Variation during the week in the incidence of acute myocardial infarction: increased risk for Japanese women on Saturdays

The CLOCK 3111T/C polymorphism is associated with hour-by-hour physical activity levels only on weekends among Japanese male and female university students

BACKGROUND

CLOCK 3111T/C has been shown to be closely associated with morningness-eveningness, such as sleep-wake rhythms in healthy humans. However, previous studies examined the physical activity (PA) in a single day, and no study has investigated the relationships between CLOCK 3111T/C polymorphism and PA for an entire week. It was hypothesized that the CLOCK 3111T/C polymorphism might be associated with diurnal PA patterns, especially on the weekends.

METHODS

Eighty-one university students (male, n=14; female, n=67; age, 20.4±2.9 years) wore a digital accelerometer for 7 successive days, including the weekend, to collect hour-by-hour objectively-measured PA. CLOCK 3111T/C polymorphism was assessed using the oral mucosa. During the study, participants recorded their wake time and bedtime each day. Furthermore, lifestyle-related variables (i.e. morningness-eveningness, habitual meal and sleep timings) were collected using questionnaires. Linear mixed-effects models assessed the association of polymorphism (TT carriers vs. TC+CC carriers) with wake time and bedtime as well as daily PA throughout the week (time).

RESULTS

TT carriers had an earlier wake time (weekly mean: 44 min [95% CI, -82 to -5 min], time interaction: p=0.026) and bedtime (weekly mean: 30 min [95% CI, -61 min to - 15 sec], time interaction: p=0.048) than TC+CC carriers. Furthermore, TT carriers' wake time and bedtime on Saturday were significantly later than on other days (gene interaction: all p<0.05). On Saturday, the hour-by-hour PA in TT carriers was significantly greater than that in TC+CC carriers (hourly mean 1.7 min [95% CI, 0.2 to 3.4 min], time: p<0.001, group: p=0.028, interaction: p=0.155).

CONCLUSIONS

CLOCK 3111T/C polymorphism may be associated with objectively measured hour-by-hour PA only on Saturday. Academic/social obligations may mask the genetically determined biological rhythm of PA on weekdays.

Biological rhythms of fatal myocardial infarction in Greece: an autopsy study

BACKGROUND

Biological rhythms, acting as an endogenous clock, prepare and assist the organism to function optimally during predictable seasonal and daily cycles. Many elements of the cardiovascular system exhibit specific rhythmical patterns. Besides genetic mechanisms, external stimuli may alter biological rhythms.

METHODS

The aim of this study was to investigate the patterns of biological rhythms in patients who suffered a fatal myocardial Infarction (MI), ascertained by macroscopical or histopathological examination. Cases of fatal MI examined during the time 2010-2017 were included in our study sample (827 cases in total). Medical History was also obtained for each case. The assessment of seasonal variation of fatal MI was accomplished by employing three different methods, Rayleigh Uniformity Test, X² Goodness-of-fit test and Edward's Seasonality Test. Statistical significance was defined as a 2-sided p value of <0.05.

RESULTS

Regarding the distribution of total cases, fatal MIs onset occurs more often during winter, with higher incidence in December and January. The weekly distribution of cases seems uniform. The circadian pattern presents higher frequencies of fatal MIs between 08:00 and 12:00 with the acrophase between 11:00 and 12:00. Further analysis was conducted separately, depending on the method of time-of-death reporting.

CONCLUSIONS

Taking under consideration the variation of the occurrence of MI related deaths, in accordance with the respective biological rhythms, public health policies more suitable to the individual requirements of every country's population may be adopted.

Lockdown Britain: Evidence for reduced incidence and severity of some non-COVID acute medical illnesses

Large reductions in emergency department attendances and hospitalisations with non-COVID acute medical illness early during the pandemic were attributed to reluctance to seek medical help and higher referral thresholds. Here, we compare acute medical admissions with a comparison cohort from 2017. Deaths in the same geographic area were examined, and Wales-wide deaths during these 4 weeks in 2020 were compared with a seasonally matched period in 2019. There were 528 patients admitted with non-COVID illness in 2020, versus 924 in 2017 (a reduction of 43%). Deaths from non-COVID causes increased by 10.9% compared with 2017, over half this rise being from neurological causes including stroke and dementia. While far fewer patients required hospitalisation as medical emergencies, rises in local non-COVID deaths proved small. Wales-wide non-COVID deaths rose by just 1% compared with 2019. The findings suggest that changes in population behaviour and lifestyle during lockdown brought about unforeseen health benefits.

A Survey of Coping Strategies With Stress in Patients With Acute Myocardial Infarction and Individuals Without a History of Fixed Myocardial Infarction

Background

This study aimed at investigating the coping strategies with stress in patients with acute myocardial infarction (MI) and individuals without a history of fixed MI and cardiovascular disorders.

Methods

This case-control crossover study was conducted from March 2015 to February 2016 on 220 patients with acute MI (MI patients) as case group and 220 patients without any history of MI and cardiovascular diseases as the control group using availability sampling method. To collect the required data, demographic information questionnaire, Holms-Raheh life stress inventory, perceived stress questionnaire, and coping inventory for stressful situations (CISS) were applied.

Results

On the basis of our findings, 118 patients (53.6%) with MI used emotion-focused coping strategy. Ninety-seven patients (82.2%) with MI who used emotion-focused coping strategy had negative perceived stress. Additionally, 71 patients (60.2%) with MI who had used emotion-focused coping strategy suffered from very high level of stress.

Conclusion

The most MI patients had very high level of stress while most people in control group had high level of stress. Most MI patients that had very high level of stress cope with it in emotion-focused coping strategy and it proves that people with higher levels of stress are more likely to use inefficient coping strategies.

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.

Emotional stressors trigger cardiovascular events

AIMS

To describe the relation between emotional stress and cardiovascular events, and review the literature on the cardiovascular effects of emotional stress, in order to describe the relation, the underlying pathophysiology, and potential therapeutic implications.

MATERIALS AND METHODS

Targeted PUBMED searches were conducted to supplement the authors' existing database on this topic.

RESULTS

Cardiovascular events are a major cause of morbidity and mortality in the developed world. Cardiovascular events can be triggered by acute mental stress caused by events such as an earthquake, a televised high-drama soccer game, job strain or the death of a loved one. Acute mental stress increases sympathetic output, impairs endothelial function and creates a hypercoagulable state. These changes have the potential to rupture vulnerable plaque and precipitate intraluminal thrombosis, resulting in myocardial infarction or sudden death.

CONCLUSION

Therapies targeting this pathway can potentially prevent acute mental stressors from initiating plaque rupture. Limited evidence suggests that appropriately timed administration of beta-blockers, statins and aspirin might reduce the incidence of triggered myocardial infarctions. Stress management and transcendental meditation warrant further study.

Depression, stress, and heart disease in earthquakes and Takotsubo cardiomyopathy

The preponderance of evidence links depressive disorder and coronary heart disease (CHD). Despite this evidence, multiple clinical trials have failed to show that effective treatment of depression favorably modifies the development, clinical course, or outcome of comorbid CHD. Possible reasons for these failures include the heterogeneity of depression, limitations of assessment instruments, limited understanding of the biology of depressive disorders, lack of biological markers, and the observation that depression may be more a product of CHD than a true risk factor for it. In this commentary, to better address the effects of externally provoked stress on physical health, we examine evidence about 2 specific examples of stress and subsequent heart disease: earthquake-induced adverse cardiac events among individuals with coronary artery disease, and stress-induced Takotsubo cardiomyopathy. In the former case, existing studies suggest that the stress and distress of earthquakes accelerate the development of poor cardiac outcomes for individuals with established coronary artery disease. In the latter example, existing case studies indicate that the profound left ventricular dysfunction of Takotsubo cardiomyopathy tends to quickly normalize once the acute stress is relieved. Together, these examples indicate that the presence or absence of prestress medical illness and its severity may better determine the outcome of the medical illness than the nature and severity of the stress, including depression. That is, any effort to look at depression among individuals with medical illness must look carefully at the medical illness itself and consider depression a possible nonspecific stress. In patients with comorbid depression and CHD, we propose using the more firmly established CHD outcome measurements to better understand how depression or other stressors and their associated treatments influence the prognosis and outcome of this medical illness.

Assessing syndromic surveillance of cardiovascular outcomes from emergency department chief complaint data in New York City

BACKGROUND

Prospective syndromic surveillance of emergency department visits has been used for near-real time tracking of communicable diseases to detect outbreaks or other unexpected disease clusters. The utility of syndromic surveillance for tracking cardiovascular events, which may be influenced by environmental factors and influenza, has not been evaluated. We developed and evaluated a method for tracking cardiovascular events using emergency department free-text chief complaints.

METHODOLOGY/PRINCIPAL FINDINGS

There were three phases to our analysis. First we applied text processing algorithms based on sensitivity, specificity, and positive predictive value to chief complaint data reported by 11 New York City emergency departments for which ICD-9 discharge diagnosis codes were available. Second, the same algorithms were applied to data reported by a larger sample of 50 New York City emergency departments for which discharge diagnosis was unavailable. From this more complete data, we evaluated the consistency of temporal variation of cardiovascular syndromic events and hospitalizations from 76 New York City hospitals. Finally, we examined associations between particulate matter ≤2.5 µm (PM(2.5)), syndromic events, and hospitalizations. Sensitivity and positive predictive value were low for syndromic events, while specificity was high. Utilizing the larger sample of emergency departments, a strong day of week pattern and weak seasonal trend were observed for syndromic events and hospitalizations. These time-series were highly correlated after removing the day-of-week, holiday, and seasonal trends. The estimated percent excess risks in the cold season (October to March) were 1.9% (95% confidence interval (CI): 0.6, 3.2), 2.1% (95% CI: 0.9, 3.3), and 1.8% (95%CI: 0.5, 3.0) per same-day 10 µg/m(3) increase in PM(2.5) for cardiac-only syndromic data, cardiovascular syndromic data, and hospitalizations, respectively.

CONCLUSIONS/SIGNIFICANCE

Near real-time emergency department chief complaint data may be useful for timely surveillance of cardiovascular morbidity related to ambient air pollution and other environmental events.

Sporting events affect spectators' cardiovascular mortality: it is not just a game

Physiologic and clinical triggers, including mental stress, anxiety, and anger, often precipitate acute myocardial infarction and cardiovascular death. Sporting events can acutely increase cardiovascular event and death rates. A greater impact is observed in patients with known coronary artery disease and when stressful features are present, including a passionate fan, a high-stakes game, a high-intensity game, a loss, and a loss played at home. Sporting events affect cardiovascular health through neuroendocrine responses and possibly an increase in high-risk behaviors. Acute mental stress increases the activity of the hypothalamic-pituitary-adrenocortical axis and the sympathetic-adrenal-medullary system while impairing vagal tone and endothelial function. Collectively, these mechanisms increase myocardial oxygen demand and decrease myocardial oxygen supply while also increasing the risk of arrhythmias and thrombosis. Measures can be taken to reduce cardiovascular risk, including the use of beta-blockers and aspirin, stress management, transcendental meditation, and avoidance of high-risk activities, such as smoking, eating fatty foods, overeating, and abusing alcohol and illicit drugs. Sporting events have the potential to adversely affect spectators' cardiovascular health, and protective measures should be considered.

Day-to-day differences in cortisol levels and molar cortisol-to-DHEA ratios among working individuals

PURPOSE

The present study was carried out to determine day-to-day differences in cortisol levels and the molar cortisol-to-dehydroepiandrosterone (DHEA) ratio (molar C/D ratio) in working subjects.

MATERIALS AND METHODS

The cortisol and DHEA levels were measured from saliva samples collected 30 minutes after awakening for 7 consecutive days in full-time working subjects that worked Monday through Saturday. To determine the day-to-day differences within subjects, the collected data was analyzed using variance (ANOVA) for a randomized complete block design (RCBD).

RESULTS

The cortisol levels from samples collected 30 minutes after awakening on workdays were similar to each other, but were significantly different from the cortisol levels on Sunday. The DHEA levels were not significantly different between the days of week. The DHEA levels on Monday and Tuesday were relatively lower than the levels on the other weekdays. The DHEA levels on Thursday and Friday were relatively higher than the other days. The molar C/D ratios on Sunday were significantly lower than those on workdays. The molar C/D ratios on Monday and Tuesday were significantly higher than those on Wednesday or other workdays.

CONCLUSION

The cortisol levels and the molar C/D ratios demonstrate differences in adrenocortical activities between workdays and non-workdays, but the molar C/D ratio additionally represents differences in adrenocortical status between the first two workdays and other workdays. Thus, it is possible that the day-to-day differences in the cortisol levels and the molar C/D ratio represent the adrenal response to upcoming work-related stress.

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.

When and why do heart attacks occur? Cardiovascular triggers and their potential role

Coronary heart disease affects 7.6% of the population in the United States, where > 900,000 myocardial infarctions (MIs) occur annually. Approximately half of all MIs have an identifiable clinical trigger. Myocardial ischemia, MI, sudden cardiac death, and thrombotic stroke each occur with circadian variation and peak after waking in the morning. In addition, physical exertion and mental stress are common precipitants of MI. Waking in the morning, physical exertion, and mental stress influence a number of physiologic parameters, including blood pressure, heart rate, plasma epinephrine levels, coronary blood flow, platelet aggregability, and endothelial function. Upregulation of sympathetic output and catecholamines increase myocardial oxygen demand and can decrease myocardial oxygen supply and promote thrombosis. Ischemia ensues when myocardial oxygen demand exceeds supply. Increases in blood pressure and ventricular contractility increase intravascular shear stress and may cause vulnerable atherosclerotic plaques to rupture, forming a nidus for thrombosis that can precipitate MI. Numerous clinical triggers of MI have been identified, including blizzards, the Christmas and New Year's holidays, experiencing an earthquake, the threat of violence, job strain, Mondays for the working population, sexual activity, overeating, smoking cigarettes, smoking marijuana, using cocaine, and particulate air pollution. Avoiding clinical triggers or participating in therapies that prevent clinical triggers from precipitating cardiac events could potentially postpone clinical events by several years and improve cardiovascular morbidity and mortality. Direct or indirect evidence suggests that the risk of triggered MIs is reduced with β-blockers, aspirin, statins, stress management, and transcendental meditation.

Incidence, admission and case-fatality of acute myocardial infarction: weekend versus weekday in a Japanese population: 16-year results from Takashima AMI Registry (1988-2003)

For acute myocardial infarction (AMI), "weekend" has been associated with higher incidence, admission, and fatality. But, very few studies in this regard are available in Japan. Day of the week variation in AMI was examined using an entire community covering 16-year AMI registration data from Japan. Data were obtained from the Takashima AMI Registry, which covers a stable population of approximately 55,000 in central Japan. There were 379 registered first ever AMI cases with 121 fatal events within 28 days of onset during 1988-2003. We divided the days into two groups: 'Weekend' (Saturday and Sunday) and 'Weekdays' (Monday to Friday). The incidence rate (per 100,000 person-year), admission rate (per 1,000 days) and 28-day case-fatality rates (per 100 events) as well as corresponding rate ratios were calculated with 95% confidence intervals. The distribution of the day of the week for onset, admission and fatality for all subjects was fairly random in our study population; incidence (chi (2) test, P = 0.8), admission (chi (2) test, P = 0.9) and case-fatality (chi (2) test, P = 0.8). The incidence, admission, and case-fatality rates were similar for the 2 day-groups. The incidence rate ratio 1.06 (95% CI: 0.9-1.3), admission ratio 1.03 (95% CI: 0.8-1.3), and case-fatality ratio 1.18 (95% CI: 0.7-1.9) showed no significant risk difference between weekend and weekday. After various adjustments, hazard ratio for weekend AMI in reference to weekday AMI was 1.07 (95% CI: 0.5-2.1). There were no obvious differences in occurrence, hospital admission and acute outcome for AMI patients in the weekday or weekend.

Winter air-mass-based synoptic climatological approach and hospital admissions for myocardial infarction in Florence, Italy

The aim of this study was to evaluate the relationship between the risk of hospital admission for myocardial infarction (MI) and the daily weather conditions during the winters of 1998-2003, according to an air-mass-based synoptic climatological approach. The effects of time lag and 2-day sequences with specific air mass types were also investigated. Studies concerning the relationship between atmospheric conditions and human health need to take into consideration simultaneous effects of many weather variables. At the moment few studies have surveyed these effects on hospitalizations for MI. Analyses were concentrated on winter, when the maximum peak of hospitalization occurred. An objective daily air mass classification by means of statistical analyses based on ground meteorological data was carried out. A comparison between air mass classification and hospital admissions was made by the calculation of a MI admission index, and to detect significant relationships the Mann-Whitney U test, the analysis of variance, and the Bonferroni test were used. Significant increases in hospital admissions for MI were evident 24h after a day characterized by an anticyclonic continental air mass and 6 days after a day characterized by a cyclonic air mass. Increased risk of hospitalization was found even when specific 2-day air mass sequences occurred. These results represent an important step in identifying reliable linkages between weather and health.

Natural and unnatural triggers of myocardial infarction

Previous analyses have suggested that factors that stimulate the sympathetic nervous system and catecholamine release can trigger acute myocardial infarction. The wake-up time, Mondays, winter season, physical exertion, emotional upset, overeating, lack of sleep, cocaine, marijuana, anger, and sexual activity are some of the more common triggers. Certain natural disasters such as earthquakes and blizzards have also been associated with an increase in cardiac events. Certain unnatural triggers may play a role including the Holiday season. Holiday season cardiac events peak on Christmas and New Year. A number of hypotheses have been raised to explain the increase in cardiac events during the holidays, including overeating, excessive use of salt and alcohol, exposure to particulates, from fireplaces, a delay in seeking medical help, anxiety or depression related to the holidays, and poorer staffing of health care facilities at this time. War has been associated with an increase in cardiac events. Data regarding an increase in cardiac events during the 9/11 terrorist attack have been mixed. Understanding the cause of cardiovascular triggers will help in developing potential therapies.

[Prehospital management of acute myocardial infarction. Data from a consecutive cohort of 115 patients in a French region in 2002]

The treatment of acute myocardial infarction is in evolution. Several strategies are utilized ranging from thrombolysis to percutaneous angioplasty (PCI), and the combination of both treatments; the latter providing an interesting compromise between treatment delay and efficiency of early myocardial reperfusion. We reviewed the early treatment strategies of acute myocardial infarctions undertaken by Samu in region 6 (south west of France) in 2002. Of a cohort of 115 patients, 83 patients (72.1%) had a revascularisation strategy: 56 (48.7%) had a primary PCI, and 27 (23.4%) had thrombolysis (92.6% being performed in the prehospital treatment). In those undergoing thrombolysis, 13 patients (48%) had ongoing features of ischaemia; excluding 4 patients who died during transport, all had a PCI at the admission in hospital. For the 14 patients with successful thrombolysis, 5 had facilitated PCI at the admission, 8 had a delayed angioplasty and 1 patient did not have angiography. Although the number of patients receiving thrombolysis in this study was small, this treatment was begun 62 minutes before primary PCI. There are important intra and extra hospital delays to the commencement of PCI. The easy utility of thrombolysis together with the potential to PCI argue in favour for a strategy of prehospital thrombolysis associated with a facilitated angioplasty.

Do weekends or evenings matter in a pediatric intensive care unit?

OBJECTIVE

To assess what independent influence, if any, weekend or evening admission to a pediatric intensive care unit (PICU) staffed 24 hrs/day, 7 days/wk by in-house, board-certified pediatric intensivists might have on mortality.

DESIGN AND PATIENTS

A retrospective study of 5,968 consecutive admissions to the PICU from August 1996 to December 2003 for patients aged 0 days to 21 yrs.

SETTING

A single, 14-bed, multidisciplinary PICU at an academic medical center.

MEASUREMENTS

Standardized mortality ratios of observed-to-predicted mortality were derived with their corresponding p values. Multivariate logistic regression was used to test the independent effect of weekend admission, weekend discharge/death, and evening PICU admission on mortality for the entire sample and, separately, for only emergency admissions, controlling for other significant predictor variables or interaction terms.

RESULTS

Overall, crude mortality was significantly higher on the weekend (weekday, 2.2%; weekend, 5.0% [p = .0000]) and in the evening (day, 2.1%; evening, 3.8% [p = .0004]). Assessing the entire sample using multivariate logistic regression, neither weekend admission (p = .146), weekend discharge/death (p = .348), nor evening PICU admission (p = .711) showed a significant relationship with mortality controlling for other significant factors. Limiting the scope to the emergency admissions subset, neither weekend admission (p = .135), weekend discharge/death (p = .278), nor evening PICU admission (p = .867) were significant predictors of mortality. Weekend and evening admissions differed in important ways from weekday and daytime admissions, making simple comparisons of crude mortality rates inappropriate. Weekend and evening admissions were more likely to be emergency, nonoperative patients; have a lower Pediatric Risk of Mortality III score but have a higher overall predicted mortality risk; and differ in the distributions of patients by primary diagnosis.

CONCLUSIONS

Using multivariate logistic regression to control for important clinical differences, neither weekend admission, weekend discharge/death, nor evening admission had a significant independent effect on mortality risk in the entire sample or for the emergency patient subset. Our findings are consistent with previous work demonstrating the benefit of intensive care units staffed 24 hrs/day, 7-days/wk by in-house, board-certified intensivists.

Longitudinal Study of Acute Myocardial Infarction in the Southeast Osaka District From 1988 to 2002

BACKGROUND

Data on clinical characteristics, long-term mortality rates, and factors influencing outcome of acute myocardial infarction (AMI) based on an unselected cohort in the percutaneous coronary intervention (PCI) era are still limited in Japan.

METHODS AND RESULTS

In the present study 415 consecutive patients with AMI who were admitted to hospital within 24 h of symptom onset between January 1988 and December 2002 were studied. There was a marked seasonal variation of AMI with a minimum in summer and a maximum in winter, as well as a marked circadian variation with a significant morning peak. Overall, 45.8% of patients were treated with primary PCI. Increased age and female sex were negatively associated with the probability of undergoing PCI. During the follow-up period (mean duration, 4.01+/-3.41 years), the unadjusted long-term all-cause mortality rate was 21.4%. Multivariate Cox regression analysis showed that age, prior cerebrovascular disease, renal failure, Killip > or =2, and ventricular tachycardia/fibrillation were independent predictors of worse long-term mortality after AMI. Furthermore, the use of PCI was independently associated with favorable long-term survival after AMI.

CONCLUSIONS

Although PCI was associated with a favorable long-term mortality, it remains underused in subsets of patients and increased use may further reduce the long-term mortality rate in Japanese AMI patients.

Effect of successful late reperfusion by primary coronary angioplasty on mechanical complications of acute myocardial infarction

It has been suggested that early treatment decreases, but late treatment increases, the risk of mechanical complications for a thrombolytic strategy. However, few studies have evaluated whether late reperfusion (LR) by primary coronary angioplasty decreases the risk of mechanical complications. A total of 2,209 patients with acute myocardial infarction treated with primary coronary angioplasty within 24 hours after the onset of symptoms were divided into 3 groups: early reperfusion (ER; < or =12 hours, n = 1,647), LR (>12 hours, n = 219), and failed reperfusion (FR; n = 343). We evaluated the incidence, risk ratio, and predictors of mechanical complications. The overall incidence of mechanical complications was 2.0%. The incidence of mechanical complications was highest in the FR group (ER 1.4%, LR 1.8%, FR 5.0%; p <0.01). After adjusting for clinical variables, the risk ratio for mechanical complications increased in the FR group compared with the LR group (risk ratio 7.34, 95% confidence interval [CI] 1.02 to 52.80; p = 0.04). Predictors of an increased risk of mechanical complications by multivariate analysis were age > or =70 years (odds ratio [OR] 3.68, 95% CI 1.56 to 8.64; p <0.01), Killip class > or =II (OR 3.73, 95% CI 1.53 to 9.12; p <0.01), absence of collateral vessels (OR 4.09, 95% CI 1.17 to 14.26; p = 0.03), and FR (OR 2.68, 95% CI 1.09 to 6.61; p = 0.03). In conclusion, successful LR by primary coronary angioplasty is associated with the reduced risk of mechanical complications in patients with acute myocardial infarction.