Surveillance of pacemaker patients by an automatic pacemaker function analyzer

This is a report of our experiences with the automatic contrast medium injector at selective coronary angiography during 836 examinations, and the quantitative evaluation of 193 single injections. Using average injection volumes per single injection of 5.0 ml for the left and 2.5 ml for the right coronary artery, a clear reduction of the quantity of contrast medium at constant definition can be registered. The variability in increase in the injection flow from 0 up to the peakflow appears to be important according to the anatomic and pathologic facts. Frequently a contrast medium reflux occurs out of the coronary ostium into the aorta. On the whole, automatic injection at selective coronary angiography is a reproducible and extensible method with few risks.     

Double pacemaker implantation

A demand-type pacemaker and an inductive radiofrequency atrial pacemaker were implanted in four patients presenting with sick sinus syndrome, bradycardia-tachycardia syndrome, Wolff-Parkinson-White syndrome, atrial flutter, and paroxysmal atrial tachycardia, and in one patient having ventricular tachycardia with ectopic ventricular beats. Our follow-up of these patients showed that double implantation is feasible and effective in controlling different types of arrhythmia occurring in the same patient.     

Erosion of pacemaker lead

This paper describes the course of a patient who had delayed breakdown of the implantation site of a permanently placed pacemaker electrode. Transvenously placed endocardial electrodes have a lower incidence of morbidity and mortality, but skin erosions and secondary infection of the electrode tracts occur in both types. Once skin erosion is suspected, it is better to resituate the pacemaker as early as possible, since any delay may invite septicemia.     

Polarization potentials causing pacemaker oversensing

This case of ectopic pancreas found in the pre-pyloric channel of a 2-day-old infant is unique. A review of the literature reveals no other cases of symptomatic ectopic pancreas in an infant of this age. In this patient, signs and symptoms were consistent with pyloric stenosis. Upper gastrointestinal study and esophagogastroduodenoscopy (EGD) revealed the diagnosis. This case is examined and the literature is reviewed.     

Pacemaker syndrome without a pacemaker

Circulatory consequences of cardiac arrhythmias are not always evident. Proper interpretation of the clinical symptoms in certain cases requires assessment of the patients' other hemodynamic characteristics. The authors present the case of a patient with left ventricular hypertrophy, who developed severe circulatory failure at the time of artrioventricular dyssynchrony in association with junctional rhythm. Analogy between the circulatory consequences of the junctional rhythm and ventricular pacing was documented by hemodynamic measurements. The patient was subsequently treated by implanting an atrioventricular pacemaker.     

Muscle potentials simulating pacemaker malfunction

Interference spikes were noted on the electrocardiogram of a patient with an implanted demand pacemaker. Runaway malfunction was suspected and the generator replaced. Subsequent investigation showec that the interference originated from fasciculation in the left leg caused by underlying neuromuscular disease. Skeletal muscle potentials can produce an electrocardiographic appearance closely resembling 'runaway' pacemaker. Such abnormalities should prompt a search for occult neuromuscular disease.     

DDD pacemaker implantation--cardiac pacemaker tips in the left atrium and ventricle by the left thoracotomy

Recently DDD pacemaker implantation for the children has undergone trials world wide; though regarding the approach, ways and positions of the epicardial lead, a few problems are still remained to be discussed. Now we report 9 cases (5 males, 4 females) of DDD pacemaker implantations by the left anterolateral thoracotomy approach. The 9 patients weighing 6.5 to 33 kg, were aged 11 months to 12 years (mean 6 years) of whom male 5, female 4 with degree of Block; 2 and 7. To all patients the stab-in type epicardial tips were implanted in the left atrium, the screw-in type ventricular epicardial tips were in the left ventricle by the 4th intercostal thoracotomy, and the pacemaker generators were beneath the fascia of the abdominal rectus muscle. We have no sensing and pacing failure, all pacemakers are working in the DDD mode well.     

The wandering pacemaker: intraperitoneal migration of an epicardially placed pacemaker and femoral nerve stimulation

A human immunodeficiency virus (HIV)-infected individual was first diagnosed with red blood cell aplasia due to B19 parvovirus infection in late 1989. Over the subsequent seven-year period, he received a total of 119 units of red blood cells (RBCs) and intravenous immunoglobulin every 2-3 weeks. In 1996 combination antiretroviral treatment with a protease inhibitor was initiated. He received four more units during the following two months and then required no more transfusions for the subsequent 24 months of follow-up. His CD4 count progressively increased and DNA polymerase chain reaction for parvovirus B19 became undetectable. Aggressive antiretroviral treatment may effectively diminish transfusion requirements among HIV-infected individuals with pure RBC aplasia resulting from parvovirus B19 infection.     

Computerised assessment of cardiac pacemaker performance

The design and use of a PDP 11/40 based automated on-line cardiac pacemaker assessment system is described. One program has been developed for testing pacemakers on the bench and another for implanted pacemaker tests. Either fixed rate or demand pacemakers can be tested. The on-line system is easy and fast to use and is also highly accurate. Parameters extracted are pulse width, rate and pulse energy. In addition, a graphical representation of the patient's ECG and the pacemaker pulse is obtained on a computer graphics terminal.     

Inhibition of a ventricular synchronous pacemaker

Noncompetitive ventricular synchronous pacemakers (VVT) have been available since 1965. Most presently available and earlier models have a single, fixed pulse-to-pulse interval divided into a total refractory period of 350 to 400 msec., followed by a sensitive period. During the refractory period the pacemaker will not respond to QSR complexes or electrical signals, but a pacer stimulus will be produced during the sensitive period. The generator cannot be inhibited under any circumstances. The Cordis Omni-Sctocor has a refractory period and two sensitive periods, during one of which the generator is inhibited. Unlike other ventricular synchronous pacers, the Omni-Ectocor is capable of inhibition by single or multiple ventricular or other signals, of slowing or increase of the stimulus formation rate which depends on the timing of the premature ventricular contractions, and of inhibition by a run of ventricular tachycardia or by electromagnetic interference. The rate of interference producing these effects is a function of the automatic rate to which the generator is programmed. All of these factors must be considered for proper interpretation of the ECG.