Emanuel Stein

Catheter Technique for Recording His Bundle Activity in Man

A technique for the routine recording of His bundle (H) activity in man using a bipolar or multipolar catheter is described. The recording catheter is inserted percutaneously, via the Seldinger method, into the right femoral vein and advanced fluoroscopically into the right atrium. Placement of the pre-formed curve at the catheter tip across the tricuspid valve in nine patients resulted in stable recordings of His bundle activity in successive cardiac cycles. Right atrial pacing resulted in progressive lengthening of the P-H interval with increasing frequency but the H to S-wave interval remained constant at all rates. Similar lengthening of the P-H interval was produced during atrial pacing when pressure was applied to the carotid sinus. The use of this recording technique in man will facilitate diagnostic interpretation of the electrocardiogram and can be used in various investigations of atrioventricular and intraventricular conduction in man.

A Study of Heart Block in Man Using His Bundle Recordings

The technique of recording His bundle electrograms in man by a tripolar electrode catheter was applied in a study of patients with first, second, and third-degree heart block. In all patients with first-degree heart block (congenital, acquired, or induced by atrial pacing), the delay in A-V conduction occurred proximal to the His bundle as evidenced by a prolonged P-H interval. The enhancement of A-V conduction (shortening the P-H interval) due to isoproterenol was qualitatively similar in the three forms of first-degree block. In cases of Wenckebach phenomenon the P-H interval progressively increased until a dropped beat occurred. The nonconducted P wave was not followed by a His deflection, indicating block proximal to the His bundle. Cases of 2:1 and 3:1 block occurring proximal to the His bundle were also studied. The usefulness of His-bundle recordings in the diagnosis of cases of complete and incomplete bilateral bundle-branch block is also demonstrated.

Study of atrioventricular conduction in man using electrode catheter recordings of His bundle activity.

The technique of recording electrograms of the His bundle, using a tripolar electrode catheter positioned across the tricuspid valve, was applied in a physiological study of atrioventricular conduction in man. Increasing the heart rate to 160 beats/min by right atrial pacing produced progressive prolongation of the P-H interval while the H-Q interval remained constant. At any given paced heart rate, digitalis caused a prolongation of the P-H interval. Isoproterenol and atropine markedly shortened the P-H interval at any given heart rate. Neither drug had any significant effect on the H-Q interval. Coupled premature atrial stimulation produced prolongation of the P-H interval alone when the resultant ventricular depolarization was normal, and prolongation of both the P-H and H-Q intervals when the resultant ventricular depolarization was aberrant.

Atrioventricular conduction in man: Effect of rate, exercise, isoproterenol and atropine on the P-R interval☆

Abstract Atrioventricular conduction was studied in 14 patients. A bipolar electrode catheter was placed in the right atrium, and the heart rate was controlled by atrial pacing. Increases in the sinus heart rate were associated with decreases in atrioventricular conduction time. When the heart rate was increased by atrial pacing, there were progressive increases in atrioventricular conduction time. Exercise, isoproterenol and atropine shortened atrioventricular conduction time. In those cases where atrioventricular conduction block occurred during atrial pacing, there was a 1:1 atrioventricular response during exercise at the same paced heart rate. Stimuli which increase the rate of discharge of the sinus pacemaker also enhance atrioventricular conduction. It is concluded that there is a fine balance between heart rate and A-V conduction. When the heart rate is increased by neurohumoral stimuli, there is a corresponding enhancement of A-V conduction. When the heart rate is increased by artificial stimulation of the atria and neurohumoral effects are not altered, there is a progressive increase in conduction time and eventual blockage of conduction at the A-V nodal region.

Termination of atrial flutter by rapid electrical pacing of the atrium

Abstract A technic has been developed for converting atrial flutter to normal sinus rhythm utilizing an intra-atrial electrode catheter and rapid impulses 10 milliamperes in magnitude delivered directly to the atrial wall. Atrial flutter has been converted to normal sinus rhythm in 3 patients after premedication with small doses of quinidine or procainamide. No anesthesia is required, the ventricle is at no time depolarized by the shock, and there is no ventricular irritability produced.

The Relation of Heart Rate to Cardiovascular Dynamics Pacing by Atrial Electrodes

Hemodynamic studies were carried out as heart rates were controlled by atrial pacing on 10 normal patients at rest and during exercise. Each patient served as his own control. In both states tested the cardiac index, left ventricular work, and peripheral resistance were not significantly altered by changes in heart rate. The stroke index and mean systolic ejection rate decreased linearly with heart rate. During exercise the cardiac index increased up to 98% and again remained constant at all paced heart rates tested. At comparable heart rates the tension-time index, left ventricular work, stroke index, and mean systolic ejection rate were higher during exercise than at rest. At comparable heart rates[see figure in the PDF file]peripheral resistance was 38% lower during exercise than at rest. Myocardial oxygen consumption, as inferred from the tension-time index, increased with heart rate in both states.

Atrial Fibrillation Produced by Atrial Stimulation

Twenty-six episodes of atrial fibrillation and flutter-fibrillation, each lasting less than 23 sec, were recorded in three normal subjects during atrial pacing studies. The cause of these atrial arrhythmias was determined to be the result of stimulation within the atrial vulnerable period.

Variations of aberrant ventricular conduction in man: evidence of isolated and combined block within the specialized conduction system. An electrocardiographic and vectorcardiographic study.

Aberrant ventricular conduction (AbC) was produced in 52 subjects, including 14 normal volunteers, by the introduction of atrial premature beats through a transvenous catheter electrode. Simultaneous standard electrocardiograms and vectorcardiogams permitted detailed analysis of configuration. Multiple patterns of AbC were produced in 29 of 52 subjects. The general categories and their frequency were as follows: right bundle-branch block without significant axis shift from control, 31; right bundle-branch block with left axis deviation, 27; left axis deviation, 14; inferior axis deviation, six; right bundle-branch block with inferior axis deviation, seven; and complete left bundle-branch block, six. These patterns were believed to depend on the location of isolated or combined functional block in the major pathways of the specialized conduction system, which include the right bundle branch, common left bundle branch, anterior division of the left bundle branch, and posterior division of the left bundle branch. The present study has documented the general varieties of AbC, their relevance to clinical cardiology, and the varieties most likely to cause diagnostic difficulty.

Controlled Heart Rate by Atrial Pacing in Angina Pectoris A Determinant of Electrocardiographic S-T Depression

This study was undertaken with a consideration of the physiological relationship between myocardial oxygen consumption and heart rate. Atrial pacing was performed in 63 resting subjects, 36 of whom had been referred for evaluation of angina pectoris. Pacing at critical controlled heart rates evoked angina pectoris in six patients of this group with chest pain and, consistently and more frequently, produced significant S-T segmental depression in 28 patients as a manifestation of myocardial ischemia. The functional test employing controlled heart rates has several advantages over other stress tests. The use of the sole stress of controlled atrial tachycardia is a new technique which has provided relatively safe, reproducible results in the objective evaluation and investigation of myocardial ischemia.

Congenital dextrocardia with anterior wall myocardial infarction

Abstract A case of anterior wall myocardial infarction in a patient with congenital dextrocardia with situs inversus is presented. The clinical, electrocardiographic, and vectorcardiographic findings are discussed with reference to the pertinent literature.