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Biomedical subjects

P Ponikowski

Publications and source records attributed to P Ponikowski.

At least 55 records · Page 3Linked to original sources
PubMed1997

Chemoreceptor dependence of very low frequency rhythms in advanced chronic heart failure.

Factors responsible for very low frequency oscillations (VLF; cycle > 30 s) in the cardiovascular system remain obscure. We tested the hypothesis that increased peripheral chemosensitivity is important in the pathogenesis of VLF oscillations in patients with chronic heart failure (CHF). Fourteen male patients with stable, moderate to severe CHF (age 60 +/- 1.1 yr, ejection fraction 23 +/- 11%) and reproducible VLF oscillations in heart rate underwent a protocol consisting of three consecutive 20-min phases during which they breathed air, hyperoxia (O2 via mask, 60% O2 concn), and air again. Autoregressive spectral analysis of R-R intervals, blood pressure, and respiration was used to quantify total oscillatory power (TP), VLF, low (0.04-0.15 Hz)- and high (0.15-0.40Hz)-frequency power, and the coherence between these signals. Peripheral chemosensitivity was studied by assessing the ventilatory response to hypoxia using transient inhalations of pure N2. Discrete VLF rhythms were seen in R-R intervals in all 14 patients, in blood pressure in 7 of 14, and in respiration in 8 of 14 patients. A significant coherence (> 0.5) between heart rate and systolic blood pressure within the VLF band with mean phase value of -140 degrees, suggesting an antibaroreflex relationship, was seen in six subjects. Transient hyperoxia abolished the VLF oscillations in most subjects (12 of 14 in R-R intervals) and decreased R-R variability power within the VLF band. This response significantly correlated with peripheral chemoreceptor sensitivity (r = 0.77, P = 0.014). This study suggests that in CHF, enhanced peripheral chemoreceptor activity may facilitate slow oscillations in the cardiorespiratory signals.

Aged↗
PubMed1997

[Transient myocardial ischemia in patients after myocardial infarction and late cell potentials].

The role of myocardial ischaemia in the development of late potentials (LP) on the signal-averaged ECG (SAECG) in patients with coronary artery disease (CAD) remains controversial. The aim of the study was to assess the influence of transient, scintigraphically-proven (Tc-99mMI-BI), exercise-induced ischaemia on the presence of LP in 51 pts with angiographically documented CAD. Patients were divided into 2 groups: 26 pts (mean age 53 +/- 7.7) without the history of myocardial infarction (MI) (Group I) and 25 pts (mean age 56.8 +/- 6.4) after MI (Group II). SAECG recording were performed at baseline (A) and during exercise-induced ischaemia (B). The following time-domain parameters of SAECG were analyzed: the root mean square voltage of the last 40 and 50 ms of filtered QRS (RMS40, 50), total time duration of filtered QRS (t0QRS) and time duration potentials < 40 microV (LPD). The ventricular late potentials (LP) were defined as the presence of at least two of the following criteria: tQRS > 114 ms, RMS 40 < 20 mV and LPD > 38 ms. We conclude that transient exercise-induced ischaemia increased the presence of LP in pts with CAD after MI but did not alter the arrhythmogenic substrate for LP in those without the history of MI.

Electrocardiography↗
PubMed1997

[The effect of long term use of amiodarone hydrochloride on time and frequency domain parameters of signal averaged electrocardiogram in patients with ischemia heart disease].

The aim of this study was to assess the influence of amiodarone hydrochloride on time- and frequency-domain parameters of signal-averaged electrocardiogram (SAECG) in patients with ischaemic heart disease (IHD). The study population consisted of 33 patients (18 female and 15 male), mean age 59.2 +/- 7.7. Amiodarone hydrochloride was orally used in the initial dose 600 mg/day for 10 days, and subsequently 200 mg/days for 6 weeks. Recording of SAECG and ambulatory Holter monitoring were made at baseline and in 10 day and after 6 weeks of therapy. The following time-domain parameters were analyzed: the root mean square voltage of the last 40 and 50 ms of the filtered QRS (RMS40 i RMS50), total time duration of filtered QRS (t-QRS) and duration of low amplitude signals < 40 microV in the terminal part of QRS (LPD). Late potentials (LP) were recognized when at least two from three criteria were fulfilled: 1) RMS40 < 20 microV, 2) t-QRS > 114 ms, 3) LPD > 38 ms. Frequency analysis of SAECG allowed to calculate the following parameters in logarithmic scale: energy spectrum > -60 dB (A) and decibel drop at 40Hz (Dd) and also in linear scale: area ratio 20-50/0-20Hz (Ar) and magnitude ratio (MR1-7). The values of RMS40 and RMS50 did not significantly change during amiodarone therapy. The obtained values of t-QRS were significantly longer after antiarrhythmic therapy, respectively 97.8 +/- 9.1 ms at the baseline, 102.1 +/- 10 ms after 10 days (p < 0.05), and 104.1 +/- 10.4 ms after 6 weeks (p < 0.005). Moreover the values of LPD did not significantly change after amiodarone treatment. At the baseline the presence of LP were observed in 3 (9%), after 10 days were recorded in 8 (24%), and after 6 weeks in 7 (22%) cases. Only in one case the LP were observed during the whole antiarrhythmic therapy. Moreover, amiodarone hydrochloride did not statistically significant change frequency-domain parameters in logarithmic scale and in linear scale.

Aged↗
PubMed1997

[The influence of exercise and dobutamine-induced ischemia on the presence of late potentials in patients after myocardial infarction].

UNLABELLED: The aim of this study was to examine the influence of transient exercise- and dobutamine-induced myocardial ischemia on time domain parameters of signal-averaged ECG (SAECG) and presence of late potentials (LP) in patients after myocardial infarction (MI). The investigation covered 85 patients after healing of MI, divided into two groups. Group I (24 males and 2 females, mean age 56.8 +/- 6.4 yrs) had exercise-induced ischemia and group II consisted of 59 patients (51 males and 8 females, mean age 58.3 +/- 8.5 years) with ischemia provoked by the intravenous dobutamine stress-testing. In each patient 2-D echocardiography, 24-h ambulatory Holter ECG, coronary arteriography were performed before stress testing. The ischemia was proven by using Tc-99m. MIBI myocardial perfusion and standard 12-lead ECG monitoring. Recordings of SAECG were registered at rest and during ischemia under influence of stress-testing. The following time-domain parameters of SAECG were analysed: the root-mean-square voltage of the last 40 and 50 ms of the filters QRS complex (RMS40, 50), total time duration of filtered QRS (t-QRS) and duration of signals lower than 40 microV (LPD). LP were detected when two or three of following criterias had been registered: RMS 40 < 20 microV, t-QRS > 114 ms, LPD > 38 s. There was no statistically significant differences in all time domain parameters of SAECG between records at the baseline and during ischemia in each study group. At the baseline LP have been registered in 11.5% and in 15% patients, respectively of group I and group II. On the top of ischemia during treadmill exercise stress-testing LP have been recorded in 27% subjects. Under influence of dobutamine-provoked ischemia LP have been registers in 25% patients. CONCLUSION: Exercise- and dobutamine-induced ischemia triggers development of LP in small grade in post-infarction patients.

Dobutamine↗
PubMed1997

[Clinical significance of atrial signal-averaged electrocardiogram in patients with electrically-induced paroxysmal atrial fibrillation].

UNLABELLED: The aim of this study was to assess the diagnostic possibilities of recording of time-domain parameters of atrial signal-averaged electrocardiogram (ASAECG) in patients with electrically-induced paroxysmal atrial fibrillation (PAF). The investigation was done in 53 patients (34 male and 19 female) mean age 47.6 +/- 13.1 with electrically induced sustained PAF- > 30 sec (group I). As a controls were forty patients (28 male and 12 female) mean age 46.2 +/- 15.3 (group II). The following time-domain parameters of ASAECG were calculated: the root mean square voltage of the terminal 10,20,30 ms of the filtered P-wave (RMS10,20,30) and total duration of filtered P-wave (PWD) and also time duration of P-wave from Frank's leads X,Y,Z (XP,YP,ZP). The values of RMS10,20,30 were statistically significant lower in patients with PAF than in controls, respectively RMS10: 3.9 +/- 1.4 microV vs 5.4 +/- 2.3 microV, p < 0.005, RMS20: 5.3 +/- 2 microV vs 6.8 +/- 2.2 microV, p < 0.001 and RMS30: 6.8 +/- 2.1 microV vs 7.4 +/- 3.6 microV, p < 0.05. Also the values of PWD were significantly longer in group I: 121 +/- 14.6 ms than in group II: 113.9 +/- 13.5 ms, 1 p < 0.02. Analysing the values of XP,YP,ZP it's occurred that only YP in PAF patients was statistically longer than in control, respectively 111 +/- 14.8 ms vs 96.7 +/- 13.8 ms, p < 0.001. The best differential criteria for identification of patients with electrically-induced PAF were RMS20 < 6 microV and PWD > 118 ms and gave sensitivity of 52%, specificity of 79%, positive predictive value of 68%, negative of 66% and diagnostic accuracy of 67%. CONCLUSIONS: 1. In patients with electrically-induced PAF the lower values of RMS10,20,30 and longer PWD were detected. 2. The criteria for identification of patients with electrically-induced paroxysmal atrial fibrillation were the values of RMS20 < 6 microV and PWD > 118 ms.

Adult↗
PubMed1996

Detection and significance of a discrete very low frequency rhythm in RR interval variability in chronic congestive heart failure.

Although in advanced chronic congestive heart failure (CHF) very low frequency (< 0.04 Hz, VLF) oscillations are prominent, the clinical importance and the physiologic basis of these rhythms have not been elucidated. To investigate the physiologic determinants of the VLF rhythms in RR interval variability, we studied 36 patients with stable, moderate to severe CHF (33 men, age: 58 +/- 8 years, ejection fraction 25 +/- 10%, peak oxygen consumption 18.1 +/- 4.6 ml/kg/min) and 12 age- and sex-matched controls using autoregressive spectral analysis of RR interval, blood pressure, and respiratory signals during controlled conditions. We quantified low frequency (LF) (0.04 to 0.15 Hz), high frequency (HF) (0.15 to 0.40 Hz), VLF, and total power (0 to 0.5 Hz), and calculated the coherence between systolic blood pressure and RR interval variability within each band. Peripheral chemosensitivity was assessed by the ventilatory response to hypoxia using transient inhalation of pure nitrogen. The influence of transient inactivation of peripheral chemoreceptors on the VLF rhythm was investigated by exposing 6 patients to hyperoxic (60% oxygen) conditions for 20 minutes. Twenty-three patients (64%) with CHF, but no controls, had a discrete VLF rhythm (0.019 +/- 0.008 Hz) in RR variability. The presence of VLF rhythm was not related to any difference in clinical parameters (etiology, New York Heart Association class, ejection fraction, oxygen uptake) but rather to a different pattern in RR interval and blood pressure variability: lower LF power (2.8 +/- 1.6 ms2 natural logarithm [ln]) compared either to patients without VLF (4.0 +/- 1.3 ms2 ln) or to controls (5.9 +/- 0.7 ms2 ln), higher percentage of power within VLF band (86.3 +/- 8.3% vs 77.5 +/- 7.9% and 61.5 +/- 14.1%) and a markedly impaired coherence between RR interval and systolic blood pressure variability within the LF band (0.26 +/- 0.10 vs 0.42 +/- 0.18 and 0.63 +/- 0.15, in patients with vs without VLF peak and controls, respectively). Patients with VLF had significantly increased hypoxic chemosensitivity, and hyperoxic conditions were able to decrease VLF power and abolish the VLF rhythm in 5 of 6 patients with CHF. Discrete VLF oscillations in RR variability are common in patients with advanced CHF and appear to be related to severely impaired autonomic regulation and suppression of baroreceptor function, with enhancement of hypoxic chemosensitivity. We hypothesize that this rhythm represents an enhanced chemoreflex harmonic oscillation in CHF patients, which may have application for arrhythmogenesis.

Autonomic Nervous System↗
PubMed1996

Transient autonomic dysfunction precedes ST-segment depression in patients with syndrome X.

Increased sympathetic drive has been suggested to play a role in the pathogenesis of syndrome X (angina pectoris, positive exercise testing, and angiographically normal coronary arteries). Heart rate variability (HRV) studies have shown that patients with syndrome X have an imbalance in autonomic nervous system activity (sympathetic predominance). However, it is not known if transient ST-segment depression which occurs in syndrome X during daily activities is related to this autonomic nervous system dysfunction. This study investigates the relation between the response of the autonomic nervous system, as assessed by HRV analysis, and the occurrence of transient ST-segment depression during 24-hour ambulatory electrocardiographic monitoring in 23 patients (4 men and 19 women, mean age 55 +/- 6 years) with syndrome X. The frequency-domain variables of HRV low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power were measured at 6-minute intervals during the 30 minutes preceding the onset of transient ST-segment depression. Fourteen patients (61%) had > or = 1 episode of ST-segment depression in the 24 hours, whereas the remaining 9 patients (39%) had no significant ST-segment change. HRV measures differed according to whether or not ST-segment depression was associated with increased heart rate. Episodes of ST-segment depression associated with increased heart rate were preceded by a reduction of high-frequency power and an increase in the low-frequency--high-frequency ratio, whereas episodes of ST-segment depression not associated with increased heart rate showed no significant HRV changes. Low-frequency power remained unchanged irrespective of heart rate. Thus, in patients with syndrome X, a sympathovagal imbalance (sympathetic predominance due to vagal tone withdrawal) precedes episodes of ST-segment depression that are associated with an increased heart rate.

Autonomic Nervous System↗
PubMed1996

Heart rhythms, ventricular arrhythmias, and death in chronic heart failure.

BACKGROUND: The aim of this study was to evaluate whether abnormalities in heart rate variability (HRV) could act as markers of ventricular tachycardia and prognosis in patients with advanced, chronic heart failure. Fifty patients with chronic heart failure (45 men; mean age, 59 +/- 9 years; New York Heart Association [NYHA] class II-III; left ventricular ejection fraction [LVEF], 19 +/- 9% and peak oxygen consumption, 16.6 +/- 5.4 mL/kg/min) caused by idiopathic dilated cardiomyopathy (n = 12) and ischemic heart disease (n = 38) were included in the study. Heart rate variability measures derived from 24-hour electrocardiographic (ECG) monitoring (Marquette 8500 recorder, Marquette Electronics, Milwaukee, WI) were calculated in the time domain and frequency domain. METHODS AND RESULTS: Twenty-five patients (50%) revealed episodes of ventricular tachycardia on 24-hour ECG monitoring (1-143 episodes). The presence of ventricular tachycardia was associated with lower LVEF but there was no difference in NYHA class and peak oxygen consumption between patients with and without ventricular tachycardia (LVEF, 16 vs 22%, P = .01; NYHA class, 2.6 vs 2.4; peak oxygen consumption, 16.5 vs 16.8 mL/kg/min, not significant). Patients with ventricular tachycardia exhibited markedly lower HRV measures. Multiple regression analysis was used to test HRV parameters as potential predictors of ventricular tachycardia. Among them, high-frequency power was the only independent predictor of the presence of ventricular tachycardia, and this predictive correlation was independent of LVEF and mean R-R interval duration. During a follow-up period of 24 +/- 18 months, 12 patients (24%) died. No difference was found in age, etiology, NYHA class, peak oxygen consumption, or occurrence of ventricular tachycardia, but a lower LVEF (15 +/- 6 vs 21 +/- 9%, P = .046) was observed in those who died compared with those who survived. Certain estimates of HRV were in contrast, lower in those who subsequently died: standard deviation of all normal R-R intervals (61 +/- 30 vs 101 +/- 33 ms), standard deviation of 5-minute mean R-R intervals (55 +/- 27 vs 92 +/- 31 ms), mean of all 5-minute standard deviations of R-R intervals (22 +/- 12 vs 37 +/- 11 ms), and the low-frequency (3.2 +/- 1.8 vs 4.8 +/- 0.9 ln ms2) and high-frequency (3.0 +/- 1.1 vs 3.8 +/- 0.8 ln ms2) components of the HRV spectrum (all differences, P < .01). In univariate Cox analysis, all of these HRV measures were independent predictors of death. Kaplan-Meier survival analysis revealed that the standard deviations of all normal R-R intervals and of 5-minute mean R-R intervals dichotomized at median values (99 and 90.5 ms, respectively) were the best predictors of mortality. CONCLUSIONS: In patients with moderate to severe chronic heart failure, depressed indices of HRV on 24-hour ambulatory ECG monitoring could be related to higher risk of ventricular tachycardia and death, suggesting that analysis of HRV could be usefully applied to risk stratification in chronic heart failure patients.

Arrhythmias, Cardiac↗
PubMed1996

Reproducibility of heart rate variability measures in patients with chronic heart failure.

1. In patients with chronic heart failure, heart rate variability is reduced with relative preservation of very-low-frequency power (< 0.04 Hz). Heart rate variability has been measured without acceptable information on its stability and the optimal recording periods for enhancing this reproducibility. 2. To this aim and to establish the optimal length of recording for the evaluation of the very-low-frequency power, we analysed 40, 20, 10 and 5 min ECG recordings obtained on two separate occasions in 16 patients with chronic heart failure. The repeatability coefficient and the variation coefficient were calculated for the heart rate variability parameters, in the time-domain (mean RR, SDRR and pNN50), and in the frequency-domain: very low frequency (< 0.04 Hz), low frequency (0.04-0.15 Hz), high frequency (0.15-0.40 Hz), total power (0-0.5 Hz). 3. Mean RR remained virtually identical over time (variation coefficient 8%). The reproducibility of time-domain (variation coefficient 25-139%) and of spectral measures (variation coefficient 45-111%) was very low. The stability of the heart rate variability parameters was only apparently improved after square root and after log transformation. 4. Very-low-frequency values derived from 5 and 10 min intervals were significantly lower than those calculated from 40 and 20 min intervals (P < 0.005). Discrete very-low-frequency peaks were detected in 11 out of 16 patients on the first 40, 20 and 10 min recording, but only in seven out of 16 when 5 min segments were analysed. 5. The reproducibility of both time or frequency-domain measures of heart rate variability in patients with chronic heart failure may vary significantly. Square root or log-transformed parameters may be considered rather than absolute units in studies assessing the influence of management on heart rate variability profile. Recordings of at least 20 min in stable, controlled conditions are to be recommended to optimize signal acquisition in patients with chronic heart failure, if very-low-frequency power in particular is to be studied.

Chronic Disease↗
PubMed1996

[The effects of long-term treatment of sotalol hydrochloride on time and frequency domain parameters of signal averaged electrocardiogram in patients with ischemic heart disease].

The aim of this study was to assess the influence of sotalol hydrochloride on time- and frequency-domain parameters of signal-averaged electrocardiogram (SAECG) in patients with ischemic heart disease (IHD). The study population consisted of 25 patients (16 women and 9 men), mean age 56.6 +/- 8.3. Sotalol was orally used in dose 160 mg/day during 6 weeks. Recording of SAECG and ambulatory Holter monitoring were made at baseline and in 10 day and after 6 weeks of therapy. The following time-domain parameters were analyzed: the root mean square voltage of the last 40 and 50ms of the filtered QRS (RMS 40 i RMS 50), total time duration of filtered QRS (t-QRS) and duration of low amplitude signals < 40 microV in the terminal part of QRS (LPD). Late potentials (LP) were recognized when at least two from three criteria were fulfilled: 1) RMS40 < 20 microV, 2) t-QRS > 114 ms, 3) LPD > 38ms. Frequency analysis of SAECG allowed to calculate the following parameters in logarithmic scale: energy spectrum > -60dB (A) and decibel drop at 40 Hz (Dd) and also in linear scale: area ratio 20-50/0-20 Hz (Ar) and magnitude ratio (MR1-7). The values of RMS40 and RMS50 and also t-QRS and LPD did not significantly change after sotalol treatment. At baseline the presence of LP was recorded in 7 (28%) cases, after 10 days of antiarrhythmic therapy only in 3 (12%), and after 6 weeks occurred in 6 (24%) cases. Moreover, sotalol hydrochloride did not statistically significant change frequency-domain parameters in logarithmic scale: A and Dd. On the other hand, the parameters in linear scale: MR1, MR4 and MR6 significantly change but these changes were not uniform. These findings suggest that oral treatment of sotalol hydrochloride did not significantly change time- and frequency-domain parameters of signal-averaged electrocardiogram in patients with ischemic heart disease.

Anti-Arrhythmia Agents↗
PubMed1996

[The influence of organic myocardial damage on parameters of signal-averaged electrocardiogram in patients with electrically-induced atrial fibrillation].

The aim of this study was to assess the effects of myocardium organic damage on time-domain parameters of atrial signal-averaged ECG (ASAECG) in patients with electrically induced paroxysmal atrial fibrillation (PAF). The investigation was done in 120 patients with subjective symptoms of cardiac rhythm disorders suggesting atrial fibrillation and for further analysis were selected 51 patients in whom atrial PAF was induced during transoesophageal pacing (TEP). Patients were divided according to organic damage of myocardium-38 pts (24 male and 14 female, mean age 52.1 +/- 11.6-group I) and without-13 pts (9 male and 4 female, mean age 35.4 +/- 9.9 -group II). In all two dimensional echocardiographic examination, 24-hours Holter monitoring, exercise testing and TEP were made. Recording of ASAECG was done with a commercially available system HIPEC-200 HA Aerotel. The following time-domain parameters of ASAECG were calculated: the root mean square voltage of the terminal 10, 20, 30 ms of the filtered P-wave (RMS 10, 20, 30) and time duration of filtered P-wave (PWD) and also time duration of P-wave from Frank's leads X, Y, Z (XP, YP, ZP). Atrial late potentials (ALP) were defined as the presence of two parameters: RMS 10 < 4 microV and PWD > 123 ms. If we compared time-domain parameters of ASAECG between examined groups it occurred that only the values of PWD attained statistically significant differences, respectively 123.3 +/- 15.4 ms vs 115 +/- 11.2 ms, p < 0.05. In 14 (36.8%) patients from first group and in 2 (15.4%) patients from second ALP were confirmed. We concluded that presence of myocardium organic damage have essentially influenced on time duration of filtered P-wave.

Adult↗
PubMed1996

[Use of body surface heart potential mapping for registration of electrical phenomenal in the atrium].

Research on body surface potential mapping concerned predominantly the ventricular excitation process. There is only very limited data available documenting surface potential distribution during atrial electric events. The goal of this study was to establish the pattern and criteria of the atrial potential maps in the healthy population, which is substantial for a prospective usefulness of the noninvasive registrations of surface maps in atrial arrhythmias. A group of 54 subjects in whom there was no clinical evidence of cardiac dysfunction underwent a procedure of body surface potential mapping. The recordings were performed using the HPM-7100 system simultaneously from 87 leads covering the entire thorax. Isopotential maps registered during the P wave were subjected to the statistical analysis by means of the own system "Heart Map" enabling the qualitative and quantitative estimation of the atrial maps. To avoid a problem of variable heart rate, a time standardization, by the division of the P wave into 10 time intervals, was applied. In order to eliminate an interindividual variability of heart location in the thorax, a distribution of the constituent values without subordinating them to the individual electrodes was proposed. In consequence, the group-mean isopotential maps of the wave P for the normal subjects were created. According to the migration of the maximum throughout the thoracic surface during the P wave, three phases of the isopotential atrial maps were determined: phase 1 (P1-P4) comprising initial 40% of the P wave, phase 2 (P5,P6)-next 20% of the P wave and phase 3 (P7-P10)-the terminal 40% of the P wave duration. These phases reflect the successive sequences of atrial excitation. During the whole atrial depolarization the minimum of potential, changing its value, was located around lead D7. Furthermore, in the results of the analysis of the constituent values sequences, for the P wave time intervals the additional quantitive parameters were calculated, i.e. areas designated by positive and negative potential and the ratio of these areas. The presented findings revealed that surface maps give the precious insight into spread of atrial excitation. Establishing of the distribution pattern and the criteria of the atrial potential maps for normals enables to undertake the further research on the use of this technique in a various atrial pathology.

Adult↗
PubMed1996

[The effect of sotalol hydrochloride therapy on atrial signal-averaged ECG in patients with paroxysmal atrial fibrillation].

The aim of this study was to evaluate of oral sotalol hydrochloride effects on atrial signal-averaged ECG (ASAECG) during time- and frequency-domain analysis in patients with paroxysmal atrial fibrillation (PAF) during ischemic heart disease (IHD). The study population of 27 was composed of 16 female and 11 male, mean age 56.1 +/- 8.4. The dose of oral sotalol was 160 mg/day for all days. Recording of ASAECG and 24-hours Holter monitoring were made at baseline, after 10 days and after 6 weeks of sotalol therapy. For ASAECG were calculated time-domain parameters: the root mean square voltage of the signals in the last 10, 20, 30 ms of the filtered P-wave (RMS 10, 20, 30) and total time duration of filtered P-wave (PWD) and time duration of P-wave for Frank leads X, Y, Z (XP, YP, ZP). During frequency-domain analysis of the terminal part of P-wave we calculated the following parameters in range from 40 Hz to 400 Hz: energy spectrum > -60 dB (A) and decibel drop at 40 Hz (Dd) in logarithmic scale and area ratio 20-50/0-20 Hz (Ar), magnitude ratio (MR1-7) in linear scale for a vector magnitude. Supraventriculat arrhythmias were estimated quantitatively and qualitatively during Holter monitoring. The following parameters were estimated in a case of PAF recording: time of manifestation, duration, number of PAF episodes per day, mean heart rate during PAF and subjective symptoms. Moreover, comparable analysis of the following parameters: dimension of left atrial, age, gender, time duration of IHD and PAF and wall motion disturbances-hypokinesis and also left ventricular ejection fraction, mitral regurgitation was done between patients with effective and no effective of antiarrhythmic therapy. Our observation have indicated that oral sotalol therapy are responsible for statistically significant decrease of total time duration of filtered P-wave (PWD) and time duration of P-wave for Frank leads X, Y, Z (XP, YP, ZP) and increase area ratio 20-50/0-20 Hz in patients with PAF during IHD. Moreover, comparable analysis of above-mentioned parameters have not showed statistically significant differences between examined patients with effective and lack of effective sotalol therapy.

Administration, Oral↗
PubMed1995

P-wave signal-averaged electrocardiogram in patients with idiopathic mitral valve prolapse syndrome and supraventricular arrhythmias.

The aim of the study was to assess whether the P-wave triggered signal-averaged ECG (SAECG) used in patients with idiopathic mitral valve prolapse syndrome could predict the risk of the development of supraventricular arrhythmias. Fifty patients with idiopathic mitral valve prolapse syndrome (15 men, 35 women, mean age: 37 +/- 9 years) were prospectively studied. P-wave triggered SAECG was recorded with a commercially available system (HIPEC-200HA Aerotel). The following parameters were calculated: the root-mean-square voltage for the terminal 10, 20, 30 ms of filtered P-wave (RMS10,20,30) and time duration of filtered P-wave (PWD). Nine patients with mitral valve prolapse syndrome (18%) revealed the occurrence of supraventricular arrhythmias on Holter monitoring whereas of the remaining 41 (82%), no clinically relevant supraventricular arrhythmias were detected. We found PWD values to be significantly longer in patients with supraventricular arrhythmias when compared with those without arrhythmias: 119.8 +/- 6.9 ms vs. 111.7 +/- 12.1 ms, respectively, P < 0.02. We conclude that P-wave triggered SAECG could be a useful technique for detecting patients with idiopathic mitral valve prolapse syndrome at risk of paroxysmal supraventricular arrhythmias.

Adult↗
PubMed1995

Circadian pattern of heart rate variability in chronic heart failure patients. Effects of physical training.

The effect of physical training on the circadian pattern of heart rate variability (recorded over 24 h in relation to both time and frequency) was assessed in 12 chronic heart failure patients randomized, in a cross-over design, to 8 weeks training or detraining, and compared with 12 age-matched normals. Training improved heart rate variability indices: all R-R interval 5 min standard deviations increased by 17.6%, the root mean square of the differences of successive R-R intervals by 34.9%, the percentage difference between adjacent normal R-R intervals > 50 ms by 112.5%, total power by 58.3%, high frequency by 128.5% and low frequency by 65.0%. Compared with controls, circadian variations in autonomic parameters were maintained in chronic heart failure. Training-induced changes were observed at different time intervals throughout the day: the highest values were at 0100 h-0700 h (detraining: low frequency 361 +/- 83 ms2, high frequency 126 +/- 47 ms2; training: low frequency 535 +/- 202 ms2, high frequency 227 +/- 115 ms2, P < 0.01) and the lowest at 1300 h-1900 h (detraining: low frequency 91 +/- 23 ms2, high frequency 39 +/- 14 ms2; training: low frequency 154 +/- 42 ms2, high frequency 133 +/- 67 ms2, P < 0.05). In chronic heart failure, training maintains and improves circadian variations in heart rate variability measures.

Aged↗
PubMed1995

Role of catecholamines and sympathetic activation as a risk factor for coronary artery disease.

After acute myocardial infarction and in chronic heart failure, several abnormalities of the autonomic control of the heart have been described, and evidence of marked neurohumoral activation has been found. Increased sympathetic activation can be identified using a number of methods, including simple or dynamic measurement of catecholamines and the study of heart rate variability by direct sympathetic nerve or muscle activity and by measurement of baroreceptor sensitivity. The analysis of heart rate variability is becoming more popular and has advantages over other more invasive methods.

Animals↗