Search PubMed⌕ Search

Biomedical subjects

R Hatala

Publications and source records attributed to R Hatala.

At least 37 records · Page 2Linked to original sources
PubMed1996

Once-daily aminoglycoside dosing in immunocompetent adults: a meta-analysis.

OBJECTIVE: To compare the efficacy, nephrotoxicity, and ototoxicity of once-daily aminoglycoside dosing with those of standard aminoglycoside regimens in immuno-competent adults. DATA SOURCES: A structured MEDLINE search from 1966 to April 1995 using the keywords aminoglycosides, drug administration schedule, and adult; bibliographic searching of review articles, position papers, and references of the selected articles; contact with primary authors of selected articles to obtain information not in the published reports and lists of potentially relevant articles. STUDY SELECTION: Randomized, controlled trials that 1) compared an intravenous once-daily aminoglycoside regimen with a standard aminoglycoside regimen in infected immunocompetent adults and 2) examined efficacy, mortality, or toxicity. DATA EXTRACTION: For each selected study, two independent reviewers assessed methodologic quality and abstracted data. The heterogeneity of individual study risk ratios was assessed and data were pooled using a random-effects model. RESULTS: Forty-two studies were reviewed for possible inclusion. Thirteen independent studies met the selection criteria, and their results were pooled. The trials had a mean methodologic quality score of 0.69 (range, 0.50 to 0.91). Heterogeneity exists among the individual risk ratios for clinical cure (P = 0.07); significant heterogeneity does not exist for the other outcomes. For the pooled efficacy outcomes, the risk ratio for bacteriologic cure is 1.02 (95% CI, 0.99 to 1.05), and the risk ratio for mortality is 0.91 (CI, 0.63 to 1.31). For the pooled toxicity outcomes, the risk ratio for nephrotoxicity is 0.87 (CI, 0.60 to 1.26), and the risk ratio for ototoxicity is 0.67 (CI, 0.35 to 1.28). CONCLUSIONS: Standard and once-daily aminoglycoside dosing regimens are equivalent with regard to bacteriologic cure, and once-daily dosing shows a trend toward reduced mortality and toxicity. However, additional studies are needed for more precise estimates of mortality and toxicity risk ratios. The equivalency of the dosing regimens, the ease of administration, reduced nursing time, and reduced variability in the timing of drug administration that are associated with once-daily dosing may mean that the once-daily regimen is clinically advantageous.

Adult↗
PubMed1996

Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials.

OBJECTIVE: To review the effect of calcium supplementation during pregnancy on blood pressure, preeclampsia, and adverse outcomes of pregnancy. DATA SOURCE: We searched MEDLINE and EMBASE for 1966 to May 1994. We contacted authors of eligible trials to ensure accuracy and completeness of data and to identify unpublished trials. STUDY SELECTION: Fourteen randomized trials involving 2459 women were eligible. DATA EXTRACTION: Reviewers working independently in pairs abstracted data and assessed validity according to six quality criteria. DATA SYNTHESIS: Each trial yielded differences in blood pressure change between calcium supplementation and control groups that we weighted by the inverse of the variance. The pooled analysis showed a reduction in systolic blood pressure of -5.40 mm Hg (95% confidence interval [CI], -7.81 to -3.00 mm Hg; P<.001) and in diastolic blood pressure of -3.44 mm Hg (95% CI, -5.20 to -1.68 mm Hg; P<.001). The odds ratio for preeclampsia in women with calcium supplementation compared with placebo was 0.38 (95% CI, 0.22 to 0.65). CONCLUSIONS: Calcium supplementation during pregnancy leads to an important reduction in systolic and diastolic blood pressure and preeclampsia. While pregnant women at risk of preeclampsia should consider taking calcium, many more patient events are needed to confirm calcium's impact on maternal and fetal morbidity.

Blood Pressure↗
PubMed1996

Effects of dietary calcium supplementation on blood pressure. A meta-analysis of randomized controlled trials.

OBJECTIVE: To review the effect of supplemental calcium on blood pressure. DATA SOURCE: We searched MEDLINE and EMBASE for 1996 to May 1994. We contacted authors of eligible trials to ensure accuracy and completeness of data and to identify unpublished trials. STUDY SELECTION: We included any study in which investigators randomized people to calcium supplementation or placebo and measured blood pressure for at least 2 weeks. Fifty-six articles met the inclusion criteria, and 33 were eligible for analysis, involving a total of 2412 patients. DATA EXTRACTION: Two pairs of independent reviewers abstracted data and assessed validity according to six quality criteria. DATA SYNTHESIS: We calculated the differences in blood pressure change between the calcium supplementation group and the control group and pooled the estimates, with each trial weighted with the inverse of the variance using a random-effects model. Predictors of blood pressure reduction that we examined included method of supplementation, baseline blood pressure, and the methodological quality of the studies. The pooled analysis showed a reduction in systolic blood pressure of -1.27 mm Hg (95% confidence interval [CI], -2.25 to -0.29 mm Hg; P=.01) and in diastolic blood pressure of -0.24 mm Hg (95% CI, -0.92 to 0.44 mm Hg; P=.49). None of the possible mediators of blood pressure reduction explained differences in treatment effects. CONCLUSIONS: Calcium supplementation may lead to a small reduction in systolic but not diastolic blood pressure. The results do not exclude a larger, important effect of calcium on blood pressure in subpopulations. In particular, further studies should address the hypothesis that inadequate calcium intake is associated with increased blood pressure that can be corrected with calcium supplementation.

Blood Pressure↗
PubMed1996

Radiofrequency catheter ablation of left atrial tachycardia originating within the pulmonary vein in a patient with dextrocardia.

A case is presented of a 38-year-old male with dextrocardia in whom radiofrequency current ablation of an incessant atrial tachycardia originating within the infero-lateral pulmonary vein was achieved. Activation mapping with detection of the earliest atrial activation was used for identification of the arrhythmogenic focus. In addition to fluoroscopy, transesophageal echocardiography was used for catheter guidance during the transseptal puncture. The present experience suggests that location of an arrhythmogenic focus within the pulmonary venous system should be considered whenever early atrial activation during ectopic atrial tachycardia is recorded at the junction between the left atrium and the pulmonary veins.

Adult↗
PubMed1996

[Catheter ablation of accessory atrioventricular conduction pathways in all locations--consecutive results of a new curative therapy of paroxysmal supraventricular tachycardia].

Accessory atrioventricular pathways are a frequent cause of paroxysmal supraventricular tachycardias. This study analyses our results with a recently developed therapeutic approach-radiofrequency (RF) catheter ablation. This was applied in 150 consecutive patients (97 men, 53 women, mean age 42 +/- 15 years) with a total of 159 accessory pathways in all locations. All but 4 patients were symptomatic, with a spectrum ranging from palpitations (146 patients), syncope (39 patients) to aborted sudden death (2 patients). Prior to ablation, 115 patients had received long-term treatment with up to 4 antiarrhythmic drugs unsuccessfully. The mean number of applied current pulses was 12 +/- 14, and the mean cumulative procedure duration was 256 +/- 243 minutes, with a cumulative fluoroscopy time of 49 +/- 72 minutes. Patients with left-sided pathways were approached via the retrograde aortic approach in 88/90 cases. One-hundred fifteen patients were treated in a single session, repeat sessions were required in the remaining 35 patients. The predominant sites of interruption of right-sided and left-sided accessory pathways were their atrial and ventricular insertion, respectively. Long-term cure was achieved in 141 patients (94%), non-life-threatening complications were observed in 3 patients (2%). These results compare well with published studies on large patient collectives and demonstrate that RF catheter ablation, which is highly cost effective, is the therapy of choice to cure symptomatic patients with accessory atrioventricular pathways in all locations.

Adult↗
PubMed1995

Three distinct patterns of ventricular activation in infarcted human hearts. An intraoperative cardiac mapping study during sinus rhythm.

BACKGROUND: Comprehensive data based on single-beat analysis of the ventricular activation sequence during sinus rhythm in infarcted hearts are currently not available. It was the aim of our study (1) to measure and analyze these activation sequences on the epicardial surface of the right and left ventricles and on the left ventricular endocardial surface, and (2) to correlate specific activation patterns with the surface ECG. METHODS AND RESULTS: Isochronal maps were computed from 127 endocardial and epicardial unipolar electrograms recorded simultaneously during sinus rhythm in 45 post-myocardial infarction patients operated on for recurrent ventricular tachycardia (age, 57 +/- 10 years [mean +/- SD], left ventricular ejection fraction, 29 +/- 9%). Patients with bundle-branch block, but not with intraventricular conduction defects, were excluded. Data such as the timing of initial and terminal activation, the number of breakthroughs, the total activation time, and the number of ventricular segments without activation were measured and analyzed according to location of the myocardial infarction. The global epicardial activation was characterized in all patients by a widespread initial breakthrough on the anterior right ventricle (16 +/- 8 milliseconds after QRS onset), which was followed by one or two other breakthroughs in 65% of patients. Subsequently, three characteristic epicardial patterns of the activation spread were found: (1) radial, from the right to the left ventricle, found in all patients with inferoposterior myocardial infarction; (2) counterclockwise rotation, in which posteroseptal crossing preceded the anteroseptal crossing, found in 38% of patients with anterior myocardial infarction; and (3) pincerlike encirclement, in which both septal crossings and/or breakthroughs occurred nearly simultaneously and merged at the left ventricular free wall (typical for apical involvement in anterior and combined myocardial infarction). The simultaneous presence of multiple major activation wave fronts typically found in patients with the pincerlike activation pattern was reflected on the surface ECG by multiphasic, notched QRS complexes. Activation delay was observed in 89% of patients, and terminal activation was topographically related to myocardial infarction in 94% of patients. Delayed activation exceeding the surface QRS was observed in 11% and 31% of cases on the endocardium and epicardium, respectively. CONCLUSIONS: These results offer a solid basis for a more precise interpretation of a wide range of electrophysiological data and provide a framework for future investigations of surface ECG reflections of endocardial and epicardial activation patterns recorded in patients with chronic myocardial infarction.

Electrocardiography↗
PubMed1995

Inadequacy of intravenous heparin therapy in the initial management of venous thromboembolism.

To determine the adequacy of initial anticoagulation by intravenous heparin for patients who have deep venous thrombosis (DVT), and the factors that influence delayed anticoagulation, independent, duplicate chart review of 63 consecutive patients who had venography-proven DVT was conducted. Adequate heparinization (AH) was defined as an activated partial thromboplastin time (PTT) of more than 1.5 times the normal laboratory control. The proportions of patients achieving AH within 24 hours and 48 hours of initial heparin bolus were 46% and 62%, respectively. Patients who weighed more were less likely to achieve AH (p < 0.05), while patients receiving care from the thromboembolism service were more likely to achieve AH (p < 0.05). Low initial infusion rate was strongly but not significantly predictive of inadequate anticoagulation (p = 0.06). The mean heparin bolus and initial infusion rates were significantly lower than those suggested in the literature (p < 0.01). The AH rates were comparable to historical controls but suboptimal compared with the rates of 66% at 24 hours and 81% at 48 hours reported in association with heparin nomogram use (p < 0.05). A heparin nomogram is likely to achieve consistently higher rates of adequate heparinization.

Aged↗
PubMed1995

[Location of atrial and ventricular insertions of accessory atrioventricular pathways using surface ECG mapping and its importance in catheter ablation therapy].

BACKGROUND: The modern non-pharmacological therapy of the WPW syndrome by means of catheter ablation is based on the interruption of the accessory pathway(-s) by radiofrequency current energy. Destruction of the morphologic substrate of the arrhythmia alters the activation wave spread in the heart. OBJECTIVES: It was the aim of this report to demonstrate the diagnostic potential of BSM in localizing both overt and concealed accessory pathways. Presented study analyzes the alterations of the cardioelectric field by means of body surface ECG mapping in two female patients with accessory pathways before and after their successful curative treatment by radiofrequency catheter ablation. METHODS: Five patients were analyzed prior and after RF catheter ablation by BSM, two of them were selected for this presentation. One patient with WPW syndrome suffered from frequent supraventricular tachycardia due to in one female patient with an overt accessory pathway. The other patient was for several years incessantly in permanent junctional reentry tachycardia due to a concealed accessory pathway. The examination comprised 12-lead ECG, orthogonal vectorcardiogram according to Frank, BSM using a regular 80-electrode-array system and signal-averaged ECG. RESULTS: The RF ablation was successful in both patients and their arrhythmia was abolished. By means of a detailed analysis of the ventricular activation prior RF ablation in the patient with WPW syndrome the precise site of the ventricular insertion of the accessory pathway in the left lateral free wall was predicted. Furthermore, alterations of the terminal QRS complex were observed when comparing pre- versus post-ablation maps. In the second patient the atrial insertion of the accessory pathway with retrograde and decremental conduction was successfully localized to the right septal region by means of pre-ablation BSM. CONCLUSIONS: Both ventricular and atrial activation can be in detail analyzed by means of BSM. Such analysis offers more precise information on the spatial component of the activation wave spread. This case report gives further evidence that BSM is a useful method for precise localization of both ventricular and atrial insertion sites of accessory pathways in patients with paroxysmal tachycardias due to this electrophysiologic abnormality. This information gained recently clinical impact since it can be directly used for faster arrhythmogenic substrate targeting during ablation therapy. (Fig. 5, Ref. 17.)

Adolescent↗
PubMed1994

Time-frequency mapping of the QRS complex in normal subjects and in postmyocardial infarction patients.

The effect of myocardial infarction upon the frequency content of the QRS complex was analyzed. Three bipolar signal-averaged surface electrograms, recorded during the early (10-15 days) and late (6 months) chronic phases of myocardial infarction, were analyzed in 61 patients and 11 healthy subjects. All patients were free of ventricular arrhythmia during 6 months of follow-up examinations. Time-frequency analysis of the QRS complex was based on the modified Wigner distribution, which is well suited to examine nonstationary character of data. Standard time-domain analysis for the presence of late potentials was used for comparison. High-frequency (> or = 90 Hz) components, separable from the dominant low-frequency components (< 90 Hz), were found in all groups. They were present throughout the QRS complex and were peaking in its middle portion. The high-frequency components were found significantly higher in postinfarction patients in both early (P < .007) and late chronic stage myocardial infarction (P < .05) compared to healthy subjects. Patients who tested positive for late potentials (24%) also had elevated high-frequency components; however, a comparable increase was also observed in late potential negative patients. Furthermore, the high-frequency component increase occurred in all patients earlier in the QRS than in its terminal 40 ms, where late potentials are traditionally evaluated. It is concluded that high-frequency components are an integral part of the QRS complex under physiologic conditions and persist in variable amount throughout its duration. The high-frequency components are increased in patients after myocardial infarction not associated with ventricular arrhythmia, and their elevation is not limited to the terminal QRS complex.

Adult↗
PubMed1994

The antihypertensive treatment and high-resolution electrocardiography.

After six months of antihypertensive treatment the regression of the initially present myocardial hypertrophy was observed: The decrease in blood pressure values is in correlation with the regression of the left ventricular hypertrophy. No correlation with parameters of high-resolution electrocardiography was noted. In one patient, a deterioration of late potentials was observed. It became more pronounced following the treatment. The monitoring of antihypertensive treatment effects by echocardiography and high-resolution electrocardiography may be therefore considered useful, especially in expected regression of the left ventricular hypertrophy. In individual cases of very outstanding regression, there exists the potential possibility of the process, resulting in the risk of arrhythmogenic substrate formation and subsequent generation of dysrhythmias.

Electrocardiography↗
PubMed1994

Taurine and myocardial noradrenaline.

Taurine (CAS 107-35-17) is an anticonvulsant used also as an adjunct in the treatment of cardiovascular disorders. Therefore, we studied its effects noradrenergic transmission in the isolated rabbit heart prelabelled with 3H-noradrenaline. At the concentrations of 1 and 10 mmol/l taurine treatment was without effect on the neuronal and extraneuronal uptake of noradrenaline by the myocardial tissue. At the highest concentration, it decreased the spontaneous release of the transmitter and enhanced its catabolism. Without any significant effect on tyramine-induced noradrenaline release, taurine decreased the release of the amine induced by dimethylphenylpiperazinium and nerve stimulation. These results suggested that taurine may reduce the peripheral sympathetic activity by accelerating noradrenaline catabolism and decreasing its release probably via its ability to prevent a rise of intracellular calcium ion.

Animals↗
PubMed1993

Bipolar transseptal radiofrequency ablation of AV node: an alternative to high energy shocks?

Atrioventricular (AV) node ablation to control ventricular response was attempted in two patients with recurrent drug refractory atrial flutter. Standard radiofrequency (RF) procedure, which delivers energy through the 4-mm tip electrode of an ablation catheter positioned at the right AV junction and a large back plate (unipolar mode), failed in both patients. As an accepted second step, high energy direct current (DC) ablation under general anesthesia was then performed in patient one. After two shocks of 200 J, complete AV block occurred, but complete recovery was noted 3 hours later. In a third session for patient 1 and in the first session for patient 2 (after 15 unsuccessful unipolar right-sided RF applications), a second ablation catheter was introduced via the femoral artery on the left side of the His bundle area under the aortic valves. Energy was then delivered in a bipolar fashion between the tip electrodes of the right-sided and the left-sided catheter. Complete and permanent AV block (follow-up: 3 and 1 months) was created within 4 and 1.5 seconds, respectively, in each patient. No complication was encountered and echocardiograms and blood levels of cardiac enzymes were all normal after the procedures. This new approach, after further evaluation, may represent a useful additional step in the strategy of AV node ablation and could be applied before high energy DC shock when the standard RF procedure is unsuccessful.

Adult↗
PubMed1993

Gliding window fast Fourier transform analysis--a new method for discovering the contribution of higher frequencies in signal-averaged ECG.

OBJECTIVE: An attempt to detect the 'parasitic contribution' of high frequencies in the electrocardiogram signal. DESIGN: A new method--gliding window fast Fourier transform analysis (GWFFTA)--was developed. It was applied in healthy subjects and in patients with acute myocardial infarction. SETTING: Faculty of Medicine and University Hospital. PATIENTS: The GWFFTA was used in 29 healthy volunteers and in a group of 30 patients with myocardial infarction, on day 7 to 14 after admission to a coronary unit. INTERVENTION: Noninvasive examination, performed under standard conditions. MAIN RESULTS: GWFFTA provides better reproducible results compared with 'classic' fast Fourier transform analysis. The parasitic contribution of high frequencies within QRS complex and ST segment in patients with acute myocardial infarction is independent of presence or absence of late potentials. Contribution of high frequencies are three times higher in patients with acute myocardial infarction than in healthy probands. CONCLUSIONS: GWFFTA is a reproducible method of detection of high frequencies during whole heart activation. Contribution of high frequencies in patients with acute myocardial infarction reflects the state of the entire myocardium. It is also confirmed by the lack of correlation with the presence or absence of late potentials. Late potentials are more reflective of focal changes.

Action Potentials↗
PubMed1992

Does the heart electric activation split upon the infarcted area? An attempt at its detection by high-resolution electrocardiography.

Based on the presumption of the activation front splitting, the authors present their own proposal for the estimation of the myocardial electric activation course and for the detection of micropotentials 'hidden' within QRS complexes by the method of high-resolution electrocardiography. After filtration of QRS complex the values of delta RMS and those of cumulative amplitudes are calculated from the initial and from the terminal parts of QRS complexes. The presence of late potentials is reflected in a slowing down of the termination of activation course. As compared with healthy subjects, a slower rise of activation was observed in patients with myocardial infarction of the anterior wall. The curves of cumulative amplitudes rose very slowly during the first 70 ms of heart ventricle activation, explained according to the hypothesis of authors as being due to splitting of the activation front at the infarction focus. The usefulness of the proposed method was checked in patients with arterial hypertension and left ventricular hypertrophy, and in a group of patients with myocardial infarction. By the construction of cumulative amplitude curves from the onset of filtered QRS complexes, myocardial foci not reflected by 'classic' late potentials can be detected. The partial cumulative amplitudes of the QRS complex are suitable for comparative studies.

Adolescent↗
PubMed1991

A proposed classification of changes in the electrocardiogram in acute myocardial infarction.

Concepts regarding the aetiology and significance of changes in the electrocardiogram in acute myocardial infarction (AMI) have been changing and modified substantially in recent years. Today, the electrocardiogram must be analysed in the light of our current knowledge. When interpreting it, one must consider all the new information that electrocardiography (including electrical field monitoring by means of body surface mapping) employing sophisticated technology can provide. Optimal electrocardiographic information and its classification in AMI require detailed evaluation of the electrocardiogram characterizing all alterations in waves, ST segment denivelizations as well as their combinations, distribution and duration. The authors propose a new classification of alterations in the electrocardiogram in AMI which takes into account also the dynamics of electrocardiographic alterations, formerly a standard parameter. Future research and, most importantly, clinical practice will show whether this electrocardiographic classification allows identification of relatively homogeneous (in terms of clinical status and prognosis) groups of patients with AMI.

Electrocardiography↗
PubMed1990

[Cardiology '89. Present trends in cardiovascular medicine at the Congress of Cardiology '89 in London April 1989].

This review summarizes selected topics discussed at one of the major congress events in cardiovascular medicine in Great Britain in 1989. The congress was attended during its five days duration by 800 participants from nearly 40 countries. The scientific programme, consisting of invited state-of-art lectures, was divided into following basic topics: coronary heart disease including risk and prevention, arhythmias, hypertension, heart failure, structural heart disease, cardiac imaging and costs-effectiveness of cardiology. The aim of the review is to bring nearer the creative atmosphere and the very advanced postgraduate level of this cardiologic meeting. Due to the actual medico-social importance of current strategies in management of ischemic heart disease and malignant arrhythmias in Czechoslovakia, special interest is devoted to these problems. Based on congress lectures an overview of the atherosclerotic plaque pathology and resulting therapeutic and prognostic implications for the management of unstable angina and myocardial infarction is given. Selected aspects of thrombolytic therapy and its impact on coronary vessel wall and myocardium are discussed, too. Some contemporary problems and updated concepts of both drug and intervention treatment of malignant ventricular arrhythmias are highlighted in a more extensive way, confronting congress speakers and recent publications.

Cardiovascular Diseases↗