Search

Copyright of Heart & Vascular Diseases / Choroby Serca & Naczyn is the property of VM Medica-VM Group (Via Medica) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Symptoms such as palpitations, fainting, dizziness and unexplained loss of consciousness are often notified by patients in clinical practice. Cardiological causes of these ailments could be various, inter alia, atriaventricular conduction disorders, supraventricular arrythmias or more life-threatening ventricular arrythmias. Diagnostics of these disorders includes a series of basic non-invasive research and more advanced specialistic methods. Presented case report shows problems of arrythmias diagnostics and imperfections of avaible methods.

Background: Prediction of recurrent malignant ventricular tachyarrhythmias after insertion of a implantable cardioverter-defibrillator (ICD) is challenging. Microvolt T-wave alternans (MTWA) seems to be a promising marker of such events in ICD recipients., Aim: To assess prognostic significance of MTWA and other noninvasive parameters in the prediction of major arrhythmic events after ICD implantation., Methods: This prospective study included 155 patients (121 male, age 59 ± 11 years) in whom ICD was implanted for secondary prevention of a sudden cardiac death. In all patients, clinical evaluation along with estimation of ejection fraction, MTWA measurement using the HearTwave Cambridge Heart system, and determination of the corrected QT interval (QTc) and QT dispersion (QTd) based on resting ECG were performed 3 days before ICD implantation. Using 24-h Holter monitoring, cardiac arrhythmias, QT interval, QT dynamicity, QT variability (QTSD) and heart rate variability (HRV) time domain parameters were determined. MTWA results were categorised, based on the accepted criteria, as positive, negative or indeterminate. In further analyses, positive and indeterminate MTWA results were grouped together as abnormal or non-negative tests [MTWA+], while negative MTWA results were considered normal [MTWA-]. During the follow-up (mean duration 21.6 ± 11.6 months), major arrhythmic cardiac events (MACE), defined as death and/or the need for ablation and/or heart transplantation due to malignant ventricular tachyarrhythmias, were recorded., Results: During the follow-up, MACE occurred in 17 (11%) patients. Abnormal MTWA before ICD implantation was found significantly more frequently in patients with MACE as compared to patients without MACE. Multivariate Cox regression analysis identified abnormal MTWA and QTSD as independent risk factors for MACE, with hazard ratios of 10.82 (95% CI 9.76-11.88; p〈 0.05) and 1.08 (95% CI 1.05-1.08), respectively. Significant differences in MACE-free survival rate with regard to MTWA results (abnormal vs normal MTWA) were shown during the follow-up (p〈 0.001). The negative predictive value of normal MTWA for MACE was 98.6%. When both MTWA and QTSD were combined, the positive predictive value increased to 35%, with a sensitivity of 82% and specificity of 81%. The probability of MACE with normal results of both these tests was 2.3%., Conclusions: Abnormal MTWA is a strong independent predictor of MACE in ICD recipients, and QTSD is a weaker predictor. In the prediction of MACE after ICD implantation, the highest predictive value was noted for abnormal MTWA combined with QTSD. Normal values of these two parameters were associated with a low probability of MACE. These results suggest that standardised MTWA evaluation can be useful for risk stratification in the clinical practice.

Prevention of sudden cardiac deaths (SCD) is one of major challenges of todays cardiology. Factors, that would permit identification of patients with highest risk of SCD, have been sought for many years now. Although ventricle-dependent sinus arrhythmia has been observed for a few decades, quantification of this phenomenon was performed by Schmidt et al., who introduced new concept of heart rate turbulence (HRT). HRT parameters comprise of turbulence onset (TO) and turbulence slope (TS). When no HRT is observed, SCD risk is markedly increased. The mechanism behind HRT is not fully known, but it is though to be caused by baroreflex sensitivity. This factor has been evaluated in many clinical studies aiming at determining methods of analysis and usefulness of HRT also in others pathological entities. This paper is a short review of these studies.

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.

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.