Heart rate variability (HRV) reflects an influence of autonomic nervous system on heart work. In healthy subjects, ratio between low and high frequency components (LF/HF ratio) of HRV spectra ...represents a measure of sympatho-vagal balance. The ratio was defined by the authorities as an useful clinical tool, but it seems that it fails to summarise sympatho-vagal balance in a clinical setting. Value of the method was re-evaluated in several categories of cardiac patients. HRV was analysed from 24-hour Holter ECGs in 132 healthy subjects, and 2159 cardiac patients dichotomised by gender, median of age, diagnosis of myocardial infarction or coronary artery surgery, left ventricular systolic function and divided by overall HRV into several categories. In healthy subjects, LF/HF ratio correlated with overall HRV negatively, as expected. The paradoxical finding was obtained in cardiac patients; the lower the overall HRV and the time-domain indices of vagal modulation activity were the lower the LF/HF ratio was. If used as a measure of sympatho-vagal balance, long-term recordings of LF/HF ratio contradict to clinical finding and time-domain HRV indices in cardiac patients. The ratio cannot therefore be used as a reliable marker of autonomic activity in a clinical setting.
Rad na sažet način donosi pregled povijesnog razvoja instituta rada za opće dobro, prikaz zakonskih izmjena koje su se dogodile u proteklom 25-ogodišnjem razdoblju vezano uz zakonsko uređenje ...izricanja i izvršavanja rada za opće dobro te prikaz sadašnjeg zakonskog okvira kojim je uređeno to područje. Nadalje, rad donosi i prikaz sudske prakse (sentenci) svih sudskih instanci u Republici Hrvatskoj te statističke podatke vezane uz izricanje i izvršavanje rada za opće dobro u proteklih 25 godina. Uz prethodno navedeno, autori nastoje upozoriti na aktualne probleme koji se pojavljuju u praksi prilikom određivanja
rada za opće dobro, njegova provođenja i izvršavanja te na navedene probleme ponuditi odgovore i rješenja.
Pubertal growth of heart was analyzed. Growth rates of "diastolic variables" of heart size were compared with that of 'systolic', and both with growth intensities of some body structures and ...functions that are related to cardiac growth. Longitudinal echocardiographic, ergometric and anthropometric measurements were performed in 84 healthy boys, aged 11.5 years at the beginning and 14.5 at the end of study. Diastolic thickness of left ventricular walls increased by a mean rate of 15% and systolic by 36% (p < 0.001). As a result, percent systolic wall thickening increased from 20% to 41% during the 3 years (p < 0.001). Other measures of cardiac contractility increased in the same manner. Increase in measures of cardiac preload and afterload corresponds to the increase in heart "diastolic" and "systolic" variables, respectively. The study gave evidences for an increase in cardiac contractility during puberty. Coexistence of two simultaneous growth models for pubertal heart: diastolic and systolic, is suggested.
Multiple system atrophy (MSA) is sporadic, progressive neurodegenerative disorder characterized clinically by autonomic dysfunction, Parkinsonism (MSA-P), and cerebellar ataxia (MSA-C) in any ...combination. Parkinsonism is present in the majority of patients (80%). Early in the course of the disease autonomic dysfunctions are present in approximately 40% of patients, while the domination of cerebellar symptoms is present in 20% of all patients. According to second consensus statement on diagnosis of MSA, to make the diagnosis of possible MSA, except Parkinsonism or a cerebellar syndrome, there must be one feature involving autonomic dysfunction plus one other additional that can include findings on history, clinical examination or changes in structural or functional imaging. We present a case of 60-year old male with Parkinsonism and cerebellar symptoms accompanied with signs of autonomic nervous system involvement. Level of autonomic dysfunction was not the level required for the diagnosis of probable MSA. On initially performed 1.5T MRI, the most prominent neurodegenerative feature of brain stem, cerebellum and basal ganglia was atrophy, however features like "hot-cross bun" sign, "slit-like" putaminal rim and middle cerebellar peduncle hyperintensities were detected only after MR imaging on higher resolution (3T) device. Our case points to the possibility that some typical structural changes that can help in diagnostic process may not be clearly visible on 1.5 T MRI devices. In such cases we suggest using 3T MRI device, if feasible, in order to demonstrate findings that may help in establishing the diagnosis of possible MSA.
The phenomenon of multiple myocardial contractions during each single cardiac cycle, triggered by a single sinus node impulse, is the most intriguing echocardiographical topic among detectible ...modalities of irregular kinetics of interventricular septum. Tissue Doppler imaging based methods gave proofs of active contractions in cases presented herein. Broad spectrum of this phenomenon, which can be found both in healthy subjects and in patients is presented. Forms of multiple myocardial contractions during the same cardiac cycle presented in this analysis are: secondary systolic contraction, postsystolic and late postsystolic contraction, multiple (three- and fourfold) contractions with combination of secondary systolic and postsystolic contraction, and combination of regular systolic, secondary systolic or postsystolic contraction with pre-contraction as a part of possible preexcitation. Explanation of mechanism generating these phenomena could be found in possible existence of accessory, concealed slow pathways of cardiac conduction system.
Abstract Activities of both autonomic nervous system divisions, sympathetic and parasympathetic, are dual – continuous, tonic and changing, modulating. Tonic activity domination accompanies ...stationary (patho)physiological conditions, while modulating activity occurs with the change of stimuli. The intensity of the two activities is inversely proportional. In patients with heart failure, spectral analysis of heart rate variability displays reduced sympathetic modulation activity during illness, as a logical consequence of an increased sympathetic tone. On the other hand, vagal modulation activity slightly decreases or does not change at the very early stage of disease, soon afterwards it increases, and after a certain period of time, with the progression of the disease, vagal modulation decreases, and finally disappears. These changes reveal sequential response of vagal tone to the progression of heart failure and consequent sympathicotonia; slight initial oscillation or unresponsiveness, soon followed by self-suppression, and then, in an advanced heart failure, by counteraction to the sympathicotonia. This model of polyphasic reaction of vagal system, dependent on the stage of heart failure, challenges traditional concept of sympathovagal interaction. By this hypothesis, the self-suppression of vagal tone occurs in order to enable full sympathetic activation of compensatory mechanisms which aim to correct hemodynamic deterioration. Once the sympathicotonia becomes inefficient and even harmful, counter-regulatory increase in vagal tone develops, in order to decrease oxygen consumption and preserve or possibly enhance residual systolic and diastolic cardiac function. Decreased vagal tonic activity is probably mediated centrally. Later increase of vagal tone is probably triggered by an increased concentration of natriuretic peptides. The existence of predominantly adrenergic IL, Ca and predominantly cholinergic IK, Ach currents and of a common If current in sinoatrial nodal cells enables such dual – synergistic and antagonistic – sympatho-vagal relationship. In conclusion, a complex, polyphasic vagal reaction to the sympathicotonia and heart failure progression is suggested by the hypothesis. Clinical and experimental studies based on this hypothesis will probably allow better insight into autonomic functions.
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