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His bundle electrograms in 51 patients requiring permanent transvenous pacemakers.
Fifty-one patients required the implantation of a Cordis Omnis-Stanicor permanent pacemaker. His bundle electrograms studies, which included right atrial pacing and sinoatrial (SA) node postsuppression recovery times, were performed prior to the implantations. Pacing and sensing thresholds were obtained in all patients. Syncope or episodes of dizziness were the presenting symptoms in virtually every patient. Twenty-eight of the 51 patients had the sick sinus syndrome. Only nine patients were in complete heart block, and an additional nine were in second-degree heart block. The His bundle electrogram technique was not particularly helpful in selecting the potential pacemaker candidate. The symptomatic patient with second- or third-degree heart block requires a pacemaker. In the sick sinus syndrome, the His bundle electrogram was a disappointing tool in detecting abnormalities. In chronic bundle branch block, the His bundle electrogram appears to play a major role. A prolonged H-V interval in a symptomatic patient, in whom a specific noncardiac cause cannot be identified, signifies that a pacemaker is required.
[Differentiation of intraventricular blocks by means of electrocardiography and vectorcardiography].
The examination was conducted in 270 patients with ischaemic heart disease and signs of intraventricular conductivity disorders. The most demonstrative signs were singled out in ECG and VCG recordings that permit one to differentiate unifascicular, bi- and trifascicular blocks. Emphasis is made on the diagnosis of focal changes in the myocardium in the presence of excitation conduction disorders in the above mentioned branches of the bundle of His.
[Disorders of intraventricular conductivity in primary myocardial infarct].
Recent knowledge of the system of intraventricular conductivity permits to diagnose much more often the different variants of blocks of the main branches of the bundle of His that develop in acute primary myocardial infarction (41.42%). Clinical and electrocardiographic examinations of 239 patients with acute primary myocardial infarction revealed unilateral conductivity disorders in the right ventricle in 19.24% of the cases, in the left ventricle -- in 13.39%, and bilateral conductivity disorders -- in 8.79%. The main branches of the bundle of His blocks were combined with atrioventricular conductivity disorders in 19 patients (20.21%), in 12 of them the atrioventricular block being a manifestation of bilateral intraventricular conductivity disorders. Patients with various conductivity disorders developed with significantly higher incidence other rhythm disorders (atrial flutter and fibrillation, paroxysmal tachycardia), which indicates to a close relationship between the functions of conductivity and excitation of the heart.
[Persistant complete atrioventricular block after right heart catheterization. His bundle recording and implantation of a pacemaker].
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[State of the heart conduction system in the sick sinus syndrome (according to the recording of the bundle of His potentials and the atrial stimulation test)].
It was established that the presence of Samoilov-Wenckebach's periods and prolongation of the H--V interval at low frequency of the imposed rhythm as well as periods of asystolia of more than 1,200 msec are most typical for these patients. An attempt was made to determine the type of cardiac stimulation indicated for such patients from the character of the disorders of rhythm observed in them and the initial frequency of their own cardiac contractions.
[Treatment of severe ventricular arrhythmia by means of repeated cardiac stimulation].
The overdrive pacing method is widely used now in clinical practice for prevention and treatment of severe ventricular disorders of the cardiac rhythm. The mechanisms of arrhythmia suppression by means of this stimulation is analysed. Indications are determined for the choice of the site of stimulation and optimal impulce frequency in ischemic heart disease, and overdosage with digitalis drugs, as well as in myocardiopathy.
Streptolysin 'O' and cardiac dysfunction.
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[Electrophysiological peculiarities of the heart. The phenomenon of intermittently fluctuating bundle-branch blockade in extrasystoles].
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[Intravenous ajmaline test in investigation of the his bundle for diagnosis of paroxysmal atrioventricular blocks (author's transl)].
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The role of A-V node and ventricular conduction system in cardiac arrhythmias.
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[Electrocardiogram in block of septal bundle of right branch].
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[Problems in electrocardiographic diagnosis].
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The second heart sound: newer concepts. Part I: normal and wide physiological splitting.
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[Arrhythmias in direct fetal electrocardiography].
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'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.
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.
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.