Biomedical subjects

R Chicote

Publications and source records attributed to R Chicote.

6 recordsLinked to original sources

PubMed1993

[Chronotropic competence in patients with the sick sinus syndrome wearing AAI or DDD pacemakers].

The prevalence of chronotropic incompetence in patients with sinus node disease (SND) is not well defined. To assess this, we evaluated 18 patients (7 men, 11 women; mean age: 64 +/- 11) with SND and permanent pacemakers (AAI/DDD) with Holter monitoring and treadmill stress test. Only 2 patients received active cardiac drugs (1, L-dopa an 1 propafenone). The treadmill tests results were compared with a control group of 15 men and 18 women (mean age: 66 +/- 5, p = NS) without organic heart disease. During ambulatory activity all pacemaker patients increased their own cardiac rate to a value higher than the programmed basic pacemaker rate. In 8 patients the maximal rate attained was over 100/min (mean 95 +/- 19/min). The maximal rate during treadmill test in pacemaker patients was 131 +/- 25 (control group 138 +/- 14, p = NS). Exercise tolerance in METs was similar in pacemaker patients (5.2 +/- 2.6) and in controls (5.8 +/- 1.2) (p = NS). Two pacemaker patients (12%) didn't reach 100/min during stress test. Most patients with SND and permanent pacemakers (AAI/DDD) are able to increase cardiac rate during exercise. Rate responsive pacing (AAIR/DDDR) should be limited to a minority of patients with true chronotropic incompetence.

Aged↗

PubMed1990

Atrial endocardial mapping in the rare form of atrial flutter.

Endocardial atrial activation mapping was performed in 7 patients with rare atrial flutter (AF), inscribing predominantly positive deflections on leads II, III and aVF. In 2 cases both a rare and a common AF were mapped on different occasions. Every case displayed circular right atrial activation. In 5 of the 7 cases rare AF direction was clockwise (craniocaudal in the septum and posterior wall and caudocranial on the lateral and anterior walls). In 2 cases rare AF direction was counterclockwise (caudocranial in the septum and posterior wall and craniocaudal in the lateral and anterior walls). Both common AF rotated counterclockwise. A "line" of conduction delay or block was present in both clockwise and counterclockwise circuits between the posterior and lateral walls, in the probable location of the crista terminalis. This line of block extended the central obstacle made by the inferior vena cava toward, but perhaps not all the way to, the superior vena cava, making activation rotate roughly around the tricuspid ring. The ridge between the inferior vena cava and the tricuspid ring was a critical anatomic "closing" point in all clockwise and counterclockwise circuits. Right atrial macroreentry underlies rare AF. Direction of activation tends to be opposite to that in common AF. The cause of the positive deflection is unclear.

Adult↗

PubMed1990

Intracardiac coiling of permanent atrial leads.

We have observed intracardiac movement of permanently implanted atrial pacing leads in two patients with AAI pacemakers. This resulted in looping of the lead body into the right atrium and ventricle, without displacement of the tip or changes in the pacing or sensing thresholds. At surgery only a single fixation ligature was found and allowed sliding of the lead through the suture sheath, in both cases. The position was corrected by gently pulling the lead. Multiple ligature fixation may avoid this complication.

Aged↗

PubMed1990

[An informatics program for the management of patients with pacemakers].

We are introducing a software package (Dbase III application) for the management of patients wearing cardiac pacemakers. It runs on any IBM compatible microcomputer with a minimum of 512 Kb RAM and a 10 Mb hard-disk. It works with 6 separate databases: 1) identification-indications; 2) implants; 3) explant-closure; 4) follow-up; 5) pacemakers, and 6) electrodes. The program runs completely by menus, tasks being started by one key stroke. The patient databases are structured following the European Pacemaker Patient Card, including its codes. Data introduction is facilitated by friendly screen formats. The pacemaker database contains 495 models and 304 electrodes of all brands. Automatic searches include: 1) hospital number (from last and/or first name); 2) complete pacing history; 3) listing of patients by stimulation mode, loss of follow-up or proximity of expected battery end of life; 4) pacemaker or electrode definition, and 5) pacemaker models contained in the database. The program has been applied by nurses for over 6 months in our service, proving its efficacy with an easier and better follow-up. The accuracy of the automatic searches has been confirmed manually.

Computers↗

PubMed1990

[Permanent atrial stimulation (AAI) in the sick sinus syndrome].

A consecutive series of 18 patients (5 males, 13 females, mean age +/- DS 65 +/- 12 and 66 +/- 13 years, respectively, and mean +/- DS Wenckebach point of 162 +/- 20 ppm) given arterial pacemakers for sinus node dysfunction (SND) were followed to study the incidence of lead failure, atrioventricular conduction disturbances and chronic atrial tachyarrhythmias. The mean follow up time +/- SD was 18 +/- 10 months. There was not lead dislodgement. Chronic voltage output was reduced to 2.5 volts in 73% of patients because of a reduced chronic pacing threshold. One patient presented acute transient rise of pacing threshold and temporary loss of atrial detection. Progression to AV block was not documented. One patient had asymptomatic Wenckebach AV block during the night while on digoxin plus amiodarone. The AV block disappeared after cessation of drug therapy. Patients with previous episodes of paroxysmal atrial fibrillation did not presented the arrhythmia during follow up, while 75% of patients with previous atrial flutter presented the arrhythmia. None of the patients had systemic embolism. In conclusion, AAI pacing is a reliable and safe mode of pacing in patients with SND.

Aged↗

PubMed1990

[Chronic stimulation thresholds using carbon and platinum electrodes].

Low-output pacemaker programming depends on the absolute value of the chronic pacing threshold. To assess the chronic threshold with three different types of leads we have used Siemens-Vario pacemakers which allow us to measure the chronic voltage threshold noninvasively. Forty six patients had a 12 mm2 platinum tip lead; 38, 12 mm2 carbon tip lead an 15, 9 mm2 carbon tip lead (Siemens, 414-415, 412 and 423). Platinum leads longevity was 45 +/- 15.9 months; 12 mm2 carbon tip leads, 28 +/- 6.5 and 9 mm2 carbon tip leads, 17 +/- 4.5. Forty two months postimplantation chronic threshold (measured at 0.5 msec pulse-width) was 1.6 +/- 0.6 V for platinum electrodes and 1 +/- 0.3 V for 12 mm2 carbon tip leads (p less than 0.001). Twenty four months postimplantation 9 mm2 carbon electrodes chronic threshold was 1 +/- 0.4 V, and 1.7 +/- 0.5 V for platinum electrodes (p less than 0.001). There were no differences between carbon tip leads with 9 and 12 mm2 pacing area. The new activated carbon tip leads have lower chronic pacing thresholds than platinum electrodes with the same pacing area. Pacemaker-patients with these new type of leads can benefit of reduced output programming and increase their pacemaker longevity.

Aged↗