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Biomedical subjects

A Erdogan

Publications and source records attributed to A Erdogan.

At least 19 recordsLinked to original sources
PubMed2001

Perforating branches of the anomalous anterior communicating complex.

The anterior communicating complex was studied in 25 cadaver specimens obtained at routine autopsy. In 15 specimens (60%), an anomalous anterior communicating artery was found. The most common anomaly identified was a multi-channeled anterior communicating artery. The first channel was always the smallest channel, and all of the perforators arose from this smallest channel 45% of the time. All other anomalous anterior communicating arteries presented with concomitant anomalous perforator anatomy.

Anterior Cerebral Artery↗
PubMed2001

Possible role of epicardial left ventricular programmed stimulation in Brugada syndrome.

A patient with recurrent syncope due to polymorphic ventricular tachycardia was diagnosed with Brugada syndrome. Programmed right ventricular stimulation could not induce arrhythmia. Epicardial stimulation from a left ventricular site through the coronary sinus led to polymorphic VT. The stimulation protocol for risk stratification in Brugada syndrome is discussed.

Adult↗
PubMed2001

Myocardial injury during radiofrequency catheter ablation: comparison of focal and linear lesions.

The aim of study was to investigate the extent of myocardial injury incurred by creation of continuous RF current induced linear ablation lesions (LL; ablation of atrial fibrillation, right atrial procedure) in comparison to focal RF lesions (FL; AV node reentry tachycardia, WPW tachycardia). In 23 patients with LL (age 51.3 +/- 11.2 years, 18 men, 5 women) and in 16 patients with FL (age 53.9 +/- 5.1 years, 8 men and 8 women), levels of creatine kinase (CK), myoglobin (MG), CKMB mass (CKMB M), CKMB activity (CKMB A), and cardiac troponin T (cTnT) were determined before and 2, 4, 8, 24, and 48 hours after ablation. CKMB A was normal in 87% in LL and 100% in FL (< 6% of CK) with median maximum CK values of 214 (45-1583) U/L in LL and 36 (29-212) U/L in FL. Peak values of all parameters were significantly higher in LL than in FL. The sensitivity of cTnT was 50% in FL and 100% in LL. In FL MG, total CK, and CKMB M were abnormal in only 12.5% of cases while in LL MG and CKMB M were pathological in 100% and total CK was abnormal in 91.3% of patients. The amount of energy and number of RF applications correlated with cTnT, MG, and CKMB M (P = 0.01). In conclusion, (1) long linear RF current lesions for ablation of atrial fibrillation are associated with significantly greater myocardial injury than focal ablations. (2) In focal lesions only cTnT provided a sensitivity of 50% in the detection of myocardial injury while in linear lesions cTnT, CKMBM, and CKMB M seemed suitable for detection of RF current induced myocardial damage with 100% sensitivity. All biochemical parameters do not differentiate patients with coronary ischemia up to 48 hours after an ablation. (3) Further investigations are necessary to determine if RF current linear lesions lead to impaired atrial contractility in cases of extensive tissue damage.

Adult↗
PubMed2001

Electrochemical potentials during radiofrequency energy delivery: a new method to control catheter ablation of arrhythmias.

AIMS: Thermal injury of subendocardial tissue leads to a release of electrolytes and free radicals from the intracellular site creating a change in electrochemical potential (eP) between the distal and the proximal catheter tip electrodes. The aim of the study was to verify the detection of ablation-induced release of electrolytes and free radicals and to assess the suitability of control-line energy delivery at ablation by measuring eP. METHODS AND RESULTS: In vitro tests under constant flow conditions were performed in a 101 bath of physiological saline solution or bovine blood. Endomyocardial preparations of fresh bovine hearts were used. Closed-loop temperature-controlled, irrigated and closed-loop eP-controlled ablations were performed. In vivo animal investigations were performed in six anaesthetized and ventilated pigs. The existence of the eP was established in the tank model and was confirmed in animal investigations. High correlations were found between eP and catheter tip temperature (r=0.87) and between maximum eP and induced lesion size (r=0.85). Also a high correlation (r=0.85, P<0.001) was found between eP and lesion volume. CONCLUSIONS: Control of energy delivery during RF ablation by the measurement of eP is feasible. In comparison with temperature controlled RF ablation, ablation guided by eP-measurement revealed a superior correlation with induced lesion size. Especially during cooled radiofrequency catheter ablation eP is the only parameter for control of energy delivery.

Action Potentials↗
PubMed2001

Chondroblastoma of the thoracic vertebra.

A 48-year-old patient with interscapular pain was admitted to our clinic. MRI revealed a mass infiltrating the second thoracic vertebra and adjacent structures. No other clinical manifestations were observed in general examination. The patient underwent surgery and subtotal removal was achieved while anterior and posterior stabilisations were performed. Diagnosis was pathologically confirmed. As thoracic chondroblastoma cases are not frequent, we decided to present this case.

Chondroblastoma↗
PubMed2000

[Recurrent syncope of unknown origin. Diagnosis with implantable "loop" recorders].

BACKGROUND: In about a third of cases of recurrent syncope a diagnosis cannot be established despite extensive cardiovascular and neurologic testing. In patients without underlying heart disease the sensitivity of conventional diagnostic testing is low. CASE REPORT: A 33-year-old male patient underwent implantation of a loop recorder (Reveal) after negative neurological and cardiovascular testing. One month after implantation sinus node arrest could be documented during a presyncope. The patient underwent pacemaker implantation and remains asymptomatic since then. CONCLUSION: In patients with syncope and a negative conventional diagnostic workup the implantable loop recorder is a helpful and cost-effective diagnostic tool.

Adult↗
PubMed2000

[Recurrent syncope in a 34-year-old woman triathlete].

HISTORY: Some weeks previously a 34-year old athlete, specializing in the triathlon, had 6 syncopes in one day. They had caused abrasions and contusions resulting from the falls. At another hospital paroxysmal atrial fibrillation had been diagnosed and treatment with disopyramide (2 x 200 mg) initiated, but she had about 15 further syncopes within 2 weeks. She was admitted for establishing their cause. INVESTIGATIONS: Initial ECGs and neurological examination failed to provide a diagnosis and she was discharged with an "event recorder". DIAGNOSIS, TREATMENT AND COURSE: Three weeks after discharge she had another syncope. The event recorder was activated by the patient's partner and revealed polymorphous ventricular tachycardia. She underwent extensive invasive cardiological tests, including a right ventricular biopsy, but no abnormality was demonstrated. However, a provocation test with ajmaline produced ST segment elevations in V1 and V2 typical of the syndrome previously described by the Brugadas (right bundle branch block, precordial ST elevations in V1-V3 and sudden cardiac death). A cardioverter-defibrillator was implanted. During the subsequent observation period of 2 month the ICD delivered one countershock, triggered by the onset of polymorphous ventricular tachycardia with syncope. CONCLUSION: In patients with serious ventricular arrhythmias but no diagnostic findings, including a normal resting ECG, a drug provocation test should be performed to exclude a Brugada syndrome.

Adult↗
PubMed2000

[Neurological events in patients with atrial fibrillation: outcome and preventive practices].

BACKGROUND: Atrial fibrillation (AF) is associated with neurologic events (transient ischemic attack (TIA) and stroke). The objective of the present study was to determine the outcome of patients with neurological events and atrial fibrillation (AF) in comparison with patients in sinus rhythm (SR), and to investigate the primary and secondary prevention practices in patients with neurological events and AF. PATIENTS AND METHODS: In a prospective, observational, single center study in a large public, university-affiliated hospital all patients admitted between 1/97 and 1/98 with acute neurologic events were registered (n = 369). The association between outcome of neurologic events as assessed by survival status, functional status (Rankin scale) and severity of event (European Stroke Scale) and heart rhythm was investigated by use of logistic regression. Antithrombotic medication on admission and at discharge was recorded. RESULTS: The mean age of the 369 patients was 75.1 +/- 10.9 years; 56.1% were female. A TIA was present in 26.2% and stroke in 73.8%. 287 patients (77.8%) were in SR and 82 in AF on admission (22.2%). In-hospital mortality was 12.7% in all patients. In patients with AF, mortality was 23.2% and 9.8% in patients with SR (p = 0.0013). Patients with AF were significantly older than patients with SR (80.4 +/- 7.5 versus 73.5 +/- 11.2 years; p < 0.001). Multivariate analysis identified heart rhythm as an independent predictor of survival (p < 0.01). Patients with AF did suffer from a more severe neurological deficit on admission and at discharge than patients with SR. In 46.3% of patients with AF severe dependency was present (Rankin 4/5), while this was the case in 28.5% of patients with SR (p < 0.01). The ESS score of patients with AF was 77.4 +/- 30.6 at discharge compared to 88.1 +/- 20.3 in patients with SR (p < 0.01). In 50 of 82 patients (61%) AF was previously known. Of these 50 patients 36% did not receive any kind of antithrombotic treatment and only 12% were receiving oral anticoagulants before the event. Of 63 surviving patients with AF 32 did not have any contraindications against anticoagulation treatment. At discharge, 14 (43.8%) of these patients were receiving oral anticoagulants, 17 aspirin or ticlopidine (53.1%) and 1 patient (3.1%) no type of antithrombotic medication. CONCLUSIONS: Neurologic events in patients with AF are more severe and outcome is significantly poorer than in patients with SR. Anticoagulation as the effective therapy for primary and secondary prevention of neurologic events is seriously underused in daily practice.

Aged↗
PubMed2000

Electrophysiological heterogeneity of atrial fibrillation and local effect of propafenone in the human right atrium: analysis based on symbolic dynamics.

UNLABELLED: A recently developed algorithm that is based on symbolic dynamics and computation of the normalized algorithmic complexity (C(alpha)) was applied to basket-catheter mapping of the atrial fibrillation (AF). The aim of our study was to analyze the spatial distribution of the C(alpha) during AF and effects of propafenone on this distribution. During right atrial mapping in 25 patients with AF 31 intra-atrial and 1 surface bipolar channels were acquired. The anatomical location of the intra-atrial electrodes was defined fluoroscopically. C(alpha) was calculated for a moving window (size: 2000 points; step 500 points). Generated C(alpha) was analyzed within 10 minutes before and after administration of propafenone. The inter-regional C(alpha) distribution was analyzed using the Friedman-test (intra-individually) and Kruskall-Wallis-H-test (inter- individually). A value of p=0.05 was set for an error probability. Inter-regional C(alpha) differences were found in all patients (p<0.001). The right atrium could be divided in high- and low complexity areas according to individual patterns. A significant C(alpha) increase in cranio-caudal direction (with the exception of septum) was confirmed inter-individually (p<0.01). The administration of propafenone enlarged the areas of low complexity. CONCLUSIONS: This new method utilizing the combination of symbolic dynamics and adaptive power estimation can provide complex evaluation of the dynamics of AF in man. High-density mapping will be required for further evaluation of results.

Algorithms↗
PubMed2000

Homogeneity and diameter of linear lesions induced with multipolar ablation catheters: in vitro and in vivo comparison of pulsed versus continuous radiofrequency energy delivery.

BACKGROUND: For invasive treatment of atrial fibrillation, linear lesions induced with multipolar ablation catheters (MAC) are needed to prevent recurrence. The aim of the study was to compare the efficacy of pulsed versus continuous radiofrequency (RF)-energy delivery using MAC. METHODS: In vitro tests were performed using endomyocardial preparations of fresh pig hearts in a 10-liter-bath of physiologic saline solution (37 degrees C) at constant flow conditions (1.5 l/min). The MAC were placed with a constant pressure of 20 ponds onto the endocardium. The energy (generator: Osypka HAT 200 S) was delivered either pulsed (4 electrodes simultaneously, 5ms duty-cycle) or continuously (each electrode separately). In vivo experiments were performed in 6 anesthetized pigs using fluoroscopic positioning of MAC at 40 different intracardial positions and with similar conditions as in vitro experiments. Lesion volume (LV) was calculated after measuring lesion diameter with a microcaliper. The homogeneity of the lesions (LH) was classified from 1-4; with 1 as highest homogeneity. RESULTS: Pulsed energy delivery produced more homogeneous linear lesions in significantly less time. There was no difference in electrode temperature values (50.2 +/- 0.8 and 51.3 +/- 1.4 degrees C) in vitro and in vivo. In the in vivo experiments, lesion depth and calculated lesion volume were less in both modes of energy delivery but pulsed energy delivery was superior regarding lesion depth and homogeneity. CONCLUSION: With pulsed energy delivery it is possible to create linear lesions of significantly greater homogeneity. Moreover, larger lesions are induced in less time by pulsed energy delivery in vitro and in vivo.

Animals↗
PubMed2000

Sensitizing capacity of azole derivatives: Part III. Investigations with anthelmintics, antimycotics, fungicides, antithyroid compounds, and proton pump inhibitors.

BACKGROUND: More than hundred azole derivatives are used today for different purposes. The majority possess antimycotic, antibacterial, anthelmintic, and antiprotozoal properties. They are used as agricultural fungicides; topical antimycotics, and, for example, in antidandruff cosmetics. More recently the antithyroid and antiulcerative activity of certain imimidazoles and benzimidazoles also has been proven, which led to the introduction of proton pump inhibitors and antithyroid drugs to the market. OBJECTIVE: Case reports from the literature and experimental studies suggest that some of the azole derivatives possess a distinct sensitizing potency. Occupational exposure either in the pharmaceutical manufacture or in the pesticide's application by farmers caused allergic contact dermatitis (ACD). However, experimental studies in guinea pigs to determine their sensitizing capacity have been performed only sporadically. METHOD: Guinea pigs were sensitized by a modified Freund's complete adjuvant (FCA) method, with 35 azoles used as agricultural fungicides, proton pump inhibitors, antimycotics, antithyroid agents, antiprotozoals, antimicrobials, anthelmintics, and wood preservatives. RESULTS: Four azoles exhibited a strong sensitizing capacity, 3 a moderate, and 11 a weak sensitizing capacity. Seventeen derivatives remained negative. Among the strong sensitizers were the 3 proton pump inhibitors omeprazole, pantoprazole, and rabeprazole, as well as the antithyroid drug carbimazole. The latter displayed the highest sensitizing power (mean response = 2.50) of all 62 azole derivatives investigated in the present and the 2 previous experimental studies. CONCLUSION: As long as the strong sensitizing azoles are used only systemically the risk of acquiring contact hypersensitivity is low. However, if the idea should arise to use them topically, for example in ointments, tinctures, or lotions against fungal infections, skin problems will probably be observed abundantly.

Animals↗
PubMed2000

Comparison of pulsed versus continuous radiofrequency energy delivery: diameter of lesions induced with multipolar ablation catheter.

The aim of this study was to compare the efficacy of pulsed versus continuous RF energy delivery via multipolar ablation catheters. In vitro tests were performed in endomyocardial preparations of fresh bovine hearts in a both of physiological saline solution (37 degrees C) at constant flow conditions (1.5 L/min). The catheters were applied to the endocardium at a constant pressure. Energy was delivered pulsed (to 4 electrodes simultaneously, 5-ms duty cycle) or continuously (to each electrode separately). In vivo experiments were performed under fluoroscopy in eight anesthetized pigs, guided by endocardial electrograms to place the catheters in 22 different intraatrial positions. Lesion volume was calculated from measurements of the lesion diameter with a microcaliper. The homogeneity of the lesions was classified from 1 (highest) to 4 (least). More homogeneous linear lesions were produced in significantly less time with pulsed than with continuous energy delivery. There were no differences in electrode temperature or impedance values in vitro and in vivo. The results in the in vitro experiments were reproducible in the intact animal experiments. Significantly larger and more homogeneous linear lesions were created more rapidly with pulsed than with continuous energy delivery.

Animals↗
PubMed1996

Prevalence and predictors of atrial fibrillation in rheumatic valvular heart disease.

The highest frequency of AF in RHD occurs in those with mitral stenosis, mitral regurgitation, and tricuspid regurgitation in combination. AF, while occurring in 29% of patients with isolated mitral stenosis and in 16% with isolated mitral regurgitation, is an infrequent finding (1%) in patients with aortic valvular disease. Left atrial diameter by univariate analysis, and age and left atrial diameter by multivariate analysis have been shown to be the most important parameters to determine the occurrence of AF in patients with RHD.

Adolescent↗
PubMed1996

Colloid cyst of the third ventricle. Evaluation of 28 cases of colloid cyst of the third ventricle operated on by transcortical transventricular (25 cases) and transcallosal/transventricular (3 cases) approaches.

The clinical and x-ray features of 28 cases of colloid cyst of the third ventricle are described. Colloid cyst is one of the most favourable space-occupying lesions of the brain for successful surgical removal, because an exact pre-operative diagnosis is possible. The surgical approach for colloid cyst of the third ventricle is discussed and the frequency of postoperative seizure is reviewed in 28 cases and compared with the literature.

Adolescent↗
PubMed1995

Tentorial meningiomas.

We report our experience with and long-term results of 37 patients with tentorial meningiomas who underwent surgery between 1972 and 1993. The average age was 43 years, and the mean duration of symptoms was 36 months. Headache (83.8%) and extremity or gait ataxia (35.1%) were the most common complaints. On neurological examination, signs of elevated intracranial pressure and cerebellar deficits (51.4%) were the most common findings, followed by third nerve involvement (35.1%). Computed tomography, angiography, and, in recent years, magnetic resonance imaging were used as diagnostic tools and for planning the surgical procedure. According to the primary site of attachment, the tentorial meningiomas were divided into three subgroups: medial, lateral, and falcotentorial. The lateral and medial tumors, with mainly supratentorial development, were approached from above by using a temporal, temporooccipital, or parietooccipital craniotomy. For tumors developing mainly in the posterior cranial fossa, suboccipital craniectomy was performed. In six patients who showed medial tentorial and petrous apex attachment, a combined subtemporal transpetrosal and retromastoid approach was performed. In 31 patients, the tumors were totally removed, and, in 6 patients, only subtotal excision could be done. Seven patients had postoperative complications, but only one of them died of severe brain edema. Our mortality rate was 2.7%. In this article, appropriate preoperative studies, surgical techniques, and surgical results are discussed.

Adult↗
PubMed1994

Primary optic nerve sheath meningiomas. Report of seven cases (clinical neuroradiological, pathological and surgical considerations in seven cases).

Between 1985 and 1993, we treated seven cases of optic nerve sheath meningiomas. The median age at onset of their symptoms was 42.14 years. All of the patients were aged between 27 and 60 females with a slowly progressive lesion. Computed tomography and/or magnetic resonance imaging were used as diagnostic procedure in our cases. We operated on using microsurgical techniques in all of these cases. Vision was preserved in the three of our cases. The definitive treatment for these lesions is surgical resection, although no single best plan for optimal management has been determined. The data indicate that only small anterior tumors may be removed with preservation of useful vision. With posterior circumferential tumors, there have been no cases of tumor removal with preservation of vision. A management strategy directed toward preservation of vision is discussed.

Adult↗
PubMed1993

Medulloblastomas.

81 patients with biopsy proven medulloblastoma with a mean age of 11.4 years were reviewed. Total removal of the tumour was accomplished in 18 cases (22.2%), subtotal removal in 55 cases (67.9%) and biopsy alone in 8 cases (9.9%). 34 patients (27.5%) had a recurrence of the tumour and 8 patients underwent a second posterior fossa exploration at the time of recurrence. In patients with total resection, five-year survival was 27.7%. With partial resection, five-year survival decreased to 14.5%. In patients with radiotherapy chemotherapy, 21.4% survived 5 years after treatment but this rate decreased to 18.4% in patients treated with radiotherapy only. The surgical mortality rate was 12.3%.

Adolescent↗