[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)]. / Sostoianie provodiashchei sistemy serdtsa pri sindrome slabosti sinusovogo uzla (po dannym registratsii potentsialov puchka Gisa i testa predserdnoi stimuliatsii).

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.

[Significance of spike potentials in the sinus nodes and atrial conduction system during interpretation of bundle-of-his electrography]. / Zur Bedeutung der Spike-Potentiale des Sinusknotens und des Vorhofsleitungssystems bei der Interpretation der His-Bündel-Elektrographie

The article deals with the issues of the His bundle electrogram (HBE) analysis, using the spike potentials of the sinus node and the atrial conductive tracts for the interpretation of the HBE. The HBE and the atrium spike potentials have been recorded in 40 dogs and in 307 patients. According to our data the onset of the A-wave on the IcECG begins in some msec earlier than the onset of the P-wave on the standard ECG leads. The spike potentials of the sinus node have been recorded directly at the sinus node area, the onset of which begins in 20-40 msec earlier than the onset of the P-wave. By our data the atrial A-wave recorded from the right atrium on the IcECG consists of the slow wave showing summary effect of the atrium depolarization and the three spikes (A1, A2, A3). They are recorded at the beginning (A1) middle (A2) and the end (A3) of the P-wave and reflect the quick impulse spread through the atrium conductive tracts. The moment of the impulse coming to the AV nodes is reflected by the atrial spike A2. The time of the impulse spread from the sinus node to the AV node shows exactly the interval from the onset of the spike potential of the sinus node till the spike A2. The interval from the spike A2 to the H-potential (A2-H) shows the impulse spread time through the AV node. The recording of the HBE and the atrium spike potentials was performed by means of the microcatheter of own construction (with the unipolar electrodes, external diameter of which does not exceed 1 mm) after our method of the heart microcatheterization through the subclavian vein.

[Method of recording the diagnostic value of the electrocardiograph of the bundle of His]. / Metod registratsii i diagnosticheskaia tsennost' elektrogrammy puchka Gisa

A method of cardiac microcatheterization introduced by the authors and effected by puncturing the left subclavian vein with a microcatheter of their original design permits recording the bundle of His electrogramme in a functional diagnosis study or in an intensive care ward. The bundle of His electrogramme was recorded in 107 patients, 72 of them having ischaemic heart disease, and 35 -- other cardiac lesions. The obtained data support the high diagnostic value of the bundle of His electrogramme, especially in determining the level of the atrioventricular block, of the reentry phenomenon, in differentiating abberant QRS complexes from ventricular extrasystoles, in diagnosing ectopic rhythms from different parts of the conductive system of the heart, and other complicated arrhythmias. The bundle of His electrogramme can be also used for the study of the effect of drugs on the conductivity function.

Recording of spike potentials of heart atria and His bundle using microcatheterization via subclavian vein.

The authors describe their own method of right heart microcatheterization by means of transcutaneous introduction of an original unipolar microcatheter into the left subclavian vein. The method makes possible recording of th His bundle electrogram as well as of spike potentials of the sinus node and atrial conduction pathways. His bundle electrograms were recorded in 237 subjects, of whom 72 had ischaemic heart disease and 115 suffered from other cardiopathies, 50 persons with non-cardiac diseases constituted the control group. The high diagnostic value of His bundle electrogram was confirmed, especially in appraising the degree of A-V block, differentiation between aberrant QRS complexes and ventricular extrasystolia, and in other arrhythmias. Recording of spike potentials of the sinus node, atrial conduction pathways, and His bundle, and determination of the interposed intervals allow selective assessments of the impulse propagation velocities in individual segments of heart conduction system, especially on drug administration, and offer valuable information on the genesis of various types of arrhythmias and conduction disturbances.