Circadian variation of acute myocardial infarction in young people

Circadian and seasonal variation in onset of acute myocardial infarction

The aim was to investigate the circadian and seasonal variation of acute myocardial infarction (AMI). Clinical data of 3867 AMI patients hospitalized from November 2010 to October 2019 in the Border Yanbian Minority Autonomous Prefecture, China were collected, and 3158 patients with definite AMI onset times were analyzed. The clinical data analyzed included the time of onset, nationality, age, laboratory data. We divided the patients into 4 groups based on the timepoint of their AMI onsets: 00:00-05:59, 06:00-11:59, 12:00-17:59, and 18:00-23:59. We also divided the patients based on nationality: Chinese Korean and Han groups. We observed that there is a circadian rhythm in the incidence of AMI, and the peak of AMI is in the morning (7:00-9:00). Unexpectedly, the incidence of AMI was significantly lower in the cold winter than that of other 3 warm seasons (P < 0.01) and the peak of AMI presented at the months of the large contrast between day and night temperature difference (over 20°C) like May of Spring and October of Fall. Finally, there was no difference in circadian rhythm between Chinese Korean and Han, although these groups differed in age, body mass index, and the inflammatory cell level. These findings have shown a different seasonal and circadian variation in onset of AMI. Further studies are required to determine the pathophysiological mechanism(s) underlying these differences and to guide prevention of AMI for reducing its mortality and disability.

The R93C Variant of PCSK9 Reduces the Risk of Premature MI in a Chinese Han Population

Background: Dyslipidemia is a common risk factor for premature myocardial infarction (PMI). Our previous work has shown that single-nucleotide polymorphisms (SNPs) of LDLR, APOB, and PCSK9 are associated with dyslipidemia, but how these SNPs correlate with risk for PMI is unknown.

Objective: This study aims to evaluate the association between SNPs of LDLR, APOB, and PCSK9 and risk of PMI in Chinese Han population.

Methods: Two cohorts were established. In Cohort 1 (413 in the PMI group and 1,239 in the control group), SNPs of APOB, LDLR, and PCSK9 with minor allele frequency (MAF) > 1%, which has been shown to impact the risk of PMI in a Chinese Han population, were thoroughly examined, and gene–environment interactions were analyzed. A model for PMI risk prediction was developed in Cohort 1 and externally validated in Cohort 2 (577 in the PMI group and 270 in the control group).

Results: The distribution of the T allele at the PCSK9 R93C variant (rs151193009, C > T) was lower in the PMI group than that in the control group (PMI vs. Control in Cohort 1, 0.8% vs. 2.3%, P_adjust < 0.05; in Cohort 2, 1.0% vs. 2.4%, P_adjust < 0.05). The T allele at PCSK9 R93C variant (rs151193009, C > T) reduced the risk of PMI by ∼60% regardless of adjusting for confounding factors (in Cohort 1, adjusted odds ratio (OR) 0.354, 95% confidence interval (CI) 0.139–0.900, p = 0.029; in Cohort 2, adjusted OR 0.394, 95% CI 0.157–0.987, p = 0.047). No gene–environment interactions were observed between the R93C variant and diabetes/hypertension/smoking in PMI occurrence in this Chinese Han population. Our model showed good performance in predicting the risk of PMI in Cohort 1 (AUC 0.839, 95% CI 0.815–0.862, p < 0.001) and in an external cohort (AUC 0.840, 95% CI 0.810–0.871, p < 0.001).

Conclusions: The PCSK9 R93C variant was associated with significantly reduced risk of PMI in the Chinese Han population, and the model we developed performed well in predicting PMI risk in this Chinese Han population.

Pcsk9 is associated with severity of coronary artery lesions in male patients with premature myocardial infarction

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (Pcsk9) correlated with incidence and prognosis of coronary heart disease. However, it is unclear whether Pcsk9 contributed to coronary artery lesion severity in patients with premature myocardial infarction (PMI). The present study investigated associations between Pcsk9 and coronary artery lesion severity in PMI patients who underwent coronary angiography (CAG).

METHODS

This prospective cohort study included young men (age ≤ 45 years, n = 332) with acute MI who underwent CAG between January 2017 and July 2019. Serum Pcsk9 levels and clinical characteristics were evaluated. SYNTAX scores (SYNergy between percutaneous coronary intervention with [paclitaxel-eluting] TAXUS stent and cardiac surgery) were calculated to quantify coronary artery lesions.

RESULTS

Serum Pcsk9 levels were positively associated with SYNTAX scores (r = 0.173, P < 0.05). The diagnostic cutoff value of PSCK9 level was 122.9 ng/mL, yielding an area under the curve (AUC) of 0.63, sensitivity 81%, and specificity 40%. Serum Pcsk9, LDL-C, Apob, NT-proBnp, CK level, and diabetes history were independent predictors of high SYNTAX scores (P < 0.05). After stratifying by serum LDL-C level (cutoff = 2.6 mmol/L), medium-high Pcsk9 levels had increased risk of high SYNTAX scores in patients with high LDL-C (P < 0.05), and higher serum Pcsk9 levels had increased risk of major adverse cardiac events (MACE) after adjusting for confounding factors (P < 0.05).

CONCLUSION

Serum Pcsk9 levels correlates with severity of coronary artery lesion in PMI patients and may serve as a biomarker for severity of coronary artery stenosis in this patient population, which may contribute to risk stratification.

Cultural factors and the circadian rhythm of ST elevation myocardial infarction in patients in a Mediterranean island

INTRODUCTION

The circadian rhythm of onset of myocardial infarction shows an increased risk during the morning hours. However, it is not clear whether habits, culture and sunshine hours differentiate circadian rhythm. The aim of this study was to investigate the influence of cultural factors on the circadian rhythm of acute myocardial infarction with ST segment elevation in a Mediterranean island.

METHOD

The study was a retrospective correlational survey. It included 123 patients with ST elevation myocardial infarction (mean age 60.7±12.6; 82% men). The 24 h of a day were divided into four six-hour periods of time for study purposes (00:01-06:00; 06:01-12:00; 12:01-18:00; and 18:01-24:00) and the chi-square test was used for the analysis.

RESULTS

A morning peak of symptoms onset of ST-elevation myocardial infarction was detected during the period 06:01-12:00 (p=0.044). In patients who were smokers, a bimodal pattern involving a morning (06:01-12:00) and an afternoon-to-night peak (18:01-24:00) (p=0.005) was detected. For patients with a history of hypertension, a morning peak of their symptoms was also detected (p=0.028). Different circadian variations were found between patients over the age of 60 years old and patients under the age of 60 years old (p=0.025).

CONCLUSIONS

Patients with ST elevation myocardial infarction seem to follow a circadian rhythm with a peak of onset of symptoms in the morning. In the smokers' subgroup, a different circadian pattern was found. The habit of smoking is likely to affect the circadian rhythm of the onset of ST elevation myocardial infarction in the Mediterranean area and culture.

Particularities of Acute Myocardial Infarction in Young Adults

Coronary heart disease occurs more often in patients over the age of 45. However, recent data shows a growing incidence of coronary events in younger patients also. Young patients with acute myocardial infarction (AMI) represent a relatively small proportion of subjects suffering from an acute ischemic event. However, they represent a subset that is distinguished from elderly patients by a different profile of risk factors, often atypical clinical presentation, and different prognosis. The prevalence of risk factors such as smoking, dyslipidemia, and a family history of coronary events is higher in this group of patients compared to the general population with AMI. Because of an important negative impact on the patients’ psychology, impaired working abilities, and a high socioeconomical burden, myocardial infarction in young patients represents an important cardiovascular pathology. This manuscript aims to present the particularities of AMI occuring at a young age, in comparison with the rest of the population with AMI.

Circadian Distribution of Acute Myocardial Infarction in Different Age Groups

Many epidemiologic studies reported a morning peak in the incidence of acute myocardial infarction (AMI). However, clinical outcomes and the relation between age distribution and circadian pattern have not been fully investigated in a large number of patients. Our study aimed to clarify the impacts of onset time in circadian variation on incidence and clinical outcomes of AMI according to age. From the Korea Acute Myocardial Infarction Registry, we gathered data of 20,685 patients from 53 centers in Republic of Korea. Data from a total of 19,915 patients (11,339 ST elevation myocardial infarction, 8,576 non-ST elevation myocardial infarction) were analyzed from the registry, after exclusion of diagnoses other than AMI. A morning-dominant incidence was shown by sinusoidal function, in all patients and in all separate age groups (age < 55, 55 ≤ age < 75, 75 ≤ age). In-hospital mortality and major adverse cardiovascular events (MACEs), including cardiac deaths, noncardiac deaths, recurrent myocardial infarction, repeated percutaneous coronary intervention, and coronary artery bypass graft at 1, 12, and 24 months' follow-up, were compared in 4 periods (00:00~05:59, 06:00~11:59, 12:00~17:59, and 18:00~23:59), and no significant difference was noted. Kaplan-Meier curve was drawn for death and MACE-free survival, and no significant different event-free survival was depicted (p value = 0.31). In conclusion, the incidences of myocardial infarction by onset time were uneven in 24 hours, in all patients and age groups, by sinusoidal function. However, there were no significant differences in in-hospital mortality or MACEs in the 4 time periods during 24 months of follow-up.

Circadian Periodicity of Ischemic Heart Disease: A Systematic Review of the Literature

The authors performed a MEDLINE search to identify reports, published during the last 20 years, focused on circadian variation of acute myocardial infarction (AMI), and prevalence and the ratios between the number of events per hour during the morning and the other hours of the day were calculated. Despite the optimization of interventional and medical therapy of AMI since the first reports of circadian patterns in AMI occurrence, it was found that such a pattern still exists and that AMI happens most frequently in the morning hours.

Myocardial Infarction in the "Young": Risk Factors, Presentation, Management and Prognosis

Myocardial infarction (MI) in the "young" is a significant problem, however there is scarcity of data on premature coronary heart disease (CHD) and MI in the "young". This may lead to under-appreciation of important differences that exist between "young" MI patients versus an older cohort. Traditional differences described in the risk factor profile of younger MI compared to older patients include a higher prevalence of smoking, family history of premature CHD and male gender. Recently, other potentially important differences have been described. Most "young" MI patients will present with non-ST elevation MI but the proportion presenting with ST-elevation MI is increasing. Coronary angiography usually reveals less extensive disease in "young" MI patients, which has implications for management. Short-term prognosis of "young" MI patients is better than for older patients, however contemporary data raises concerns regarding longer-term outcomes, particularly in those with reduced left ventricular systolic function. Here we review the differences in rate, risk factor profile, presentation, management and prognosis between "young" and older MI patients.

Circadian pattern of symptoms onset in patients ≤35 years presenting with ST-segment elevation acute myocardial infarction

BACKGROUND

There are scarce data regarding the circadian pattern of symptoms onset in young patients presenting with acute myocardial infarction (AMI). We explored whether young patients with ST-segment elevation AMI exhibit a circadian variation in symptoms onset.

METHODS

We recruited prospectively 256 consecutive patients who had survived their first ST-segment elevation AMI ≤35 years of age. Patients were categorized into 4 groups by 6-h intervals over 24 h.

RESULTS

In 49 patients (19.1%) the clinical presentation of AMI was atypical. The symptoms onset was as follows: 00:01 to 06:00, 19.1%, 06:01 to 12:00, 32.4%; 12:01 to 18:00, 28.1%; and 18:01 to 24:00, 20.3%. There was a significant association between the time of day and the likelihood of symptoms onset (Rayleigh test, p<0.001). Between 00:01 and 06:00 the incidence of AMI onset was lower than expected and between 06:01 and 12:00 was higher (p=0.034 and p=0.011, respectively), whereas in the other 6-h period groups no difference was found between expected and observed AMI incidence (p=0.280 and p=0.131). No significant differences were found regarding clinical characteristics, i.e. traditional risk factors, reperfusion treatment of AMI, ejection fraction of left ventricle, time interval from pain onset to hospital arrival, dietary habits and physical activity, among the 6-h period groups.

CONCLUSIONS

ST-segment elevation AMI in individuals ≤35 years of age follows a circadian pattern with a morning peak. This information might be useful for the prompt diagnosis and treatment of AMI in very young patients which occurs rarely and frequently with atypical clinical presentation.

Weaker circadian activity rhythms are associated with poorer executive function in older women

STUDY OBJECTIVES

Older adults and patients with dementia often have disrupted circadian activity rhythms (CARs). Disrupted CARs are associated with health declines and could affect cognitive aging. We hypothesized that among older women, weaker CARs would be associated with poorer cognitive function 5 y later.

DESIGN

Prospective observational study.

SETTING

Three US clinical sites.

PARTICIPANTS

There were 1,287 community-dwelling older women (82.8 ± 3.1 y) participating in an ongoing prospective study who were free of dementia at the baseline visit.

MEASUREMENTS AND RESULTS

Baseline actigraphy was used to determine CAR measures (amplitude, mesor, and rhythm robustness, analyzed as quartiles; acrophase analyzed by peak activity time < 13:34 and > 15:51). Five years later, cognitive performance was assessed with the Modified Mini-Mental Status Examination (3MS), California Verbal Learning Task (CVLT), digit span, Trail Making Test B (Trails B), categorical fluency, and letter fluency. We compared cognitive performance with CARs using analyses of covariance adjusted for a number of health factors and comorbidities. Women in the lowest quartile for CAR amplitude performed worse on Trails B and categorical fluency compared to women in the highest quartile (group difference (d) = 30.42 sec, d = -1.01 words respectively, P < 0.05). Women in the lowest quartile for mesor performed worse on categorical fluency (d = -0.86 words, P < 0.05). Women with a later acrophase performed worse on categorical fluency (d = -0.69 words, P < 0.05). Controlling for baseline Mini-Mental State Examination and sleep factors had little effect on our results.

CONCLUSION

Weaker circadian activity rhythm patterns are associated with worse cognitive function, especially executive function, in older women without dementia. Further investigation is required to determine the etiology of these relationships.