Silent ischemia: clinical relevance

Diagnosis and treatment of ischemia-producing coronary stenoses improves 5-year survival of patients undergoing major vascular surgery

OBJECTIVE

Patients undergoing vascular surgery procedures have poor long-term survival due to coexisting coronary artery disease (CAD), which is often asymptomatic, undiagnosed, and undertreated. We sought to determine whether preoperative diagnosis of asymptomatic (silent) coronary ischemia using coronary computed tomography (CT)-derived fractional flow reserve (FFRCT) together with postoperative ischemia-targeted coronary revascularization can reduce adverse cardiac events and improve long-term survival following major vascular surgery METHODS: In this observational cohort study of 522 patients with no known CAD undergoing elective carotid, peripheral, or aneurysm surgery we compared two groups of patients. Group I included 288 patients enrolled in a prospective Institutional Review Board-approved study of preoperative coronary CT angiography (CTA) and FFRCT testing to detect silent coronary ischemia with selective postoperative coronary revascularization in addition to best medical therapy (BMT) (FFRCT guided), and Group II included 234 matched controls with standard preoperative cardiac evaluation and postoperative BMT alone with no elective coronary revascularization (Usual Care). In the FFRCT group, lesion-specific coronary ischemia was defined as FFRCT ≤0.80 distal to a coronary stenosis, with severe ischemia defined as FFRCT ≤0.75. Results were available for patient management decisions. Endpoints included all-cause death, cardiovascular death, myocardial infarction (MI), and major adverse cardiovascular events (MACE [death, MI, or stroke]) during 5-year follow-up.

RESULTS

The two groups were similar in age, gender, and comorbidities. In FFRCT, 65% of patients had asymptomatic lesion-specific coronary ischemia, with severe ischemia in 52%, multivessel ischemia in 36% and left main ischemia in 8%. The status of coronary ischemia was unknown in Usual Care. Vascular surgery was performed as planned in both cohorts with no difference in 30-day mortality. In FFRCT, elective ischemia-targeted coronary revascularization was performed in 103 patients 1 to 3 months following surgery. Usual Care had no elective postoperative coronary revascularizations. At 5 years, compared with Usual Care, FFRCT guided had fewer all-cause deaths (16% vs 36%; hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.22-0.60; P < .001), fewer cardiovascular deaths (4% vs 21%; HR, 0.11; 95% CI, 0.04-0.33; P < .001), fewer MIs (4% vs 24%; HR, 0.13; 95% CI, 0.05-0.33; P < .001), and fewer MACE (20% vs 47%; HR, 0.36; 95% CI, 0.23-0.56; P < .001). Five-year survival was 84% in FFRCT compared with 64% in Usual Care (P < .001).

CONCLUSIONS

Diagnosis of silent coronary ischemia with ischemia-targeted coronary revascularization in addition to BMT following major vascular surgery was associated with fewer adverse cardiovascular events and improved 5-year survival compared with patients treated with BMT alone as per current guidelines.

Prediction and causal inference of cardiovascular and cerebrovascular diseases based on lifestyle questionnaires

Cardiovascular and cerebrovascular diseases (CCVD) are prominent mortality causes in Japan, necessitating effective preventative measures, early diagnosis, and treatment to mitigate their impact. A diagnostic model was developed to identify patients with ischemic heart disease (IHD), stroke, or both, using specific health examination data. Lifestyle habits affecting CCVD development were analyzed using five causal inference methods. This study included 473,734 patients aged ≥ 40 years who underwent specific health examinations in Kanazawa, Japan between 2009 and 2018 to collect data on basic physical information, lifestyle habits, and laboratory parameters such as diabetes, lipid metabolism, renal function, and liver function. Four machine learning algorithms were used: Random Forest, Logistic regression, Light Gradient Boosting Machine, and eXtreme-Gradient-Boosting (XGBoost). The XGBoost model exhibited superior area under the curve (AUC), with mean values of 0.770 (± 0.003), 0.758 (± 0.003), and 0.845 (± 0.005) for stroke, IHD, and CCVD, respectively. The results of the five causal inference analyses were summarized, and lifestyle behavior changes were observed after the onset of CCVD. A causal relationship from 'reduced mastication' to 'weight gain' was found for all causal species theory methods. This prediction algorithm can screen for asymptomatic myocardial ischemia and stroke. By selecting high-risk patients suspected of having CCVD, resources can be used more efficiently for secondary testing.

Asymptomatic Type 2 Perioperative Myocardial Infarction Detected before Anesthetic Induction in a Patient Undergoing Non-Cardiac Surgery-A Case Report

Background: Perioperative myocardial infarction (PMI) is a life-threatening complication in major non-cardiac surgeries (NCS) and constitutes the most common cause of postoperative morbidity and mortality. A PMI that is associated with prolonged oxygen supply-demand imbalance and its etiology is defined as a type 2 MI. Asymptomatic myocardial ischemia can occur in patients with stable coronary artery disease (CAD), especially those with comorbidities such as diabetes mellitus (DM), hypertension, or, in some cases, without any risk factors. Case: We report a case of asymptomatic PMI in a 76-year-old patient with underlying hypertension and DM without a previous history of CAD. During the induction of anesthesia, abnormal electrocardiography was discovered, and the surgery was postponed after further studies revealed almost completely occluded three-vessel CAD and type 2 PMI. Conclusions: Anesthesiologists should closely monitor and evaluate the associated cardiovascular risk, including cardiac biomarkers of each patient before surgery, to minimize the possibility of PMI.

Evaluation of Outpatients in the Post-COVID-19 Period in Terms of Autonomic Dysfunction and Silent Ischemia

INTRODUCTION AND OBJECTIVE

In this context, the objective of this study is to evaluate the 24-hour ambulatory electrocardiography (ECG) recordings, autonomous function with heart rate variability (HRV), and silent ischemia (SI) attacks with ST depression burden (SDB) and ST depression time (SDT) of post-COVID-19 patients.  Materials and methods: The 24-hour ambulatory ECG recordings obtained >12 weeks after the diagnosis of COVID-19 were compared between 55 consecutive asymptomatic and 73 symptomatic post-COVID-19 patients who applied to the cardiology outpatient clinic with complaints of palpitation and chest pain in comparison with asymptomatic post-COVID-19 patients in Kars Harakani state hospital. SDB, SDT, and HRV parameters were analyzed. Patients who had been on medication that might affect HRV, had comorbidities that might have caused coronary ischemia, and were hospitalized with severe COVID-19 were excluded from the study.

RESULTS

There was no significant difference between symptomatic and asymptomatic post-COVID-19 patients in autonomic function. On the other hand, SDB and SDT parameters were significantly higher in symptomatic post-COVID-19 patients than in asymptomatic post-COVID-19 patients. Multivariate analysis indicated that creatine kinase-myoglobin binding (CK-MB) (OR:1.382, 95% CI:1.043-1.831; p=0.024) and HRV index (OR: 1.033, 95% CI:1.005-1.061; p=0.019) were found as independent predictors of palpitation and chest pain symptoms in post-COVID-19 patients.

CONCLUSION

The findings of this study revealed that parasympathetic overtone and increased HRV were significantly higher in symptomatic patients with a history of COVID-19 compared to asymptomatic patients with a history of COVID-19 in the post-COVID-19 period. Additionally, 24-hour ambulatory ECG recordings and ST depression analysis data indicated that patients who experienced chest pain in the post-COVID-19 period experienced silent ischemia (SI) attacks.

Large vessel occlusions requiring repeated mechanical thrombectomy caused by silent myocardial infarction in a young adult

OBJECTIVES

Silent myocardial ischemia, defined as objective evidence of myocardial ischemia without symptoms, is associated with ischemic stroke. Nevertheless, silent myocardial infarction is a rare cause of ischemic stroke, especially in young adults with no medical history.

MATERIALS AND METHODS

Herein, we report a young adult patient with acute ischemic stroke treated with repeated mechanical thrombectomy for recurrent large vessel occlusions caused by left ventricular thrombus following a silent myocardial infarction.

RESULTS

A 40-year-old man was transferred by ambulance to our hospital because of a generalized seizure. He was diagnosed with cerebral infarction and left middle cerebral artery occlusion. We performed intravenous thrombolysis and mechanical thrombectomy. Recanalization was achieved and his symptoms gradually improved. However, the day after treatment he developed bilateral cerebellar infarction and basilar artery occlusion. We performed a second mechanical thrombectomy and recanalization was achieved. Transthoracic echocardiography revealed a mobile left ventricular thrombus. Although he had no previous chest symptomatic episodes, cardiac examination confirmed myocardial infarction of unknown onset. He was diagnosed with acute ischemic stroke with large vessel occlusions caused by left ventricular thrombus following a silent myocardial infarction. Anticoagulation therapy reduced the amount of thrombus. At 1-year follow-up, he had not experienced any recurrences or symptoms.

CONCLUSIONS

Silent myocardial infarction should be considered a cause of ischemic stroke in young adults, even without any vascular risk factors. Recurrent large vessel occlusion may occur in patients with left ventricular thrombus, and repeated mechanical thrombectomy should be considered for treatment.

Cardiotoxicity from Capecitabine Chemotherapy: Prospective Study of Incidence at Rest and During Physical Exercise

BACKGROUND

Physical activity may increase the risk of cardiotoxicity (myocardial ischemia, major arrhythmias) of 5-Fluorouracil, but this risk has never been investigated for its prodrug capecitabine.

PATIENTS AND METHODS

One hundred and ninety-two consecutive patients undergoing capecitabine chemotherapy from December 1, 2010 through July 31, 2016 were prospectively evaluated. The baseline evaluation included electrocardiography (ECG) and echocardiography (2DE); a follow-up evaluation, including ECG and exercise stress testing (2DE in case of ECG abnormalities), was done after ≥10 days of treatment. Cardiotoxicity was suspected from ischemic ECG changes, new kinetic abnormalities at 2DE, Lown classification ≥2 ventricular arrhythmia, symptomatic arrhythmias, or positive stress test, and confirmed by a negative stress test after capecitabine washout.

RESULTS

Cardiotoxicity was diagnosed in 32 patients (16.7%): six at rest and 26 during exercise. All 32 patients had ECG abnormalities: ST-segment changes (24 patients), negative T-waves (2) and/or arrhythmias: ventricular arrhythmias (14 cases), supraventricular tachycardia (2), complete heart block (1). Eight patients had typical symptoms, 6 had atypical symptoms, 1 had syncope, 17 (53%) were asymptomatic. Cardiotoxicity was more common in patients with atypical symptoms during daily life (OR = 15.7) and in those on a therapeutic schedule of 5 days/week (OR = 9.44).

CONCLUSION

Capecitabine cardiotoxicity is frequent, and often elicited by physical effort. Oncologists, cardiologists, and general practitioners should be aware of this risk. Active cardiotoxicity surveillance with ECG (and echocardiogram and/or stress testing in suspected cases) during therapy is recommended.

CLINICAL TRIALS REGISTRATION NUMBER

CRO-2010-17.

Dynamic detection and reversal of myocardial ischemia using an artificially intelligent bioelectronic medicine

Myocardial ischemia is spontaneous, frequently asymptomatic, and contributes to fatal cardiovascular consequences. Importantly, myocardial sensory networks cannot reliably detect and correct myocardial ischemia on their own. Here, we demonstrate an artificially intelligent and responsive bioelectronic medicine, where an artificial neural network (ANN) supplements myocardial sensory networks, enabling reliable detection and correction of myocardial ischemia. ANNs were first trained to decode spontaneous cardiovascular stress and myocardial ischemia with an overall accuracy of ~92%. ANN-controlled vagus nerve stimulation (VNS) significantly mitigated major physiological features of myocardial ischemia, including ST depression and arrhythmias. In contrast, open-loop VNS or ANN-controlled VNS following a caudal vagotomy essentially failed to reverse cardiovascular pathophysiology. Last, variants of ANNs were used to meet clinically relevant needs, including interpretable visualizations and unsupervised detection of emerging cardiovascular stress. Overall, these preclinical results suggest that ANNs can potentially supplement deficient myocardial sensory networks via an artificially intelligent bioelectronic medicine system.

Cardiovascular disease and COVID-19: a consensus paper from the ESC Working Group on Coronary Pathophysiology & Microcirculation, ESC Working Group on Thrombosis and the Association for Acute CardioVascular Care (ACVC), in collaboration with the European Heart Rhythm Association (EHRA)

The cardiovascular system is significantly affected in coronavirus disease-19 (COVID-19). Microvascular injury, endothelial dysfunction, and thrombosis resulting from viral infection or indirectly related to the intense systemic inflammatory and immune responses are characteristic features of severe COVID-19. Pre-existing cardiovascular disease and viral load are linked to myocardial injury and worse outcomes. The vascular response to cytokine production and the interaction between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and angiotensin-converting enzyme 2 receptor may lead to a significant reduction in cardiac contractility and subsequent myocardial dysfunction. In addition, a considerable proportion of patients who have been infected with SARS-CoV-2 do not fully recover and continue to experience a large number of symptoms and post-acute complications in the absence of a detectable viral infection. This conditions often referred to as 'post-acute COVID-19' may have multiple causes. Viral reservoirs or lingering fragments of viral RNA or proteins contribute to the condition. Systemic inflammatory response to COVID-19 has the potential to increase myocardial fibrosis which in turn may impair cardiac remodelling. Here, we summarize the current knowledge of cardiovascular injury and post-acute sequelae of COVID-19. As the pandemic continues and new variants emerge, we can advance our knowledge of the underlying mechanisms only by integrating our understanding of the pathophysiology with the corresponding clinical findings. Identification of new biomarkers of cardiovascular complications, and development of effective treatments for COVID-19 infection are of crucial importance.

Prevalence of unrecognized or "silent" myocardial ischemia in chronic kidney disease patients: Protocol for a systematic review and meta-analysis

INTRODUCTION

Chronic kidney disease (CKD) patients are at an extremely high risk of silent myocardial ischemia (SMI). However, there is a dearth of evidence on the worldwide prevalence of this very lethal and yet unrecognizable complication of CKD. The proposed systematic review and meta-analysis aims to estimate the global prevalence of SMI among CKD patients.

METHODS AND ANALYSES

This protocol was conceived according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) statement. The systematic review will involve all observational studies and clinical trials published until April 30, 2021, and reporting on the prevalence of SMI in CKD patients. Electronic sources including MEDLINE, Embase, Web of Science, and Cochrane database of systematic reviews will be perused for potentially eligible studies, restricted to only studies published in English or French. Two investigators will independently select studies and use a pre-pilot tested form to extract data. Further, they will independently perform a qualitative assessment of the risk of bias and overall quality of the selected studies, followed by a quantitative assessment using funnel plots and Egger's tests. The heterogeneity between studies will be assessed with the Cochrane's Q statistic, and the I2 statistic will measure the percentage of variation across studies that is due to their heterogeneity rather than chance; the I2 will decide if a meta-analysis can be conducted. In case it cannot be conducted, a descriptive analysis will be performed. Otherwise, study-specific estimates will be pooled using either a fixed-effects or a random-effects model, depending on the value of the I2 statistic. Subgroup and random effects meta-regression analyses will further investigate the potential sources of heterogeneity. Finally, sensitivity analyses will be performed to measure the impact of low-quality studies on the results of the meta-analysis, and power calculations will determine the probability that we will detect a true effect if it does exist.

PROSPERO REGISTRATION NUMBER

CRD42020211929.

STRENGTHS AND LIMITATIONS OF THIS STUDY

The intended systematic review and meta-analysis will fill the knowledge gap on the global prevalence of silent myocardial ischemia (SMI) in CKD patients. The eligible studies will be identified through a methodic literature search followed by a rigorous screening process; we will then use robust meta-analysis tools to pool the data and provide reliable estimates of the global prevalence of SMI in CKD patients. Two major limitations could be: the predominance of clinical trials that might limit the generalizability of the findings, given that some informative patients might have been sidelined by the strict inclusion criteria of these studies; the high probability of type 1 error originating from the important number of subgroup and sensitivity analyses.

Prevalence of asymptomatic or "silent" myocardial ischemia in diabetic patients: Protocol for a systematic review and meta-analysis

INTRODUCTION

Myocardial ischemia (MI) is a top ranked cause of death among diabetic patients, yet it is mostly asymptomatic or "silent". There is a need for summary epidemiologic measures on this highly lethal and unnoticeable complication of diabetes. The proposed systematic review and meta-analysis aims to estimate of the global prevalence of silent MI among diabetic patients.

METHODS AND ANALYSIS

This protocol was prepared according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) statement. The systematic review will include all observational studies published until March 23, 2021 and reporting on the prevalence of silent MI in diabetic patients. Electronic sources including MEDLINE(PubMed), Embase, Cochrane Library, and Web of Science will be searched for potentially eligible studies, restricted to only studies published in English. Two investigators will select studies and use a pre-pilot tested form to extract data. Further, they will independently perform a qualitative assessment of the risk of bias and overall quality of the selected studies, followed by a quantitative assessment using funnel plots and Egger's tests. The heterogeneity between studies will be assessed with the Cochrane's Q statistic, and the I2 statistic will measure the percentage of variation across studies that is due to their heterogeneity rather than chance; it will decide if a meta-analysis can be conducted. In case a meta-analysis cannot be conducted, a descriptive analysis will be performed. Otherwise, study-specific estimates will be pooled using either a fixed-effects or a random-effects model depending on the value of the I2 statistic. Subgroup and random effects meta-regression analyses will be used to further investigate the potential sources of heterogeneity. Finally, sensitivity analyses will be performed to measure the impact of low-quality studies on the results of the meta-analysis, and power calculations will determine the probability that we will detect a true effect if it does exist.

STRENGTHS AND LIMITATIONS OF THIS STUDY

The intended review will provide an up-to-date summary of the global prevalence of silent MI in diabetic patients. We will conduct a thorough literature search for eligible studies, and we will use robust meta-analysis tools to provide reliable estimates of the global prevalence of silent MI in diabetic patients. Two major limitations could be: the predominance of clinical trials that might limit the generalizability of the findings, given that the strict inclusion criteria of these studies might have excluded other patients; the risk of type 1 error emanating from the high number of subgroup and sensitivity analyses.

PROSPERO REGISTRATION NUMBER

CRD42019138136.

Ambulatory and silent myocardial ischemia in women with coronary microvascular dysfunction: Results from the Cardiac Autonomic Nervous System study (CANS)

BACKGROUND

Up to two-thirds of patients with obstructive coronary artery disease (CAD) have silent ischemia (SI), which predicts an adverse prognosis and can be a treatment target in obstructive CAD. Over 50% of women with ischemia and no obstructive CAD have coronary microvascular dysfunction (CMD), which is associated with adverse cardiovascular outcomes. We aimed to investigate the prevalence of SI in CMD in order to consider it as a potential treatment target.

METHODS

36 women with CMD by coronary reactivity testing and 16 age matched reference subjects underwent 24-h 12-lead ambulatory ECG monitoring (Mortara Instruments) after anti-ischemia medication withdrawal. Ambulatory ECG recordings were reviewed by two-physician consensus masked to subject status for SI measured by evidence of ≥1 minute horizontal or downsloping ST segment depression ≥1.0 mm, measured 80 ms from the J point.

RESULTS

Demographics, resting heart rate, and systolic blood pressure were similar between CMD and reference subjects. Thirty-nine percent of CMD women had a total of 26 SI episodes vs. 0 episodes in the reference group (p = 0.002). Among these women 13/14 (93%) had SI, and few episodes (3/26, 12%) were symptomatic. Mean HR at the onset of SI was 96 ± 13 bpm and increased to 117 ± 16 bpm during the ischemic episodes. 87% reported symptoms that were not associated with ST depressions.

CONCLUSIONS

Ambulatory ischemia is prevalent in women with CMD, with a majority being SI, while most reported symptoms were not accompanied by ambulatory ischemia. Clinical trials evaluating anti-ischemic medications should be considered in the CMD population.

Ambulatory electrocardiographic monitoring as a diagnostic tool for ischemic heart disease in women

Introduction. Ischemic heart disease(IHD) is currently the leading cause of mortality in women. In this study we aimed to evaluate ambulatory electrocardiographic monitoring(AECGm) as a diagnostic test for IHD in women. Material and method. The study included 225 female who underwent AECGm divided into 2 groups: 136 previously diagnosed with IHD(IHD+) and 89 controls(IHD-). The IHD+ group was subdivided into AECGm ischemia subgroup(I+) and AECGm non-ischemia subgroup(I-). AECGm was assessed for presence of myocardial ischemia (ST segment depression >5mm), duration and ischemic load (the percentage that episodes of myocardial ischemia accounted throughout the recording). Results and discussions. Patients mean age was 62.31±12.51years. The IHD+ and IHD- groups were similar regarding associated risk factors (hypertension, obesity, dyslipidemia, diabetes mellitus), echocardiographic parameters (left ventricular size, ejection fraction, kinetic disorders), minimum and maximum heart rates(MaxHR) on AECGm. Statistically significant differences were identified regarding presence of atrial fibrillation episodes(AFibE) (IHD+:21.3% vs IHD-:8.9%), myocardial ischemia (IHD+:55.14% vs IHD-:42.69%), ischemic load (IHD+:15.23±30.54% vs IHD-:4.7±15.65%), duration of ischemia (IHD+:174.16±380.75 minutes vs IHD-:59.44 ± 209.02 minutes). In multivariate analysis, ischemia episodes, ischemic load and duration of ischemia were predicted by obesity, MaxHR and AFibE. Statistically significant differences were also identified regarding presence of AFibE (I+:30% vs I-:8.9%), MaxHR (I+:120 vs I-:111beats/minute), obesity (I+:20% vs I-:41%), diabetes mellitus (I+:16% vs I-:69%), hypertension (I+:76% vs I-:90%). Conclusions. Although myocardial ischemia was also present in IHD- group, our study demonstrated that the diagnosis of IHD can be established by AECGm using the threshold values of ischemic load (> 27%) and ischemic duration (> 315minutes).

Thoracic radiotherapy as a risk factor for heart ischemia in subjects treated with chest irradiation and chemotherapy and without classic cardiovascular RISK factors

BACKGROUND AND PURPOSE

Radiation Induced Heart Disease (RIHD) represents a late effect of chest irradiation, contributing in increasing mortality rate in oncological patients by affecting pericardium, myocardium, valvs and coronaries. Currently, regarding the risk of Coronary Artery Disease (CAD), a cardiological screening involving exercise stress electrocardiography after 5-10 years from radiotherapy is advised. We sought to determine the rate of ischemia at exercise stress electrocardiography in a population of patients without cardiovascular risk factors who sustained radiotherapy, using a cohort of patients presenting with at least one cardiovascular risk factor as control group.

DESIGN AND METHODS

A population of 115 patients who sustained chest irradiation (and associated chemotherapy), presenting without classic cardiovascular risk factors or typical symptoms suggesting CAD, was evaluated with exercise stress electrocardiography. 135 patients with at least one risk factor for cardiovascular disease candidate to stress testing for primary prevention or for atypical symptoms served as control group.

RESULTS

The cohort of irradiated patients without classical cardiovascular risk factors is younger (48.7 ± 10.1 vs 60.5 ± 10.8 years, p < 0.001) and presents a lower percentage of males when compared with the control group. In this latter group 25.9% of subjects has diabetes, 62.9% dyslipidaemia, 67.4% hypertension and 19.2% actively smoke. Despite this important differences regarding classic cardiovascular risk factors, no significant differences were found in the number of positive exercise stress electrocardiography (10.4 vs 5.9%, p = ns).

CONCLUSIONS

Chest irradiation represents a strong cardiovascular risk factor. In fact, prevalence of positive ECG-stress test is not different (nor higher and nor lower) in irradiated subjects without cardiovascular risk and not irradiated patients with classic cardiovascular risk.

Diagnosis and management of silent coronary ischemia in patients undergoing carotid endarterectomy

BACKGROUND

Coronary artery disease is the primary cause of death in patients with carotid artery disease and silent ischemia is a marker for adverse coronary events. A new noninvasive cardiac diagnostic test, coronary computed tomography-derived fractional flow reserve (FFR_CT) can reliably identify ischemia-producing coronary stenosis in patients with coronary artery disease and help to select patients for coronary revascularization. The purpose of this study is to determine the prevalence of silent coronary ischemia in patients undergoing carotid endarterectomy (CEA) and to evaluate the usefulness of FFR_CT in selecting patients for coronary revascularization to decrease cardiac events and improve survival.

METHODS

Patients with no cardiac history or symptoms admitted for elective CEA were enrolled in a prospective, open-label, institutional review board-approved study and underwent preoperative coronary computed tomography angiography (CTA) and FFR_CT with results available to physicians for patient management. Lesion-specific coronary ischemia was defined as FFR_CT of 0.80 or less distal to a focal coronary stenosis with an FFR_CT of 0.75 or less, indicating severe ischemia. Primary end point was incidence of major adverse cardiovascular events (MACE; defined as cardiovascular death, myocardial infarction, or stroke) at 30 days and 1 year.

RESULTS

Coronary CTA and FFR_CT was performed in 90 CEA patients (age 67 ± 8 years; male 66%). Lesion-specific coronary ischemia was found in 51 patients (57%) with a mean FFR_CT of 0.71 ± 0.14. Severe coronary ischemia was present in 39 patients (43%), 26 patients had multivessel ischemia, and 5 had left main disease. CEA was performed as scheduled in all patients with no postoperative deaths or myocardial infarctions. There were no MACE events at 30 days. After recovery from surgery, 36 patients with significant lesion-specific ischemia underwent coronary angiography with coronary revascularization (percutaneous coronary intervention or coronary artery bypass grafting) in 30 patients (33%). Survival at 1 year was 100% and freedom from MACE was 98%.

CONCLUSIONS

Patients undergoing CEA have a high prevalence of unsuspected (silent) coronary ischemia, which may place them at risk for coronary events. Preoperative diagnosis of silent ischemia using CTA and FFR_CT can identify high-risk patients and help to guide patient management. Selective postoperative coronary revascularization of patients with significant ischemia may decrease the risk of cardiac events and improve survival, but longer follow-up is needed and prospective, controlled trials are indicated.

Effects of silent myocardial ischemia on functional fitness and physical independence in 60–79-year-old adults

Objective

Methods

Results

Conclusion

Reprint of "Electrocardiographic definition of silent myocardial infarction in population studies: A call to standardize the standards"

According to the American Heart Association, 170,000 new silent myocardial infarctions (SMI) occur annually in the United States. Prior studies from the general population also have shown that SMI is common, but the rates varied widely. Some studies reported SMI rates as low as 4% while others reported rates as high as 57% of the total MIs. Reports on the prognostic significance of SMI compared to clinically recognized MI also have been inconsistent. Although SMI could be detected using cardiac imaging, electrocardiogram (ECG) has been the most common method for detection of SMI in both clinical and research settings due to it is low-cost and wide availability. This report highlights certain ECG methodological aspects that need to be taken into consideration when interpreting findings from population studies addressing SMI. Examples from population studies will be used in this report to show how deviation and differences in applications of the ECG standard definitions of SMI, ECG processing methods, and the frequency of ECG recording in population studies could impact the results, which may explain the wide range of rates and inconsistent conclusions about the prognostic significance of SMI. A summary of the gaps in knowledge of the SMI research is provided. By highlighting the lack of uniform approach in defining SMI despite the availability of standard definitions and pointing out the gaps in knowledge, it is hoped that a call for standardizing the use of the current standards will emerge.

Risk stratification for coronary artery disease in multi-ethnic populations: Are there broader considerations for cost efficiency?

Coronary artery disease (CAD) screening and diagnosis are core cardiac specialty services. From symptoms, autopsy correlations supported reductions in coronary blood flow and dynamic epicardial and microcirculatory coronaries artery disease as etiologies. While angina remains a clinical diagnosis, most cases require correlation with a diagnostic modality. At the onset of the evidence building process much research, now factored into guidelines were conducted among population and demographics that were homogenous and often prior to newer technologies being available. Today we see a more diverse multi-ethnic population whose characteristics and risks may not consistently match the populations from which guideline evidence is derived. While it would seem very unlikely that for the majority, scientific arguments against guidelines would differ, however from a translational perspective, there will be populations who differ and importantly there are cost-efficacy questions, e.g., the most suitable first-line tests or what parameters equate to an adequate test. This article reviews non-invasive diagnosis of CAD within the context of multi-ethnic patient populations.

Cardiovascular magnetic resonance imaging in the prospective, population-based, Hamburg City Health cohort study: objectives and design

BACKGROUND

The purpose of this work is to describe the objectives and design of cardiovascular magnetic resonance (CMR) imaging in the single center, prospective, population-based Hamburg City Health study (HCHS). The HCHS aims at improving risk stratification for coronary artery disease (CAD), atrial fibrillation (AF) and heart failure (HF).

METHODS

The HCHS will finally include 45,000 inhabitants of the city of Hamburg (Germany) between 45 and 74 years who undergo an extensive cardiovascular evaluation and collection of biomaterials. Risk-scores for CAD, AF and HF are used to create enriched subpopulations who are invited for CMR. A total number of approximately 12,362 subjects will undergo CMR and incident CAD, AF and HF will be assessed after 6 years follow-up. The standard CMR protocol includes cine-CMR, T1 and T2 mapping, aortic/mitral valve flow measurements, Late gadolinium enhancement, angiographies and measurements of aortic distensibility. A stress-perfusion scan is added in individuals at risk for CAD. The workflow of CMR data acquisition and analyses was evaluated in a pilot cohort of 200 unselected subjects.

RESULTS

The obtained CMR findings in the pilot cohort agree with current reference values and demonstrate the ability of the established workflow to accomplish the objectives of HCHS.

CONCLUSIONS

CMR in HCHS promises novel insights into major cardiovascular diseases, their subclinical precursors and the prognostic value of novel imaging biomarkers. The HCHS database will facilitate combined analyses of imaging, clinical and molecular data ("Radiomics").

Prognostic value of proximal left coronary artery flow velocity detected by transthoracic Doppler echocardiography

BACKGROUND

Lesions in the proximal left coronary artery (LCA) are associated with a poor prognosis compared with other lesional sites. Transthoracic Doppler echocardiography (TTDE) can help to detect proximal LCA flow, and an accelerated coronary flow velocity (CFV) indicates the presence of proximal LCA lesions. This study aimed to investigate the prognostic value of CFV in the proximal LCA measured by TTDE.

METHODS

We enrolled 1472 consecutive hemodynamically stable patients with known or suspected heart disease whose CFV was successfully detected using TTDE accompanied by routine echocardiography between 2008 and 2011. The primary outcome was cardiac death (acute myocardial infarction, heart failure, or sudden cardiac death) and patients were followed up over a median of 6.3 years.

RESULTS

Overall, 42 cardiac deaths (3%) were observed. An increased CFV was significantly associated with the outcome in several models based on potential confounders (age, rate pressure product, Framingham Risk Score, diabetes, coronary artery disease, hemoglobin, brain natriuretic peptide, estimated glomerular filtration rate, left ventricular mass, left ventricular ejection fraction, and E/e'). Using a receiver operating characteristic curve analysis, the optimal cut-off value for the CFV to the association of the outcome was 37 cm/s (area under the curve, 0.70; sensitivity, 82%; specificity, 62%). In sequential Cox proportional hazards models, the CFV added incremental prognostic information to the clinical and basic echocardiographic parameters (chi-squared: 110.7 to 146.6, P < 0.01).

CONCLUSIONS

An increased CFV in the proximal LCA was associated with cardiac death, incremental to the clinical and basic echocardiographic parameters.

Acute coronary syndrome in the oncology patient: An avoidable event?

5-Fluorouracil is a first-line agent in several cancer-therapy regimens. Cardiotoxicity is common, with coronary artery disease being an important risk factor. We report the case of an acute coronary syndrome presumably induced by 5-FU, in a patient with previously unknown and asymptomatic coronary artery disease, with an estimated intermediate risk for cardiovascular events. Pre-chemotherapy risk evaluation and optimal patient care are still not standardized in this clinical scenario.

Hospital-Confirmed Acute Myocardial Infarction: Prehospital Identification Using the Medical Priority Dispatch System

Introduction

Early recognition of an acute myocardial infarction (AMI) can increase the patient’s likelihood of survival. As the first point of contact for patients accessing medical care through emergency services, emergency medical dispatchers (EMDs) represent the earliest potential identification point for AMIs. The objective of the study was to determine how AMI cases were coded and prioritized at the dispatch point, and also to describe the distribution of these cases by patient age and gender.

Hypothesis/Problem

No studies currently exist that describe the EMD’s ability to correctly triage AMIs into Advanced Life Support (ALS) response tiers.

Methods

The retrospective descriptive study utilized data from three sources: emergency medical dispatch, Emergency Medical Services (EMS), and emergency departments (EDs)/hospitals. The primary outcome measure was the distributions of AMI cases, as categorized by Chief Complaint Protocol, dispatch priority code and level, and patient age and gender. The EMS and ED/hospital data came from the Utah Department of Health (UDoH), Salt Lake City, Utah. Dispatch data came from two emergency communication centers covering the entirety of Salt Lake City and Salt Lake County, Utah.

Results

Overall, 89.9% of all the AMIs (n=606) were coded in one of the three highest dispatch priority levels, all of which call for ALS response (called CHARLIE, DELTA, and ECHO in the studied system). The percentage of AMIs significantly increased for patients aged 35 years and older, and varied significantly by gender, dispatch level, and chief complaint. A total of 85.7% of all deaths occurred among patients aged 55 years and older, and 88.9% of the deaths were handled in the ALS-recommended priority levels.

Conclusion

Acute myocardial infarctions may present as a variety of clinical symptoms, and the study findings demonstrated that more than one-half were identified as having chief complaints of Chest Pain or Breathing Problems at the dispatch point, followed by Sick Person and Unconscious/Fainting. The 35-year age cutoff for assignment to higher priority levels is strongly supported. The Falls and Sick Person Protocols offer opportunities to capture atypical AMI presentations.

ClawsonJJ, GardettI, ScottG, FivazC, BarronT, BroadbentM, OlolaC. Hospital-confirmed acute myocardial infarction: prehospital identification using the Medical Priority Dispatch System. Prehosp Disaster Med. 2018;33(1):29–35.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Risk factors for silent myocardial ischemia in patients with well-controlled essential hypertension

Silent myocardial ischemia (SMI) is frequently observed in patients with essential hypertension (EH). The major risk factor for SMI is uncontrolled blood pressure (BP), but SMI is also observed in patients with well-controlled BP. To evaluate the prevalence of SMI and the factors associated with SMI in EH patients with well-controlled BP. The medical records of 859 EH patients who underwent simultaneous 24-h ambulatory blood pressure monitoring (ABPM) and 24-h ambulatory electrocardiogram recording (AECG) were retrospectively evaluated. Each SMI episode was characterized by: (a) ST segment depression ≥0.5 mm; (b) duration of ST segment depression >60 s; and (c) reversibility of the ST segment depression. Overall 126 EH patients (14.7 %) had at least one episode of SMI. The SMI events were more frequent among patients with poorly controlled compared to those with well-controlled BP [86/479 (17.95 %) vs. 40/380 (10.52 %), p < 0.01]. Among EH patients with well-controlled BP, current and past smoking as well as the presence of an additional metabolic syndrome (MetS) constitutive element (obesity, impaired fasting glucose level or dyslipidemia) were significantly associated with the occurrence of SMI. In all EH patients with well-controlled BP and AECG evidence of SMI, there were one or more coronary artery stenotic lesions greater than 50 % found at coronary angiography. In EH patients who are current smokers, or have one or more additional components of a MetS there is markedly reduced benefit associated with good BP control with regard to the occurrence of myocardial ischemia: in this patient category, an AECG may help detect this condition.

Improvement of Subjective Well-Being by Ranolazine in Patients with Chronic Angina and Known Myocardial Ischemia (IMWELL Study)

Introduction

We aimed to assess if ranolazine would improve angina symptoms among patients with documented myocardial ischemia.

Methods

Eligible subjects had chronic stable angina and at least one coronary stenosis with fractional flow reserve (FFR) ≤0.80 or at least one chronic total occlusion (CTO) without attempted revascularization. Subjects were randomized to oral ranolazine 500 mg twice daily for 1 week, then ranolazine 1000 mg twice daily for 15 weeks versus matching placebo. The primary end point was change in angina at 16 weeks as assessed by the Seattle Angina Questionnaire (SAQ).

Results

Between September 2014 and January 2016, 25 subjects were randomized to ranolazine versus 25 to placebo. The most common reason for eligibility was CTO (72%), while the remainder had myocardial ischemia documented by low FFR. The mean FFR was 0.57 ± 0.12. Sixty-eight percent of subjects were on two or more anti-angina medications at baseline. Study medication was discontinued in 32% (eight of 25) of the ranolazine group versus 36% (nine of 25) of the placebo group. By intention-to-treat, 46 subjects had baseline and follow-up SAQ data completed. Ranolazine was not associated with an improvement in angina compared with placebo at 16 weeks. The results were similar among 33 subjects that completed study medication. The incidence of ischemia-driven hospitalization or catheterization was 12% (three of 25) of the ranolazine group versus 20% (five of 25) in the placebo group (p > 0.05).

Conclusions

In subjects with chronic stable angina and documented myocardial ischemia, ranolazine did not improve angina symptoms at 16 weeks.

Funding

Gilead.

Clinical trial registration

The study was registered at ClinicalTrials.gov (NCT02265796).

Management standards for stable coronary artery disease in India

Coronary artery disease (CAD) is one of the important causes of cardiovascular morbidity and mortality globally, giving rise to more than 7 million deaths annually. An increasing burden of CAD in India is a major cause of concern with angina being the leading manifestation. Stable coronary artery disease (SCAD) is characterised by episodes of transient central chest pain (angina pectoris), often triggered by exercise, emotion or other forms of stress, generally triggered by a reversible mismatch between myocardial oxygen demand and supply resulting in myocardial ischemia or hypoxia. A stabilised, frequently asymptomatic phase following an acute coronary syndrome (ACS) is also classified as SCAD. This definition of SCAD also encompasses vasospastic and microvascular angina under the common umbrella.

Ambulatory monitoring of myocardial ischemia in the 21st century-an opportunity for high frequency QRS analysis

Ambulatory monitoring represents an effective tool for the assessment of silent and transient myocardial ischemia during routine daily activities. Incidence of silent ischemia can provide important prognostic information about patients with coronary artery disease or acute coronary syndrome, as well as about post-myocardial infarction patients. The current technological progress enables development of powerful and miniaturized wearable devices for Holter monitoring. Higher sampling rates, dynamic range, and extended computational and storage capacity allow for considering of more complex methodological solutions such as high-frequency QRS analysis for diagnosing myocardial ischemia. Implementation of suitable methodologies for advanced detection of myocardial ischemia into modern ambulatory monitoring devices creates the potential of making the ambulatory myocardial ischemia monitoring a valuable diagnostic tool in clinical practice.

Cardiovascular Testing in Asymptomatic Patients: Carotid Duplex, Cardiac Stress Testing, Screen for Peripheral Arterial Disease

Approximately one-third of deaths in the United States are from cardiovascular disease. Managing modifiable risk factors is paramount to reducing risk of heart disease and stroke. It is logical to try to identify patients with silent disease that may predispose them to significant morbidity and mortality. Unfortunately, it is unclear if routine screening for the presence of carotid stenosis, coronary artery disease, and peripheral arterial disease is beneficial. Many of these tests are expensive. This review explores the evidence behind screening tests, costs associated with the tests, and the implications of positive screening for each of the 3 listed conditions.

Variability of Automated Intraoperative ST Segment Values Predicts Postoperative Troponin Elevation

BACKGROUND

Intraoperative electrocardiographic monitoring is considered a standard of care. However, there are no evidence-based algorithms for using intraoperative ST segment data to identify patients at high risk for adverse perioperative cardiac events. Therefore, we performed an exploratory study of statistical measures summarizing intraoperative ST segment values determine whether the variability of these measurements was associated with adverse postoperative events. We hypothesized that elevation, depression, and variability of ST segments captured in an anesthesia information management system are associated with postoperative serum troponin elevation.

METHODS

We conducted a single-institution, retrospective study of intraoperative automated ST segment measurements from leads I, II, and III, which were recorded in the electronic anesthesia record of adult patients undergoing noncardiac surgery. The maximum, minimum, mean, and SD of ST segment values were entered into logistic regression models to find independent associations with myocardial injury, defined as an elevated serum troponin concentration during the 7 days after surgery. Performance of these models was assessed by measuring the area under the receiver operator characteristic curve. The net reclassification improvement was calculated to quantify the amount of information that the ST segment values analysis added regarding the ability to predict postoperative troponin elevation.

RESULTS

Of 81,011 subjects, 4504 (5.6%) had postoperative myocardial injury. After adjusting for patient characteristics, the ST segment maximal depression (e.g., lead I: odds ratio [OR], 1.66; 95% confidence interval [CI], 1.26-2.19; P = 0.0004), maximal elevation (e.g., lead I: OR, 1.70; 95% CI, 1.34-2.17; P < 0.0001), and SD (e.g., lead I: OR, 0.16; 95% CI, 0.06-0.42; P = 0.0002) were found to have statistically significant associations with myocardial injury. Increased SD was associated with decreased risk when accounting for the maximal amount of ST segment depression and elevation and for patient characteristics. The ST segment summary statistics model had fair discrimination, with an area under the receiver operator characteristic curve of 0.71 (95% CI, 0.68-0.73). Addition of ST segment data produced a net reclassification improvement of 0.0345 (95% CI, 0.00016-0.0591; P = 0.0474).

CONCLUSIONS

Analysis of automated ST segment values obtained during anesthesia may be useful for improving the prediction of postoperative troponin elevation.

CT angiography of the lower extremity and coronary arteries using 256-section CT: a preliminary study

AIM

To investigate the possible use of a 256-section computed tomography (CT) prospective electrocardiography (ECG)-gated wide volume scanning protocol for combined angiography of the lower extremity and coronary arteries, after a single injection of contrast medium, in patients with lower extremity peripheral arterial disease (PAD).

MATERIALS AND METHODS

Thirty-four patients with suspected PAD underwent CT angiography (CTA) with a prospective ECG-gated protocol that covered the level of the tracheal bifurcation to the foot sole. Digital subtraction angiography (DSA) of the lower extremity arteries was performed on patients requiring therapeutic intervention. Image quality and stenosis of the coronary and lower extremity arteries were assessed.

RESULTS

A total of 93.1% of the coronary segments were adequate for diagnosis. 17 (50%) patients showed coronary artery stenosis ≥50%. A total of 95.8% of the lower extremity arterial segments were adequate for diagnosis. Twenty-eight patients with severe lower extremity arterial stenosis or occlusion underwent DSA. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTA for the detection of significant lower arterial stenosis (≥50%) was 94.8%, 97.2%, 95.3%, 96.9%, and 96.3%, respectively.

CONCLUSION

Using the prospective ECG-gated wide volume CTA protocol, images of the coronary and lower extremity arteries suitable for diagnosis can be acquired simultaneously after a single injection of contrast agent. In addition to accurately diagnosing PAD, combined angiography may be used to screen for coronary heart disease in patients with PAD.

A Cohort Study of Myocardial Perfusion Imaging in Veteran Patients Without Symptoms: Contributing Factors and Results of Testing

Myocardial perfusion imaging (MPI) is commonly used to detect ischemia. Concerns about silent ischemia may encourage orders for MPI in asymptomatic patients. Factors contributing to this practice are poorly described and the clinical utility is questionable.We conducted a single center retrospective cohort investigation on Veterans who underwent MPI between December 2010 and July 2011. We gathered data on symptoms, baseline characteristics, results of MPI, and cardiovascular events within 1 year. MPI were categorized using 2009 appropriate use criteria (AUC).Of 592 patients, 127 (21.5%) had no symptoms at the time of MPI. Comparing symptomatic and asymptomatic patients, no differences were observed in baseline characteristics except abnormal ECG, more common in asymptomatic patients (n = 86, 67.7% vs. n = 232, 49.9% for symptomatic patients, P < 0.0001). Asymptomatic MPI were more commonly inappropriate (n = 26, 21.5% vs. n = 31, 6.7% for appropriate/uncertain, P < 0.0001). Detection of ischemia between patients with and without symptoms was not different (P = 0.86); however, among asymptomatic MPI that also demonstrated ischemia, none were inappropriate (n = 10 appropriate, n = 7 uncertain). In multivariate regression, 2 factors were associated with asymptomatic status, abnormal ECG (odds ratio [OR] 2.29, 95% confidence interval [CI] 1.5-3.49) and age over the median (OR 0.63, 95% CI: 0.41-0.95).A substantial portion of MPI tests are ordered for patients without symptoms. When compared to symptomatic patients, MPI for asymptomatic patient were more commonly inappropriate; however, the prevalence of ischemia was similar. MPI may be clinically relevant in some asymptomatic patients and decisions to test should be based on the AUC.

The ischaemic constellation: an alternative to the ischaemic cascade-implications for the validation of new ischaemic tests

The ischaemic cascade is the concept that progressive myocardial oxygen supply-demand mismatch causes a consistent sequence of events, starting with metabolic alterations and followed sequentially by myocardial perfusion abnormalities, wall motion abnormalities, ECG changes, and angina. This concept would suggest that investigations that detect expressions of ischaemia earlier in the cascade should be more sensitive tests of ischaemia than those that detect expressions appearing later in the cascade. However, careful review of the studies on which the ischaemic cascade is based suggests that the ischaemic cascade concept may be less well supported by the literature than assumed. In this review we explore this, discuss an alternative method for conceptualising ischaemia, and discuss the potential implications of this new approach to clinical studies and clinical practice.

Usefulness of the integrated scoring model of treadmill tests to predict myocardial ischemia and silent myocardial ischemia in community-dwelling adults (from the Rancho Bernardo study)

To investigate the association between analyses of submaximal treadmill exercise test (TMT) and long-term myocardial ischemia (Mis) and silent Mis in community-dwelling older adults, 898 Rancho Bernardo Study participants (mean age 55 years) without coronary heart disease underwent TMT and were followed up to 27 years. The main outcome measures are incidence of Mis and silent Mis. During follow-up, 97 Mis and 103 silent Mis events occurred. We measured ST change, inability to achieve target heart rate, abnormal heart rate recovery (HRR), and chronotropic incompetence (ChI). Each parameter was a significant predictor for Mis and silent Mis. An integrated scoring model was based on these 4 parameters and defined as sum of numbers of abnormal parameters. After multiple adjustments, an integrated scoring model independently predicted Mis and silent Mis. The incidence rates of abnormalities of parameters are 36.5% for 1 abnormality, 9.1% for 2 abnormalities, and 2.0% for 3 or 4 abnormalities. Compared with those with normal results, participants with 1 or 2 abnormalities had significantly increased risk for Mis (hazard ratio [HR] 1.79 or 2.34, respectively) and silent Mis (HR 1.80 or 2.64, respectively). Participants with 3 or more positive findings showed an even greater risk for Mis (HR 7.96 [3.02 to 21.00]) and silent Mis (HR 3.22 [0.76 to 13.60]). In conclusion, ST change, ChI, abnormal HRR, inability to achieve target heart rate, and integrated scoring model of TMT were independent predictors of long-term Mis and silent Mis in an asymptomatic middle-aged population. Management of ChI or abnormal HRR in an asymptomatic population may prevent future ischemic heart disease and thus improve the quality of life.

Ultrasound molecular imaging of transient acute myocardial ischemia with a clinically translatable P- and E-selectin targeted contrast agent: correlation with the expression of selectins

OBJECTIVE

The diagnosis of acute coronary syndrome remains challenging especially in patients without clear symptoms or electrocardiographic and/or biomarker features. A hallmark of ischemia/reperfusion is activation of endothelial cells leading to altered expression of molecular markers, including selectins. In this context, we aimed to validate the value of ultrasound molecular imaging for detecting transient myocardial ischemia by using a clinically translatable dual P- and E-selectin-targeted ultrasound contrast agent (UCA) and microbubble (MB(selectin)).

MATERIAL AND METHODS

Transient (20 minutes) myocardial ischemia of rat heart was produced by ligation of the left anterior descending coronary artery ligation followed by 2-, 5-, or 24-hour reperfusion. Imaging of the transient ischemic event was achieved by the use of MB(selectin). Performance of this clinically translatable targeted UCA was compared with that of antibody-targeted streptavidin MBs. Finally, immunohistochemistry staining of rat myocardial ischemic tissue was performed to assess expression of selectins accessible to targeted UCA.

RESULTS

In rats subjected to myocardial ischemia (20 minutes) followed by reperfusion (2 hours), injection of MB(selectin) produced high late phase (ie, 10-minute postinjection) ultrasound molecular imaging enhancement in the myocardium, which colocalized with the ischemic area. Late phase enhancement persisted 5 and 24 hours after reperfusion. Similarly, the use of MBP and MBE, comprising antibodies specific for P- and E-selectin, respectively, showed high late-phase enhancement within the ischemic area compared with remote myocardial tissue. Two and 5 hours after ischemia has resolved, a persistent expression of these 2 selectins was detected. After 24 hours of reperfusion, only MBE produced late phase enhancement within the ischemic myocardium. Immunohistochemical findings revealed that both P- and E-selectin were expressed and accessible on the surface of the activated endothelium 2 and 5 hours after the acute ischemic event, whereas only E-selectin remained accessible after 24 hours.

CONCLUSIONS

Ultrasound molecular imaging of transient myocardial ischemia using dual selectin-targeted UCA is able to monitor the time course of expression of selectins after resolution of the ischemic event, paving the way for a large clinical diagnostic window.

A novel method to capture the onset of dynamic electrocardiographic ischemic changes and its implications to arrhythmia susceptibility

Background

This study investigates the hypothesis that morphologic analysis of intracardiac electrograms provides a sensitive approach to detect acute myocardial infarction or myocardial infarction‐induced arrhythmia susceptibility. Large proportions of irreversible myocardial injury and fatal ventricular tachyarrhythmias occur in the first hour after coronary occlusion; therefore, early detection of acute myocardial infarction may improve clinical outcomes.

Methods and Results

We developed a method that uses the wavelet transform to delineate electrocardiographic signals, and we have devised an index to quantify the ischemia‐induced changes in these signals. We recorded body‐surface and intracardiac electrograms at baseline and following myocardial infarction in 24 swine. Statistically significant ischemia‐induced changes after the initiation of occlusion compared with baseline were detectable within 30 seconds in intracardiac left ventricle (P<0.0016) and right ventricle–coronary sinus (P<0.0011) leads, 60 seconds in coronary sinus leads (P<0.0002), 90 seconds in right ventricle leads (P<0.0020), and 360 seconds in body‐surface electrocardiographic signals (P<0.0022). Intracardiac leads exhibited a higher probability of detecting ischemia‐induced changes than body‐surface leads (P<0.0381), and the right ventricle–coronary sinus configuration provided the highest sensitivity (96%). The 24‐hour ECG recordings showed that the ischemic index is statistically significantly increased compared with baseline in lead I, aVR, and all precordial leads (P<0.0388). Finally, we showed that the ischemic index in intracardiac electrograms is significantly increased preceding ventricular tachyarrhythmic events (P<0.0360).

Conclusions

We present a novel method that is capable of detecting ischemia‐induced changes in intracardiac electrograms as early as 30 seconds following myocardial infarction or as early as 12 minutes preceding tachyarrhythmic events.

The clinical significance of continuous ECG (ambulatory ECG or Holter) monitoring of the ST-segment to evaluate ischemia: a review

Silent ischemia is a common manifestation of coronary artery disease (CAD). Continuous ECG (cECG) monitoring is an effective tool for assessing the frequency and duration of silent ischemic episodes for patients with CAD and for risk stratifying asymptomatic patients or those after an acute coronary syndrome by identifying those at increased risk for future cardiovascular events or death. cECG also allows monitoring of the effectiveness of therapy in patients with CAD. Treatment strategies targeted toward the elimination of silent ischemia have shown that revascularization was better than medical therapy in eliminating silent ischemia, but large scale, prospective studies targeting silent ischemia as a treatment endpoint are still lacking. Future research is warranted to study the effects of newer medical agents or the selected use of revascularization in those patients with persistent silent ischemia despite current medical regiments.

Prognostic impact of the presence and absence of angina on mortality and cardiovascular outcomes in patients with type 2 diabetes and stable coronary artery disease: results from the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) trial

OBJECTIVES

The purpose of this analysis was to assess in patients with type 2 diabetes and stable coronary artery disease (CAD) whether the risk of all-cause mortality and cardiovascular events varied according to the presence or absence of angina and angina equivalent symptoms.

BACKGROUND

Data on the prognostic value of symptoms in these patients are limited.

METHODS

Post-hoc analysis was performed in 2,364 patients with type 2 diabetes and documented CAD enrolled in the BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) trial to determine the occurrence of death and composite of death, myocardial infarction, and stroke during a 5-year follow-up according to cardiac symptoms at baseline.

RESULTS

There were 1,434 patients with angina (A), 506 with angina equivalents (E), and 424 with neither of these (N). The cumulative death rates (total 316) were 12% in A, 14% in E, and 10% in N (p = 0.3), and cardiovascular composite rates (total 548) were 24% in A, 24% in E, and 21% in N (p = 0.5). Compared with N, the hazard ratios adjusted for confounders were not different for death in A (1.11; 99% CI: 0.81 to 1.53) and E (1.17; 99% CI: 0.81 to 1.68) or for cardiovascular events in A (1.17; 99% CI: 0.92 to 1.50) and E (1.11; 99% CI: 0.84 to 1.48).

CONCLUSIONS

Whatever their symptom status, patients with type 2 diabetes and stable CAD were at similar risk of cardiovascular events and death. These findings suggest that these patients may be similarly managed in terms of risk stratification and preventive therapies. (Bypass Angioplasty Revascularization Investigation 2 Diabetes [BARI 2D]; NCT00006305).

Acute electrocardiographic changes during smoking: an observational study

OBJECTIVE

To study the temporal relationship of smoking with electrophysiological changes.

DESIGN

Prospective observational study.

SETTING

Tertiary cardiac center.

PARTICIPANTS

Male smokers with atypical chest pain were screened with a treadmill exercise test (TMT). A total of 31 such patients aged 49.8±10.5 years, in whom TMT was either negative or mildly positive were included. Heart rate variability (HRV) parameters of smokers were compared to those of 15 healthy non-smoking participants.

INTERVENTIONS

All patients underwent a 24 h Holter monitoring to assess ECG changes during smoking periods.

RESULTS

Heart rate increased acutely during smoking. Mean heart rate increased from 83.8±13.7 bpm 10 min before smoking, to 90.5±16.4 bpm during smoking, (p<0.0001) and returned to baseline after 30 min. Smoking was also associated with increased ectopic beats (mean of 5.3/h prior to smoking to 9.8/h during smoking to 11.3/h during the hour after smoking; p<0.001). Three patients (9.7%) had significant ST-T changes after smoking. HRV index significantly decreased in smokers (15.2±5.3) as compared to non-smoking controls participants (19.4±3.6; p=0.02), but the other spectral HRV parameters were comparable.

CONCLUSIONS

Heart rate and ectopic beats increase acutely following smoking. Ischaemic ST-T changes were also detected during smoking. Spectral parameters of HRV analysis of smokers remained in normal limits, but more importantly geometrical parameter-HRV index-showed significant abnormality.