Long-Term Outcomes of Non-ST-Elevation Myocardial Infarction Without Creatine Kinase Elevation - The J-MINUET Study

Impact of Climate on the Incidence of Acute Coronary Syndrome - Differences Between Japan and Thailand

Background: Although there are many reports of temperature being associated with the onset of acute coronary syndrome (ACS), few studies have examined differences in ACS due to climatic differences between Japan and Thailand. The aim of this joint Japan-Thailand study was to compare patients with myocardial infarction in Japanese and Thai hospitals in different climates. Methods and Results: We estimated the climate data in 2021 for the Wakayama Prefecture and Chonburi Province, two medium-sized cities in Japan and Thailand, respectively, and ACS patients who were treated at the Wakayama Medical University (WMU) and Burapha University Hospital (BUH), the two main hospitals in these provinces (ACS patient numbers: WMU, n=177; BUH, n=93), respectively. In the Chonburi Province, although the average temperature was above 25℃, the number of ACS cases in BUH varied up to threefold between months (minimum: July, 4 cases; maximum: October, 14 cases). In Japan and Thailand, there was a mild to moderate negative correlation between temperature-atmospheric pressure at the onset of ACS, but different patterns for temperature-humidity (temperature-atmospheric pressure, temperature-humidity, and atmospheric pressure-humidity: correlation index; r=-0.561, 0.196, and -0.296 in WMU vs. r=-0.356, -0.606, and -0.502 in BUH). Conclusions: The present study suggests that other climatic conditions and factors, not just temperature, might be involved in the mechanism of ACS.

Predictive Value of CHADS2, CHA2DS2-VASc and R2-CHADS2 Scores for Short- and Long-Term Major Adverse Cardiac Events in Non-ST-Segment Elevation Myocardial Infarction

BACKGROUND

Non-ST-elevation myocardial infarction (NSTEMI) carries a poor prognosis, and accurately prognostication has significant clinical importance. In this study, we analyzed the predictive value of the CHADS2, CHA2DS2-VASc, and R2-CHADS2scores for major adverse cardiac events (MACE) following percutaneous coronary intervention (PCI) in patients with NSTEMI using data from a prospective multicenter registry.Methods and Results: The registry included 440 consecutive patients with NSTEMI and coronary artery disease who underwent successful PCI. Patients were clinically followed for up to 3 years or until the occurrence of MACE. MACE was defined as a composite of all-cause death and nonfatal MI. During the follow-up period, 55 patients (12.5%) experienced MACE. Risk analysis of MACE occurrence, adjusted for the multivariable model, demonstrated a significant increase in risk with higher CHADS2, CHA2DS2-VASc, and R2-CHADS2scores. Kaplan-Meier analysis showed a higher incidence of MACE in patients with higher CHADS2, CHA2DS2-VASc, and R2-CHADS2scores, both in the short- and long-term periods.

CONCLUSIONS

Patients with NSTEMI and higher CHADS2, CHA2DS2-VASc, and R2-CHADS2scores displayed a greater incidence of MACE.

Prognostic implications of non-infarct-related territory unrecognized myocardial infarction in patients with non-ST-segment-elevation acute coronary syndrome

BACKGROUND

Prognostic value of non-infarct-related territory (non-IR) unrecognized myocardial infarction (UMI) in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) remains to be elucidated. We sought to evaluate the prognostic impact of non-IR UMI in patients with first NSTE-ACS presentation.

METHODS

This retrospective single-center analysis was conducted in patients with NSTE-ACS without prior history of coronary artery disease, who underwent uncomplicated urgent percutaneous coronary intervention (PCI) within 48 h of admission between August 2014 and January 2018. All patients underwent postprocedural cardiac magnetic resonance imaging (CMR) within 30 days after PCI. Non-IR UMI was defined as the presence of non-IR delayed gadolinium enhancement with an ischemic distribution pattern. We investigated the association of non-IR UMI, other CMR findings and baseline clinical characteristics with major adverse cardiac events (MACE), defined as death, non-fatal myocardial infarction, stroke, late revascularization, and hospitalization for congestive heart failure.

RESULTS

A total of 168 NSTE-ACS patients were included [124 men (73.8 %); 66 ± 11 years]. Non-IR UMI was detected in 28 patients (16.7 %). During a median follow-up of 32 (15-58) months, MACE occurred in 10 (35.7 %) patients with non-IR UMI, and 20 (14.3 %) patients without (p = 0.013). Cox's proportional hazards analysis showed that the presence of non-IR UMI was an independent predictor of MACE (hazard ratio [HR], 2.37, 95 % confidence interval [CI], 1.09-5.18, p = 0.030). In patients with NSTE-ACS undergoing urgent PCI, the prevalence of non-IR UMI was 16.7 %.

CONCLUSIONS

Non-IR UMI provided prognostic information independent of conventional risk factors and the extent of myocardial injury caused by NSTE-ACS.

Impact of non-gated computed tomography on the timing of invasive strategy of patients with non-ST-elevation acute coronary syndrome

Background

This study aimed to examine the clinical role of non-gated computed tomography (CT) in ruling out fatal chest pain in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS), with a focus on the time of arrival at the hospital to coronary angiography (CAG) and peak creatine kinase (CK) levels.

Methods

We retrospectively examined 196 NSTE-ACS patients who were admitted with urgently diagnosed NSTE-ACS and underwent percutaneous coronary intervention between March 2019 and October 2022. The patients were divided into three groups, namely, non-CT group, CT and defect- group, and CT and defect+ group, based on whether they underwent a CT scan and the presence or absence of perfusion defects on the CT image.

Results

After the initial admission for NSTE-ACS, 40 patients (20.4%) underwent non-gated CT prior to CAG. Among these 40 patients, 27 had a perfusion defect on the CT scan. The incidence of contrast-induced nephropathy was not different among the three groups. The CT and defect+ group had a shorter arrival-to-CAG time than that of the non-CT group. In NSTE-ACS patients with elevated CK levels, the CT and defect+ group had lower peak CK levels than those in the non-CT group.

Conclusion

NSTE-ACS patients with perfusion defects on non-gated CT had a shorter time from arrival to CAG, which might be associated with a lower peak CK. Non-gated CT might be useful for early diagnosis and early revascularization in the clinical setting of NSTE-ACS.

Strategy of dual antiplatelet therapy for patients with ST-elevation myocardial infarction and non-ST-elevation acute coronary syndromes: A systematic review and network meta-analysis

BACKGROUND

Various durations and de-escalation strategies of dual antiplatelet therapy (DAPT) after ST-elevation myocardial infarction (STEMI) or non-ST-elevation acute coronary syndromes (NSTE-ACS) have been tested in randomized controlled trials (RCT)s. However, evidence by specific ACS subtype is unknown.

METHODS

PubMed, EMBASE, and Cochrane CENTRAL were searched in February 2023. RCTs on DAPT strategies included STEMI or NSTE-ACS patients with standard DAPT (12 months) with clopidogrel or potent P2Y12 inhibitors, short-term DAPT (≤6 months) followed by potent P2Y12 inhibitors or aspirin, unguided de-escalation from potent P2Y12 inhibitors to low-dose potent P2Y12 inhibitors or clopidogrel at one month, and guided selection with genotype or platelet function tests were identified. The primary outcome was the net adverse clinical events (NACE) defined as a composite of major adverse cardiovascular events (MACE) and clinically relevant bleeding events.

RESULTS

Twenty RCTs with a combined total population of 24,745 STEMI and 37,891 NSTE-ACS patients were included. In STEMI patients, unguided de-escalation strategy was associated with a lower rate of NACE compared with standard DAPT using potent P2Y12 inhibitors (HR:0.57; 95% CI:0.34-0.96) without increased risk of MACE. In NSTE-ACS patients, unguided de-escalation strategy was associated with a lower rate of NACE compared with the guided selection strategy (HR:0.65; 95% CI:0.47-0.90), standard DAPT using potent P2Y12 inhibitors (HR:0.62; 95% CI:0.50-0.78) and standard DAPT using clopidogrel (HR:0.73; 95% CI:0.55-0.98) without increased risk of MACE.

CONCLUSION

Unguided de-escalation strategy was associated with a reduced risk of NACE and may be the most effective DAPT strategy for STEMI and NSTE-ACS.

Multimodality coronary imaging to predict non-culprit territory unrecognized myocardial infarction in Non-ST-Elevation acute coronary syndrome

PURPOSE

Unrecognized myocardial infarction (UMI) detected by cardiac magnetic resonance (CMR) imaging is associated with adverse outcomes in patients with acute and chronic coronary syndrome. This study aimed to assess the predictors of optical coherence tomography (OCT) and coronary computed tomography angiography (CCTA) findings for non-infarct-related (non-IR) territory UMI in patients presenting with non-ST-elevation acute coronary syndrome (NSTE-ACS).

METHODS

We investigated 69 patients with a first clinical episode of NSTE-ACS who underwent pre-percutaneous coronary intervention (PCI) 320-slice CCTA, uncomplicated urgent PCI with OCT assessment within 24 h of admission, and post-PCI CMR. UMI was assessed using late gadolinium enhancement to identify regions of hyperenhancement with an ischemic distribution pattern in non-IR territories.

RESULTS

Non-IR UMI was detected in 11 patients (15.9%). Lower ejection fraction, higher Gensini score, higher Agatston score, high pericoronary adipose tissue attenuation (PCATA), OCT-defined culprit lesion plaque rupture, and OCT-defined culprit lesion cholesterol crystal were significantly associated with the presence of non-IR UMI. On dividing the total cohort was divided into five groups according to the numbers of two OCT-derived risk factors and two CCTA-derived risk factors, the frequency of non-IR UMI frequency significantly increased according to the number of these relevant risk features (p < 0.001). Patients with all of the non-IR UMI risk factors showed 50% prevalence of non-IR UMI, compared with 2.2% of patients with low risk factors (≤ 2).

CONCLUSIONS

Integrated CCTA and culprit lesion OCT assessment may help identify the presence of non-IR UMI, potentially providing prognostic information in patients with first NSTE-ACS episode.

Factors associated with complications in ST-elevation myocardial infarction: a single-center experience

BACKGROUND

ST-elevation myocardial infarction (STEMI) is a major public health problem. This study aimed to determine the prevalence and identify the determinants of STEMI-related complications in the Cardiology Intensive Care Unit of the Sud Francilien Hospital Center (SFHC).

METHODS

We retrospectively analyzed the data of 315 patients with STEMI aged ≥ 18 years. Logistic regression was used to identify factors independently associated with the occurrence of complications.

RESULTS

Overall, 315 patients aged 61.7 ± 13.4 years, of whom 261 were men, had STEMI during the study period. The hospital frequency of STEMI was 12.7%. Arrhythmias and acute heart failure were the main complications. Age ≥ 75 years (adjusted odds ratio [aOR], 5.18; 95% confidence interval [CI], 3.92-8.75), hypertension (aOR, 3.38; 95% CI, 1.68-5.82), and cigarette smoking (aOR, 3.52; 95% CI, 1.69-7.33) were independent determinants of acute heart failure. Meanwhile, diabetes mellitus (aOR, 1.74; 95% CI, 1.09-3.37), history of atrial fibrillation (aOR, 2.79; 95% CI, 1.66-4.76), history of stroke or transient ischemic attack (aOR, 1.99; 95% CI, 1.31-2.89), and low high-density lipoprotein-cholesterol (HDL-C) levels (aOR, 3.70; 95% CI, 1.08-6.64) were independent determinants of arrhythmias.

CONCLUSION

STEMI is a frequent condition at SFHC and is often complicated by acute heart failure and arrhythmias. Patients aged ≥ 75 years, those with hypertension or diabetes mellitus, smokers, those with a history of atrial fibrillation or stroke, and those with low HDL-C levels require careful monitoring for the early diagnosis and management of these complications.

Predictors of Major Adverse Cardiovascular and Cerebrovascular Events After Acute Coronary Syndromes: A Retrospective Observational Study Using YoMDB Database

Objectives

Despite the rapid aging of the population in Japan, clinical predictors for major adverse cerebrovascular and cardiovascular events (MACCE) in patients with new onset of acute coronary syndromes (ACS) have not been well studied. This study therefore aimed to identify the predictors of MACCE in the first onset of ACS patients requiring care.

Materials and Methods

Using the Yokohama Original Medical Database, we identified 3,373 patients who experienced a first onset of ACS and had certified care information from April 2014 to March 2016. The incidence proportion of MACCE from June 2014 to March 2018 was retrospectively investigated. Each patient's independence of daily living (IDL) was classified as one of three categories (reference, mild and severe).

Results

Predictors of MACCE were identified using multivariate logistic regression analysis. Impaired IDL was associated with increased MACCE, with adjusted odds ratios for reference, mild and severe of 1.00, 1.35 (95% confidence intervals 1.14-1.60) and 2.12 (95% confidence intervals 1.61-2.80; P for trend < 0.001), respectively.

Conclusions

This study revealed that male sex, chronic kidney disease, atrial fibrillation, high-intensity statin use, low-intensity statin use, and lower IDL (representing less independence) were the predictors of MACCE requiring care for a first onset of ACS. Further research will be required to understand the results of interventions for the identified predictors of MACCE.

Reproducing extracellular matrix adverse remodelling of non-ST myocardial infarction in a large animal model

The rising incidence of non-ST-segment elevation myocardial infarction (NSTEMI) and associated long-term high mortality constitutes an urgent clinical issue. Unfortunately, the study of possible interventions to treat this pathology lacks a reproducible pre-clinical model. Indeed, currently adopted small and large animal models of MI mimic only full-thickness, ST-segment-elevation (STEMI) infarcts, and hence cater only for an investigation into therapeutics and interventions directed at this subset of MI. Thus, we develop an ovine model of NSTEMI by ligating the myocardial muscle at precise intervals parallel to the left anterior descending coronary artery. Upon histological and functional investigation to validate the proposed model and comparison with STEMI full ligation model, RNA-seq and proteomics show the distinctive features of post-NSTEMI tissue remodelling. Transcriptome and proteome-derived pathway analyses at acute (7 days) and late (28 days) post-NSTEMI pinpoint specific alterations in cardiac post-ischaemic extracellular matrix. Together with the rise of well-known markers of inflammation and fibrosis, NSTEMI ischaemic regions show distinctive patterns of complex galactosylated and sialylated N-glycans in cellular membranes and extracellular matrix. Identifying such changes in molecular moieties accessible to infusible and intra-myocardial injectable drugs sheds light on developing targeted pharmacological solutions to contrast adverse fibrotic remodelling.

Clinical impact of beta-blockers at discharge on long-term clinical outcomes in patients with non-reduced ejection fraction after acute myocardial infarction

BACKGROUND

Beta-blockers are associated with several clinical benefits in patients with reduced left ventricular ejection fraction (REF) after acute myocardial infarction (AMI), such as lower rates of mortality, recurrence of myocardial infarction, and heart failure. However, the long-term prognosis of beta-blockers has rarely been investigated in patients with non-REF after AMI. This study aimed to investigate the clinical benefits of beta-blockers in these patients.

METHODS

A total of 3281 consecutive patients who were hospitalized within 48 h after AMI were registered in the J-MINUET study. Patients who underwent primary percutaneous coronary intervention (PCI) and had a left ventricular ejection fraction ≥40 % were enrolled, and patients who died during admission were excluded. Included patients were divided into two groups according to the prescription of beta-blockers at discharge. Their characteristics and clinical outcomes were compared.

RESULTS

The number of AMI patients treated with beta-blockers was 1353 (70.4 %). Patients who received beta-blockers were younger and had a higher incidence of hypertension, dyslipidemia, and ST-segment elevation myocardial infarction than those who did not receive beta-blockers. The peak creatine kinase level after primary PCI was significantly higher in patients who received beta-blockers. These patients also had a lower incidence of a composite of all-cause death, myocardial infarction, and stroke compared to those that did not receive beta-blockers (7.3 % vs. 11.9 %, p = 0.001). Multivariate analysis showed that beta-blocker use was an independent factor for better clinical outcomes.

CONCLUSIONS

The J-MINUET study revealed the clinical benefit of beta-blockers in AMI patients with non-REF after primary PCI.

Prognostic Significance of Percutaneous Coronary Intervention for First Acute Myocardial Infarction with Heart Failure: Five-Year Follow-Up Results

Objective

The study aimed to investigate the incidence and influencing factors of heart failure after 5 years of percutaneous coronary intervention (PCI) for first acute myocardial infarction.

Methods

A total of 1235 patients, diagnosed as acute myocardial infarction and treated with PCI in Beijing Anzhen Hospital, Capital Medical University, from January 1, 2014, to December 31, 2014, were enrolled. Based on the exclusion criteria, 671 patients were followed up to obtain echocardiographic results 5 years after the onset of myocardial infarction (from January 1, 2019, to December 31, 2019). Of 671 patients, 62 were lost to follow-up. Finally, 609 patients were recruited in this study. According to the results of the echocardiographic examination, patients were divided into a heart failure group (n = 97) (LVEF < 50%) and a nonheart failure group (n = 512) (LVEF ≥ 50%). The clinical characteristics were compared between the two groups, and the influencing factors of heart failure after 5 years of PCI in patients with acute myocardial infarction were analyzed using logistic regression and receiver-operating characteristic (ROC) analyses.

Results

Of 609 patients, 97 had heart failure within 5 years after PCI for first myocardial infarction, with an incidence of 15.9%. Multivariate regression analysis finally examined the predictors related to the occurrence of heart failure, including age (aOR, 1.008; 95% confidence interval (CI), 1.054–1.123; P ≤ 0.001), peak troponin I level (aOR, 1.020; 95% CI, 1.006–1.034; P = 0.004), left ventricular ejection fraction (LVEF) (during admission) (aOR, 0.908; 95% CI, 0.862–0.956; P ≤ 0.001), and left ventricular end-diastolic dimension (LVEDD) (at admission) (aOR, 1.136; 95% CI, 1.016–1.271; P = 0.025).

Conclusion

In this study, the incidence of heart failure (LVEF < 50%) in patients with acute myocardial infarction who underwent PCI was 15.9% at a five-year follow up. Age, peak troponin I level, and LVEDD (at admission) were risk factors for heart failure, while LVEF (at admission) of patients during hospitalization was a protective factor for heart failure.

Association Between the Expression of MicroRNA-125b and Survival in Patients With Acute Coronary Syndrome and Coronary Multivessel Disease

Background

MicroRNAs (miRNA, miR) have an undeniable physiological and pathophysiological significance and act as promising novel biomarkers. The aim of the study was to investigate blood-derived miRNAs and their association with long-term all-cause mortality in patients with multivessel disease (MVD) suffering from acute coronary syndrome (ACS).

Materials and Methods

This study was an observational prospective study, which included 90 patients with MVD and ACS. Expression of miR-125a, miR-125b, and miR-223 was analysed by polymerase chain reaction (PCR). Patients were followed-up for a median of 7.5 years. All-cause mortality was considered as the primary endpoint. Adjusted Cox-regression analysis was performed for prediction of events.

Results

Elevated expression of miR-125b (&gt;4.6) at the time-point of ACS was associated with increased long-term all-cause mortality (adjusted [adj.] hazard ratio [HR] = 11.26, 95% confidence interval [95% CI]: 1.15–110.38; p = 0.038). The receiver operating characteristic (ROC) analysis showed a satisfactory c-statistics for miR-125b for the prediction of long-term all-cause mortality (area under the curve [AUC] = 0.76, 95% CI: 0.61–0.91; p = 0.034; the negative predictive value of 98%). Kaplan–Meier time to event analysis confirmed an early separation of the survival curves between patients with high vs low expression of miR-125b (p = 0.003). An increased expression of miR-125a and miR-223 was found in patients with non-ST-segment elevation ACS (NSTE-ACS) as compared to those with ST-segment elevation myocardial infarction (STEMI) (p = 0.043 and p = 0.049, respectively) with no difference in the expression of miR-125b between the type of ACS.

Conclusion

In this hypothesis generating study, lower values of miR-125b were related to improved long-term survival in patients with ACS and MVD. Larger studies are needed to investigate whether miR-125b can be used as a suitable predictor for long-term all-cause mortality.

CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) update 2022

Primary Percutaneous Coronary Intervention (PCI) has significantly contributed to reducing the mortality of patients with ST-segment elevation myocardial infarction (STEMI) even in cardiogenic shock and is now the standard of care in most of Japanese institutions. The Task Force on Primary PCI of the Japanese Association of Cardiovascular Interventional and Therapeutics (CVIT) society proposed an expert consensus document for the management of acute myocardial infarction (AMI) focusing on procedural aspects of primary PCI in 2018. Updated guidelines for the management of AMI were published by the European Society of Cardiology (ESC) in 2017 and 2020. Major changes in the guidelines for STEMI patients included: (1) radial access and drug-eluting stents (DES) over bare-metal stents (BMS) were recommended as a Class I indication, (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. In 2020, updated guidelines for Non-ST-Elevation Myocardial Infarction (NSTEMI) patients, the followings were changed: (1) an early invasive strategy within 24 h is recommended in patients with NSTEMI as a Class I indication, (2) complete revascularization in NSTEMI patients without cardiogenic shock is considered as Class IIa recommendation, and (3) in patients with atrial fibrillation following a short period of triple antithrombotic therapy, dual antithrombotic therapy (e.g., DOAC and single oral antiplatelet agent preferably clopidogrel) is recommended, with discontinuation of the antiplatelet agent after 6 to 12 months. Furthermore, an aspirin-free strategy after PCI has been investigated in several trials those have started to show the safety and efficacy. The Task Force on Primary PCI of the CVIT group has now proposed the updated expert consensus document for the management of AMI focusing on procedural aspects of primary PCI in 2022 version.

Differences in mortality and causes of death between STEMI and NSTEMI in the early and late phases after acute myocardial infarction

Background

The detailed causes of death in non–ST-segment–elevation myocardial infarction (NSTEMI) have not been adequately evaluated compared to those in ST-segment elevation myocardial infarction (STEMI).

Methods

The study population was 6,228 AMI patients who underwent percutaneous coronary intervention (STEMI: 4,625 patients and NSTEMI: 1,603 patients). The primary outcome was all-cause death.

Results

Within 6 months after AMI, the adjusted mortality risk was not significantly different between NSTEMI patients and STEMI patients (HR: 0.83, 95%CI: 0.67–1.03, P = 0.09). Regarding the causes of death within 6 months after AMI, mechanical complications more frequently occurred in STEMI patients than in NSTEMI patients, while proportions of post resuscitation status on arrival and heart failure were higher in in NSTEMI patients than in STEMI patients. Beyond 6 months after AMI, the adjusted mortality risk of NSTEMI relative to STEMI was not significantly different. (HR: 1.04, 95%CI: 0.90–1.20, P = 0.59). Regarding causes of death beyond 6 months after AMI, almost half of deaths were cardiovascular causes in both groups, and breakdown of causes of death was similar between NSTEMI and STEMI.

Conclusion

The mortality risk within and beyond 6 months after AMI were not significantly different between STEMI patients and NSTEMI patients after adjusting confounders. Deaths due to post resuscitation status and heart failure were more frequent in NSTEMI within 6 months after AMI.

Role of Creatine Kinase in the Troponin Era: A Systematic Review

Introduction

The diagnosis of non-ST-elevated myocardial infarction (NSTEMI) depends on a combination of history, electrocardiogram, and cardiac biomarkers. The most sensitive and specific biomarkers for cardiac injury are the troponin assays. Many hospitals continue to automatically order less sensitive and less specific biomarkers such as creatine kinase (CK) alongside cardiac troponin (cTn) for workup of patients with chest pain. The objective of this systematic review was to identify whether CK testing is useful in the workup of patients with NSTEMI symptoms.

Methods

We undertook a systematic review to ascertain whether CK ordered as part of the workup for NSTEMI was useful in screening patients with cardiac chest pain. The MEDLINE, Embase, and Cochrane databases were searched from January 1995–September 2020. Additional papers were added after consultation with experts. We screened a total of 2,865 papers, of which eight were included in the final analysis. These papers all compared CK and cTn for NSTEMI diagnosis.

Results

In each of the eight papers included in the analysis, cTn showed a greater sensitivity and specificity than CK in the diagnosis of NSTEMI. Furthermore, none of the articles published reliable evidence that CK is useful in NSTEMI diagnosis when troponin was negative.

Conclusion

There is no evidence to continue to use CK as part of the workup of NSTEMI acute coronary syndrome in undifferentiated chest pain patients. We conclude that CK should not be used to screen patients presenting to the emergency department with chest pain.

Impact of Chronic Kidney Disease on In-Hospital and 3-Year Clinical Outcomes in Patients With Acute Myocardial Infarction Treated by Contemporary Percutaneous Coronary Intervention and Optimal Medical Therapy - Insights From the J-MINUET Study

BACKGROUND

The impact of chronic kidney disease (CKD) on long-term outcomes following acute myocardial infarction (AMI) in the era of modern primary PCI with optimal medical therapy is still in debate.Methods and Results:A total of 3,281 patients with AMI were enrolled in the J-MINUET registry, with primary PCI of 93.1% in STEMI. CKD stage on admission was classified into: no CKD (eGFR ≥60 mL/min/1.73 m²); moderate CKD (60>eGFR≥30 mL/min/1.73 m²); and severe CKD (eGFR <30 mL/min/1.73 m²). While the primary endpoint was all-cause mortality, the secondary endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause death, cardiac failure, myocardial infarction (MI) and stroke. Of the 3,281 patients, 1,878 had no CKD, 1,073 had moderate CKD and 330 had severe CKD. Pre-person-days age- and sex-adjusted in-hospital mortality significantly increased from 0.014% in no CKD through 0.042% in moderate CKD to 0.084% in severe CKD (P<0.0001). Three-year mortality and MACE significantly deteriorated from 5.09% and 15.8% in no CKD through 16.3% and 38.2% in moderate CKD to 36.7% and 57.9% in severe CKD, respectively (P<0.0001). C-index significantly increased from the basic model of 0.815 (0.788-0.841) to 0.831 (0.806-0.857), as well as 0.731 (0.708-0.755) to 0.740 (0.717-0.764) when adding CKD stage to the basic model in predicting 3-year mortality (P=0.013; net reclassification improvement [NRI] 0.486, P<0.0001) and MACE (P=0.046; NRI 0.331, P<0.0001) respectively.

CONCLUSIONS

CKD remains a useful predictor of in-hospital and 3-year mortality as well as MACE after AMI in the modern PCI and optimal medical therapy era.

Current Status and Effect of Outpatient Cardiac Rehabilitation After Percutaneous Coronary Intervention in Japan

Background: Although cardiac rehabilitation (CR) has been reported to be associated with better clinical outcomes in patients with cardiovascular diseases, there are few nationwide studies about CR participation by patients with coronary artery disease in Japan.

Methods and Results: We performed a nationwide retrospective cohort study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan between April 2014 and March 2018. Patients were divided into 2 groups (acute coronary syndrome [ACS] and stable coronary artery disease [sCAD]), and the rates of participation in in- and outpatient CR after percutaneous coronary intervention (PCI) were investigated. Propensity score-matched analysis was performed and the association between outpatient CR participation and all-cause mortality 3 months after PCI was examined. Overall, 616,664 patients (ACS, n=202,853; sCAD, n=413,811) were analyzed. The participation rates of CR increased annually. The participation rate was higher for inpatient than outpatient CR in both the ACS (52% vs. 9%, respectively) and sCAD (15% vs. 3%, respectively) groups. Prognosis was better for patients with than without outpatient CR in both the ACS (hazard ratio [HR] 0.52; 95% confidence interval [CI] 0.47–0.59) and sCAD (HR 0.72; 95% CI 0.65–0.80) groups.

Conclusions: Outpatient CR was associated with a better prognosis in patients with ACS or sCAD. The participation rates of outpatient CR following PCI were extremely low in Japan.

Comparison of coronary atherosclerotic disease burden between ST-elevation myocardial infarction and non-ST-elevation myocardial infarction: Non-culprit Gensini score and non-culprit SYNTAX score

Background

Patients with non‐ST‐elevation myocardial infarction (NSTEMI) have worse long‐term prognoses than those with ST‐elevation myocardial infarction (STEMI).

Hypothesis

It may be attributable to more extended coronary atherosclerotic disease burden in patients with NSTEMI.

Methods

This study consisted of consecutive 231 patients who underwent coronary intervention for myocardial infarction (MI). To assess the extent and severity of atherosclerotic disease burden of non‐culprit coronary arteries, two scoring systems (Gensini score and synergy between percutaneous coronary intervention with Taxus and cardiac surgery [SYNTAX] score) were modified by subtracting the score of the culprit lesion: the non‐culprit Gensini score and the non‐culprit SYNTAX score.

Results

Patients with NSTEMI had more multi‐vessel disease, initial thrombolysis in myocardial infarction (TIMI) flow grade 2/3, and final TIMI flow grade 3 than those with STEMI. As compared to STEMI, patients with NSTEMI had significantly higher non‐culprit Gensini score (16.3 ± 19.8 vs. 31.2 ± 25.4, p < 0.001) and non‐culprit SYNTAX score (5.8 ± 7.0 vs. 11.1 ± 9.7, p < 0.001).

Conclusions

Patients with NSTEMI had more advanced coronary atherosclerotic disease burden including non‐obstruction lesions, which may at least in part explain higher incidence of cardiovascular events in these patients.

Guideline adherence and long-term clinical outcomes in patients with acute myocardial infarction: a Japanese Registry of Acute Myocardial Infarction Diagnosed by Universal Definition (J-MINUET) substudy

BACKGROUND

The association between guideline adherence and long-term outcomes in patients with acute myocardial infarction in real-world clinical practice remains unclear.

METHODS

We investigated 3283 consecutive patients with acute myocardial infarction who were selected from a prospective, nation-wide, multicentre registry (J-MINUET) database covering 28 institutions in Japan between July 2012 and March 2014. Among the 2757 eligible patients, we evaluated the use of seven guideline-recommended therapies, including urgent revascularisation, door-to-balloon time of 90 minutes or less, and five discharge medications (P2Y12 inhibitors on aspirin, beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, statins, lipid-lowering drugs). The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, cardiac failure and urgent revascularisation for unstable angina up to 3 years.

RESULTS

The overall median composite guideline adherence was 85.7%. Patients were divided into the following three groups: complete (100%) adherence group (n=862); moderate adherence (75% to <100%) group (n=911); and low adherence (0-75%) group (n=984). The rate of adverse cardiovascular events was significantly lower in the complete adherence group than in the low and moderate adherence groups (log rank P<0.0001). Multivariate Cox regression analysis showed complete guideline adherence was also significantly associated with lower adverse cardiovascular events compared with low guideline adherence (hazard ratio 0.66; 95% confidence interval 0.52-0.85; P=0.001).

CONCLUSION

The use of guideline-based therapies for patients with acute myocardial infarction in contemporary clinical practice was associated with significant decreases in adverse long-term clinical outcomes.

TRIAL REGISTRATION

UMIN Unique trial Number: UMIN000010037.

Validation study of the modified HEART and HEAR scores in patients with chest pain who visit the emergency department

Aim

To validate the efficacy of the history, electrocardiogram, age, risk factors, and troponin (HEART) and history, electrocardiogram, age, and risk factors (HEAR) scores in a Japanese cohort.

Methods

We used the data of patients who visited our emergency department between 1 December, 2015 and 31 May, 2017. Patients aged ≥20 years who presented with non‐traumatic and undifferentiated chest pain were eligible for the study. On the basis of the total score, the patients were stratified as low risk (HEART and HEAR scores of 0–3), intermediate risk (HEART and HEAR scores of 4–6), and high risk (HEART score of 7–10 and HEAR score of 7–8). The major adverse cardiac events (MACEs) that occurred within 6 weeks were investigated, and the diagnostic value and efficiency of both scores were analyzed.

Results

In total, 132 patients were included in the HEART score analysis and 220 patients in the HEAR score analysis. The incidence rates of MACEs in patients with low, intermediate, and high risks were 0%, 23.2%, and 63.6% in the HEART score analysis and 4.7%, 22.9%, and 62.5% in the HEAR score analysis (P < 0.001), respectively. The identification of MACEs in low‐risk patients had a negative predictive value in the HEART score (1.00; 95% confidence interval, 0.90–1.00) and HEAR score (0.95; 95% confidence interval, 0.89–0.99) analyses.

Conclusion

The modified HEART and HEAR scores were effective in identifying patients with chest pain who are at low risk of MACEs at an emergency department in Japan.

Feasibility of management of hemodynamically stable patients with acute myocardial infarction following primary percutaneous coronary intervention in the general ward settings

BACKGROUND

Although current guidelines recommend admission to the intensive/coronary care unit (ICU/CCU) for patients with ST-segment elevation myocardial infarction (MI), routine use of the CCU in uncomplicated patients with acute MI remains controversial. We aimed to evaluate the safety of management in the general ward (GW) of hemodynamically stable patients with acute MI after primary percutaneous coronary intervention (PCI).

METHODS

Using a large nationwide administrative database, a cohort of 19426 patients diagnosed with acute MI in 52 hospitals where a CCU was available were retrospectively analyzed. Patients with mechanical cardiac support and Killip classification 4, and those without primary PCI on admission were excluded. A total of 5736 patients were included and divided into the CCU (n = 3488) and GW (n = 2248) groups according to the type of hospitalization room after primary PCI. Propensity score matching was performed, and 1644 pairs were matched. The primary endpoint was in-hospital mortality at 30 days.

RESULTS

The CCU group had a higher rate of Killip classification 3 and ambulance use than the GW group. There was no significant difference in the incidence of in-hospital mortality within 30 days among the matched subjects. Multivariable Cox proportional hazard model analysis among unmatched patients supported the findings (hazard ratio 1.12, 95% confidence interval 0.66-1.91, p = 0.67).

CONCLUSIONS

The use of the GW was not associated with higher in-hospital mortality in hemodynamically stable patients with acute MI after primary PCI. It may be feasible for the selected patients to be directly admitted to the GW after primary PCI.

Prognostic Impact of B-Type Natriuretic Peptide on Long-Term Clinical Outcomes in Patients with Non-ST-Segment Elevation Acute Myocardial Infarction Without Creatine Kinase Elevation

Although B-type natriuretic peptide (BNP) has gradually gained recognition as an indicator in risk stratification for patients with acute myocardial infarction (AMI), the prognostic impact on long-term clinical outcomes in patients with non-ST-segment elevation acute myocardial infarction (NSTEMI) without creatine kinase (CK) elevation remains unclear.This prospective multicenter study assessed 3,283 consecutive patients with AMI admitted to 28 institutions in Japan between 2012 and 2014. We analyzed 218 patients with NSTEMI without CK elevation (NSTEMI-CK) for whom BNP was available. In the NSTEMI-CK group, patients were assigned to high- and low-BNP groups according to BNP values (cut-off BNP, 100 pg/mL). The primary endpoint was defined as a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, cardiac failure, and urgent revascularization for unstable angina up to 3 years. Primary endpoints were observed in 60 (33.3%) events among patients with NSTEMI-CK. Kaplan-Meier analysis revealed a significantly higher event rate for primary endpoints among patients with high BNP (log-rank P < 0.001). After adjusting for covariates, a higher BNP level was significantly associated with long-term clinical outcomes in NSTEMI-CK (adjusted hazard ratio, 4.86; 95% confidence interval, 2.18-12.44; P < 0.001).The BNP concentration is associated with adverse long-term clinical outcomes among patients with NSTEMI-CK who are considered low risk. Careful clinical management may be warranted for secondary prevention in patients with NSTEMI-CK with high BNP levels.

Impact of high-dose statin on cardiovascular outcomes in real-world patients with ST-elevation acute myocardial infarction

Little is known about the impact of a high-dose statin on cardiovascular outcomes after ST-elevation acute myocardial infarction (STEMI) in real-world Japanese patients. Between July 2011 and June 2017, 1110 consecutive STEMI patients underwent primary percutaneous coronary intervention at our hospital and were discharged. A high-dose statin was administered in 117 patients (10.5%) and non-high-dose statin was administered in 947 patients (85.3%). The low-density lipoprotein cholesterol level was significantly higher in the high-dose statin group at admission (129.8 ± 44.9 vs. 110.4 ± 32.7, p < 0.0001), but the levels were not significantly different at follow-up (86.7 ± 25.7 vs. 85.0 ± 25.0, p = 0.52). The cumulative 2-year incidence of a composite of cardiac death, myocardial infarction, ischemic stroke, and any unplanned coronary revascularization was significantly lower in the high-dose statin group (6.2% vs. 16.9%, log-rank p = 0.004). Propensity score matched analysis indicated similar results. Among the types of coronary revascularization, a high-dose statin was significantly correlated with a lower rate of de novo lesion revascularization (hazard ratio 0.31; 95% confidence interval 0.08-0.83; p = 0.02). The results of our analyses indicate that administration of a high-dose statin may result in better cardiovascular outcomes after STEMI mainly by reducing the rate of revascularization for de novo lesions regardless of the achieved low-density lipoprotein cholesterol level in real-world patients.

Prediction of Long-Term Outcomes in ST-Elevation Myocardial Infarction and Non-ST Elevation Myocardial Infarction with and without Creatinine Kinase Elevation-Post-Hoc Analysis of the J-MINUET Study

BACKGROUND

A Japanese prospective, nation-wide, multicenter registry (J-MINUET) showed that long-term outcomes were worse in non-ST elevation acute myocardial infarction (NSTEMI), diagnosed by increased cardiac troponin levels, compared to STEMI. This was observed in both non-STEMI with elevated creatine kinase (CK) (NSTEMI+CK) and non-STEMI without elevated CK (NSTEMI-CK). However, predictive factors for long-term outcomes in STEMI, NSTEMI+CK, and NSTEMI-CK have not been elucidated.

METHODS

Using the Cox proportional hazards model, we determined significant independent predictors of long-term outcomes from a total of 111 parameters evaluated in the J-MINUET study in each of our groups, including STEMI, NSTEMI+CK, and NSTEMI-CK. Then, we calculated the risk score using the regression coefficients for the determined independent predictors for the strict prediction of long-term outcomes.

RESULTS

Prognostic factors, as well as composite cardiovascular events and all-cause death, were different between STEMI, NSTEMI+CK, and NSTEMI-CK. Risk scores could effectively and powerfully predict both composite cardiovascular events and all-cause death in each group.

CONCLUSIONS

The prediction of long-term outcomes using cored parameters of baseline demographics and clinical characteristics is feasible and could prove useful in establishing therapeutic strategies in patients with STEMI, NSTEMI+CK, and NSTEMI-CK.

Impact of peripheral artery disease on prognosis after myocardial infarction: The J-MINUET study

BACKGROUND

Patients with peripheral artery disease (PAD) are at high risk of cardiovascular events, including myocardial infarction (MI), stroke, and cardiovascular death. However, the impact of PAD on prognosis in Japanese patients with acute MI remains unclear.

METHODS

The Japanese registry of acute Myocardial INfarction diagnosed by Universal dEfiniTion (J-MINUET) is a prospective multicenter registry that registered 3283 patients with acute MI. Among them, 2970 patients with available data of PAD were divided into the following 4 groups: 2513 patients without prior MI or PAD (None group), 320 patients with only prior MI (Prior MI group), 100 patients with only PAD (PAD group), and 37 patients with both previous MI and PAD (Both group). The primary endpoint was a composite of all-cause death, non-fatal MI, non-fatal stroke, cardiac failure, and urgent revascularization for unstable angina.

RESULTS

The 3-year cumulative incidence of the primary endpoint was 26.9% in None group, 41.4% in Prior MI group, 48.0% in PAD group, and 60.3% in Both group (p < 0.001). In multivariate analysis, hazard ratio using None group as reference was 1.55 (95% confidence intervals 1.25-1.91; p < 0.001) for MI group, 2.26 (1.61-3.07; p < 0.001) for PAD group, and 2.52 (1.52-3.90; p < 0.001) for Both group.

CONCLUSIONS

Concomitant PAD was associated with poor prognosis in Japanese patients with acute MI.

Difference in the in-hospital prognosis between ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction with high Killip class: Data from the Japan Acute Myocardial Infarction Registry

BACKGROUND

ST-segment elevation myocardial infarction is known to be associated with worse short-term outcome than non-ST-segment elevation myocardial infarction. However, whether or not this trend holds true in patients with a high Killip class has been unclear.

METHODS

We analyzed 3704 acute myocardial infarction patients with Killip II-IV class from the Japan Acute Myocardial Infarction Registry and compared the short-term outcomes between ST-segment elevation myocardial infarction (n = 2943) and non-ST-segment elevation myocardial infarction (n = 761). In addition, we also performed the same analysis in different age subgroups: <80 years and ≥80 years.

RESULTS

In the overall population, there were no significant difference in the in-hospital mortality (20.0% vs 17.1%, p = 0.065) between ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction groups. Patients <80 years of age also showed no difference in the in-hospital mortality (15.7% vs 15.2%, p = 0.807) between ST-segment elevation myocardial infarction (n = 2001) and non-ST-segment elevation myocardial infarction (n = 453) groups, whereas among those ≥80 years of age, ST-segment elevation myocardial infarction (n = 942) was associated with significantly higher in-hospital mortality (29.3% vs 19.8%, p = 0.001) and in-hospital cardiac mortality (23.3% vs 15.0%, p = 0.002) than non-ST-segment elevation myocardial infarction (n = 308). After adjusting for covariates, ST-segment elevation myocardial infarction was a significant predictor for in-hospital mortality (odds ratio 2.117; 95% confidence interval, 1.204-3.722; p = 0.009) in patients ≥80 years of age.

CONCLUSION

Among cases of acute myocardial infarction with a high Killip class, there was no marked difference in the short-term outcomes between ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction in younger patients, while ST-segment elevation myocardial infarction showed worse short-term outcomes in elderly patients than non-ST-segment elevation myocardial infarction. Future study identifying the prognostic factors for the specific anticipation intensive cares is needed in this high-risk group.

Impact of Cardio-Ankle Vascular Index on Long-Term Outcome in Patients with Acute Coronary Syndrome

Aim: The purpose of this study is to investigate the impact of arterial stiffness assessed using Cardio-ankle Vascular Index (CAVI) on long-term outcome after acute coronary syndrome (ACS).

Methods: A total of 387 consecutive patients (324 males; age, 64 ± 11 years) with ACS were enrolled. We examined CAVI and brachial-ankle pulse wave velocity (ba PWV) as the parameters of arterial stiffness. The patients were divided into two groups according to the cut-off value of CAVI determined using the receiver operating characteristic curve for the prediction of major adverse cardiovascular events (MACE): low-CAVI group, 177 patients with CAVI < 8.35; high-CAVI group, 210 patients with CAVI ≥ 8.35. The primary endpoint was the incidence of MACE (cardiovascular death, recurrence of ACS, heart failure requiring hospitalization, or stroke).

Results: A total of 62 patients had MACE. Kaplan-Meier analysis demonstrated a significantly higher probability of MACE in the high-CAVI group than in the low-CAVI group (median follow-up: 62 months; log-rank, p < 0.001). Multivariate analysis suggested that CAVI was an independent predictor of MACE (hazard ratio [HR], 1.496; p = 0.02) and cardiovascular death (HR, 2.204; p = 0.025), but ba PWV was not. We investigated the incremental predictive value of adding CAVI to the GRACE score (GRS), a validated scoring system for risk assessment in ACS. Stratified by CAVI and GRS, a significantly higher rate of MACE was seen in patients with both higher CAVI and higher GRS than the other groups (p < 0.001). Furthermore, the addition of CAVI to GRS enhanced net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI, 0.337, p = 0.034; and IDI, 0.028, p = 0.004).

Conclusion: CAVI was an independent long-term predictor of MACE, especially cardiovascular death, adding incremental clinical significance for risk stratification in patients with ACS.

Association of onset-season with characteristics and long-term outcomes in acute myocardial infarction patients: results from the Japanese registry of acute myocardial infarction diagnosed by universal definition (J-MINUET) substudy

It is known that incidence and short-term mortality rate of acute myocardial infarction (AMI) tend to be higher in the cold season. The aim of our study was to investigate the association of onset-season with patient characteristics and long-term prognosis of AMI. This was a prospective, multicenter, Japanese investigation of 3,283 patients with AMI who were hospitalized within 48 h of symptom onset between July 2012 and March 2014. Patients were divided into 3 seasonal groups according to admission date: cold season group (December-March), hot season group (June-September), and moderate season group (April, May, October, and November). We identified 1356 patients (41.3%) admitted during the cold season, 901 (27.4%) during the hot season, and 1026 (31.3%) during the moderate season. We investigated the seasonal effect on patient characteristics and clinical outcomes. Baseline characteristics of each seasonal group were comparable, with the exception of age, Killip class, and conduction disturbances. The rates of higher Killip class and complete atrioventricular block were significantly higher in the cold season group. The 3-year cumulative survival free from major adverse cardiac events (MACE) rate was the lowest in the cold season (67.1%), showing a significant difference, followed by the moderate (70.0%) and hot seasons (72.9%) (p < 0.01). Initial severity and long-term prognoses were worse in patients admitted during the cold season. Our findings highlight the importance of optimal prevention and follow-up of AMI patients with cold season onset.

Admission Heart Rate Is a Determinant of Effectiveness of Beta-Blockers in Acute Myocardial Infarction Patients

BACKGROUND

Beta-blockers are standard therapy for acute myocardial infarction (AMI). However, despite current advances in the management of AMI, it remains unclear whether all AMI patients benefit from β-blockers. We investigated whether admission heart rate (HR) is a determinant of the effectiveness of β-blockers for AMI patients. Methods and Results: We enrolled 3,283 consecutive AMI patients who were admitted to 28 participating institutions in the Japanese Registry of Acute Myocardial Infarction Diagnosed by Universal Definition (J-MINUET) study. According to admission HR, we divided patients into 3 groups: bradycardia (HR <60 beats/min, n=444), normocardia (HR 60 to ≤100 beats/min, n=2,013), and tachycardia (HR >100 beats/min, n=342). The primary endpoint was major adverse cardiac events (MACE), including all-cause death, non-fatal MI, non-fatal stroke, heart failure (HF), and urgent revascularization for unstable angina, at 3-year follow-up. Beta-blocker at discharge was significantly associated with a lower risk of MACE in the tachycardia group (23.6% vs. 33.0%; P=0.033), but it did not affect rates of MACE in the normocardia group (17.8% vs. 18.4%; P=0.681). In the bradycardia group, β-blocker use at discharge was significantly associated with a higher risk of MACE (21.6% vs. 12.7%; P=0.026). Results were consistent for multivariable regression and stepwise multivariable regression.

CONCLUSIONS

Admission HR might determine the efficacy of β-blockers for current AMI patients.

CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI.

Electromechanical wave imaging and electromechanical wave velocity estimation in a large animal model of myocardial infarction

Echocardiography is often used in the clinic for detection and characterization of myocardial infarction. Electromechanical wave imaging (EWI) is a non-invasive ultrasound-based imaging technique based on time-domain incremental motion and strain estimation that can evaluate changes in contractility in the heart. In this study, electromechanical activation is assessed in infarcted heart to determine whether EWI is capable of detecting and monitoring infarct formation. Additionally, methods for estimating electromechanical wave (EW) velocity are presented, and changes in the EW propagation velocity after infarct formation are studied. Five (n  =  5) adult mongrels were used in this study. Successful infarct formation was achieved in three animals by ligation of the left anterior descending (LAD) coronary artery. Dogs were survived for a few days after LAD ligation and monitored daily with EWI. At the end of the survival period, dogs were sacrificed and TTC (tetrazolium chloride) staining confirmed the formation and location of the infarct. In all three dogs, as soon as day 1 EWI was capable of detecting late-activated and non-activated regions, which grew over the next few days. On final day images, the extent of these regions corresponded to the location of infarct as confirmed by staining. EW velocities in border zones of infarct were significantly lower post-infarct formation when compared to baseline, whereas velocities in healthy tissues were not. These results indicate that EWI and EW velocity might help with the detection of infarcts and their border zones, which may be useful for characterizing arrhythmogenic substrate.