Seasonal Variation in Onset of Myocardial Infarction—A 7‐year single‐center study in Italy

Seasonal variation in in-hospital outcomes of Takotsubo-syndrome-related admissions: A National Inpatient Analysis, 2019

Takotsubo syndrome (TTS) is a transitory stress-related cardiomyopathy characterized by acute but reversible left ventricular failure. The disease most commonly affects postmenopausal women following a traumatic experience, often presenting as an acute myocardial infarction (MI), and its prevalence is increasing globally. Cardiovascular events such as Acute Coronary Syndrome (ACS) and stroke have well-defined seasonal variations and are most common in the winter [[8], [9], [10]]. However, there is insufficient data on the impact of such climatic variations on the etiopathogenesis and outcomes of TTS-related hospitalization in the United States.

Seasonal pattern in elderly hospitalized with acute kidney injury: a retrospective nationwide study in Italy

Purpose

Acute kidney injury (AKI) frequently complicates hospitalization and is associated with in-hospital mortality (IHM). It has been reported a seasonal trend in different clinical conditions. The aim of this study was to evaluate the possible relationship between seasons of the year and IHM in elderly hospitalized patients with AKI.

Methods

We selected all admissions complicated by AKI between 2000 and 2015 recorded in the Italian National Hospital Database. ICD-9-CM code 584.xx identified subjects with age ≥ 65 years and age, sex, comorbidity burden, need of dialysis treatment and IHM were compared in hospitalizations recorded during the four seasons. Moreover, we plotted the AKI observed/expected ratio and percentage of mortality during the study period.

Results

We evaluated 759,720 AKI hospitalizations (mean age 80.5 ± 7.8 years, 52.2% males). Patients hospitalized with AKI during winter months had higher age, prevalence of dialysis-dependent AKI, and number of deceased patients. In whole population IHM was higher in winter and lower in summer, while the AKI observed/expected ratio demonstrated two peaks, one in summer and one in winter. Logistic regression analysis demonstrated that parameters such as age, autumn, winter, comorbidity burden were positively associated with IHM.

Conclusion

We conclude that a seasonality exists in AKI, however, relationship between seasons and AKI could vary depending on the aspects considered. Both autumn and winter months are independent risk factors for IHM in patients with AKI regardless of age, sex and comorbidity burden. On the contrary, summer time reduces the risk of death during hospitalizations with AKI.

Takotsubo Syndrome in New Zealand: Current Knowledge and Future Challenges

Takotsubo syndrome (TS), also known as apical ballooning syndrome is a transient stress-related cardiomyopathy characterised by acute but reversible left ventricular dysfunction. The condition tends to occur in postmenopausal women after a stressful event. At presentation TS typically mimics acute myocardial infarction (MI) and the incidence of TS has been increasing worldwide. This is likely a consequence of an improved awareness of the existence of this syndrome and easier access to early echocardiography and coronary angiography. However, its aetiology remains poorly understood and it is probably still underdiagnosed. Similar to other countries. TS is being increasingly recognised in New Zealand. In this review, we discuss the demographics, clinical features and outcomes of patients with TS in New Zealand. Doing so informs us not only of the pattern of disease in New Zealand but it also provides insights into the condition itself. This article is protected by copyright. All rights reserved.

Measuring Spatial Accessibility to Hospitals of Acute Myocardial Infarction in Multi Period Scale: A Case Study in Shijingshan District, Beijing, China

The hospital accessibility of Acute Myocardial Infarction (AMI) emergency treatment is of great importance, not only for improving the survival rate of patients but also for protecting the basic human right to health care. Traditional AMI emergency treatment research often does not consider ways to shorten the travel time to hospitals for AMI patients and does not reflect the actual time it takes to travel to hospitals, which is critical to AMI emergency treatment. To avoid these shortcomings, this study proposes a method of accessibility measurement based on Web Mapping API (Application Programming Interface) to obtain travel time to hospitals during different periods, then calculated the AMI hospital accessibility based on these detailed data. This study considered the Shijingshan District, Beijing, China, as an empirical case. The study discovered significant differences in the temporal and spatial characteristics of the AMI hospital accessibility on weekdays and weekends. The analysis revealed that travel time to hospitals and traffic congestion are the two main factors affecting AMI hospital accessibility. The research results shed new light on the accessibility of urban medical facilities and provide a scientific basis with which local governments can optimize the spatial structure of medical facilities.

The mortality rates in registries of patients with STEMI are highly affected by inclusion criteria and population characteristics

BACKGROUND

Different mortality rates are reported in registries of patients with ST-segment elevation myocardial infarction (STEMI), but comparisons between registries are challenging.

AIMS

To determine whether the higher mortality rate in our regional French registry (SCALIM) is related to different inclusion criteria and demographic characteristics.

METHODS

The SCALIM registry included all patients with STEMI within the first 24 h in the region of Limousin, France (06/2011-01/2015). To compare mortality rates with other contemporary registries in France and European neighbouring countries, the others' inclusion criteria were applied to the SCALIM registry.

RESULTS

Among 1501 patients included, in-hospital and 1-month mortality were 8.2% and 8.8% respectively, significantly higher than many other registries. The use of inclusion criteria from EMUST (France), MINAP (UK) or LOMBARDIMA (Italy) markedly decreased the number of enrolled patients by 64%, 36%, and 21%, respectively. When those inclusion criteria were applied to the SCALIM registry, difference in in-hospital and 1-month mortality rates between other registries and ours remained significant. In the multivariate analysis, age, initial acute pulmonary oedema (Killip class ≥2), complication occurring before percutaneous coronary intervention, absence of transfer to an interventional cardiology centre for primary angioplasty and lack of reperfusion therapy within 12 h were associated with higher risk of 1-month mortality (all p < 0.05). Age (65 versus 63.3 years, p < 0.001) was higher and reperfusion rate (84.2 versus 74.7%, p < 0.001) was significantly lower in SCALIM than FAST-MI, the national French registry on STEMI patients. Interestingly, the 3% of patients included in SCALIM who would be excluded from FAST-MI registry had 91% mortality at one month.

CONCLUSION

Higher mortality rate in our regional SCALIM registry is in part due to differences in inclusion criteria and demographic data. Consensus should be made to harmonise inclusion criteria in STEMI registries for the sake of comparability.

Role of climatic factors in the incidence of Takotsubo syndrome: A nationwide study from 2012 to 2016

Aims

This study aimed to investigate the influence of climatic factors on the onset of Takotsubo syndrome (TTS).

Methods and results

We performed a retrospective nationwide study among patients registered in the Japanese Registry of All Cardiac and Vascular Diseases and Diagnosis Procedure Combination (JROAD–DPC) discharge database, between 2012 and 2016. Before the analysis, a multicentre validation study was conducted for assessing the accuracy of the JROAD–DPC classification for TTS. First, we investigated the seasonal variation of incidences of TTS. Second, we analysed the associations between the incidence of TTS and climatic factors using the hierarchical Poisson regression modelling, and we also investigated the associations between typhoon landfalls and hospitalization for TTS, using the fixed‐effects conditional Poisson regression model. The sensitivity and specificity for diagnosis were 83% and 100%, respectively. Then we analysed 5643 patients with TTS. The mean patient age was 74 (standard deviation ± 11) years; 79% were female. TTS was diagnosed significantly more frequently in the summer and early autumn. The incidence of TTS was related to higher temperatures; adjusted incidence rate ratios were 1.46 [95% confidence interval (CI): 1.33–1.60, P < 0.01] and 1.47 (95% CI: 1.34–1.62, P < 0.01) for temperatures of 20–25°C and >25°C, respectively. The incidence rate ratio for the first 2 days after a typhoon landfall was 1.85 (95% CI: 1.07–3.19; P = 0.03).

Conclusions

This study demonstrates distinct patterns of seasonal variation in the incidence of TTS, as well as a significant association between its onset and climatic factors, including typhoon landfalls.

The Impact of the Circadian Genes CLOCK and ARNTL on Myocardial Infarction

The circadian rhythm regulates various physiological mechanisms, and its disruption can promote many disorders. Disturbance of endogenous circadian rhythms enhances the chance of myocardial infarction (MI), showing that circadian clock genes could have a crucial function in the onset of the disease. This case-control study was performed on 1057 participants. It was hypothesized that the polymorphisms of one nucleotide (SNP) in three circadian clock genes (CLOCK, ARNTL, and PER2) could be associated with MI. Statistically significant differences, estimated by the Chi-square test, were found in the distribution of alleles and genotypes between MI and no-MI groups of the CLOCK (rs6811520 and rs13124436) and ARNTL (rs3789327 and rs12363415) genes. According to the results of the present study, the polymorphisms in the CLOCK and ARNTL genes could be related to MI.

Takotsubo Cardiomyopathy With Inconspicuous Initial Electrocardiogram: A Potentially Serious Cardiac Pathology Related to Emotional Stress

Introduction: Takotsubo cardiomyopathy (TCM) is frequently associated with emotional or physical stress. Thus, patients with TCM might present primarily at a psychiatric clinic. Appropriate diagnosis and therapy may thus be delayed. Case report: A 43-year-old female patient presented as an emergency to the psychiatric outpatient clinic after experiencing severe work-related bullying. On admission, she complained of acute left thoracic chest pain as well as depressed mood, low energy, anhedonia, generalized anxiety, and sleep difficulties, present for several weeks. The initial electrocardiogram (ECG) was unremarkable; serum troponin levels, however, were markedly elevated. The patient was transferred to the department of cardiology. Via cardiac catheterization and MRI, an acute coronary syndrome was excluded and apical ballooning and left ventricular dysfunction, compatible with TCM, was found. Conclusion: Patients with acute psychopathology, recent emotional or physical stress, and acute cardiothoracic symptoms should receive immediate cardiological investigations. As the ECG may be normal in patients with TCM, concurrent measurement of the troponin serum level is recommended. Psychiatrists should consider TCM in patients who report recent stressful events accompanied by cardiothoracic symptoms.

Seasonal and monthly variability in the incidence of venous thromboembolism

Many studies showed that the occurrence of cardiovascular and cerebrovascular events exhibits a seasonal and monthly variation. Evidences of a seasonal and monthly variation in the incidence of venous thromboembolism (VTE) are more conflicting. We conducted a systematic review and a meta-analysis of the literature to assess the presence of an infradian rhythm of this disease. MEDLINE and EMBASE databases were searched up to January 2010. Monthly and seasonal variation in the incidence of VTE were analysed. We included studies analysing seasonal or monthly aggregation in the incidence of deep-vein thrombosis (DVT) and/or pulmonary embolism (PE) with an objective diagnosis of VTE. Two authors independently reviewed and extracted data. Seventeen studies for a total of about 35,000 patients were included. Twelve studies analysed the seasonal variation and 10 studies the monthly variation of VTE. Our results showed a significantly increased incidence of VTE in winter (chi-square 146.04, p <0.001), with a relative risk (RR) of VTE of 1.143 (99% CI [1.141, 1.144]), and a significantly increased incidence of VTE in January (chi-square 232.57, p <0.001) with an RR of VTE of 1.194 (99% CI 1.186, 1.203). Subgroup analyses including only idiopathic venous thromboembolic events confirmed the results of principal analyses. In conclusion, our data support the presence of an infradian pattern in the incidence of venous thromboembolic events, with a significantly higher risk in Winter and in January. Future studies are needed to better clarify the mechanisms behind this pattern.

Chronobiology of Takotsubo Syndrome and Myocardial Infarction: Analogies and Differences

Several pathophysiologic factors, not harmful if taken alone, are capable of triggering unfavorable events when presenting together within the same temporal window (chronorisk), and the occurrence of many cardiovascular events is not evenly distributed in time. Both acute myocardial infarction and takotsubo syndrome seem to exhibit a temporal preference in their onset, characterized by variations according to time of day, day of the week, and month of the year, although with both analogies and differences.

Broken heart, tako-tsubo or stress cardiomyopathy? Metaphors, meanings and their medical impact

The cardiac impact of psychological stress historically and socially understood as boundary experiences of human life has long since become an icon. From the aching heart to the sudden death provoked by awe, horror, grief, anger, and humiliation on one side and extreme enchantment, enthusiasm, and excitement on the other, the broken heart has become a globally recognized and powerful metaphor present from folklore to popular culture to high literature and back to everyday communication. In medicine, the "broken heart syndrome" is described as a relatively new nosological entity that has been used synonymously with the term tako-tsubo or stress cardiomyopathy. Among those three terms, however, the broken heart most vividly draws the connection between conditions under which lived experience triggers cardiac damage and conversely, cardiovascular death occurs. According to Hassan and Yamasaki (2013) [1] and quite apart from the general perception medical notions of the broken heart indeed go back to at least 1967, when Rees and Lutkins studied the death rate among 903 relatives of patients who died in Wales. They found that 4.8% of bereaved close relatives died within a year of bereavement compared with 0.68% of a non-bereaved control group. Among widows and widowers, the mortality rate was even 10 times greater than that of the matched controls. After the first year of bereavement, however, mortality rates of relatives of a deceased person did not differ significantly from the control group Rees and Lutkins (1967) [2]. Similar findings were published by Parkes et al. (1969) [3] following up on 4486 widowers at the age of 55 for 9years following the death of their wives in 1957. During the first six months after the spouse had died, the mortality rate of the widowers was 40% above the rate of married men of the same age. While it seems plausible to accept the etiological role and pathogenic impact of personal loss, the pathogenic processes causing death remained relatively blurred. We will explain, why inaccurately stressing the fact that the broken heart and/or tako-tsubo syndrome would be a relatively new way of looking at stress-related cardiomyopathy as outlined by Yoshikawa (2015) [4] and why attaching stress-related cardiomyopathy to culturally powerful yet value-laden metaphors, might obstruct pathways to a better understanding, prevention and clinical management of the disease. By looking at narrative understandings and clinical representations of the broken heart, we aim to highlight the need for a more contextualised view of the broken heart syndrome in order to facilitate multi- and transdisciplinary approaches aiming at its prediction, prevention, and treatment.

Breaking heart: chronobiologic insights into takotsubo cardiomyopathy

A considerable amount of evidence has shown that the major acute cardiovascular diseases, ie, myocardial infarction, sudden cardiac death, stroke, pulmonary embolism, and rupture or dissection of aortic aneurysms do not occur randomly in time, but exhibit specific temporal patterns in their onset, according to time of day, month or season, and day of the week. This contributes to the definition of "chronorisk", where several factors, not harmful if taken alone, are capable of triggering unfavorable events when presenting all together within the same temporal window. This article reviews the actual knowledge about time of onset of takotsubo cardiomyopathy.

Winter cardiovascular diseases phenomenon

This paper review seasonal patterns across twelve cardiovascular diseases: Deep venous thrombosis, pulmonary embolism, aortic dissection and rupture, stroke, intracerebral hemorrhage, hypertension, heart failure, angina pectoris, myocardial infarction, sudden cardiac death, venricular arrythmia and atrial fibrillation, and discuss a possible cause of the occurrence of these diseases. There is a clear seasonal trend of cardiovascular diseases, with the highest incidence occurring during the colder winter months, which have been described in many countries. This phenomenon likely contributes to the numbers of deaths occurring in winter. The implications of this finding are important for testing the relative importance of the proposed mechanisms. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures.

Chronobiology in aortic diseases - "is this really a random phenomenon?"

Although acute aortic rupture or dissection is relatively uncommon, it ranks in third position among necropsy-confirmed causes of out-of-hospital sudden death in the general population. Similar to other acute cardiovascular events (e.g., acute myocardial infarction, sudden death, stroke, and pulmonary embolism) there is a growing body of evidence regarding temporal patterns in onset, characterized by circadian, seasonal and weekly variations for aortic aneurysms. On one hand, it is possible that these cardiovascular diseases share common underlying pathophysiologic mechanisms, e.g., increase in blood pressure, heart rate, sympathetic activity, basal vascular tone, vasoconstrictive hormones, and prothrombotic tendency. On the other hand, the possibility exists that the connecting link is an internal disruption (dyssynchrony) of some molecular mechanisms intrinsic to the peripheral biological clock (that of cardiomyocyte is the most widely investigated). Such disruption may contribute to cardiovascular disease and biological rhythms - an intriguing hypothesis for future research.

Ambulance demand: random events or predicable patterns?

BACKGROUND

Occupational, social and recreational routines follow temporal patterns, as does the onset of certain acute medical diseases and injuries. It is not known if the temporal nature of injury and disease transfers into patterns that can be observed in ambulance demand. This review examines eligible study findings that reported temporal (time of day, day of week and seasonal) patterns in ambulance demand.

METHODS

Electronic searches of Medline and Cumulative Index of Nursing and Allied Health Literature were conducted for papers published between 1980 and 2011. In addition, hand searching was conducted for unpublished government and ambulance service documents and reports for the same period.

RESULTS

38 studies examined temporal patterns in ambulance demand. Six studies reported trends in overall workload and 32 studies reported trends in a subset of ambulance demand, either as a specific case type or demographic group. Temporal patterns in overall demand were consistent between jurisdictions for time of day but varied for day of week and season. When analysed by case type, all jurisdictions reported similar time of day patterns, most jurisdictions had similar day of week patterns except for out-of-hospital cardiac arrest and similar seasonal patterns, except for trauma. Temporal patterns in case types were influenced by age and gender.

CONCLUSIONS

Temporal patterns are present in ambulance demand and importantly these populations are distinct from those found in hospital datasets suggesting that variation in ambulance demand should not be inferred from hospital data alone. Case types seem to have similar temporal patterns across jurisdictions; thus, research where demand is broken down into case types would be generalisable to many ambulance services. This type of research can lead to improvements in ambulance service deliverables.

Chronobiological variation in the occurrence of Tako-tsubo cardiomyopathy: experiences of two tertiary cardiovascular centers

BACKGROUND

There have been few data to review and analyze the temporal preference of the onset of Tako-tsubo cardiomyopathy (TTC). Aim of this study was to investigate chronobiological variations in the occurrence of TTC and changes of these variations according to age and gender.

METHODS

One hundred and thirty-seven patients were enrolled from our TTC registry database from January 2004 to December 2010 in Korea.

RESULTS

The median age of the entire study population was 59 years (inter-quartile range 53-72 years). The majority of patients were women (n = 101, 74%). The onset of TTC differed as a function of season (P = .001), with the peak in July and the nadir in March. Events were most frequent in summer (n = 53%, 38.7%) and least so in winter (n = 26, 19%, chi-square = 13.92, P = .003). TTC was most frequent in the morning (n = 56, 40.9%) and least so at night (n = 22, 16.1%, chi-square = 21.98, P = .001). Also, TTC was most frequent on Monday (n = 34, 24.8%) and least so on Saturday (n = 7, 5.1%, chi-square = 30.44, P = .001). Stressor pattern, age and gender do not influence these increases of occurrence in summer, on Monday, and in the morning of TTC.

CONCLUSIONS

TTC seems to exhibit a temporal variation of occurrence with preferred peaks during morning, Monday, and summer. Stressor pattern, age and gender do not influence these temporal patterns of the occurrence of TTC. Further studies are needed to investigate the potential link between chronobiological variations of TTC onset and underlying pathophysiologic mechanisms.

Warm winter is associated with low incidence of ST elevation myocardial infarctions and less frequent acute coronary angiographies in an alpine country

BACKGROUND

Weather conditions influence symptoms in chronic stable coronary artery disease (CAD). Whether the ongoing climate change, with continuous and rapid temperature increases, also has an impact on the incidence and outcome of non-ST elevation (NSTEMI) and ST elevation (STEMI) myocardial infarctions referred for acute coronary angiography (CA) is less clear.

METHODS

According to weather data from the Institute of Meteorology and Geophysics, Innsbruck University, the 2005/2006 winter was very cold (CW) and the 2006/2007 winter extraordinarily warm (WW). As the overall invasive management of patients with acute coronary syndromes did not change substantially within these winters, we compared patients referred for acute CA suffering an acute STEMI or NSTEMI, their risk factors and in-hospital mortality rates between these two consecutive winters.

RESULTS

As expected, the average temperature was lower (- 1.6 vs. + 5.9°C; p < 0.001) and humidity was higher (82 vs. 79%; p < 0.012) in CW compared to WW, with no significant differences in other weather conditions (rainfall: 59 vs. 39 days; sunshine: 3.9 vs. 4.3 h/day; air pressure: 713.04 vs. 713.76 hPa). There were no differences in the number of overall CA (987 vs. 983) between these two winters, whereas the number of acute CA (12.9 vs. 10.4% of overall CA; p = 0.046) and the diagnosis of STEMI as an indication of acute CA (74.0% vs. 62.7%; p = 0.046) were higher in CW. Furthermore, patients in CW were younger (58.2 ± 12.4 vs. 61.7 ± 11.7 years; p < 0.03), had higher LDL cholesterol (134.8 ± 44.6 vs. 116.7 ± 36.0 mg/dl; p < 0.003) and were less frequently hypertensives (52.8 vs. 70.6%; p < 0.01). Other traditional risk factors were not different between WW and CW. In addition, there were no differences in in-hospital mortality rates in invasively diagnosed CAD, patients' nationalities (Austrians: 78.0 vs. 77.5%) and time from pain to arrival in the cath lab in STEMI patients (3.9 ± 3.5 vs. 3.8 ± 3.1 h).

CONCLUSION

The average temperature increase of 7.5°C from the cold to the warm winter was associated with a decrease in acute coronary angiographies, in particular due to a lower incidence of STEMI referred for primary percutaneous intervention.

Tako-tsubo cardiomyopathy: is there a preferred time of onset?

The occurrence of major cardiovascular events is not randomly distributed over time, but exhibits chronobiological patterns, i.e., circadian, weekly, or seasonal. No systematic studies on the temporal preference of onset of Tako-tsubo cardiomyopathy (TTC) are known. We performed a computer-assisted search of the literature (from 2000 to January 2010), with the following search terms: transient left ventricular apical ballooning syndrome, takotsubo-like left ventricular dysfunction, ampulla cardiomyopathy, tako-tsubo or takotsubo cardiomyopathy, tako-tsubo, apical ballooning. Criteria for publication inclusion were (a) reporting of original data, (b) inclusion of at least 30 or more cases, (c) adherence to the requested diagnostic criteria for TTC. We focused on studies including in their purposes the "time of onset" of events. Out of the 19 studies found, 7 (4 from Europe, 1 each from Asia, Australia and USA) specifically addressed this aspect. A circadian (morning) and a seasonal (summer) higher frequency of events was found. TTC seems to exhibit a temporal variation of onset, with preferred peaks during morning and summer. Stress and catecholamines, also according to their temporal organization, might play a pivotal role. The demonstration of time frames characterized by highest frequency of occurrence might help to try to ensure maximal protection during particularly vulnerable periods.

Temporal variation of out-of-hospital cardiac arrests in an equatorial climate

OBJECTIVE

We aimed to determine whether there is a seasonal variation of out-of-hospital cardiac arrests (OHCA) in an equatorial climate, which does not experience seasonal environmental change.

METHODS

We conducted an observational prospective study looking at the occurrence of OHCA in Singapore. Included were all patients with OHCA presented to Emergency Departments across the country. We examined the monthly, daily, and hourly number of cases over a three-year period. Data was analyzed using analysis of variance (ANOVA).

RESULTS

From October, 1st 2001 to October, 14th 2004, 2428 patients were enrolled in the study. Mean age for cardiac arrests was 60.6 years with 68.0% male. Ethnic distribution was 69.5% Chinese, 15.0% Malay, 11.0% Indian, and 4.4% Others. There was no significant seasonal variation (spring/summer/fall/winter) of events (ANOVA P = 0.71), monthly variation (P = 0.88) or yearly variation (P = 0.26). We did find weekly peaks on Mondays and a circadian pattern with daily peaks from 9-10 am.

CONCLUSIONS

We did not find any discernable seasonal pattern of cardiac arrests. This contrasts with findings from temperate countries and suggests a climatic influence on cardiac arrest occurrence. We also found that sudden cardiac arrests follow a circadian pattern.

Seasonal and weekly patterns of hospital admissions for nonfatal and fatal myocardial infarction

OBJECTIVE

This retrospective study, based on the database of hospital admissions of the region Emilia-Romagna [RER], Italy, was aimed to confirm the existence of a seasonal or weekly pattern of hospital admission of acute myocardial infarction (AMI) and to verify possible differences between nonfatal or fatal cases.

METHODS

The study included all cases of patients with AMI hospitalized between 1998 and 2006. Day of admission was categorized, respectively, into four 3-month intervals, into twelve 1-month intervals, and into seven 1-day intervals for statistical analysis, performed by chi(2) test goodness of fit and partial Fourier series on total cases, males, females, and nonfatal and fatal cases.

RESULTS

The database included 64 191 cases of AMI (62.9% males, 12.3% fatal). Acute myocardial infarction was most frequent in winter and least in summer (P < .0001). The highest number of cases was recorded in January and the lowest in July (P < .0001). Chronobiologic analysis showed winter peaks for total cases (January, P = .035), females (December, P = .009), and fatal cases (January, P < .001). Acute myocardial infarction was most frequent on Monday and least on Sunday (P < .0001). Comparing observed vs expected events, there was a significantly higher frequency of cases on weekdays and reduced on weekends, for total (P < .0001), nonfatal (P < .0001), and fatal cases (P = .0001).

CONCLUSIONS

This study confirms a significantly higher frequency of AMI admissions in winter and on a Monday. No difference in the frequency of nonfatal vs fatal events, depending of patients' admissions on weekdays or weekends, was found.

Seasonal Variation in Occurrence of Pulmonary Embolism: Analysis of the Database of the Emilia‐Romagna Region, Italy

Seasonal variation in the occurrence of cardiovascular and cerebrovascular events, including pulmonary embolism (PE), has been reported; however, recent large-scale, population-based studies conducted in the United States did not confirm such seasonality. The aim of this large-scale population study was to determine whether a temporal pattern in the occurrence of PE exists. The analysis considered all consecutive cases of PE in the database of all hospital admissions of the Emilia Romagna region in Italy at the Center for Health Statistics between January 1998 and December 2005. PE cases were first grouped according to season of occurrence, and the data were analyzed by the chi(2) test for goodness of fit. Then, inferential chronobiologic (cosinor and partial Fourier) analysis was applied to monthly data, and the best-fitting curve for the annual variation was derived. The total sample consisted of 19,245 patients (8,143 male, mean age 71.6+/-14.1 yrs; 11,102 female, mean age 76.1+/-13.7 yrs). Of these, 2,484 were <65 yrs, 5,443 were between 65 and 74, and 11,318 were > or = 75 yrs. There were 4,486 (23.3%) fatal-case outcomes. PE occurred least frequently in spring (n=4,442 or 23.1%) and most frequent in winter (n=5,236 or 27.2%, goodness of fit chi(2)=75.75, p<0.001). Similar results were obtained for subgroups formed by gender, age, fatal/non-fatal outcome, presence/absence of major underlying co-morbid conditions, and specific risk factors. Inferential chronobiological analysis identified a significant annual pattern in PE, with the peak between November and December for the total sample of cases (p<0.001), males (p<0.001), females (p=0.002), fatal and non-fatal cases (p<0.001 for both), and subgroups formed by age (<65 yrs, p=0.012; 65-74 yrs, p<0.001; > or = 75 yrs, p=0.012). This pattern was independent of the presence/absence of hypertension (p=0.003 and p<0.001, respectively), pulmonary disease (p<0.001 and p<0.001, respectively), stroke (p<0.001 and p=0.004, respectively), neoplasms (p=0.005 and p=0.001, respectively), heart failure (p=0.022 and p<0.001, respectively), and deep vein thrombosis (p=0.002 and p<0.001, respectively). However, only a non-statistically significant trend was found for subgroups formed by cases of diabetes mellitus, infections, renal failure, and trauma.

Twenty‐Four‐Hour and Annual Variation in Onset of Epistaxis in Osler Disease

Osler disease is an autosomal dominant disorder of the fibrovascular tissue characterized by arteriovenous malformations with multi-systemic haemorrhages. Recurrent epistaxis is the predominant symptom in more than 90% of patients. Recent studies showed circadian and seasonal patterns in the onset of nosebleeds, similar to acute cardiovascular events, such as myocardial infarction and stroke. The aim of this study was to determine whether such patterns would also apply to the onset of epistaxis in patients with Osler disease. In all, 110 patients with Osler disease who were under treatment for recurrent epistaxis at the University Hospital of Mannheim were requested to complete a questionnaire addressing the intensity and frequency of epistaxis according to the classification of Bergler et al., as well as circadian and circannual rhythmicity in the occurrence of epistaxis according to visual analogue scales (VAS). More than half of the patients claimed to experience daily to weekly episodes of recurrent epistaxis. The occurrence of epistaxis showed a biphasic 24 h pattern, with a primary peak in the morning (05:00-8:00 h) and smaller secondary peaks in the evening (17:00-20:00 h and 21:00-00:00 h). No significant seasonal variation was found in the onset of epistaxis. However, a slight tendency, with a peak in winter months, was observed. Similar to other chronobiological studies on nosebleeds, this study showed that the 24 h pattern and seasonal tendency in the onset of epistaxis even applied to patients with Osler disease. Further investigations are necessary to determine the pathological mechanism underlying this phenomenon.

Temporal Variations of Coagulation Factor VII Activity in Mice Are Influenced by Lighting Regime

It was recently reported that the circadian clock machinery controls plasma levels of factor (F) VII, the serine protease triggering blood coagulation. Here, by exploiting the mouse model, this study showed that variations of photoperiod (i.e., winter or summer conditions or simulated chronic jetlag conditions) have a strong impact on plasma FVII activity levels. Under conditions mimicking summer or winter photoperiods, FVII activity showed a clear 24 h rhythmicity. Interestingly, mean daily FVII activity levels were significantly reduced in mice exposed to summer photoperiods. Behavioral activity rhythms under both photoperiods were synchronized to LD cycles, and the amount of activity per 24 h was comparable. The authors also investigated the influence of chronic jetlag (CJL) on the FVII activity rhythms, which can be easily mimicked in mice through continuous abrupt shifts in the lighting schedule. The exposure of mice to simulated CJL of either consecutive westward or consecutive westward and eastward flights for 15 days did not abolish the behavioral activity rhythms but was associated with a period significantly different from 24 h. Intriguingly, both types of CJL exerted a strong influence on FVII activity rhythms, which were virtually suppressed. Moreover, the mean daily FVII activity was significantly lower in the CJL than in the winter photoperiod condition. Taken together, these findings in mice provide novel insights into the modulation of FVII activity levels, which might have implications for human pathophysiology.

Temporal Patterns of Hospital Admissions for Transient Ischemic Attack: A Retrospective Population-based Study in the Emilia-Romagna Region of Italy

Acute cerebrovascular events are not randomly distributed over time but show specific temporal patterns of occurrence. However, most studies focused stroke and little is known about transient ischemic attack. This study aimed to explore the existence of a temporal pattern of transient ischemic attack and the possible influence by the most common risk factors. The analysis included all hospital admissions with the ICD9-CM code for TIA, recorded in the database of the Emilia Romagna region of Italy (1998-2006; n = 43642, mean age 76.8 ± 11.5 years, 45.5% males). Transient ischemic attack was most frequent in autumn and winter and less common in spring and summer (P < 0.0001), with the highest number of cases in October and the lowest in February, and also most frequent on Monday (P < 0.0001). This study shows a seasonal and weekly pattern in occurrence of transient ischemic attack, independent of sex and the presence of the most common risk factors.

Seasonal variation in the occurrence of venous thromboembolism: data from the MASTER Registry

Many studies showed that the occurrence of cardiovascular and cerebrovascular events exhibits a seasonal variation. As for venous thromboembolism (VTE), not univocal results are available, and studies are mainly retrospective. We aimed to confirm the existence of a seasonal pattern in the occurrence of VTE on a large prospective population. The analysis considered consecutive cases of VTE enrolled into the MASTER Registry in 25 Italian hospitals, between January 2002 and November 2004. The total population consisted of 2119 subjects (1056 men, mean age 59 +/- 18 years). The total sample was divided into subgroups by gender, age (<40, 41-60, 61-80, > or = 80 years), type of event (first episode; proximal or distal; upper or lower limb; idiopathic or secondary deep vein thrombosis or pulmonary embolism, or both), and underlying risk factors, eg, cancer, previous VTE, estroprogestinic therapy, lack of prophylaxis, immobilization, surgery, pregnancy or puerperium, and medical diseases. Cases were grouped according to season and month of occurrence, and the data were analyzed by either the chi(2) test for goodness of fit and chronobiological analysis. VTE was most frequent in Autumn and less frequent in Spring (32.9% vs 19%, respectively, chi(2) = 90.62; P < .001). This pattern was shown for most subgroups. Chronobiological analysis identified a significant rhythmic annual pattern, with a main September-October peak for several subgroups (men, age 41-60 and 61-80 years, secondary event, previous VTE, immobilization), and a trend for most of the others. It is possible that subjects at increased risk could perhaps deserve appropriate or potentiated VTE prophylaxis in certain periods of the year.

The effect of experimental diabetes on the twenty-four-hour pattern of the vasodilator responses to acetylcholine and isoprenaline in the rat aorta

The aim of this study was to investigate whether time-dependent variations in the relaxant effect of acetylcholine, an endothelium-dependent vasorelaxant via muscarinic receptors, and isoprenaline, a nonselective beta-adrenoceptor agonist in rat aorta, are influenced by streptozotocin (STZ)-induced experimental diabetes. Adult male rats were divided randomly into two groups: control and STZ-induced (STZ, 55 mg/kg, intraperitoneal) diabetes. The animals were synchronized to a 12:12 h light-dark cycle (lights on 08:00 h) and sacrificed at six different times of day (1, 5, 9, 13, 17, and 21 hours after lights on; HALO) eight weeks after STZ injection. The in vitro responsiveness of thoracic aorta rings obtained from control and diabetic rats to acetylcholine (10(-9)-10(-5) M) and isoprenaline (10(-10)-10(-3) M) was determined in six different times. EC(50) (the concentration inducing half of the maximum response) values and maximum responses were calculated from cumulative concentration-response curves of the agonists and were analyzed with respect to time and STZ treatment. Treatment, time, and interactions between treatment and time were tested by two-way analysis of variance (ANOVA). To analyze differences due to biological time, one-way ANOVA was used. STZ treatment did not significantly change EC(50) values or maximum responses for both agonists. There were statistically significant time-dependent variations in the EC(50) values for isoprenaline and maximum responses for both acetylcholine and isoprenaline in control groups by one-way ANOVA, but significant time-dependent variations disappeared in the aortas isolated from STZ-induced diabetic rats. The vasodilator responses to acetylcholine and isoprenaline failed to show any significant interaction (treatmentxtime of study) between STZ treatment and time of sacrifice in both EC(50) values and maximum responses by two-way ANOVA. These results indicate there is a basic temporal pattern in the responses to acetylcholine and isoprenaline in rat aorta which continues in diabetes. It is shown for the first time that experimental diabetes does not change the 24 h pattern of responses to acetylcholine and isoprenaline, and that time-dependent variations in the responses to these agonists disappear in diabetic animals. Although further studies are required to define the underlying mechanism(s) of these findings, results suggest that experimental diabetes can modify the time-dependent vasorelaxant responses of rat aorta. This may help to understand the circadian rhythms in cardiovascular physiology and pathology or in drug effects in diabetes.

Outcomes assessment of clinical information system implementation: a practical guide

Healthcare information systems (HIS) play a vital role in quality of care and the organization's daily operations. Consequently, increasing numbers of clinicians have been involved in HIS implementation, particularly for clinical information systems (CIS). Implementation of these systems is a major organizational investment, and its outcomes must be assessed. The purpose of this article is to provide clinicians and frontline informaticians with a practical guide to assess these outcomes, focusing on outcome variables, assessment methods, and timing of assessment. Based on in-depth literature reviews and their empirical experiences, the authors identified 3 frequently used outcomes: user satisfaction, clinical outcomes, and financial impact. These outcomes have been assessed employing various methods, including randomized controlled trials, pre- and post-test studies, time and motion studies, surveys, and user testing. The timing for outcomes assessments varied depending on several factors, such as learning curves or patients conditions. In conclusion, outcomes assessment is essential for the success of healthcare information technology, and the CIS implementation team members must be prepared to conduct and/or facilitate these studies.

Recent change in the annual pattern of sexually transmitted diseases in the United States

This study analyzed the 1999 to 2003 database of the Center for Disease Control and Prevention (CDC) for seasonal and longer-term time trends in the sexually transmitted diseases (STDs) of chlamydia, gonorrhea, and syphilis in the United States. Linear regression was used to ascertain time trends, and a linear mixed auto-regression model was applied to determine the statistical significance of the major peaks relative to the annualized time series mean. A statistically significant increasing trend during the 5 yr span was documented only in the incidence of chlamydia. No clear annual periodicity was detected in any of the STDs; instead, significant three-month cycles were documented in all the STDs, with prominent peaks evident in March, May, August, and November. The March and May peaks could be associated with the sexual activities of young adults during spring break, which for different colleges and universities, commences as early as mid- to late-February and concludes as late as early- to mid-April, when huge numbers of sexually active youth congregate at beach resort settings. We propose the August peak is representative of summer sexual activity, in particular, of youths during school recess when adult supervision is poor. Finally, the autumn peak seems to be an expression of an endogenous annual rhythm in human reproductive biology, exemplified by elevated levels of testosterone in young males and sexual activity at this time of the year.

New insights into the circadian rhythm of acute myocardial infarction in subgroups

The aim of this study was to determine the existence of the circadian rhythm (CR) in the onset of acute myocardial infarction (AMI) in different patient subgroups. Information was collected about 41,244 infarctions from the database of the ARIAM (Analysis of Delay in AMI) Spanish multicenter study. CR in AMI were explored in subgroups of cases categorized by age, gender, previous ischemic heart disease (PIHD), outcome in coronary care unit, infarction electrocardiograph (ECG) characteristics (Q wave or non-Q wave), and location of AMI. Cases were classified according to these variables in the different subgroups. To verify the presence of CR, a simple test of equality of time series based on the multiple-sinusoid (24, 12, and 8 h periods) cosinor analysis was developed. For the groups as a whole, the time of pain onset as an indicator of the AMI occurrence showed a CR (p<0.0001), with a morning peak at 10:10 h. All the analyzed subgroups also showed CR. Comparison between subgroups showed significant differences in the PIHD (p<0.01) and infarction ECG characteristics (p<0.01) groups. The CR of the subgroup with Q-wave infarction differed from that of non-Q wave subgroup (p<0.01) when the patients had PIHD (23% in Q wave infarction vs. 39.2% in non-Q wave). AMI onset followed a CR pattern, which is also observed in all analyzed subgroups. Differences in the CR according to the Q/non-Q wave infarction characteristics could be determined by PIHD. The cosinor model fit with three components (24, 12, and 8 h periods) showed a higher sensitivity than the single 24 h period analysis.

Circadian variation of blood pressure and the vascular response to asynchronous stress

The diurnal variation in the incidence of myocardial infarction and stroke may reflect an influence of the molecular clock and/or the time dependence of exposure to environmental stress. The circadian variation in blood pressure and heart rate is disrupted in mice, Bmal1(-/-), Clock(mut), and Npas2(mut), in which core clock genes are deleted or mutated. Although Bmal1 deletion abolishes the 24-h frequency in cardiovascular rhythms, a shorter ultradian rhythm remains. Sympathoadrenal function is disrupted in these mice, which reflects control of enzymes relevant to both synthesis (phenylethanolamine N-methyl transferase) and disposition (monoamine oxidase B and catechol-O-methyl transferase) of catecholamines by the clock. Both timing and disruption or mutation of clock genes modulate the magnitude of both the sympathoadrenal and pressor but not the adrenocortical response to stress. Despite diurnal variation of catecholamines and corticosteroids, they are regulated differentially by the molecular clock. Furthermore, the clock may influence the time-dependent incidence of cardiovascular events by controlling the integration of selective asynchronous stress responses with an underlying circadian rhythm in cardiovascular function.

Seasonality and coronary heart disease deaths in United States firefighters

United States firefighters have a high on-duty fatality rate, and coronary heart disease is the leading cause. Seasonality affects the incidence of cardiovascular events in the general population, but its effects on firefighters are unknown. This study statistically examined the seasonal and annual variation of all on-duty coronary heart disease deaths among US firefighters between 1994 and 2004 using the chi-square distribution and Poisson regression model of the monthly fatality counts. It also examined the effect of ambient temperature (apparent as well as wind chill temperature) on coronary heart disease fatalities during the study span using a time-stratified, case-crossover study design. When grouped by season, we observed the distribution of the 449 coronary heart disease fatalities to show a relative peak in winter (32%) and relative nadir in spring (21%). This pattern was significantly different (p=0.005) from the expected distribution under the null hypothesis of season having no effect. The pattern persisted in additional analyses, stratifying the deaths by the type of duty in which the firefighters were engaged at the time of their deaths. In the Poisson regression model of the monthly fatality counts, the overall goodness-of-fit between the actual and predicted case counts was excellent (chi(4)(2)=16.63; p=0.002). Two distinct peaks were detected: one in January-February and the other in August-September. Overall temperature was not associated with increased risk of on-duty death. After allowing for different effects of temperature in mild/hot versus cold periods, a 1 degrees C increase was not protective in cold weather; nor did it increase the risk of death in warmer weather. The findings of this study reveal statistical evidence for excess coronary heart disease deaths among firefighters during winter; however, the temporal pattern of coronary heart disease deaths was not linked to temperature variation. The seasonal pattern was also found to be independent of duty-related risks.

Seasonality of primarily childhood and young adult infectious diseases in the United States

The Center for Disease Control (CDC) in the United States collects and maintains records of communicable (so-called notifiable) infectious diseases that cause significant morbidity and mortality and impact the national economy. This investigation focused on seasonal patterns in the primarily childhood and young adult infectious diseases of meningococcal meningitis, mumps, pertussis, typhoid fever, streptococcal toxic shock syndrome (1990 to 2003 CDC database), and varicella (1993 to 2003 CDC database). Linear regression was performed to ascertain the trend in the incidence of each disease, and multi-component cosinor analysis was applied to determine and describe periodicities. Significant decreasing trends in incidence were detected in meningococcal meningitis, mumps, typhoid fever, and streptococcal toxic shock syndrome, and increasing trends were found in pertussis and varicella. Significant annual patterns were documented in meningococcal meningitis (January peak), mumps (April peak), pertussis (August peak), varicella (April peak), typhoid fever (August peak), and in the hospital-acquired streptococcal toxic shock syndrome (February peak). Such seasonal patterns and long-term trends in infectious diseases are of practical public health significance in indicating which can benefit from timely prevention interventions.

Chronotherapeutic dose schedule of phenytoin and carbamazepine in epileptic patients

The objective of this study was to compare the efficacy and safety of a chronotherapeutic dosing schedule of phenytoin and carbamazepine versus a conventional dosing schedule for the treatment of tonic-clonic epileptic patients. Of 148 epileptic subjects found to have subtherapeutic trough drug levels (subtherapeutic group, STG), 103 subjects who completed the study were randomized to either STG I (n=51) for treatment by the conventional dosing schedule (tablet phenytoin 100-400 mg/day OD or BD, tablet carbamazepine 200-800 mg BD, or both, equally divided doses with no fixed time of drug intake), with a dose increment but no change in usual time of drug administration allowed; or to STG II (n=52), with no dose increment permitted but a shift in all or most (two-thirds or three-fourths) of the daily dose of one or both medications to 20:00 h. The 62 patients who experienced drug toxicity reactions (toxicity group, TG) and who had serum drug levels in the toxic range were assigned to TG I for dose reduction or TG II for dose reduction and drug administration at 20:00 h. Those 16 subjects in STG I and 47 subjects in STG II who initially evidenced subtherapeutic trough drug concentrations exhibited therapeutic drug levels by the end of four weeks of treatment (p<0.01). A significantly greater number of TG II, as compared to TG I, subjects who experienced toxic reactions showed improved drug tolerance. There were no poor responders and more good responders (control of epilepsy for one year) in STG II compared to STG I subjects. The findings of this study indicate that a chronotherapeutic dosing schedule of phenytoin and carbamazepine involving the administration of most or all the daily dose of medication(s) at 20:00 h can improve the response of diurnally active epileptic patients not responding to standard doses, achieve therapeutic drug levels, and reduce toxic manifestations in subjects having drug concentrations beyond the therapeutic range.

Central and peripheral clocks in cardiovascular and metabolic function

The molecular circadian clock entrains biological rhythms to a 24-hour schedule. Aspects of cardiovascular physiology and, indeed, the incidence of myocardial infarction and stroke are also subject to diurnal variation. The use of rodent models of disrupted clock function has begun to elucidate the role of the molecular clock in the pathophysiology of cardiovascular and metabolic disease.