Sympathetic overactivity and low parasympathetic activity is an autonomic dysfunction (AD) which enhances cardiac mortality. In the present study, the impact of AD on the mortality in patients after myocardial infarction was evaluated. We examined 162 patients 7-21 days after myocardial infarction, 20 patients of whom died in the course of two years. Baroreflex sensitivity (BRS) was estimated by spectral analysis of spontaneous fluctuations of systolic blood pressure and cardiac intervals (Finapres, 5 min recording, controlled breathing 20/min). The heart rate variability was determined as SDNN index (mean of standard deviations of RR intervals for all 5-min segments of 24-hour ECG recordings). BRS < 3 ms/mm Hg and/or SDNN index < 30 ms were taken as markers of AD. The risk stratification was performed according to the number of the following standard risk factors of increased risk of cardiac mortality (SRF): ejection fraction < 40 %, positive late potentials and the presence of ventricular extrasystoles > 10/h. No difference in mortality between patients with AD (4 %) and without AD (4.5 %) was found in 92 patients without SRF, the mortality in 6 patients with three SRF was 66.6 %. Five of these patients had AD. Out of 64 patients with one or two SRF, 32 had AD. The mortality of patients without AD was 6.25 % and 31.2 % of those with AD (p<0.025). It is concluded that AD enhanced two-years mortality five fold in our patients with moderate risks., N. Honzíková, B. Semrád, B. Fišer, R. Lábrová., and Obsahuje bibliografii
a1_Non-invasive methods of determination of baroreflex sensitivity (BRS, ms/mmHg) are based on beat-to-beat systolic blood pressure and inter-beat interval recording. Sequential methods and spectral methods at spontaneous breathing include transient superposition of breathing and 0.1 Hz rhythms. Previously, a cross-spectral method of analysis was used, at constant breathing rate using a metronome set at 0.33 Hz, enabling separate determination of BRS at 0.1 Hz (BRS0.1Hz) and respiratory rhythms (BRS0.33Hz). The aim of the present study was to evaluate the role of breathing in the spectral method of BRS determination with respect to age and hypertension. Such information would be important in evaluation of BRS at pathological conditions associated with extremely low BRS levels. Blood pressure was recorded by Finapres (5 minutes, controlled breathing at 0.33 Hz) in 118 healthy young subjects (YS: mean age 21.0±1.3 years), 26 hypertensive patients (HT: mean age 48.6±10.3 years) with 26 age-matched controls (CHT: mean age 46.3±8.6 years). A comparison of BRS0.1Hz and BRS0.33Hz was made. Statistically significant correlations were found between BRS0.1Hz and BRS0.33Hz in all groups: YS: r=0.52, p<0.01, HT: r=0.47, p<0.05, and CHT: r=0.70, p<0.01. The regression equations indicated the existence of a breathing-dependent component unrelated to BRS (YS: BRS0.33Hz=2.63+1.14*BRS0.1Hz; HT: BRS0.33Hz=3.19+0.91*BRS0.1Hz; and CHT: BRS0.33Hz=1.88+ +1.01*BRS0.1Hz; differences between the slopes and the slope of identity line were insignificant). The ratios of BRS0.1Hz to BRS0.33Hz were significantly lower than 1 (p<0.01) in all groups (YS: 0.876±0.419, HT: 0.628±0.278, and CHT: 0.782±0.260). Thus, BRS evaluated at the breathing rate overestimates the real baroreflex sensitivity. This is more pronounced at low values of BRS, which is more important in patients with pathologic low BRS., a2_For diagnostic purposes we recommend the evaluation of BRS at the frequency of 0.1 Hz using metronome-controlled breathing at a frequency that is substantially higher than 0.1 Hz and is not a multiple of 0.1 Hz to eliminate respiratory baroreflexnon- related influence and resonance effect on heart rate fluctuations., P. Bothová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The aim of this study was a comparison of risk stratification for death in patients after myocardial infarction (MI) and of risk stratification for malignant arrhythmias in patients with implantable cardioverter-defibrillator (ICD). The individual risk factors and more complex approaches were used, which take into account that a borderline between a risky and non-risky value of each predictor is not clear-cut (fuzzification of a critical value) and that individual risk factors have different weight (area under receiver operating curve - AUC or Sommers´ D - Dxy). The risk factors were baroreflex sensitivity, ejection fraction and the number of ventricular premature complexes/hour on Holter monitoring. Those factors were evaluated separately and they were involved into logit model and fuzzy models (Fuzzy, Fuzzy-AUC, and Fuzzy-Dxy). Two groups of patients were examined: a) 308 patients 7-21 days after MI (23 patients died within period of 24 month); b) 53 patients with left ventricular dysfunction examined before implantation of ICD (7 patients with malignant arrhythmia and electric discharge within 11 month after implantation). Our results obtained in MI patients demonstrated that the application of logit and fuzzy models was superior over the risk stratification based on algorithm where the decision making is dependent on one parameter. In patients with implanted defibrillator only logit method yielded statistically significant result, but its reliability was doubtful because all other tests were statistically insignificant. We recommend evaluating the data not only by tests based on logit model but also by tests based on fuzzy models., P. Honzík ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Beside heart failure and metabolic syndrome, atrial fibrillation is termed the cardiovascular epidemic of the 21st century. Its increased morbidity and mortality is alarming. The present, most effective therapy of atrial fibrillation is catheter ablation. Successful ablation of atrial fibrillation prevents the occurrence and progression of electrical, structural and mechanic myocardium remodelling, improves function of the left ventricle, and prevents the risk of thrombembolism. Onset of sinus rhythm activates the reversal remodelling leading to wall reconstruction and atrium reduction. The paper reviews the technique and presents own experience with catheter ablation., R. Lábrová, J. Špinar, N. Honzíková., and Obsahuje bibliografii a bibliografické odkazy