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Biomedical subjects

J Gialafos

Publications and source records attributed to J Gialafos.

12 recordsLinked to original sources
PubMed1989

Spontaneous displacement of a pacemaker electrode and its subsequent successful reimplantation.

A case of what was assumed to be twiddler's syndrome was caused by spontaneous twisting and displacement of the electrode on the fortieth postoperative day. The pacemaker had not been manipulated by the patient, the pocket was tight, and the proximal electrode was well secured. The complication was managed successfully by reimplanting the same electrode after stiffening the lead near the generator with a portion of the stylet.

Aged↗
PubMed1987

Pacemaker inhibition by myopotentials associated with motion and exercise.

The standard exercise tests are usually inadequate for revealing the nature of oversensing problems associated with skeletal muscle myopotentials. We used special exercises, designed to test the rectus abdominis (RA) and pectoralis major (PM) muscle groups specifically, in a study of a large number of paced patients. We examined a total of 252 paced patients, with or without symptoms and in steady pacing rhythm, for the occurrence of pacemaker inhibition (215 VVI, 15 VVI Activitrax and 22 DDD, from 9 different manufacturers). Inhibition was observed in 75 (34.9%) of the conventional VVI, in 4 (26.6%) of the VVI Activitrax and in 17 (77.3%) of the DDD paced patients. It was found that both the PM and RA were capable of causing inhibition alone in some cases, while in others a synergy of the two groups was required. It is clear that the RA must always be considered as a possible serious source of inhibiting myopotentials, irrespective of the location of the pacemaker. The most effective exercise for eliciting PM exertion was pulling the flexed arm towards the chest against resistance, while in the supine position. For RA exertion, the best exercise was raising the head and trunk from the supine position and holding the trunk at an angle of about 30 degrees to the horizontal. Both these exercises gave good, consistently reproducible results.

Cardiac Pacing, Artificial↗
PubMed1985

Inhibition of demand pacemakers by myopotentials.

The inhibition of unipolar demand pacemakers by myopotentials was studied in 215 paced patients with or without symptoms and in steady pacing rhythm. ECG recordings were taken of all patients at rest and during effort in which maximal muscular strength from the pectoralis major (PM) and rectus abdominis (RA) muscles was required. In 75 patients (34.9%) transient pacing inhibition was observed. In these patients myopotentials from the PM and RA muscles were recorded simultaneously at rest and during special effort. The PM was the dominant source of inhibiting myopotentials in 50.7% of the total patients with oversensing and the RA was dominant in 28%. In the remaining 21.3%, neither of these muscle groups alone was able to cause inhibition and a clear synergy of both the PM and RA muscles was required. When oversensing occurred in a pacemaker implanted in the thoracic wall, the PM was the dominant cause in 54.4% of patients and the RA in 23.5%, while a synergy of both muscles was required in the remaining 22%. When the pacemaker was implanted in the abdominal wall, the RA was the dominant source of inhibiting myopotentials in all but two patients.

Abdominal Muscles↗
PubMed1977

Re-entry ectopic ventricular rhythm caused by artificial pacing.

Two cases with coupled ectopic ventricular rhythm associated with artificial pacing are presented. The premature ventricular beats appeared at a fixed distance from the R of the previous electrical stimulus complex and when pacing was stopped ventricular arrest occurred. This provides strong evidence that the ectopic ventricular beats were dependent on the electrical stimulus and therefore that they were produced by its re-entry. It was observed that the re-entry phenomenon occurred at low rates. This arrhythmia even persisted after the permanent pacing and was successfully suppressed by procainamide in both cases.

Aged↗
PubMed1976

The contribution of right ventricular angiocardiography to the diagnosis of tricuspid valvular stenosis (Observations made on 3 patients).

The right ventricular angiocardiographic findings, in the anterioposterior projection, are described on three patients with tricuspid valvular stenosis. During diastole, the tricuspid valve was delineated as an arcline contour, placed between the non opacified right atrium and the opacified right ventricle, and it was displaced to the left of the spine. Its mobility was diminished. Right ventricular angiocardiography seems to be a useful method for the diagnosis of the tricuspid valvular stenosis and the estimation of the pathology and the functional condition of the tricuspid valve. The method is recommended for further evaluation.

Adult↗
PubMed1976

Haemodynamic alterations of the left ventricle during right atrial pacing.

The left ventricular haemodynamic alterations during right atrial pacing were studied in 12 cases. Cardiac index varied little: during maximal rate however, its mean value was slightly lower than the resting one. Stroke index decreased inversely to the heart rate. The course of these indices did not separate the normal from abnormal cases. Ventricular function curves (VFCs) were constructed by relating the changes of left ventricular (LV) end-diastolic pressure (EDP) to those of stroke index (SI). In 4 normal cases the curves were steep, showing a fall of EDP with relatively large decrease of SI; in 3 cases of congestive myocardiopathy they were flat, showing fall of EDP in two and increase in one, with relatively small decrease of SI; in 5 patients with effort angina LVEDP initially decreased. This initial fall of VFCs was steep in two with normal and flattened in three with impaired resting LV function. Increase of EDP, evidently due to development of ischaemia, followed in all; it exceeded resting EDP in two out of three cases developing angina and in one out of two not developing angina. Our findings support the view that the increase of LVEDP is due to decrease of both myocardial contractility and compliance.

Adult↗
PubMed1976

Mechanical alterations of the left ventricle during right atrial pacing.

The effect of increasing heart rate by right atrial pacing on the peak value of the first derivative of left ventricular (LV) pressure(dp/dt) and the maximal velocity of the contractile element (KVmax) was studied in 12 cases. Peak dp/dt was poor as regards its sensitivity in reflecting the changes of contractility, due to its strong dependence on LV end-diastolic (EDP) and systolic pressure. KVmax increased constantly in the 4 normals and in 2 cases of ischaemic heart disease which did not develop angina; the increase exceeded 90 ml sec-1 in the former and one of the latter cases in which resting LV function was normal. In contrast, it decreased during the development of ischaemia in two of the three cases which developed angina; in the third case, in which also resting LV function was seriously impaired, the course of KVmax was almost flat. A similar flat course was observed in the three cases of congestive myocardiopathy. the above alterations of KV max were independent of the EDP and proportional to the basic contractility and its anticipated changes during pacing.

Adult↗
PubMed1975

The significance of intraventricular electrocardiogram in artificial heart pacing. Observations made on 232 patients.

From 1972-1975, 232 consecutive patients suffering from A/V block were paced intravenously in the Cardiac Department. Medical School, University of Athens. Of these, 124 were female and 108 male. Their age range was between 49 and 85 years. Besides fluoroscopic and threshold control, the intraventricular electrocardiogram (E.C.G.)., recorded from the tip of the electrode, was used as a guide for the accurate positioning of the catheter-electrode in the right ventricle. An injury pattern with an elevation of the ST segment of at least 3 mV and characteristic and steady morphology was obtained when the electrode tip was satisfactorily impacted in the right position. As a consequence of this, an initial stimulation threshold below 0.7 mA was obtained in all cases and pacing failure, due to catheter displacement was noted in only 11 cases (5%), without any apparent increase in the incidence of right ventricular perforation.

Action Potentials↗