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Biomedical subjects

D Velimirovic

Publications and source records attributed to D Velimirovic.

11 recordsLinked to original sources
PubMed1994

Isolation of a Puumala-like virus from Mus musculus captured in Yugoslavia and its association with severe hemorrhagic fever with renal syndrome.

An outbreak of severe hemorrhagic fever with renal syndrome (HFRS) occurred in 1988 in Pozarevac, Serbia, Yugoslavia. The disease was diagnosed in 4 children and 1 adult, and 1 of the children died. Rodents were captured from the same area and virus isolation attempted. A hantavirus, POZ-M1, was isolated from lung tissues of hantavirus antigen-positive Mus musculus. Serology and restriction enzyme digestion of polymerase chain reaction-amplified segments from this virus showed that it was a strain of Puumala (PUU) virus, the causative agent of nephropathia epidemica. While Clethrionomys glareolus is the major rodent host for PUU virus, these results suggest that M. musculus may also play an important role in harboring and transmitting PUU-like viruses. The serologic association of this virus with patients with severe HFRS reaffirms that PUU-like viruses may cause severe disease in addition to the generally mild form normally associated with nephropathia epidemica.

Animals↗
PubMed1993

Control of ventricular rate by interatrial septal incision and crista terminalis myotomy in the patients with atrial fibrillation undergoing mitral valve replacement.

The aim of the study was to analyze the effect of surgical moderation of conduction from the atrium to the atrio-ventricular (AV) node on ventricular response in 30 patients with atrial fibrillation (AF) undergoing mitral valve replacement (MVR). Besides the usual diagnostics, echocardiographic evaluation of the size of the left atrium was performed in all patients, as a parameter of stability of rhythm conversion by drugs. Surgical treatment was applied exclusively in cases where, judging by these parameters, there was little chance for drug treatment to be effective. All patients (mean age 50 years) had severe mitral valve disease (NYHA III and IV), chronic AF and irregular ventricular rate, and underwent mitral valve replacement with mechanical valve. The patients were divided into three groups of ten patients each. In group I: MVR was combined with interatrial septal incision (IASI) to study the effect of the moderation of conduction from the interatrial septum to the AV node; in group II: after MVR, IASI was combined with crista terminalis myotomy (CTM) to study the additional effect of the moderation of conduction along the crista terminalis to the AV node; in group III (control): MVR was performed through left atriotomy, without antiarrhythmic incisions. Ventricular response was studied in two phases: In the immediate postoperative period (up to 7 days), using continuous electrocardiographic (ECG) monitoring, and 2 months postoperatively, using 24 h Holter monitoring with the results compared to a preoperative 24 h recording. Postoperative AF occurred in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMed1992

Belgrade virus: a new hantavirus causing severe hemorrhagic fever with renal syndrome in Yugoslavia.

Two biologically and genetically distinct hantaviruses were isolated from blood and urine specimens collected from four Yugoslavian patients with clinically severe hemorrhagic fever with renal syndrome (HFRS). Viral isolates from three patients, designated strains Belgrade 1-3, were distinct from Hantaan, Seoul, Puumala, and Prospect Hill viruses as determined by plaque-reduction neutralization tests and restriction analysis of enzymatically amplified M-segment fragments. The fourth isolate, called Kraljevo, was indistinguishable from Hantaan virus. Strains Belgrade 1 and 2, like the Kraljevo strain, caused a fatal meningoencephalitis in newborn mice inoculated with 100 pfu of virus intracerebrally and intraperitoneally. Strain Belgrade 3 was much less neurovirulent, requiring 30,000 pfu of virus to cause fatal disease in mice. These data indicate that two distinct hantaviruses, one of which constitutes a new serotype, cause clinically severe HFRS in Yugoslavia.

Adult↗
PubMed1991

Epidural lead fracture caused by material processing fault.

Fracture of the epidural lead (Pisces Quad 3487) is documented in four out of eight patients with an implanted Itrel pacing system for treatment of peripheral vascular disease. In two patients, lead fracture was established during x-ray fluoroscopy. In the remaining two patients, x-ray examination did not reveal any fracture, due to proximity of the fragments. Microscopic examination of the extracted lead, however, confirmed lead fracture, as well as the presence of tissue fluid and thrombus between the two ends of the spiral shaped lead, but no insulation defect was observed. A cross-sectional area on the fracture line of the broken lead was examined using scanning electron microscopy. It was found, by tracing the radial marks to their point of convergence, that the initial microcrack started from a large inclusion of the calcium-silicon type at the lead surface. The initial microcrack was propagated by the fatigue mechanism. The presence of a large inclusion at the surface suggests that the main cause of the failure of the investigated epidural leads could be improper fabrication of the material. The high incidence of epidural lead fracture in our group suggests that this complication should be considered as a possible cause of epidural spinal electrical stimulation pacing system dysfunction.

Adult↗
PubMed1991

The etiology of syncope in pacemaker patients.

A total of 46 patients with syncopal episodes after VVI pacemaker implantation were studied. Of these, 92% had one to three syncopal episodes and 8% more than three. All underwent a thorough clinical examination, which included chest X ray, echocardiogram, neurological exam, and the following protocol: 24-hour Holter monitoring, EEG, blood pressure (BP) measurement in three positions, Doppler exam of the carotid vessels, fasting blood glucose, and head-up tilt table test (60 minutes, 60 degrees). Holter monitoring showed exit block in two patients (4.3%) and failed sensing in one (2.1%). In two patients there was unilateral slowing on EEG. Orthostatic hypotension was found in four patients (8.6%), and hypoglycemia in three insulin-dependent diabetics. An occlusive atherosclerotic plaque in the carotid artery was found in three patients (6.5%). Syncope was induced in 17 patients (36.9%) by the tilt table test, after a mean standing time of 47 +/- 11 minutes. The mean resting systolic BP of these patients was 140 +/- 24 mmHg, and fell to a mean level of 56 +/- 8 mmHg (mean systolic BP drop was 79 +/- 8 mmHg). Sixteen of these 17 patients with positive tilt table were being paced at the time of syncope and one had a spontaneous heart rate of 73 beats/min. In 14 cases (30.4%) the cause of syncopal episodes after this extensive workup remained unexplained. These results indicate that pacemaker dysfunction is not a major cause of syncopal episodes in pacemaker patients and that these are most often due to vasovagal syncope. Long-term follow-up is warranted to determine the prognostic significance of various types of syncope in pacemaker patients.

Blood Pressure↗
PubMed1990

Upper urothelial tumours and the Balkan nephropathy. Inference from the study of a family pedigree.

In an area heavily affected by both Balkan nephropathy (BN) and upper urothelial tumours (UUT), an outbreak of UUT (followed later by BN) affected at least four of five siblings. Their cousins developed BN in a high proportion but no one of them had any sign of UUT. It has been suggested that host factors determine the outcome of exposure to the same agent(s) responsible for both diseases.

Aged↗
PubMed1989

Circadian variations of heart rate and STIM-T interval: adaptation for nighttime pacing.

In order to determine the optimal pacing rate for pacemaker patients at night, 150 normal subjects with regular sinus rhythm and free of manifest heart disease, were studied using 24-hour Holter monitoring. Minimum and average heart rates were analyzed on an hourly basis. The study group was divided into six age groups, 25 subjects each, ranging from 20-29 years to 60-69 years. The minimum heart rate during the night was found to be lower than 65 ppm for all groups. The youngest subjects showed the largest variation in the minimum heart rate. The results suggest that an automatic lowering of the pacing rate during the night would allow for longer periods of sinus rhythm, thereby improving hemodynamic performance and reducing pacemaker power consumption. Suitable sensors for automatic lowering of the pacing rate include inbuilt 24-hour clock systems and the QT interval that lengthens during sleep.

Adult↗
PubMed1988

Association between stimulated QT interval and ventricular rhythm disturbances: influence of autonomic nervous system.

To examine the association between ventricular rhythm disturbances and changes in the pacemaker-induced stimulated T interval (STIM-T interval), we compared findings from monitoring of two patient groups. The first group consisted of 15 patients with QTX microprocessor pacemakers and the second group consisted of 198 patients with documented ventricular rhythm disturbances and coronary artery disease (CAD). In the first group, which was free of ventricular rhythm disturbances and manifest coronary artery disease, the STIM-T interval was measured every 4 hours over a 36-hour period at four pacemaker frequency settings (70, 80, 90, and 100) in order to observe the circadian variation of the STIM-T interval as a function of changes in autonomic nervous system (ANS) tone. The second group was comprised of patients with CAD and over 30 VES/hrs (Lown grade classification 1-5), and taking no antiarrhythmic medication. These patients were followed using 24-hour Holter monitoring over a minimum of 23 hours and with less than 5% artifact/recording. Information regarding mean hourly heart rate, total number of VES, VES pairs, VT runs, and ischemic episodes in this group was compared with changes in the STIM-T interval in the first group. The STIM-T interval was found to be shorter during the day and longer at night at all heart rate settings. The total frequency of VES, of VES pairs, VT runs, and ischemic episodes in the second group varies in a similar circadian fashion. The greatest total number of VES, of VES pairs, VT runs, and ischemic episodes was recorded in the waking hours, at the same time when the STIM-T interval is the shortest, while this number was significantly lower during sleep, when the STIM-T interval of the first group is the longest. This coincidence of circadian variation pattern between STIM-T interval in group I, and ventricular arrhythmias and ischemic episodes in group II, suggests that alterations in ANS tone reflected in the STIM-T interval may be an important factor in the occurrence of these untoward events.

Adult↗
PubMed1986

Target lead--low threshold electrode.

Acute and chronic threshold measurements were compared for three different electrodes: the Medtronic Target Tip model 4011, the Medtronic Ring Tip Model 6971 and the Siemens-Elema Carbon Tip Model 412S. The results of this study show that acute thresholds are lower with the Target Tip lead as compared to the other two. This finding applies to chronic thresholds as well. The results of this study favor programming to lower output energies while maintaining adequate safety margins with this lead system.

Electrodes, Implanted↗
PubMedDate not supplied

Results of 132 PTFE (Gore-Tex) bifurcated graft implantations.

One hundred and thirty-two PTFE bifurcated prosthetic grafts were implanted during the course of a bicentre study conducted at the abovenamed institutions from 1982 to 1986. The study included 118 males and 14 females with an average age of 62 years. One hundred and eighteen patients suffered from aorto-iliac occlusive disease and 14 from abdominal aortic aneurysms (AAA). Five patients had already undergone previous surgery (redo operations), with extirpation of thrombosed Dacron prostheses. Proximal end to end anastomoses were fashioned in 94 cases (71.2%), while end to side anastomoses were performed in 38 cases (28.8%). The distal anastomoses were to the iliac arteries in 11 cases, the common femoral artery in 89 cases and the deep femoral artery in 32 cases.

Aorta, Abdominal↗