Philip Samet

His bundle (BH) electrograms were recorded in 123 patients. The electrocardiogram showed only left axis deviation (LAD) in ten, right bundle branch block (RBBB) with a normal axis in thirty, RBBB and LAD with or without old myocardial infarction in sixty-eight and RBBB with right axis deviation (RAD) in fifteen. Thirteen of these patients were restudied at intervals of six months to two years. The conduction times through the atrioventricular (A-V) node (A-H) and His-Purkinje system ...

Twenty-one patients with complete heart block (CHB) were studied by recording His bundle (BH) electrograms. The site of block was localized proximal or distal to the site at which the BH electrogram was recorded. Eighteen patients had block distal to the recorded BH deflection. One of these 18 patients had a narrow QRS complex indicating block within the His bundle; the other 17 had wide QRS complexes probably due to bilateral bundle-branch block. The three patients with block proximal ...

Fourteen patients with conduction defects were analyzed by using bundle of His (BH) recordings. The BH electrograms were validated by BH and right atrial pacing (AP). In 12 patients with Mobitz type II A-V block, failure in impulse transmission for the dropped beats was localized distal to the recording site of the BH. Three of these 12 patients showed normal QRS complexes. In two of these three, the QRS complexes remained unchanged during intermittent periods of complete heart block ...

The phenomenon of postpacing depression of cardiac pacemakers was utilized to evaluate the sinus-node function in 56 patients by analyzing the sinus-node recovery time (SRT), that is, the interval between the last paced P wave and the following sinus P wave. Corrected SRT (CSRT) is defined as the recovery interval in excess of the sinus cycle (SRT — sinus cycle length). The SRT was measured following sinus-node suppression by (1) isolated premature beats (PABs) and (2) atrial pacing (AP) ...

The evolutionary pattern of occlusive coronary artery disease was studied by comparing coronary cinearteriographic findings in repeated catheterizations of 85 patients. Fifty-six percent of 16 medically treated patients with coronary artery disease were found to have progression of occlusive coronary artery disease in the repeated study. Patients who had progressive coronary artery disease were similar to those with nonprogressive disease in age and in duration and severity of disease. A ...

An experimental model for the study of conduction disturbances in the proximal His-Purkinje system after acute myocardial ischemia was produced in 24 dogs by ligation of the anterior septal artery. Eighteen of the 19 dogs that survived the initial vulnerable arrhythmic period showed different degrees of conduction disturbance in the bundle of His, right and left bundles or any combination thereof usually within 1 to 2 12 hours after ligation. In 14 experiments normal conduction was ...

The contributions of atrial systole to ventricular filling are emphasized by analyses of pressure curve data in (1) patients with complete heart block studied by right and left heart catheterization, (2) patients with sinus rhythm and atrial fibrillation and (3) sinus rhythm and ventricular premature beats. The level of systolic and diastolic right and left heart pressures varies with the temporal relation between the P and QRS complexes in patients with complete heart block. Peak ...

Eight patients were studied by simultaneous intracardiac recordings of the specialized conduction system from left and right heart. Five patients had normal A-V conduction, one had left axis deviation (LAD), and two had bundle-branch block. Bundle of His (BH) and right bundle (RB) recordings from the right heart were obtained and validated as previously described. In addition a bipolar electrode catheter was introduced into the root of the aorta and left ventricle via the right brachial ...

Seven patients with massive thrombosis on a Bjork-Shiley aortic valve prosthesis are described. This complication was documented in 5 percent of our patients with a Bjork-Shiley valve and occurred 3 to 19 months (mean 13 months) after insertion of the prosthesis. Only one patient had adequate anticoagulant therapy at the time of diagnosis. All patients had acute or subacute clinical deterioration. Anginal chest pain was the presenting symptom in four patients, and acute left ventricular ...

In 10 patients, 24 episodes of supraventricular tachycardia were treated by rapid electrical stimulation of the right atrium. One episode of sinus tachycardia, eight episodes of atrial tachycardia, two episodes of atrial flutter, and 13 episodes of A-V junctional tachycardia occurred. In each case the diagnosis of the arrhythmia was documented by obtaining unipolar and bipolar intra-atrial electrograms. In three cases of supraventricular tachycardia the ventricular rate was slowed as a ...

Many recent clinical studies of the His-Purkinje system have utilized intracardiac catheter recordings. This study describes a technique for recording activity of the ventricular specialized conduction system from the body surface. Unlike the standard electrocardiographic signals, approximately one mV at the body surface, the electrical activity of the His-Purkinje system is in the microvolt range at the body surface. In 15 anesthetized dogs, His bundle electrograms, standard ECG ...

In order to determine the associated hemodynamic events, angina pectoris was induced by an atrial pacing technic. In all patients developing angina pectoris, ischemic changes were noted electrocardiographically. The hemodynamic findings were variable: in some patients no changes were noted; in others, significant increases in cardiac output, left ventricular end-diastolic pressures (LVEDP), and femoral arterial and pulmonary arterial pressures occurred. These changes suggest that, ...

To elucidate the architecture of the left bundle branch, activation of Purkinje (P) and myocardial (M) cells of the canine left ventricular endocardial surface was mapped in vitro before and after lesions were placed in the proximal left bundle branch. Close bipolar electrodes or microelectrodes were employed to record P and M potentials by standard techniques. The left bundle branch has conspicuous and straight border fibers that continue as bridging strands to the papillary muscles. In ...

The influence of ouabain on various spontaneous and experimentally-induced cardiac rhythms was determined. Twenty-three mongrel dogs, anesthetized with sodium pentobarbital (30 mg. per kilogram) were digitalized by the administration of ouabain, 10 μg per kilogram every 10 minutes, until toxicity developed. A Lead II electrocardiogram, His bundle electrogram, and aortic blood pressure were continuously monitored. During sinus rhythm (average HR: 152 ± 25 beats/min.) the rate of this ...

Fifty-two patients with sinoatrial disturbances causing syncope, dizzy spells, heart failure or predisposition to ventricular tachyarrhythmias were treated with permanent cardiac pacing between January 1966 and June 1970. They were followed up from 12 to 60 months. The rhythm disorders treated with permanent pacer implantation were: (1) sinus bradycardia (27 patients); (2) sinoatrial block or arrest (10 patients); (3) brady-tachyarrhythmia syndrome (11 patients); and (4) sinus ...