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M Curione

Publications and source records attributed to M Curione.

44 records · Page 3Linked to original sources
PubMedDate not supplied

The chaotic component of human heart rate variability shows a circadian periodicity as documented by the correlation dimension of the time-qualified sinusal R-R intervals.

OBJECTIVE: This study investigates the hypothesis that the nonlinear component of human heart rate (HR) variability might show a periodic structure over the 24-h span. Such a postulate could explain how the chaotic component might coexist with the deterministic periodic variability of instantaneous HR in beat per minute. MATERIALS AND METHODS: The sinusal R-R intervals (sRRi) of the Holter EKG of 10 clinically healthy subjects (5 M, 5 F, 23-30 years) were analyzed per each hour of the day-night span according to two methods for the nonlinear chaotic variability, i.e., the correlation dimension method, and the linear periodic variability, i.e., periodic regression analysis. RESULTS: The hourly-qualified correlation integrals were found to show a significant circadian rhythm, with an acrophase located during the night in coincidence with the longest duration of the sRRi and the lowest rate of cardiac pulse. CONCLUSIONS: The rhythmic structure of the chaotic component of the human HR variability let us to think that a deterministic periodic chaos of fractal type regulates the nonlinear cardiac dynamics. Such a periodic structure allows the chaos to be compatible with the deterministic linear periodicity of circadian type which characterizes the within-day variability of human HR.

Adult↗
PubMedDate not supplied

[Circadian periodicity in human heart rate daily variability disorders: subsequent demonstrations through a chronobiological approach to the values of estimated alpha exponent on sinusal R-R intervals].

OBJECTIVE: The present study is aimed at giving a further demonstration that the disorder in human heart rate variability is characterized by a circadian periodicity. Such an evidence has been provided by estimating the alpha exponent of the Lévy's stable distribution approximated to the histogram of the differences between the durations of two adjacent sinusal R-R intervals. MATERIALS AND METHODS: The purpose has been pursued by estimating the alpha exponent on fragments of one hour of the Holter electrocardiogram executed in 10 clinically healthy subjects (5 males and 5 females, ranging in age from 23 to 30 years). RESULTS: The chronobiological analysis of the hourly-qualified values of the alpha exponent has demonstrated a significant circadian rhythm for this coefficient. CONCLUSIONS: The significant circadian periodicity of the alpha exponent is a further evidence that the disorder in human heart rate variability, herein represented by the extreme variability of the differences between the durations of two consecutive sinusal R-R intervals, is characterized by a periodic recursivity.

Adult↗
PubMedDate not supplied

Analysis of the chaotic component of the sinusal R-R intervals as a tool for detecting a silent cardiac dysautonomia in type 2 diabetes mellitus.

This study explores the heart rate (HR) variability (V) in order to detect whether the chaotic component of the sinusal R-R intervals (SRRI) can be interpreted as an early indicator of a silent cardiac neurovegetative dysautonomia in apparently uncomplicated Type 2 diabetic patients (DP). The SRRI were provided by the 24-h Holter ECG of 10 Type 2 DP (5 M and 5 F, mean age = 41 +/- 5 years). Control data were obtained by the 24-h Holter ECG of 10 clinically healthy subjects (CHS, 5 M and 5 F, mean age = 38 +/- 6 years). The chaotic component of HRV was investigated via the correlation dimension (CD) analysis (A) of the SRRI, performed per each hour of the ECG recording. The hourly-qualified series of SRRI, HR and CD index (I) were, in turn, analyzed via methods of conventional statistics and chronobiology, the latter ones for assessing the circadian rhythm (CR). The CDI CR was found to peak during the night in CHS, and to be unphysiologically rotated to the diurnal hours of the day in Type 2 DP. The diurnal inversion of the CDI CR in Type 2 DP suggests that the chaotic component of HRV shows an abnormal rhythnic pattern over the day-night period. Considering that the investigated Type 2 DP were lacking of documentable signs of cardiac neuropathy, it is hypothesized that the diurnal phase of shift CDI CR might be a potential indicator of a silent autonomic cardiac dysfunction in Type 2 DP. Such a hypothesis waits for further confirmations.

Adult↗
PubMedDate not supplied

Treatment of myocardial infarction: hypotensive effect of different thrombolytic agents.

The incidence of hypotension in patients treated with thrombolytic agents for myocardial infarction was investigated in a series of 71 patients, 17 treated with urokinase, 35 with rtPA and 19 with APSAC. Hypotension was observed in 23.5% of the first group, in 5.5% of the second, and in 42.10% of the third (p < 0.002 between rtPA and APSAC). In the inferior location hypotensive reaction was much more frequent than in anterior one (p < 007) especially if a right ventricular involvement was associated. Even if hypotension is a minor and generally harmless complication, it poses many practical problems, and its occurrence must be taken into account when choosing a fibrinolytic treatment.

Antihypertensive Agents↗
PubMedDate not supplied

[The "natural" history of ischemic cardiopathy, Incidence of coronary events in the follow-up of 114 ambulatory patients].

In the last decade advances in cardiovascular research improved remarkably our understanding of coronary heart disease. However many important problems are so far unresolved. In the present study we focused on the "natural" history of ischemic heart disease in a group of 114 patients. One hundred-seven patients had recent myocardial infarction, and seven suffered from angina. They were observed for a mean period of five years (one to 168 months). Forty-nine patients (42.9%) had no coronary events; sixty-five had angina, myocardial infarction or both. The myocardial infarction was however rare (five cases). The most frequent presentation of angina was stable and effort angina, which sometimes subsided after a period of presence. The classification of angina was often very difficult in cases of effort angina with very low threshold. No relevant differences were found between patients with and without coronary events according to age, sex, duration of follow-up, location of previous myocardial infarction. A significant difference was found in the prevalence of risk factors only for hypertension, which was more frequent in patients with coronary events. Smokers were more frequent in group without coronary events. In our opinion, the most interesting conclusion is that, almost half of these patients remained completely asymptomatic for a very long period.

Adult↗