C-reactive protein of ≥ 20 mg/L and ultrasound finding of an effusion ≥ 7 mm has a high specificity and sensitivity in diagnosing paediatric hip septic arthritis.

PURPOSE: Differentiating septic arthritis (SA) from transient synovitis (TS) in children remains a diagnostic challenge. Several algorithms have been developed to diagnose SA including Kocher's criteria and its subsequent modifications, but reports show variable efficacy. This study aims to examine the diagnostic utility of a novel method only using C-reactive protein (CRP) and ultrasound (US) findings of effusion in differentiating SA from TS, determine the optimal values for these predictors and validate this method against existing clinical predictors. METHODS: A 5-year retrospective study was performed including all paediatric patients with acute, non-traumatic hip pain with a suspicion of SA. All patients were evaluated using Kocher's criteria, Caird's criteria, and the novel method. Multivariate logistic regression was performed to identify independent clinical predictors of SA. The degree of agreement between the various methods were assessed using Cohen's kappa (k). Receiver operating characteristics (ROC) curves were used to examine the diagnostic accuracy of this novel method as well as to determine optimal cut-offs for US effusion and CRP in diagnosing SA. RESULTS: Hundred and one patients were recruited. CRP and effusion on US were found to be independent predictors of SA. Both Kocher's and Caird's method showed good specificity (98.9%) but extremely poor sensitivity for SA (0%). When Kocher's four clinical predictors were present, probability of SA was only 59.16%. The k for both Kocher's and Caird's methods, was -0.017 indicating poor agreement. However the k in the novel method was 0.641, indicating good agreement. CONCLUSION: Our study showed that the novel method using CRP (≥ 20 mg/L) and US finding of effusion (≥ 7 mm) has a high specificity (97%) and sensitivity (71%) in diagnosing SA.

Bell's palsy workup: Does audiometry add value?

OBJECTIVE: To investigate if routine audiometry in Bell's palsy patients has prognostic value. METHODS: Retrospective case review was conducted on all Bell's palsy patients (n=191) seen at the tertiary otolaryngology specialist outpatient clinic from 2015 to 2017. Correlation of ipsilesional audiometric thresholds with patients' time-to-recovery and initial clinical severity (measured by House-Brackmann (HB) scoring) were used for the prognostic outcome measure. Audiometry results were analyzed using three contiguous frequency pure-tone average (1kHz, 2kHz, 4kHz). Statistical analysis was done via Stata (v13.1), significance tests were 2-sided at 5% significance level. RESULTS: There was no significant difference between audiometric thresholds between the ipsilesional ear and the contralateral ear (p=0.87). Time-to-recovery was significantly longer for patients with severe initial presentation as compared to mild and moderate severity (p<0.01). There was no correlation found between the audiometry results and HB score at presentation (p=0.39). There was no correlation found between ipsilesional audiometric thresholds and time-to-recovery (p=0.58). CONCLUSION: Our study suggests that routine audiometry has limited prognostic value in Bell's palsy patients.

Changing patient profile, hearing aid use and disability among first-time hearing aid users in Singapore over a decade.

OBJECTIVES: To examine the time trends in demographics, hearing characteristics, hearing aid (HA) choices, usage and patient-reported disability among first-time HA users in Singapore over a decade. DESIGN: Cross-sectional study. Study sample: 1052 subjects issued with HAs at a tertiary hospital from 2004 to 2013. RESULTS: An increase in number of first time HA users were seen from 2004 to 2013. Although mean age did not change significantly, the proportion of older adults (>80 years) being fitted increased (p for trend = 0.033). Inflation adjusted cost of HAs rose over time (p < 0.001 for trend). Bilateral HA uptake increased (adjusted odds ratio [AOR] = 1.58 (95% Confidence Interval [CI] 1.35-1.85) while use of customisable HAs decreased (AOR = 0.74, 95% CI 0.66-0.84) over the period. A decrease in the proportion of subjects reporting 5 or more disabilities (AOR = 0.45, 95% CI 0.34-0.59) and using their HAs >7 hours daily (AOR = 0.45, 95% CI 0.34-0.59) was seen. CONCLUSION: From 2004 to 2013, there was a positive trend towards HA uptake in Singapore. Bilateral HA uptake increased while customisable in ear type of HA use decreased. While hearing disability showed a decreasing trend, HA usage remained suboptimal.

Impact of Vitamin E supplementation on vascular function in haptoglobin genotype stratified diabetes patients (EVAS Trial): a randomised controlled trial.

AIMS: Vitamin E (Vit-E) may preferentially improve cardiovascular risk in haptoglobin 2-2 (Hp2-2) genotype diabetes individuals. We studied the impact of Vit-E supplementation on vascular function in diabetes individuals stratified by haptoglobin genotype in Singapore. METHODS: In this 24-week, double blind, placebo-controlled RCT, we recruited 187 subjects (101 Hp2-2, 86 non-Hp2-2). INTERVENTION: alpha-tocopherol-400 IU. PRIMARY OUTCOME: Change in EndoPAT-derived reactive-hyperaemia index (RHI) and augmentation index (AIx); Secondary Outcomes: Pulse-Wave velocity (Sphygmocor-PWV), carotid intima media thickness (CIMT), inflammation (hsCRP), derivatives of reactive-oxygen metabolites (dROMs), biological antioxidant-potential (BAPs), HbA1c, LDL-C, HDL-C and oxidised LDL-C (ox-LDL). RESULTS: Overall, with Vit-E supplementation no significant change in RHI, PWV, CIMT, hsCRP, dROMS, BAPs, HDL-C and HbA1c was observed (p > 0.05); an increase in LDL-C with concomitant decrease in ox-LDL, and incidentally increase in eGFR was observed (p < 0.05). No interaction effect with haptoglobin genotype was seen for all outcomes (p > 0.05). Subgroup analysis: In the non-Hp-2-2 group, Vit-E supplementation led to a higher EndoPAT-derived AIx, accompanied by higher LDL and ox-LDL concentrations (p < 0.05); Hp2-2 group: Vit-E supplementation led to higher eGFR when compared to the non-Hp2-2 group (exploratory) (p < 0.05). We observed an interaction effect for baseline haptoglobin concentration (threshold > 119 mg/dl) with intervention in terms of increased EndoPAT-derived AIx in the Hp > 119 mg/dl group whereas no change in the group with Hp ≤ 119 mg/dl. CONCLUSION: Vit-E supplementation did not show any preferential benefit or deleterious effect on vascular function in Hp2-2 diabetes subjects in Singapore. A possible deleterious effect of an increase in arterial stiffness in individuals with Hp > 119 mg/dl was observed. Future studies should consider personalisation based on baseline Hp concentrations in patients with T2DM rather than just Hp2-2 genotype to evaluate impact on the detailed lipid pathways, cardiac and renal physiology. The impact of ethnic differences needs to be explored in greater details.

Patients with acute and chronic coronary syndromes have elevated long-term thrombin generation.

Coronary artery disease is a leading cause of morbidity and mortality worldwide. Despite significant advances in revascularization strategies and antiplatelet therapy with aspirin and/or P2Y12 receptor antagonist, patients with acute coronary syndrome (ACS) continue to be at long-term risk of further cardiovascular events. Besides platelet activation, the role of thrombin generation (TG) in atherothrombotic complications is widely recognized. In this study, we hypothesized that there is an elevation of coagulation activation persists beyond 12 months in patients with ACS and chronic coronary syndrome (CCS) when compared with healthy controls. We measured TG profiles of patients within 72 h after percutaneous coronary intervention, at 6-month, 12-month and 24-month. Our results demonstrated that TG of patients with ACS (n = 114) and CCS (n = 40) were persistently elevated when compared to healthy individuals (n = 50) in peak thrombin (ACS 273.1 nM vs CCS 287.3 nM vs healthy 234.3 nM) and velocity index (ACS 110.2 nM/min vs CCS 111.0 nM/min vs healthy 72.9 nM/min) at 24-month of follow-up. Our results suggest a rationale for addition of anticoagulation to antiplatelet therapy in preventing long-term ischemic events after ACS. Further research could clarify whether the use of TG parameters to enable risk stratification of patients at heightened long-term procoagulant risk who may benefit most from dual pathway inhibition.

Factors Influencing Hearing Disability and Reduction in Disability among First-time Hearing Aid Users in Singapore.

INTRODUCTION: This study aims to examine the factors associated with self-reported hearing disability and early reduction in disability after first-time hearing aid (HA) fitting in Singapore. METHODS: Retrospective record review of 1,068 subjects issued with HAs at a tertiary hospital from 2001 to 2013. RESULTS: Subjects reporting ≥5 disabilities reduced from 90% to 24% after HA fitting. 'Difficulty hearing in noise' was the commonest disability before and after HA fitting, while 'needs to increase volume of TV/radio' was the disability with most improvement after fitting. In multivariable models, having worse pure tone audiometry (PTA) thresholds of the better hearing ear and being ethnically Chinese were associated with subjects reporting more hearing disabilities. A higher proportion of subjects reported a reduction rather than an absence of disability after HA fitting. In multivariable models, daily HA usage for ≥4 hours, sensorineural hearing loss (HL) and worse PTA thresholds of the better hearing ear were associated with reduction in more disabilities after HA fitting. CONCLUSION: Hearing disability is high among first-time HA users in Singapore. Ethnicity and PTA thresholds were associated with self-reported hearing disability. After HA fitting, higher daily HA usage, sensorineural HL, and worse PTA thresholds of the better hearing ear were associated with early reduction in disability. Patient counselling on the benefits of HL rehabilitation could focus on hearing disability rather than PTA thresholds. The management of patients' expectations could focus on reducing rather than eliminating disability.

Interview Functional Independence Measure score: self-reporting as a simpler alternative to multidisciplinary functional assessment.

INTRODUCTION: The Functional Independence Measure (FIM) is a validated, objective assessment of functional status. It is widely used in rehabilitation centres but may not be practical for all patients due to time and/or personnel constraints. Studies show positive and negative agreement on self-reported FIM scores for patients with spinal cord injuries and amputees. We tested the validity of the self-reported FIM motor score among stroke patients. METHODS: We conducted a prospective double-blind comparative study of patient self-reporting against multidisciplinary assessment, using the standard FIM algorithm. All eligible stroke patients (n = 47) admitted to our rehabilitation centre were included. 33 patients were included in the final analysis. RESULTS: There was substantial agreement on overall FIM motor score between patient self-reporting and multidisciplinary assessment (intraclass correlation coefficient [ICC] 0.651, 95% confidence interval 0.404-0.811). The scores of individual motor items also showed fair-to-good agreement (ICC range 0.431-0.618), except for eating, grooming, bathing and dressing of the lower body (ICC < 0.400). CONCLUSION: There was no FIM assessment for 14 (29.8%) patients, highlighting the need for alternative assessment tools. Discrepancies in some scores could be due to patients' ignorance of their own limitations or feelings of embarrassment about reporting. Our results may not be valid for patient populations with cognitive or communication deficits. However, a modest agreement between patient self-reporting and multidisciplinary assessment of FIM motor score was demonstrated. Although patients tend to overrate their performance, self-reported FIM motor scores could be an alternative in situations where multidisciplinary FIM assessment is difficult.

Sleep Apnea Evolution and Left Ventricular Recovery After Percutaneous Coronary Intervention for Myocardial Infarction.

STUDY OBJECTIVES: Sleep apnea is often newly diagnosed in patients presenting with ST-segment elevation myocardial infarction (STEMI). We assessed longitudinal changes in apnea-hypopnea index (AHI) and sleep apnea phenotype after STEMI and determined its association with changes in the left ventricular ejection fraction (LVEF). METHODS: A total of 101 eligible patients with STEMI underwent consecutive sleep studies and echocardiographic studies within 5 days of admission and at 6-month follow-up. Sleep apnea (AHI ≥ 15 events/h) was further divided into obstructive sleep apnea (OSA) or central sleep apnea (CSA). RESULTS: Both AHI (mean difference -6.4 events/h, 95% confidence interval [CI] -9.6 to 3.3, P < .001) and LVEF (mean difference 2.6%, 95% CI 1.3 to 4.0, P < .001) improved from baseline to 6 months. The improvement in AHI was associated with an increase in LVEF (ß = -.47, 95% CI -.86 to -.07, P = .023) and a decrease in left ventricular end-systolic volume (LVESV) (ß = .25, 95% CI .07 to .43, P = .007). Of the patients with OSA at baseline (46%), resolution of OSA was seen in 48% at 6 months. Of those with CSA at baseline (12%), conversion to OSA was seen in 83%. In contrast, among those with no sleep apnea (42%) at baseline, the diagnosis remained the same in 93% at 6 months. CONCLUSIONS: Concurrent changes in AHI, LVEF, and LVESV were seen after STEMI. Sleep studies performed on admission are reliable in excluding sleep apnea. However, patients with OSA or CSA on admission warrant re-evaluation due to evolution of the sleep apnea phenotype.

Plasma Ceramides as Prognostic Biomarkers and Their Arterial and Myocardial Tissue Correlates in Acute Myocardial Infarction.

We identified a plasma signature of 11 C14 to C26 ceramides and 1 C16 dihydroceramide predictive of major adverse cardiovascular events in patients with acute myocardial infarction (AMI). Among patients undergoing coronary artery bypass surgery, those with recent AMI, compared with those without recent AMI, showed a significant increase in 5 of the signature's 12 ceramides in plasma but not simultaneously-biopsied aortic tissue. In contrast, a rat AMI model, compared with sham control, showed a significant increase in myocardial concentrations of all 12 ceramides and up-regulation of 3 ceramide-producing enzymes, suggesting ischemic myocardium as a possible source of this ceramide signature.

Factors influencing degree of hearing loss at presentation, hearing aid choice, and usage in first time hearing aid users in Singapore.

OBJECTIVE: To examine the factors associated with late presentation at first hearing aid (HA) fitting, HA choice and usage among users in Singapore. DESIGN: Retrospective cross-sectional study. STUDY SAMPLE: 1068 subjects issued with HAs at a tertiary hospital from 2001 to 2013. RESULTS: Half of the subjects presented with more severe (>55 dB) hearing loss (HL) in their better ear. In multivariable analysis, older age, Malay ethnicity, conductive and mixed HL, and combination type of HL were associated with more severe HL at first presentation. Over 70% of subjects were older than 65 years. Worse pure tone audiometry (PTA) thresholds of the better ear, gradual onset and sensorineural HL were associated with older age presentation. For unilaterally fitted subjects, PTA thresholds were the only determinant of having the better ear aided. Better PTA thresholds, younger age and sensorineural HL were associated with choosing in ear compared to behind the ear HAs. Younger age and worse PTA of the better ear were associated with ≥4 h of daily HA usage. CONCLUSIONS: Age, ethnicity and type of HL were important determinants for more severe HL at first HA fitting. Older patients and those with better hearing were less likely to use their HAs regularly.

Prognostic Implications of Dual Platelet Reactivity Testing in Acute Coronary Syndrome.

Studies on platelet reactivity (PR) testing commonly test PR only after percutaneous coronary intervention (PCI) has been performed. There are few data on pre- and post-PCI testing. Data on simultaneous testing of aspirin and adenosine diphosphate antagonist response are conflicting. We investigated the prognostic value of combined serial assessments of high on-aspirin PR (HASPR) and high on-adenosine diphosphate receptor antagonist PR (HADPR) in patients with acute coronary syndrome (ACS). HASPR and HADPR were assessed in 928 ACS patients before (initial test) and 24 hours after (final test) coronary angiography, with or without revascularization. Patients with HASPR on the initial test, compared with those without, had significantly higher intraprocedural thrombotic events (IPTE) (8.6 vs. 1.2%, p ≤ 0.001) and higher 30-day major adverse cardiovascular and cerebrovascular events (MACCE; 5.2 vs. 2.3%, p = 0.05), but not 12-month MACCE (13.0 vs. 15.1%, p = 0.50). Patients with initial HADPR, compared with those without, had significantly higher IPTE (4.4 vs. 0.9%, p = 0.004), but not 30-day (3.5 vs. 2.3%, p = 0.32) or 12-month MACCE (14.0 vs. 12.5%, p = 0.54). The c-statistic of the Global Registry of Acute Coronary Events (GRACE) score alone, GRACE score + ASPR test and GRACE score + ADPR test for discriminating 30-day MACCE was 0.649, 0.803 and 0.757, respectively. Final ADPR was associated with 30-day MACCE among patients with intermediate-to-high GRACE score (adjusted odds ratio [OR]: 4.50, 95% confidence interval [CI]: 1.14-17.66), but not low GRACE score (adjusted OR: 1.19, 95% CI: 0.13-10.79). In conclusion, both HASPR and HADPR predict ischaemic events in ACS. This predictive utility is time-dependent and risk-dependent.

Hearing impairment and hearing aid usage in Singapore.

OBJECTIVE: To examine the epidemiological and audiological profile, pattern of hearing aid (HA) fitting and usage among HA users in Singapore. DESIGN: Retrospective cross-sectional study. STUDY SAMPLE: Cohort of 1068 subjects issued with HAs at a tertiary hospital between 2001 and 2013. RESULTS: Mean age was 70 years with 50.8% male. Mean hearing loss (HL) was 63.1 dB and 69.5% had at least moderate-severe HL. Sensorineural HL was present in 66.4% and 69.8% had symmetrical HL. "Behind-the-Ear" HAs were cheaper than "In-Ear" HAs. Standard "Behind-The-Ear" HAs were also cheaper than "Receiver-in-Canal" HAs. Among In-Ear HAs, "In-the-Canal" and "Completely-in-Canal" were more popular than "In-the-Ear" HAs despite costing more. HA was used ≥4 days/week by 85.6% but >7 h per day by only 35.7%. Only 18% received bilateral first HA fitting. In multivariate analysis, younger age and symmetrical HL were predictors of bilateral HA uptake while better Pure-Tone-Audiometry of aided ear and >7 h of daily HA usage were predictors of successive HA fitting. CONCLUSIONS: HA users in Singapore were elderly and presented with advanced HL. Bilateral HA adoption and average daily use were low compared to other developed countries. Future research on understanding the suboptimal HA usage should explore patients' motivation, hearing disability, and HA effectiveness.

Hybrid PET/CT and PET/MRI imaging of vulnerable coronary plaque and myocardial scar tissue in acute myocardial infarction.

BACKGROUND: Following an acute coronary syndrome, combined CT and PET with 18F-NaF can identify coronary atherosclerotic plaques that have ruptured or eroded. However, the processes behind 18F-NaF uptake in vulnerable plaques remain unclear. METHODS AND RESULTS: Ten patients with STEMI were scanned after 18F-NaF injection, for 75 minutes in a Siemens PET/MR scanner using delayed enhancement (LGE). They were then scanned in a Siemens PET/CT scanner for 10 minutes. Tissue-to-background ratio (TBR) was compared between the culprit lesion in the IRA and remote non-culprit lesions in an effort to independently validate prior studies. Additionally, we performed a proof-of-principle study comparing TBR in scar tissue and remote myocardium using LGE images and PET/MR or PET/CT data. From the 33 coronary lesions detected on PET/CT, TBRs for culprit lesions were higher than for non-culprit lesions (TBR = 2.11 ± 0.45 vs 1.46 ± 0.48; P < 0.001). Interestingly, the TBR measured on the PET/CT was higher for infarcted myocardium than for remote myocardium (TBR = 0.81 ± 0.10 vs 0.71 ± 0.05; P = 0.003). These results were confirmed using the PET/MR data (TBR = 0.81 ± 0.10 for scar, TBR = 0.71 ± 0.06 for healthy myocardium, P = 0.03). CONCLUSIONS: We confirmed the potential of 18F-NaF PET/CT imaging to detect vulnerable coronary lesions. Moreover, we demonstrated proof-of-principle that 18F-NaF concurrently detects myocardial scar tissue.

Inter-Ethnic Differences in Quantified Coronary Artery Disease Severity and All-Cause Mortality among Dutch and Singaporean Percutaneous Coronary Intervention Patients.

BACKGROUND: Coronary artery disease (CAD) is a global problem with increasing incidence in Asia. Prior studies reported inter-ethnic differences in the prevalence of CAD rather than the severity of CAD. The angiographic "synergy between percutaneous coronary intervention (PCI) with taxus and cardiac surgery" (SYNTAX) score quantifies CAD severity and predicts outcomes. We studied CAD severity and all-cause mortality in four globally populous ethnic groups: Caucasians, Chinese, Indians and Malays. METHODS: We quantified SYNTAX scores of 1,000 multi-ethnic patients undergoing PCI in two tertiary hospitals in the Netherlands (Caucasians) and Singapore (Chinese, Indians and Malays). Within each ethnicity we studied 150 patients with stable CAD and 100 with ST-elevated myocardial infarction (STEMI). We made inter-ethnic comparisons of SYNTAX scores and all-cause mortality. RESULTS: Despite having a younger age (mean age Indians: 56.8 and Malays: 57.7 vs. Caucasians: 63.7 years), multivariable adjusted SYNTAX scores were significantly higher in Indians and Malays than Caucasians with stable CAD: 13.4 [11.9-14.9] and 13.4 [12.0-14.8] vs. 9.4 [8.1-10.8], p<0.001. Among STEMI patients, SYNTAX scores were highest in Chinese and Malays: 17.7 [15.9-19.5] and 18.8 [17.1-20.6] vs. 15.5 [13.5-17.4] and 12.7 [10.9-14.6] in Indians and Caucasians, p<0.001. Over a median follow-up of 709 days, 67 deaths (stable CAD: 37, STEMI: 30) occurred. Among STEMI patients, the SYNTAX score independently predicted all-cause mortality: HR 2.5 [1.7-3.8], p<0.001 for every 10-point increase. All-cause mortality was higher in Indian and Malay STEMI patients than Caucasians, independent of SYNTAX score (adjusted HR 7.2 [1.5-34.7], p=0.01 and 5.8 [1.2-27.2], p=0.02). CONCLUSION: Among stable CAD and STEMI patients requiring PCI, CAD is more severe in Indians and Malays than in Caucasians, despite having a younger age. Moreover, Indian and Malay STEMI patients had a greater adjusted risk of all-cause mortality than Caucasians, independent of SYNTAX score.

Ethnicity Modifies Associations between Cardiovascular Risk Factors and Disease Severity in Parallel Dutch and Singapore Coronary Cohorts.

BACKGROUND: In 2020 the largest number of patients with coronary artery disease (CAD) will be found in Asia. Published epidemiological and clinical reports are overwhelmingly derived from western (White) cohorts and data from Asia are scant. We compared CAD severity and all-cause mortality among 4 of the world's most populous ethnicities: Whites, Chinese, Indians and Malays. METHODS: The UNIted CORoNary cohort (UNICORN) simultaneously enrolled parallel populations of consecutive patients undergoing coronary angiography or intervention for suspected CAD in the Netherlands and Singapore. Using multivariable ordinal regression, we investigated the independent association of ethnicity with CAD severity and interactions between risk factors and ethnicity on CAD severity. Also, we compared all-cause mortality among the ethnic groups using multivariable Cox regression analysis. RESULTS: We included 1,759 White, 685 Chinese, 201 Indian and 224 Malay patients undergoing coronary angiography. We found distinct inter-ethnic differences in cardiovascular risk factors. Furthermore, the associations of gender and diabetes with severity of CAD were significantly stronger in Chinese than Whites. Chinese (OR 1.3 [1.1-1.7], p = 0.008) and Malay (OR 1.9 [1.4-2.6], p<0.001) ethnicity were independently associated with more severe CAD as compared to White ethnicity. Strikingly, when stratified for diabetes status, we found a significant association of all three Asian ethnic groups as compared to White ethnicity with more severe CAD among diabetics, but not in non-diabetics. Crude all-cause mortality did not differ, but when adjusted for covariates mortality was higher in Malays than the other ethnic groups. CONCLUSION: In this population of individuals undergoing coronary angiography, ethnicity is independently associated with the severity of CAD and modifies the strength of association between certain risk factors and CAD severity. Furthermore, mortality differs among ethnic groups. Our data provide insight in inter-ethnic differences in CAD risk factors, CAD severity and mortality.

Circadian Dependence of Infarct Size and Acute Heart Failure in ST Elevation Myocardial Infarction.

OBJECTIVES: There are conflicting data on the relationship between the time of symptom onset during the 24-hour cycle (circadian dependence) and infarct size in ST-elevation myocardial infarction (STEMI). Moreover, the impact of this circadian pattern of infarct size on clinical outcomes is unknown. We sought to study the circadian dependence of infarct size and its impact on clinical outcomes in STEMI. METHODS: We studied 6,710 consecutive patients hospitalized for STEMI from 2006 to 2009 in a tropical climate with non-varying day-night cycles. We categorized the time of symptom onset into four 6-hour intervals: midnight-6:00 A.M., 6:00 A.M.-noon, noon-6:00 P.M. and 6:00 P.M.-midnight. We used peak creatine kinase as a surrogate marker of infarct size. RESULTS: Midnight-6:00 A.M patients had the highest prevalence of diabetes mellitus (P = 0.03), more commonly presented with anterior MI (P = 0.03) and received percutaneous coronary intervention less frequently, as compared with other time intervals (P = 0.03). Adjusted mean peak creatine kinase was highest among midnight-6:00 A.M. patients and lowest among 6:00 A.M.-noon patients (2,590.8±2,839.1 IU/L and 2,336.3±2,386.6 IU/L, respectively, P = 0.04). Midnight-6:00 A.M patients were at greatest risk of acute heart failure (P<0.001), 30-day mortality (P = 0.03) and 1-year mortality (P = 0.03), while the converse was observed in 6:00 A.M.-noon patients. After adjusting for diabetes, infarct location and performance of percutaneous coronary intervention, circadian variations in acute heart failure incidence remained strongly significant (P = 0.001). CONCLUSION: We observed a circadian peak and nadir in infarct size during STEMI onset from midnight-6:00A.M and 6:00A.M.-noon respectively. The peak and nadir incidence of acute heart failure paralleled this circadian pattern. Differences in diabetes prevalence, infarct location and mechanical reperfusion may account partly for the observed circadian pattern of infarct size and acute heart failure.