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At least 685 records · Page 38Linked to original sources
PubMed1977

Abnormalities of cardiac conduction in sinus node disease. Correlation with clinical findings.

His bundle recordings, sinus recovery time and the response to atropine were studied in 28 patients with symptomatic sinus node disease. The electrophysiological data were correlated with the clinical picture and the course of the disease. The marked prolongation of sinus recovery time and a decidedly diminished responsiveness to atropine may increase the accuracy of clinical assessment of the disease but negative results of these tests do not exclude even serious dysfunction of the node. The His bundle electrogram provides a more thorough evaluation of AV conduction and should be taken into account when permanent electrotherapy is being considered.

Adolescent↗
PubMed1976

[Cardiovascular disorders in young military personnel. Treatment and readjustment].

The vascular disturbances most commonly encountered in conscripts are examined and the features leading to their diagnosis and the consequent differentiation of organic heart diseases are described. Rhythm variations, auscultation abnormalities (systolic, diastolic and vascular murmurs, additional tones) and ECG alterations thus detected are seen as instances of functional disorders, of a non-dangerous nature that will regress or disappear in the course of time.

Adult↗
PubMed1976

Rapid overdrive pacing of refractory tachyarrhythmias in patients after open-heart surgery.

The efficacy of rapid ventricular pacemaker overdrive in the treatment of supraventricular and ventricular tachyarrhythmias is presented as a new approach to the management of these rhythm disorders inpatients after cardiac surgery. This mode of therapy is exemplified in the control of heart rate and return of normal sinus rhythm in patients with both types of tachyarrhythmias refractory to conventional antiarrhythmic agents. In addition, the pathogenesis and mechanisms of pacemaker overdrive in termination these rhythm disturbances are delineated.

Bundle-Branch Block↗
PubMed1976

Ankylosing spondylitis with complete heart block.

A patient with complete heart block due to ankylosing spondylitis exhibited an unusually brisk increase in ventricular rate with exercise. Despite broad ventricular (QRS) complexes, His bundle electrograms demonstrated a His deflection before each QRS complex and thus established the level of atrioventricular (A-V) block to be proximal to or localized to the His bundle. A junctional pacemaker accounted for the brisk response to exercise, atropine, or isoproteronol. Left bundle branch block pattern and prolongation of infranodal conduction time (H-Q) suggested additional disease involving the His bundle and/or right fascicle. Wide-spread disease affecting A-V nodal and infranodal conduction was compatible with pathologic changes seen in this disease. Because the pacemaker was able to respond to stress promptly and with appropriate increase in heart rate, the patient appeared not to warrant pacemaker implantation in his present state.

Atropine↗
PubMed1976

The retrograde His bundle deflection: its recognition and value in the analysis of tachyarrhythmias induced by stimulation on the T wave.

Interpretation of deflections presumably retrograde His bundle in origin has to be performed in context considering the coexisting changes in simultaneously recorded intracardiac and surface leads. His bundle electrocardiography thus conceived is helpful in the analysis of the runs of ectopic beats elicited by premature ventricular stimulation during the antecedent T wave in patients without coronary artery or primary myocardial disease. Identification of AV nodal echoes within the paroxysms as well as the subsequent runs of reciprocating tachycardias, was possible in patients with and without preexcitation, although a thorough study of these cases also requires recording of coronary sinus and low lateral right atrial electrograms. The behavior of the retrograde H deflection in respect to the first extra beat following the premature QRS complex helped in excluding bundle branch reentry. The latter is improbable in patients with 'complete' bundle branch block pattern, if extra beats show a contralateral bundle branch morphology. However, in absence of bundle branch block, retrograde H deflections were not helpful in elucidating the mechanisms of pacemaker-induced intraventricular (bundle branch, fasicular or vulnerability-related) reentry.

Atrioventricular Node↗
PubMed1976

[Disorders of intraventricular conductivity in ischemic heart disease].

An analysis of 439 cases of interventricular blocks in ischaemic heart disease is presented, 75.2% of the disorders developing in the branches of the left His' bundle. Intraventricular block was more common in cases of large focal myocardial changes. Bifascicular blocks preceeded full atrioventricular block more often than other forms of intraventricular conductivity dosorders. The greatest difficulties were encountered in the electrocardiographic diagnosis of focal changes in the posterior wall of the left ventricle when the left anterior branch of His' bundle was blocked.

Bundle of His↗
PubMed1976

Surgical correction of cardiogenic shock.

Cardiogenic shock as a result of myocardial infarction demands an aggressive diagnostic and therapeutic approach to improve survival. First, the patient likely to develop shock should be identified early in his course so that interventions to reduce or contain infarct progression and thus prevent shock can be instituted. If the patient's condition deteriorates, prompt precise diagnosis of the cause of the hemodyanamic impairment must be made at the bedside with Swan-Ganz right heart catheterization and echocardiography, and, if potentially surgically correctable disease is present, left heart catheterization with coronary angiography in the catheterization laboratory should be done. Surgical repair of anatomic disruptions of the heart ventricular septal defect, or mitral valve rupture is frequently life-saving. At present, operative intervention for shock secondary to massive myocardial infarction alone remains a challenge.

Aortic Aneurysm↗
PubMed1976

'Supernormal' phase in hemiblock conduction.

A case is described where the basic sinus rhythms is associated with an advanced degree of left anterior hemiblock. The rhythm is complicated by atrial extrasystoles, associated with a lesser degree of left anterior hemiblock. This paradox of 'supernormality' is explained on a critical interplay of differential refractoriness within the divisions of the left bundle-branch.

Adult↗
PubMed1978

Electrophysiological properties of intravenous metoprolol in man.

Electrophysiological changes produced by intravenous (0.1 mg/kg) metoprolol, a new selective beta 1-blocking agent devoid of intrinsic activity, were studied in 16 subjects with estimated normal impulse formation and conduction. The most important effects were sinus bradycardia, mild increase of sinoatrial conduction time, depression of intranodal conduction, and prolongation of AV node refractory periods. Sinus node recovery time and atrial refractory periods were unmodified. Infranodal conduction and the refractory periods of the His-Purkinje system, as well as of the bundle-branches, were unchanged. These effects are compared with those observed after intravenous propranolol, pindolol, and oxprenolol.

Adult↗
PubMed1978

Mahaim conduction producing left axis deviation and normal QRS.

An unusual patient is described in whom electrophysiological studies strongly suggest the occurrence of Mahaim conduction. The patient whose electrocardiogram previously showed a left anterior hemiblock pattern then developed advanced atrioventricular (AV) block (AH block). Beats conducted through the atrioventricular node always had a short HV interval (20 ms) and QRS complexes of left anterior hemiblock pattern. Junctional escape beats always had a normal HV interval (50 ms) with normal intraventricular conduction. His bundle pacing showed the StV interval and QRS contour of escape beats. These findings suggest the existence of an accessory pathway (Mahaim fibres) passing from the area of block, presumably the uppermost portion of the His bundle, to the posteroinferior division of the left bundle-branch. The surface electrocardiogram did not show the characteristic delta wave of the Wolff-Parkinson-White syndrome. Our observations suggest that patients in whom there is conduction along Mahaim fibres may show only the pattern of intraventricular conduction defect without a delta wave.

Cardiac Complexes, Premature↗