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N Kolev

Publications and source records attributed to N Kolev.

At least 19 recordsLinked to original sources
PubMed2001

Effects of maturity and training on bimanual ballistic isometric handgrip.

We studied maturity and training effects on maximal force and accuracy of force targeting during ballistic handgrips. Male right-handed nontrained adolescents (16-20 yrs.), trained adolescents (oarsmen--16-18 yrs.) and nontrained adults (21-44 yrs.) did right (R) unilateral (UL), left (L) UL handgrip and bilateral (BL) maximal ballistic handgrips. Next, they targeted 30% of maximal respective UL handgrip. We found peak force L:R ratios in adolescents significantly closer to 1 compared to nontrained adults suggesting less hemisphere dominance in adolescents, especially in trained ones. Nontrained adolescents showed smaller bilateral deficit for L hand than the other groups. Adolescents showed a significant underestimation of L hand during BL task (-4.6%), especially oarsmen (-8.7%), while adults showed neither overestimation, nor underestimation during all tasks. The disappearance of the asymmetry of bilateral deficit and L hand errors of force targeting suggest a diminution of neural cross-talk from dominant to non-dominant hand and its better estimate with maturity.

Adolescent↗
PubMed2000

[Local screening program for prostate cancer].

OBJECTIVE: By massive screening of men between 50 and 75 years of age, to find those of them that are in the early stage of the carcinoma of the prostate and evaluate the usefulness of applying this method nationwide. PATIENTS AND METHODS: 183 male Pleven citizens between 50 and 75 years of age underwent clinical examination, digital rectal examination (DRE) and serum prostate-specific antigen (PSA) determination. Those with suspicious DRE or PSA > 4 ng/ml underwent further examinations: transrectal ultrasonography (TRUS) and biopsy. The sensitivity and specificity of these tests were determined. RESULTS: The mean age of the patients was 63.66 years. Six of them (3.28%) had suspicious DRE while PSA was > 4 ng/ml in 10 (5.46%) patients. Biopsy proved cancer in 2 (1.09%) patients. We needed 6 biopsies to prove one cancer. PSA had the highest sensitivity (100%), while DRE had the highest specificity (97.8%). CONCLUSION: Because of its high sensitivity, PSA could be used for massive screening of the carcinoma of the prostate. However, the low percent (1.09%) of the new-found patients with cancer and the relatively high price of the investigation leave this question open for the time being.

Aged↗
PubMed1999

Transesophageal echocardiographic assessment of right heart hemodynamics during high-frequency jet ventilation.

STUDY OBJECTIVE: To evaluate right ventricular dimensions and function by echocardiography in anesthetized patients during superimposed high-frequency jet ventilation (HFJV). DESIGN: Prospective clinical study. SETTING: University hospital operating room. PATIENTS: 20 ASA physical status I patients undergoing elective minor otorhinolaryngological surgery, and undergoing conventional mechanical ventilation with subsequent superimposed HFJV. INTERVENTIONS: Two-dimensional transesophageal echocardiography with a 5-MHz multiplane transducer to determine right ventricular dimensions and function from a mid-esophageal view. Insertion of a radial artery catheter for monitoring blood pressure and blood gases. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial blood pressure, and right ventricular end-diastolic and end-systolic volumes determined by echocardiography, stroke volume, and ejection fraction. Measurements were performed after 10 minutes of conventional positive pressure ventilation (control) and after 10 minutes of subsequent superimposed HFJV at similar peak and positive end-expiratory airway pressures. Right ventricular systolic and diastolic volumes, stroke volume, and ejection fraction did not reveal statistical significant differences after transition to HFJV. Interventricular septum did not show any abnormalities in motion. In contrast, interatrial septum demonstrated momentary mid-systolic bows toward the left atrium in 9 of 17 patients (53%) during conventional ventilation, but in 15 of 17 patients (88%) during jet ventilation. Heart rate and mean arterial blood pressure remained unchanged, but arterial oxygen tension values were higher and arterial carbon dioxide tension values lower during HFJV. CONCLUSION: Transesophageal echocardiographic evaluation of right heart hemodynamics did not show any significant difference after transition of ventilation to superimposed HFJV applying similar airway pressures. Furthermore, superimposed HFJV was safe and effective, it improved oxygenation, and it facilitated carbon dioxide elimination.

Adult↗
PubMed1998

Quantification of mitral regurgitant flow using proximal isovelocity surface area method: a transesophageal echocardiography perioperative study.

OBJECTIVE: To investigate the usefulness of the color Doppler proximal isovelocity surface area (PISA) method, compared with the jet area method, in determining the severity of mitral regurgitation in the perioperative period using angiographic grading as a reference method. DESIGN: Randomized, controlled prospective study. SETTING: Single university hospital. METHODS: Thirty-three patients with native mitral valve insufficiency of different grade were studied. The color jet area in the left atrium, as well as PISA regurgitant stroke volume (RSV), were established. PISA RSV was calculated using a formula derived from previous in vitro and human studies: RSV = 2 pi r2 x v x RTVI/RPFV x (inlet angle/180 degrees), in which r is the radial distance between the first aliasing contour (red/blue interface); v is the aliasing velocity that is read from the color bar; RTVI is the time-velocity integral of the regurgitant jet from the continuous wave Doppler recordings; and RPFV is the corresponding peak flow velocity of the continuous wave regurgitant jet. RESULTS: The rank correlation coefficient between the angiographic grade of mitral regurgitation and the PISA method was rsp = 0.89 (p < 0.0001), and for the jet area was rsp = 0.44 (p < 0.01). There was close concordance between angiographic and PISA measurements of RSV (r = 0.92, p < 0.0001). Further, scatterplot of difference between the two measurements plotted against the mean of measurements showed good agreement. CONCLUSIONS: It was concluded that in patients with mitral regurgitation during the perioperative period, the PISA method is more suitable than the jet area method to determine the severity of mitral regurgitation, and only it provides a reliable technique to differentiate between grade I-II mitral regurgitation in patients with eccentric regurgitant jet and grade III-IV mitral regurgitation in patients with jet size that is bigger than transesophageal echocardiography left atrial size.

Adult↗
PubMed1998

The influence of transoesophageal echocardiography on intra-operative decision making. A European multicentre study. European Perioperative TOE Research Group.

The role of transoesophageal echocardiography (TOE) in anaesthesia remains controversial because it is a rapidly evolving technique with few proven benefits and considerable cost. Recently, the Society of Cardiovascular Anaesthesiologists has published practice guidelines for the use of peri-operative TOE. To determine the current role of transoesophageal echocardiography and the relative impact of category-based transoesophageal echocardiographic indications the present study investigated its use in seven Western European countries. The study sample was taken from a prospective cohort of 224 patients with acute or chronic haemodynamic disturbances or at risk of myocardial ischaemia. All patients were monitored with two-lead electrocardiography and radial and pulmonary artery catheters, as well as biplane or multiplane transoesophageal echocardiography. A total of 2232 clinical interventions were made in these patients. The most frequently observed intervention was the administration of a fluid bolus (45% of all interventions). Overall, transoesophageal echocardiography was the most important guiding factor in 560 (25%) interventions. It was the most important monitor in guiding the following therapeutic interventions: anti-ischaemic therapy--207 of 372 interventions (56%); fluid administration--275 of 996 (28%) interventions; vasopressor or inotrope administration--56 of 316 (16%) interventions; vasodilator therapy--six of 142 (4%) interventions and depth of anaesthesia--four of 211 (2%) interventions. We found that transoesophageal echocardiography is frequently influential in guiding clinical decision making and is used most frequently for category II indications but category I indications were associated with more frequent change in management.

Adult↗
PubMed1997

A rare presentation of thoracic aortic dissection as detected by transoesophageal echocardiography.

A case of atypical movement of the intimal flap (tear) during aortic aneurysm dissection is reported. Aortic dissection is caused by the sudden development of a tear in the aortic intima, opening the way for a column of blood driven by the force of the arterial pressure to enter the aortic wall, destroying the media and stripping the intima from the adventitia for variable distance along the length of the aorta. Echocardiographically, aortic dissection is characterized by separation of the normal single dominant echo from the aortic wall in the region of the dissection into two discrete echoes. The inner echo arises from the tunica intima, whereas the outer echo arises from the medial and adventitial structures external to the tear and it is possible to identify two lumens separated by an intimal flap within the aorta. The two echoes generally move in unison with one another, i.e. movement of the flap away from the true lumen during systole and recoil during diastole as the blood flows from true to false lumen. The dissection flap can also move inward during systole owing to the suction caused by high-velocity flow (Venturi effect), as shown in this case report. In any instances, motion of the intimal flap during the cardiac cycle is strong evidence of dissecting aneurysm.

Aged↗
PubMed1997

Biplane transoesophageal echocardiographic detection of myocardial ischaemia in patients with coronary artery disease undergoing non-cardiac surgery: segmental wall motion vs. electrocardiography and haemodynamic performance.

Intra-operative segmental wall motion abnormalities (SWMA) detected by transoesophageal echocardiography (TOE) have been shown to be a sensitive indicator of myocardial ischaemia. To determine the incidence and characteristics of segmental wall motion abnormalities and to relate these changes to perioperative myocardial ischaemia, biplane TEE, electrocardiogram (ECG) (II+V5) and pulmonary capillary wedge pressure (PCWP) were continuously monitored in 62 consecutive patients with ischaemic heart disease undergoing non-cardiac surgery. Short-axis view at mid-papillary level in transverse scan (T-scan) and long-axis in longitudinal (L-scan) two-chamber view were used for wall motion analysis. New segmental wall motion abnormalities were detected in 16 of 64 patients (25%) using biplane transoesophageal echocardiography. Monoplane transoesophageal echocardiography showed a sensitivity of 75% and a specificity of 100%, electrocardiogram two lead showed a sensitivity of 56% and a specificity of 98%, whereas pulmonary capillary wedge pressure had a sensitivity of 25%, and a specificity of 93% and pressure rate quotient (PRQ) < 1 demonstrated sensitivity of 19% and a specificity of 92% in the detection of myocardial ischaemia. It is concluded that the long-axis view of the left ventricle provides additional information for the detection of segmental wall motion abnormalities. Neither changes in haemodynamic performance nor in electrocardiography leads II and V5 match those of transoesophageal echocardiography for the identification of myocardial ischaemia.

Adult↗
PubMed1997

Validity of acoustic quantification colour kinesis for detection of left ventricular regional wall motion abnormalities: a transoesophageal echocardiographic study.

Transoesophageal echocardiography is a sensitive monitor for intraoperative myocardial ischaemia. Colour kinesis is a new technology for echocardiographic assessment of regional wall motion based on acoustic quantification. We have examined the feasibility and accuracy of quantitative segmental analysis of colour kinesis images to provide objective evaluation of systolic regional wall motion during the perioperative period using transoesophageal echocardiography (TOE). Two-dimensional echocardiograms were obtained in the transgastric short-axis and long-axis views in 60 patients with coronary artery disease undergoing noncardiac surgery. End-systolic colour overlays superimposed on the grey scale images were obtained with colour kinesis to colour encode left ventricular endocardial motion throughout systole. These colour-encoded images were divided into segments and compared with corresponding conventional two-dimensional images. Six hundred of a potential 720 left ventricular wall segments were of sufficient resolution for grading by experts; they diagnosed wall motion abnormalities in 61 of these segments by a conventional method. In comparing the conventional TOE method with colour kinesis, there were 60 true positives, 482 true negatives, 57 false positives and 1 false negative result. This yielded a sensitivity of 98%, specificity of 89%, positive predictive value of 51% and negative predictive value of 100%. Translational and rotational movement of the heart and papillary muscle interference were common problems accounting for false positive diagnoses. We conclude that colour kinesis provides a basis for objective and on-line evaluation of left ventricular regional wall motion which is a sensitive but non-specific method. It may be a useful aid for the less experienced because it can potentially direct the anaesthetist's attention towards specific segments.

Adult↗
PubMed1996

Transoesophageal echocardiographic assessment of mitral and aortic valve function during cardiopulmonary resuscitation.

There has been controversy over whether forward blood flow during closed-chest cardiopulmonary resuscitation (CPR) is generated by a general increase in intrathoracic pressure (chest-pump theory) or by creating atrioventricular gradients that close the mitral valve and open the aortic valve during thoracic compression (cardiac pump theory). The crucial issue is the position of the mitral valve during the downstroke of chest movement. Questions remain over the actual mechanics of mitral and aortic valve function. This report describes an intraoperative cardiac arrest followed by CPR during which routinely instituted two-dimensional transoesophageal Doppler echocardiography enabled study of the motion of the valves of the left heart and the transmitral blood flow.

Aged↗
PubMed1996

A new scoring system, using Doppler transmitral diastolic measurement, identifies transient myocardial ischaemia.

In patients with acute transient myocardial ischaemia, changes in left ventricular filling produce alterations in transmitral diastolic flow velocity and isovolumic relaxation time. In this study a scoring system derived from isovolumic relaxation time and indices from transmitral flow velocity was used to evaluate perioperative transient myocardial ischaemia. Fifty three patients with known coronary artery disease or at risk were studied. Ischaemic events were assessed using Doppler transoesophageal echocardiography midoesophageal left ventricular four-chamber view planes. Diastolic Doppler ratios of peak early to atrial peak (E/A), deceleration time, deceleration rate and isovolumic relaxation time were scored using standard methods. An evaluation of peri-operative ischaemic events could be important for patients with a non-ischaemic cause for abnormal segmental wall motion, as the use of a two-dimensional scoring system has limitations. Acute changes in the Doppler ratio of peak early to atrial peak must be interpreted cautiously during surgery. Diastolic dysfunction commonly occurs during ischaemia and recognition of this may alter the approach to monitoring as well as to treatment.

Adult↗