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Beata Sredniawa

Publications and source records attributed to Beata Sredniawa.

11 recordsLinked to original sources
PubMed2006

Current developments in microvolt T-wave alternans.

Microvolt T-wave alternans (MTWA), the beat-to-beat fluctuation in T wave amplitude and morphology, is closely linked to vulnerability to ventricular arrhythmias in various experimental and clinical conditions. Clinically, MTWA is most commonly measured using the spectral method, although non-spectral methods for its assessment from ambulatory electrocardiographical recordings also have been developed. Recent studies suggest that the quantitative assessment of TWA may also be clinically relevant. The standardisation of the criteria for abnormal MTWA test still needs to be completed. The expansion of indications for implantable cardioverter-defibrillator (ICD) therapy following the positive results of the MADIT-II and SCD-HeFT trials might have unacceptable economic and medical consequences, and therefore new tests are needed to better discriminate patients who will and will not benefit from ICD implantation. A recent meta-analysis of MTWA studies revealed an overall positive predictive value for arrhythmic events of 19.3%, negative predictive value of 97.2%, and 3.77% univariate relative risk of arrhythmic events. The negative predictive value of MTWA in MADIT-II type patients has been reported to be 97.5%. The predictive value of the test varied significantly in different patient population. Current data support the use of MTWA testing for evaluation of patients with low ejection fraction who are considered for ICD implantation. The independence of the prognostic value of MTWA from other clinical and electrophysiological variables needs further confirmation.

Journal Article↗
PubMed2006

Effect of percutaneous interventions within the coronary sinus on the success rate of the implantations of resynchronization pacemakers.

BACKGROUND: Cardiac resynchronization therapy (CRT) becomes a "gold standard" in therapy of selected patients with advanced heart failure. We set out to evaluate the feasibility and safety of percutaneous interventions within coronary sinus (CS) and their effect on the success rate of left ventricular (LV) lead implantation during CRT. METHODS: The study analyzed eight consecutive patients with the indications for CRT, who needed additional procedures within CS to overcome technical problems during left ventricular (LV) electrode implantation. The analyzed group consisted of three subgroups: patients in whom percutaneous balloon angioplasty within CS was needed (n = 4); patients with acute instability of the lead, requiring stenting of the vein to fix the electrode (n = 2); and patients with the stenting of CS due to late dislocation of the lead (n = 2). Success rate, procedure duration, fluoroscopy, complications, and electrical parameters of leads were analyzed. RESULTS: Success rate of the procedures was 87.5%; additional interventions increased overall efficacy of CRT implantation at our center from 88% to 98% (P < 0.05). Procedure duration (155.0 minute) and fluoroscopy time (42.5 minute) remained acceptable for the patient and operator; however, both were higher than in the procedures performed routinely in our hospital. Electrical properties of the LV leads were stable and within normal ranges during the observation period. We noted two local dissections of CS during the procedure, which remained clinically silent. CONCLUSION: Percutaneous interventions within CS seem to be feasible and safe treatment options, which can improve the short- and long-term success rates of CRT.

Adult↗
PubMed2005

Methods of assessment and clinical relevance of QT dynamics.

The dependence on heart rate of the QT interval has been investigated for many years and several mathematical formulae have been proposed to describe the QT interval/heart rate (or QT interval/RR interval) relationship. While the most popular is Bazett's formula, it overcorrects the QT interval at high heart rates and under-corrects it at slow heart rates. This formulae and many others similar ones, do not accurately describe the natural behaviour of the QT interval. The QT interval/RR interval relationship is generally described as QT dynamics. In recent years, several methods of its assessment have been proposed, the most popular of which is linear regression. An increased steepness of the linear QT/RR slope correlates with the risk of arrhythmic death following myocardial infarction. It has also been demonstrated that the QT interval adapts to heart rate changes with a delay (QT hysteresis) and that QT dynamics parameters vary over time. New methods of QT dynamics assessment that take into account these phenomena have been proposed. Using these methods, changes in QT dynamics have been observed in patients with advanced heart failure, and during morning hours in patients with ischemic heart disease and history of cardiac arrest. The assessment of QT dynamics is a new and promising tool for identifying patients at increased risk of arrhythmic events and for studying the effect of drugs on ventricular repolarisation.

Journal Article↗
PubMed2005

Circadian and sex-dependent QT dynamics.

The dynamic QT relationship between the QT and RR intervals in normal individuals, including sex differences, has not been well examined. The aim of this Holter monitor-based study was to assess circadian and sex-related variations in QT dynamics in healthy subjects. The study population consisted of 50 healthy volunteers (mean age = 32 +/- 6 years, 25 men), in whom 24-hour digital Holter monitoring and QT interactive, beat-by-beat analyses were performed. The mean lengths of QT and RR intervals were measured from the 24-hour recordings. In order to assess QT dynamics, QT/RR linear regression was performed, and the slope was calculated over 24 hour and for day and night periods, and both genders separately. In the whole population, the mean QT interval was 356.5 +/- 19.2 ms and RR interval was 785.9 +/- 80.7 ms. The mean value of the slope over 24 hour was 0.17 +/- 0.03, though significantly steeper during the day (0.13 +/- 0.03) than at night (0.09 +/- 0.03, P < 0.001). The analysis of QT/RR dynamics over 24 hour revealed a significantly steeper slope in women (0.18 +/- 0.03) than in men (0.16 +/- 0.03, P = 0.006), as well as during daytime (0.14 +/- 0.03 vs 0.12 +/- 0.03, P = 0.04). Circadian variations and sex differences were observed in QT dynamics. The latter may explain the greater susceptibility of women to torsades de pointes during treatment with drugs that prolong repolarization.

Adolescent↗
PubMed2005

Effectiveness of radiofrequency catheter ablation of right ventricular outflow tract tachycardia using the CARTO system.

BACKGROUND: Ventricular ectopy or ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) are the most common forms of arrhythmias in patients with structurally normal heart. Pharmacological treatment is effective in no more than 50% of patients, whereas radio-frequency catheter ablation (RFCA) offers a much higher success rate. AIM: To assess early and late outcome in patients with RVOT arrhythmias treated with RFCA combined with electro-anatomical mapping system (CARTO). METHODS: The study group consisted of 34 consecutive patients (mean age 38.8+/-12.0 years, range 21-52 years, 11 males, 23 females) with symptomatic arrhythmias originating from RVOT, who underwent RFCA in our department between December 2001 to July 2003. RFCA was performed with the use of the CARTO system. The power of RF current was set at 40 Watts, duration -- 90 seconds, and maximal temperature -- 55 degrees C. In order to assess short- and long-term RFCA efficacy, a 24-hour Holter ECG monitoring was performed before RFCA and shortly after the procedure as well as one and three months afterwards. Effective RFCA was defined as the reduction of ventricular ectopy <1000 / 24 hours in Holter monitoring performed just after the procedure. RESULTS: Holter ECG monitoring performed after RFCA showed that the procedure was effective in 30 (88.2%) patients. In the remaining four patients no significant reduction in the frequency of ventricular ectopy was noted, however, no complex ventricular arrhythmias were present. In none of the patients neither early nor late complications were observed. The mean follow-up duration was 15.6 months (range 5-26 months). During Holter ECG monitoring performed one and three months after RFCA, a recurrence of frequent ventricular ectopy (7139 beats / 24 hours) was found in one patient, however, without complex arrhythmias. The remaining patients, in whom RFCA was found to be effective at Holter ECG monitoring performed just after the procedure, continue to be free from arrhythmia and do not require antiarrhythmic agents. CONCLUSIONS: RFCA with the use of the CARTO system is effective and safe in the treatment of arrhythmias originating from RVOT.

Adult↗
PubMed2005

[Holter monitoring in the prognosis of sudden cardiac death--new experiences and possibilities].

Sudden cardiac death is a great problem of nowadays. Patients suffer from coronary artery disease, myocarditis, dilated and hypertrophic cardiomyopathy, congenital and acquired heart diseases have a higher risk of sudden cardiac death. Holter monitoring allows to estimate the sudden cardiac death risk by risk factors analysis. We estimate arrhythmias, presence of ischaemia, QT interval, heart rate variability. Moreover, the event Holter is a useful method of searching the cause of syndromes which do not appear every single day.

Death, Sudden, Cardiac↗
PubMed2003

Comparison of heart rate variability between surgical and interventional closure of atrial septal defect in children.

This study was designed to compare reduced heart rate variability (HRV) in children with atrial septal defect (ASD) after surgical ASD closure with interventional (Amplatzer device) closure. Reduced HRV was observed in all children with ASD before treatment. HRV was further impaired 1 month after surgical ASD closure but not after catheter device closure. Three months after treatment, HRV indexes tended to normalize in both groups.

Adolescent↗
PubMed2003

Heart rate variability in heart failure.

BACKGROUND: Heart rate variability (HRV) depicts the functional status of the autonomic nervous system and its effects on sinus node. Recently, HRV analysis has been introduced in patients with heart failure (CHF) to identify those who are at risk of cardiac death. AIM: To analyse HRV in patients with CHF with depressed left ventricular ejection fraction (EF) and to relate HRV parameters to EF, NYHA functional class and other clinical parameters. METHODS: The study group consisted of 105 patients with CHF (88 males, 17 females, mean age 54+/-12 years); 77 patients had ischaemic cardiomyopathy, and 28 - dilated cardiomyopathy. All patients were in NYHA class II-IV and had EF <40%. The mean value of echocardiographically assessed EF was 26.9+/-8.3%. The control group consisted of 30 gender- and age-matched healthy subjects. HRV analysis was performed in the time-domain from 24-hour Holter ECG. RESULTS: All HRV variables were significantly lower in patients with CHF than in controls. Patients with NYHA class II had higher values of SDNN and SDANN than those in class III or IV. Patients with sustained or non-sustained ventricular tachycardia (VT) detected during Holter monitoring had lower SDNN and SDANN values than those without VT. Patients with diabetes had significantly lower SDNN and rMSSD values than the patients without diabetes. Similar results were found when patients with or without hypertension were compared. HRV parameters were similar in patients either with ischaemic or dilated cardiomyopathy. Also the values of EF were similar (27.4+/-8.4 vs 25.0+/-8.3%, respectively, NS). In the whole group of patients with CHF the values of SDNN and SDANN significantly correlated with EF (SDNN p<0.001, r=0.42; SDANN p<0.001, r=0.51). This correlation was stronger in the subset of patients with ischaemic cardiomyopathy (SDNN p=0.002. r=0.54; SDANN p=0.002; r=0.53) than in those with dilated cardiomyopathy (SDNN p=0.012, r=0.23; SDANN p=0.008, r=0.42). A significant negative correlation was found between all HRV parameters and NYHA class (SDNN p<0.001, r = -0.33; SDANN p<0.001, r = -0.38; rMSSD p<0.001, r = -0.13). CONCLUSIONS: HRV is depressed in patients with CHF compared with healthy subjects. Among patients with CHF, HRV is further decreased in patients with more advanced NYHA class, lower EF and in those with diabetes, hypertension or VT on Holter monitoring.

Adult↗
PubMed2002

[Permanent junction reciprocating tachycardia--treatment with radiofrequency current ablation].

The patients with WPW syndrome demonstrate wide scale of clinical manifestation, from asymptomatic course to sudden cardiac death. Among this patients it is possible to identify the small group of patients with rare kind of atrioventricular reentrant tachycardia named permanent junctional reciprocating tachycardia (PJRT) associated with increased risk of development tachycardia-induced cardiomyopathy. This patients should be successful treated by radiofrequency catheter ablation (RFCA). Aim of the study was assessment of efficacy and safety of RFCA procedure in patients with preexcitation syndrome and PJRT. Analyzed group consisted of 7 patients with PJRT selected from 163 consecutive patients with symptomatic WPW--syndrome undergo electrophysiological study (EPS) and RFCA. Analyzed group consist of 4 women and 3 men. Mean age of patients was 22.71 SD +/- 7.99 (from 14 to 38 years). Every patients underwent EPS and RFCA simultaneously. Success-rate in first session was 71.42% (5 patients were successful ablated). Two women underwent second ablation one who has recurrent symptomatic arrhythmia and another who initially was unsuccessfully treated in first session. This two additional procedures were successful. RFCA-duration time was average 107.85 minutes SD +/- 21.95 (min-80, max-145 min) and fluoroscopy--time amount from 28 min to 55 min average 38.58 min (SD +/- 11.14). Among analyzed patients we did not noticed any complications during ablation procedure. Patients with PJRT could be safe and successfully treated using RFCA.

Adolescent↗
PubMed2002

[Sudden cardiac death and inherited repolarization disorders].

Repolarization disorders leading to ventricular tachyarrhythmias are common causes of sudden cardiac death. Two of the disorders have been recently described at the molecular level revealing gene mutations: long QT syndrome, characterized by a prolonged QT interval corrected for heart rate and high incidence of malignant ventricular tachycardia, mainly torsade de pointes, and Brugada syndrome characterized by a ST segment elevation in the right precordial leads (V1-V3), right bundle branch block and idiopathic ventricular fibrillation. This review outlines current understanding of molecular genetic basis and pathophysiology of these diseases. On the basis of these repolarization disorders lay ion channel dysfunctions. The new discoveries may in the future allow a better diagnosis by genetic testing and raise the possibility of effective treatment by means of the gene-specific therapy.

Arrhythmias, Cardiac↗