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Biomedical subjects

M I El Gamal

Publications and source records attributed to M I El Gamal.

9 recordsLinked to original sources
PubMed1995

P wave oversensing in a unipolar VVI pacemaker.

A 45-year-old male had a VVI pacemaker implanted 20 years ago because of complete heart block. Because of perforation of the lead the pulse generator was removed after 4 weeks and a second lead was implanted from the contralateral side. Recently, the patient presented with symptoms of lightheadedness and syncope associated with prolonged pauses in the electrocardiogram. From the ECG, the ECG interpretation channel, and intracardiac electrogram telemetry, it was concluded that the VVI pacemaker was inhibited by P waves. The most likely explanation for this phenomenon was an insulation defect in the functioning lead caused by friction with the abandoned lead at the level of the high right atrium.

Electrocardiography↗
PubMed1985

Improved success rate of percutaneous transluminal graft and coronary angioplasty with the El Gamal guiding catheter.

In the period between October 1980 and December 1982 we evaluated the outcome of percutaneous transluminal graft and coronary angioplasty when a Judkins type guiding catheter (J gc) was initially used, but the lesion could not be passed and a subsequent attempt was made with the El Gamal guiding catheter (EG gc). Seven of twelve attempts to dilate stenotic coronary artery bypass grafts failed. The EC gc was tried in six, five were successfully dilated; one failed. Our initial attempts to dilate a stenosed right coronary artery failed in 16 of 68 attempts. The EG gc was attempted in 14. We successfully dilated ten, two dissections required emergency coronary artery bypass grafting (CABG); two failed. Our initial attempts to dilate a left anterior descending artery stenosis failed in 14 of 109 attempts. Six lesions were passed when the EG gc was tried. Five were successfully dilated, and one acute dissection required emergency CABG; eight failed. The EG gc is useful for transluminal angioplasty of stenosed aortocoronary bypass grafts. It increased the success rate of right coronary artery dilatation from 76-91%, but was of limited use in dilatation of left anterior descending lesions.

Angioplasty, Balloon↗
PubMed1985

Ventriculoatrial conduction: a cause of atrial malpacing in AV universal pacemakers. A report of two cases.

Retrograde atrial activation during ventricular pacing has often been a cause of intermittent or persistent arrhythmias (pacemaker-mediated tachycardia) in AV universal pacemakers. We recently encountered two cases in which VA conduction was responsible for atrial malpacing in patients with an implanted AV universal pacemaker, one programmed in DDD and one in DVI mode. Atrial malpacing was induced by the atrial refractoriness due to retrograde activation. In the first patient, it was observed when the pacemaker was programmed to a rate of 110 ppm (lower rate) and an AV interval of 200 ms in order to check crosstalk. In the second patient, it was observed after ventricular premature contractions.

Aged↗
PubMed1984

Balloon inflation caused by contrast injection through the guiding catheter: an unusual observation during coronary angioplasty.

Balloon inflation caused by contrast injection through the guiding catheter has been observed during several angioplasty procedures. The phenomenon is observed when employing an 8F USCI guiding catheter in combination with an ACS dilatation catheter. Two cases demonstrating the phenomenon are described in detail, together with an in vitro experiment that illustrates and quantifies the mechanism.

Aged↗
PubMed1984

Myopotential interference inducing pacemaker tachycardia in a DVI programmed pacemaker.

A 67-year-old male, suffering from ventricular tachycardia unresponsive to drug therapy, received a universal AV sequential pacemaker (DDD,M). The pacemaker was programmed in the DVI mode, pacing rate 100 bpm, AV interval 250 ms. After implantation, the patient experiences two episodes of tachycardia that proved to be pacemaker tachycardia with a rate of 150 bpm. The first period was self-terminating, and the second had to be stopped by reprogramming the pulse generator. Pacemaker tachycardia could easily be provoked by instructing the patient to contract the pectoral muscle adjacent to the pulse generator. To our knowledge, this is the first report of pacemaker tachycardia provoked by myopotentials in a pulse generator programmed in the DVI mode.

Aged↗
PubMed1983

False inhibition of an atrial demand pacemaker caused by an insulation defect in a polyurethane lead.

A patient who had an atrial demand pacemaker (AAI) presented with irregular pacing at a routine examination 5 months after implantation. When a magnet was applied over the pulse generator regular fixed rate pacing was obtained, thus proving oversensing in the system. Reprogramming the input sensitivity level to 2.5 and 5.0 mV did not solve the problem. Programming the pulse generator to the triggered mode (AAT) showed acceleration of the stimulation rate but also inhibition of the system. An S-S interval of 1260 ms was measured at a programmed interval of 857 ms (70 bpm). The pulse generator was disconnected and the intra-atrial electrogram was recorded. This showed different spurious signals varying in morphology and amplitude. Fortunately we were able to remove the lead (Medtronic 6991-U) from the atrial appendage. Subsequently a Helifix 12 mm AT lead was successfully implanted in the right atrial appendage and the same pulse generator was connected to the newly implanted lead. When the removed lead was examined by the manufacturer, a small tear in the insulation of the wire was detected. The dimensions of the tear were 0.1 X 0.7 mm. The tear was caused by stress corrosion cracking in the polyurethane tubing of the lead.

Bradycardia↗
PubMed1981

Chronic ventricular pacing with ventriculo-atrial conduction versus atrial pacing in three patients with symptomatic sinus bradycardia.

Three patients with symptomatic sinus bradycardia due to sick sinus syndrome were treated with permanent ventricular pacing for periods ranging from 2.5 to 4 years. All three patients had ventriculo-atrial conduction on routine electrocardiography. Although ventricular pacing was effective, they complained of fatigue, lightheadedness, and near syncope. Hemodynamic studies revealed the presence of regular cannon waves in the right atrium as well as in the pulmonary artery wedge pressure curves. Temporary atrial pacing resulted in disappearance of the cannon waves and a significant rise in cardiac output (32-48%). After normal atrio-ventricular conduction was confirmed by rapid atrial stimulation and His bundle electrocardiography, the pacing mode was changed to permanent atrial pacing on demand. The effort tolerance of the patients markedly improved, and the previously mentioned symptoms disappeared. Control hemodynamic studies 9 to 12 months after implantation of the atrial demand pacemaker showed that the improvement in cardiac performance was maintained.

Aged↗
PubMed1981

Externally induced irreversible runaway pacemaker.

An implanted ventricular demand pulse generator started firing at a rate of 1200 ppm during routine pacemaker follow-up utilizing the Vitatron VA 1000 pacemaker analyzer. This resulted in complete loss of capture; fortunately the patient had an intrinsic heart rate of 50 bpm and remained asymptomatic. Emergency replacement of the pulse generator resulted in re-establishment of effective ventricular pacing. An artificial origin of the impulses from the measuring equipment was excluded. To the best of our knowledge this is the first report of an externally induced irreversible runaway pacemaker.

Adams-Stokes Syndrome↗