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Biomedical subjects

M Bilitch

Publications and source records attributed to M Bilitch.

At least 37 records · Page 2Linked to original sources
PubMed1980

Fascicular premature beats with narrow QRS in the presence of bundle-branch block.

The electrocardiogram of a sixty-two-year-old male revealed right bundle-branch block, left anterior superior fascicular block, and right precordial Q waves consistent with anteroseptal myocardial infarction. Premature beats with narrow QRS (100 ms) occurred intermittently; coupling intervals varied between 560-600 ms. His bundle electrogram confirmed the fascicular origin of the premature beats. During atrial prematuring studies, it was shown that an appropriately timed premature beat could prolong infra-His conduction time, but QRS normalization was not achieved. The possible electrophysiologic mechanisms that could result in a normal QRS complex with fascicular premature beats in this patient are discussed; a new mechanism is suggested.

Arrhythmias, Cardiac↗
PubMed1980

Clinical experience with a programmable pacemaker.

As part of a study to evaluate a new programmable pacemaker, 15 patients received lithium-powered R-wave inhibited, unipolar pulse-generators (CPI Model 0505). Five were initial implants (Group I) and 10 were pulse generator replacements (Group II). The follow-up period ranged from 1 to 18 months (mean 11 months). There were 5 deaths unrelated to the pacemaker. Three instances of pacemaker failure were identified and were characterized by a sudden loss of pacemaker output. THe malfunction, traced to a 10 kHz timing crystal, has been corrected in subsequently manufactured pulse-generators. In 11 patients, the pacemakers were programmed at a pulse width which was twice the threshold determined at 3 months. Four were programmed at 0.1 ms, three at 0.2 ms and four at 0.4 ms. Although no complications were seen in patients programmed at 0.1 ms pulse width, it might be advisable to leave pacemakers at 0.2 ms or greater for chronic pacing in patients with a pulse width threshold at 0.05 mg.

Aged↗
PubMed1979

Intracardiac electrocardiography during permanent pacemaker implantation: predictors of cardiac perforation.

Intracardiac electrograms from 50 successive patients undergoing permanent pacemaker implantation have been analyzed. There were 29 male and 21 female patients aged 14 to 93 years (mean age 68.4 years). The electrograms were obtained using methods that simulated the wave form that would be detected by unipolar cardiac pacemakers. Three types of electrographic patterns were identified: qR pattern with a q/R ratio of less than 1 (type I): QR pattern with a Q/R ratio between 1 and 4.4 (type II); and Qr pattern with a Q/r ratio between 12 and 15 (type III). A type I pattern was seen in 29 patients (58 percent), type II in 18 (36 percent) and type III in 3 patients (6 percent). The duration of the follow-up period ranged from 3 weeks to 20 months (mean 9.7 months); three patients were lost to follow-up study. There were four deaths apparently unrelated to the pacemaker. Recognizable problems (either pacing or sensing failure) occurred in one patient (6 percent) with a type II pattern, in two patients (66.7 percent) with a type III pattern and in no patient with a type I pattern. On the basis of these data it is suggested that at the time of pacemaker implantation, intracardiac electrograms with a type I pattern indicating good pacing thresholds and sensing should be sought. If type II wave forms occur with good pacing thresholds and sensing then the electrode could probably be left in position. The incidence of a type III pattern is rare; when it does occur it is greatly suggestive of myocardial perforation. When this pattern is seen, the pacemaker catheter must be repositioned.

Adolescent↗
PubMed1979

Early malfunction of transvenous pacemaker electrodes. A three-center study.

A 3-year study by three medical centers has revealed a 1-year electrode malfunction rate of 7.4%; most malfunctions occurred within the first 30 days. The incidence of unavoidable early malfunction (3.2%) fell within the 5% standards suggested by the committee report of the Inter-Society Committee on Heart Diseases. Incidences of obscure cause (3.2%) may be difficult to identify prospectively and may be, to a certain extent, unavoidable. The majority of the malfunctions (4.2%) showed specific clues that indicated that they were preventable. Successful repositioning was achieved on the first attempt in 80.6% of the cases with malfunction, and only 0.7% required ultimate myocardial electrode implantation. The principal clues to potentially unsatisfactory positioning included the presence of a large right ventricle with or without tricuspid insufficiency, current thresholds greater than 0.5 mA and ST-segment deviations on the intracardiac electrogram of less than 2 mV. Electrode malfunction may be more common with bipolar than with unipolar electrodes; but significant differences in the incidence of malfunction among different unipolar electrodes were observed. These data indicate that further developments in transvenous electrode design are warranted.

Arrhythmia, Sinus↗