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Biomedical subjects

D Velimirović

Publications and source records attributed to D Velimirović.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Metabolic parameters in the evaluation of frequency-adaptive sensors in pacemakers].

A comparison was made between metabolic parameters during exercise in patients with implanted dual sensor VVIR pacemakers. We analyzed two groups of patients with implanted dual sensor responsive pacemakers. The first group was composed of 14 patients (mean age 37.7 years) who had implanted Topaz pacemakers. The second group of 9 patients had a Legend Plus (mean age 44.7 years). A control group consisted of 54 healthy individuals (mean age 40.4 years). Testing was performed on treadmill, using a stepwise staircase loading CAEP protocol. Directly measured and mathematically calculated parameters used in assessment of metabolic impact of pacemaker function were: minute ventilation (MV), MV/body surface, MV/body mass unit, oxygen consumption, oxygen consumption/body surface, oxygen consumption/heart rate (oxygen pulse), oxygen consumption/body mass unit, carbon dioxide production, respiratory index. The majority of the observed parameters revealed no statistically significant difference between the control group and the patients with dual sensor or single sensor controlled rate response. However, oxygen pulse showed a statistically significant difference when comparing the group with single sensor controlled rate response with dual sensor controlled rate response and control group (p < 0.05). Other parameters indicating an advantage of dual sensor controlled rate were the time period of reaching anaerobic threshold (respiratory index) and exercise duration. They both displayed a statistically significant difference between dual sensor controlled rate response and single sensor rate response (p < 0.05) with no significant difference compared to control group (p > 0.05).

Adult↗
PubMedDate not supplied

[Analysis of programmed pacing rate levels in patients with the carotid sinus hypersensitivity syndrome and implanted Clarity pacemakers].

New Clarity DDDR pacemaker system (Vitatron Medical B.V.) Clarity DDDR, provides an option for recognizing sudden rate drop and responding by intervention pacing until it detects the recovering. In patients in whom syncopal episodes are mainly caused by occasional drops in heart rate, Sudden Rate Drop Intervention feature intends to provide high rate intervention pacing. We have implanted 10 of these devices in our Centre, 2 of which in patients with hypersensitive carotid sinus syndrome. In patients with carotid sinus syndrome it is possible to provoke this situation by sinus caroticus massage. In both patients, we activated Sudden Rate Drop Intervention on DDD mode pacing and used protocol for testing the necessary level of sudden Rate Drop Intervention Rate. Both patients gave their informed consent to be submitted to this testing. Pacemaker software assumes rate intervention level of 110 bpm. We tested our patients for rate levels of 90 and 110 bpm. Massaging the carotid sinus during 5 seconds, we provoked sudden Rate Drop Intervention 10 times, in each patient, 5 times at intervention rate of 90 and 5 times at 110 bpm. Patients were unaware of the programmed intervention rate and were merely expected to report any different sensations experienced during the testing. In all 20 tests, pacemaker responded to sudden rate drop elicited by carotid sinus massage (100%), that was verified by selected event recordings. After the massage, no patient experienced any sensation at sudden rate drop intervention rate level of 90 bpm in a total od 10 tests (100%), while 8 of 10 messages at 110 bpm intervention rate provoked palpitations (80%). We concluded that lowering of Sudden Rate Drop Intervention Rate Level from 110 BPM to 90 BPM did not affect the reliability of system reaction, but changes of patient's awareness of heart beats. As a final conclusion, it should be said that basic prerogatives of a pacing system are: safety and efficacy with minimal energy consumption, and in this case, quality of life option that a patient practically does not feel intervention when it occurs, are all met.

Cardiac Pacing, Artificial↗
PubMedDate not supplied

[The small aorta syndrome].

Angiograms of 956 patients (94.7% of males and females) with aortoiliac occlusive disease were analyzed retrospectively. The existence of small aorta syndrome (SAS) was documented in 9 female patients with a mean age of 41.1 yrs. In this population the incidence was 0.9%; however, in the female patients the incidence was higher (18%). Clinical signs of arterial insufficiency of the lower limbs included: claudication in 8 pts and digital gangrene in 1 patient. Risk factor status was as follows: cigarette smoking was present in 100%, hypertension in 33%, obesitas in 25% and hyperlipidemia in 20% of cases. Dimensions of aortoiliac segments on angiograms and belongs to SAS were made by De Laurentis classification. Aortoiliac segment dimensions of SAS determined on angiograms were compared with operative findings. The mean cross sectional area of the infrarenal aorta was 14.1 mm, at the bifurcation 10 mm, common iliac artery 8 mm, and external iliac artery 4.3 mm. Of 9 female patients with small aorta syndrome 8 were operated by bypass technique. The mean follow-up time was 12.3 months. In 7 pts the reconstructive vascular procedure was successful. In one patient the graft became occluded, 3 month after operation, due to poor run-off. This necessitated limb amputation.

Adult↗