundle branch block--late ventricular tachyarrhythmias and outcome.

One hundred and thirty consecutive patients with anterior myocardial infarction complicated by bundle branch block were retrospectively analyzed. Sixty died within 1 week of infarction. Of the remaining 70 patients, 36 had electrophysiology study with programmed stimulation 8-90 (mean 20) days after infarction.