Embolic Myocardial Infarction as a Consequence of Atrial Fibrillation: A Prevailing Disease of the Future

Use of the CHA2DS2-VASc score to predict subsequent myocardial infarction in atrial fibrillation

BACKGROUND

The risk of subsequent myocardial infarction (MI) varies widely in patients with atrial fibrillation (AF). No convenient scoring system currently exists to identify MI in AF. While each element of the CHA2DS2-VASc (congestive heart failure; hypertension; age ≥75 years [doubled]; type 2 diabetes; previous stroke or thromboembolism [doubled]; vascular disease; age 65-75 years; and sex category) score can increase the likelihood of MI, this retrospective longitudinal study aimed to determine the accuracy of the CHA2DS2-VASc score in predicting subsequent MI risk in AF.

METHODS

A total of 29,341 patients with AF were enrolled and followed up from January 2010 until the first occurrence of MI or until December 2020. The primary endpoint was the occurrence of subsequent MI.

RESULTS

The average age of the study population was 71 years, and 43.2% were male. The mean CHA2DS2-VASc score was found to be higher in patients with AF who had experienced an MI than in those who had not (3.56 ± 1.92 vs. 3.32 ± 1.81, p < 0.001). During the long-term follow-up, the risk of subsequent MI increased by 22% with every one-point increase in the CHA2DS2-VASc score (hazard ratio 1.22, 95% confidence interval 1.19-1.25; p < 0.001). Kaplan-Meier analysis revealed that high CHA2DS2-VASc scores were more likely to experience an MI than those with low CHA2DS2-VASc scores (log-rank p < 0.001). Furthermore, the CHA2DS2-VASc score was a significant predictor of MI in multivariate regression analysis.

CONCLUSION

The CHA2DS2-VASc score is a valuable predictor of subsequent MI risk in patients with AF.

Association Between Stable Coronary Artery Disease and Hospital Readmissions Following Catheter Ablation for Atrial Fibrillation

OBJECTIVE

To evaluate the association of stable coronary artery disease (CAD) with readmission following hospitalization for catheter ablation (CA) for atrial fibrillation (AF).

PATIENTS AND METHODS

Using the Nationwide Readmissions Database, we identified all hospitalizations from the last quarter of 2015 through 2019 with a Medicare Severity-Diagnosis Related Group designation for a percutaneous intracardiac procedure, a procedure code for CA, and a primary discharge diagnosis of AF. Cases of acute coronary syndrome (ACS) at index hospitalization were excluded to define stable CAD. The primary outcome was all-cause 90-day hospital readmission; secondary end points included readmissions for AF, repeated CA, ACS, and heart failure (HF).

RESULTS

Among 28,466 hospitalizations for CA for AF identified, 3171 (11.1%) involved patients with stable CAD. No hospitalizations included patients with HF diagnosis codes. The incidence of 90-day all-cause readmission was higher in patients with stable CAD (18.4% [400 of 2172] vs 14.4% [2549 of 17,667]; P=.006), as was the incidence of subsequent hospitalization with ACS (5.3% [21] vs 1.1% [28]; P<.001) or HF (17.0% [68] vs 10.2% [260]; P=.007). The incidence of readmission within 90 days with recurrent AF did not differ for those with or without stable CAD (21.9% [88] vs 26.5% [675]; P=.217). Pooled analysis of 90-day HF readmissions revealed a higher incidence among older patients, those with chronic kidney or pulmonary disease, and those with persistent and chronic AF subtypes.

CONCLUSION

Results of this large-scale analysis suggest that among patients hospitalized for CA for AF, stable CAD is associated with hospital readmissions within 90 days, including admissions for ACS and decompensated HF.

A Self-Sustaining Antioxidant Strategy for Effective Treatment of Myocardial Infarction

Myocardial infarction (MI) is the leading cause of death worldwide and can lead to the loss of cardiac function and heart failure. Reactive oxygen species (ROS) play a key role in the pathological progression of MI. The levels and effects of ROS are significantly different in three unique pathological stages of MI, and most antioxidants cannot make corresponding adjustments to eliminate ROS, which leads to a great compromise to treat MI with antioxidants. Herein, an innovative self-sustaining antioxidant strategy is developed to treat MI with self-sustaining selenium-embedded nanoparticles (SSSe NPs). SSSe NPs possess unique self-sustaining antioxidant effects at different pathological stages of MI. This strategy of on-demand ROS elimination during different pathological stages demonstrated excellent MI treatment efficacy and effectively reversed heart failure to normal heart function. The therapeutic mechanism of SSSe NPs is intensively investigated through a series of experiments and mainly involved five critical aspects of myocardial repair: protecting mitochondria, reducing cardiomyocyte apoptosis and ferroptosis, reducing inflammation and fibrosis, and promoting angiogenesis. This strategy not only provides a promising treatment option for MI but also offers inspiration for other ischemic diseases.

Pathophysiology and mechanisms of Acute Coronary Syndromes: athero-thrombosis, immune-inflammation and beyond

INTRODUCTION

The pathophysiology of atherosclerosis and its acute complications, such as the Acute Coronary Syndromes (ACS), is continuously under investigation. Immunity and inflammation seem to play a pivotal role in promoting formation and grow of atherosclerotic plaques. At the same time, plaque rupture followed by both platelets' activation and coagulation cascade induction lead to intracoronary thrombus formation. Although these phenomena might be considered responsible of about 90% of ACS, in up to 5-10% of acute syndromes a non-obstructive coronary artery disease (MINOCA) might be documented. This paper gives an overview on athero-thrombosis and immuno-inflammation processes involved in ACS pathophysiology also emphasizing the pathological mechanisms potentially involved in MINOCA.

AREAS COVERED

The relationship between immuno-inflammation and atherothrombosis is continuously updated by recent findings. At the same time, pathophysiology of MINOCA still remains a partially unexplored field, stimulating the research of potential links between these two aspects of ACS pathophysiology.

EXPERT OPINION

Pathophysyiology of ACS has been extensively investigated; however, several grey areas still remain. MINOCA represents one of these areas. At the same time, many aspects of immune-inflammation processes are still unknown. Thus, research should be continued to shed a brighter light on both these sides of "ACS" moon.

Validating an Idiopathic Dilated Cardiomyopathy Diagnosis Using Cardiovascular Magnetic Resonance: The Dilated Cardiomyopathy Precision Medicine Study

BACKGROUND

Coronary angiography to identify coronary artery disease has been foundational to distinguish the cause of dilated cardiomyopathy (DCM), including the assignment of idiopathic or ischemic cardiomyopathy. Late gadolinium enhancement (LGE) with cardiovascular magnetic resonance (CMR) has emerged as an approach to identify myocardial scar and identify etiology.

METHODS

The DCM Precision Medicine Study included patients with left ventricular dilation and dysfunction attributed to idiopathic DCM, after expert clinical review excluded ischemic or other cardiomyopathies. Ischemic cardiomyopathy was defined as coronary artery disease with >50% narrowing at angiography of ≥1 epicardial coronary artery. CMR was not required for study inclusion, but in a post hoc analysis of available CMR reports, patterns of LGE were classified as (1) no LGE, (2) ischemic-pattern LGE: subendocardial/transmural, (3) nonischemic LGE: midmyocardial/epicardial.

RESULTS

Of 1204 idiopathic DCM patients evaluated, 396 (32.9%) had a prior CMR study; of these, 327 (82.6% of 396) had LGE imaging (mean age 46 years; 53.2% male; 55.4% White); 178 of the 327 (54.4%) exhibited LGE, and 156 of the 178 had LGE consistent with idiopathic DCM. The remaining 22 had transmural or subendocardial LGE. Of these 22, coronary angiography was normal (13), showed luminal irregularities (3), a distant thrombus (1), coronary artery disease with <50% coronary artery narrowing (1), or was not available (4).

CONCLUSIONS

Of 327 probands enrolled in the DCM Precision Medicine Study cohort who had LGE-CMR data available, an ischemic-pattern of LGE was identified in 22 (6.7%), all of whom had idiopathic DCM as adjudicated by expert clinical review.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03037632.

Cardiac magnetic resonance imaging unmasks presumed embolic myocardial infarction due to patent foramen ovale case report

Background

Occurrence of paradoxical coronary embolism is reported in up to 10–15% of all myocardial infarctions but embolic infarctions presumed to be as a result of a patent foramen ovale (PFO) are rare. Although rare, it is important to identify these patients as they need appropriate investigations to confirm their diagnosis and guide further treatment.

Case summary

We present the case of a gentleman with troponin positive chest pain with non-obstructed coronaries on invasive coronary angiogram. Subsequent cardiac magnetic resonance imaging (MRI) demonstrated multi-focal myocardial infarctions in several coronary artery territories. Further investigations including echocardiogram were performed in order to identify a cause and source of the embolic infarctions and led to the diagnosis of patent foramen ovale. The patient was treated as myocardial infarction with non-obstructed coronary arteries most likely due to embolic phenomena in the presence of a PFO.

Conclusion

Multiple focal infarctions in multiple coronary artery territories should raise the suspicion of an intra-cardiac shunt. Multi-modality imaging with cardiac MRI and echocardiogram is important in correctly identifying any source of emboli and the diagnosis of any intra-cardiac shunt. Whilst PFO closure is a possible treatment for patients, considerations regarding risk stratification and local provisions needs to be taken into account. Patients should be referred to the appropriate subspecialist to ensure suitable long-term follow-up.

Coronary Embolism despite CHA₂DS₂-VASc Score of Zero: Should We Reconsider Anticoagulation?

Coronary embolism (CE) is a rare but important cause of acute coronary syndrome. The most common source of emboli is considered to be infective endocarditis and atrial fibrillation. Various studies have estimated the prevalence of coronary embolism; however, diagnosis is challenging. Often, it is difficult to differentiate. Nonetheless, this is an important step as treating the underlying cause of an embolism is essential to limit recurrence. However, while this condition may have fatal consequences, due to its uncommon occurrence, there is no consensus on diagnosis and management. We present a case of a 53-year-old obese male, with a history of paroxysmal atrial fibrillation not on anticoagulation due to a low CHA₂DS₂-VASc score, who presented with chest pain associated with lightheadedness. ECG on admission revealed coarse atrial fibrillation, and troponin was gradually elevating on serial lab workup. Coronary angiography revealed a distal left anterior descending artery occlusion with apical wall akinesis without any evidence of atherosclerotic coronary artery disease. A presumptive diagnosis of coronary embolism secondary to paroxysmal atrial fibrillation was made, and the patient was started on anticoagulation despite a low CHA₂DS₂-VASc score. This case not only highlights coronary embolism but also illustrates that a low CHA₂DS₂-VASc score does not mean there is no risk of emboli. For such patients, it is important to take clinical reasoning into account along with the CHA₂DS₂-VASc score to determine the benefit of anticoagulation.

Detection of Myocardial Infarction by Cardiac Magnetic Resonance in Embolic Stroke Related to First Diagnosed Atrial Fibrillation

INTRODUCTION

Elevated troponin levels are found in a significant number of patients who are diagnosed with acute embolic stroke (AES) after first diagnosed atrial fibrillation (AF). These myocardial injuries, which are known as cardiocerebral infarction (CCI), are potentially caused by coronary embolism and correspond to simultaneous cardiac and cerebral embolisms. However, this severe condition remains poorly understood. In this prospective study, we aimed to investigate the prevalence and the cardiac magnetic resonance (CMR) characteristics of CCI.

MATERIALS AND METHODS

Consecutive patients with first diagnosed AF hospitalized for AES in a neurovascular intensive care unit from 2019 to 2020 were included. Troponin Ic kinetic were measured <72 h, MRI and coronary angiography or CT scan were performed <7 days after admission. Patients with significant coronary lesions were excluded.

RESULTS

During the study period, 1150 patients with strokes were hospitalized in the neurovascular intensive care unit (ICU). Of these patients, 955 had an ischemic stroke and 97 had a transient ischemic attack. Among the 44 patients with AES and with first diagnosed AF, 34 patients underwent CMR and CMR analysis identified 12 MI. A significant rise in troponin (>0.10 µg/L) was observed in 35% of the total population (12/34 patients). More specifically, a rise was seen in 23% of the AES without MI group, 58% of the AES with MI. In addition, coronary embolism was identified in 3 patients who underwent coronary angiography (3/12) and MI was often (30%) localized in infero-latero-medial and infero-apical segments. Most AES were localized in the superficial sylvian territory.

CONCLUSION

We found a high prevalence of CMR-confirmed double embolization sites in the acute phase of an embolic stroke. Further studies are required to better characterize the pathophysiology, clinical course and prognostic value of CCI. Moreover, optimal management strategies, including antiplatelet therapy, remain to be determined.

A Ghost in Coronary Artery - Coronary Artery Embolism After Discontinuation of Rivaroxaban in a Patient With Atrial Fibrillation: Case Report and Review of Literature

Coronary artery embolism (CAE) is a rare clinical entity that can cause acute myocardial infarction (AMI). The exact prevalence of coronary artery embolism is unknown. CAE was found to be associated with conditions that can lead to thrombo-embolism, including infective endocarditis, atrial fibrillation, mitral valve disease, valve surgery. Herein, we report a 78-year-old male with a past medical history of atrial fibrillation on rivaroxaban who presented to the hospital emergency department complaining of chest pain. The patient's anticoagulation therapy was recently held due to a concern for gastrointestinal bleeding. After further evaluation of the patient's symptoms and reviewing his electrocardiogram (ECG) which showed ST-depression in lateral leads and ST-elevation in aVR, urgent cardiac catheterization was done which showed left main coronary artery thrombosis extending into the left anterior descending artery (LAD) and left circumflex artery (LCX). The patient was started on a heparin drip and underwent a successful aspiration thrombectomy with subsequent improvement in his symptoms.

Applying the CHA2DS2-VASc score to predict the risk of future acute coronary syndrome in patients receiving catheter ablation for atrial fibrillation

•

AF patients without catheter ablation have a higher risk of future ACS when compared to normal control group.

•

The presence of AF without catheter ablation is an independent risk factor for future acute coronary events.

•

Catheter ablation to AF could reduce future risk of acute coronary events over a very long-term follow-up.

•

The cut-off value of baseline CHA₂DS₂-VASc score ≥ 4 can strongly predict future acute coronary events in patients with AF.

Objective

It remains unknown whether catheter ablation for atrial fibrillation (AF) reduces future acute coronary syndrome (ACS) risk or whether the CHA₂DS₂-VASc score has a role in predicting this risk. We aimed to compare very long-term risk of ACS between patients who received catheter ablation to AF or antiarrhythmic medications and controls without AF.

Methods

Propensity scores were calculated for each patient and used to assemble a cohort of 787 patients undergoing AF ablation in 2003–2012. Patients were compared to an equal number of AF patients treated with antiarrhythmic medications and a control group without AF. Patients with previous coronary events were excluded. The primary endpoint was ACS occurrence.

Results

Baseline clinical characteristics were comparable. After a mean 9.1 ± 3.2-year follow-up, the ablation group had lower incidence of new onset ACS than the medication and non-AF control groups (annual incidence: 0.15%. 0.78%, and 0.35%; with 2.67, 4.16, and 10.44 cases/1000 person-years, respectively; P < 0.001). After adjusting for multiple confounders, the ablation group had lower future ACS risk than the medication (hazard ratio [HR]: 0.20, 95% confidence interval [CI]: 0.13–0.30) and control groups (HR: 0.30, 95% CI: 0.20–0.45). The CHA₂DS₂-VASc score was a strong predictor of ACS (HR: 1.61, 95% CI: 1.47–1.76; AUC: 85.9%, 95% CI: 78.5–93.2%). A baseline CHA₂DS₂-VASc score ≥ 4 predicted future ACS (positive predictive rate: 14.3%).

Conclusions

This study suggested that catheter ablation for AF may be beneficial to reduce future ACS risk in AF patients, and a high baseline CHA₂DS₂-VASc score can predict future acute coronary events.

Embolic myocardial infarction. Literature review and own research results

Patients with embolic myocardial infarction (MI) represent a high-risk group and, accordingly, require special attention of clinicians. This article discusses the most common causes of MI, related diagnostic criteria, antithrombotic therapy, and myocardial revascularization in this category of patients. The data of own clinical experience are also given.

[Myocardial Infarction in the Group of Patients With Atrial Fibrillation]

Prevalence of patients with myocardial infarction (MI) and atrial fibrillation (AF) has been growing every year. These patients represent a highest risk group and, thus, require special attention of clinicians. The article foсused on mechanisms of the AF and MI interaction, special aspects of prediction depending on the type of AF and MI, and the issue of antithrombotic therapy in this patient category. A group of AF-associated, embologenic MIs was isolated, and diagnostic criteria and therapeutic regimens were provided.

Targeted anti-IL-1β platelet microparticles for cardiac detoxing and repair

An acute myocardial infarction (AMI) induces a sterile inflammatory response that facilitates further heart injury and promotes adverse cardiac remodeling. Interleukin-1β (IL-1β) plays a central role in the sterile inflammatory response that results from AMI. Thus, IL-1β blockage is a promising strategy for treatment of AMI. However, conventional IL-1β blockers lack targeting specificity. This increases the risk of serious side effects. To address this problem herein, we fabricated platelet microparticles (PMs) armed with anti-IL-1β antibodies to neutralize IL-1β after AMI and to prevent adverse cardiac remodeling. Our results indicate that the infarct-targeting PMs could bind to the injured heart, increasing the number of anti-IL-1β antibodies therein. The anti-IL-1β platelet PMs (IL1-PMs) protect the cardiomyocytes from apoptosis by neutralizing IL-1β and decreasing IL-1β-driven caspase-3 activity. Our findings indicate that IL1-PM is a promising cardiac detoxification agent that removes cytotoxic IL-1β during AMI and induces therapeutic cardiac repair.

Coronary Embolism and Myocardial Infarction: A Scoping Study

Coronary embolism is a cause of acute myocardial infarction (AMI)in which obstructive foci enter the coronary circulation, block normal blood flow and precipitate ischemia. Precise studies focusing on patient population affected, pathophysiological mechanisms, and treatment strategies are scanty, in spite of a reported prevalence estimated at 2.9%. As the understanding of myocardial infarction without evidence of coronary artery disease continues to grow, an in-depth review of this previously seldomly reported subtype of coronary ischemia was in order. Patients suffering coronary embolism are 15 to 20 years younger than traditional AMI patients with a slight predominance towards male sex, which resembles the gender data of the populations affected by non-traditional myocardial infarction in published reports. While the expected prevalence rate of cardiovascular disease risk factors such as hypertension and hyperlipidemia are present, this population also has a relatively high prevalence of atrial fibrillation and valve pathology, especially endocarditis. Initial presentation is indistinguishable from other causes of myocardial infarction however fever is commonly present, when endocarditis with valvular involvement is the primary cause of the coronary embolism. Mechanical thrombectomy is the mainstay of treatment, followed by percutaneous coronary intervention. Mortality is the highest in patients who do not receive targeted treatment for the coronary embolism, particularly if only antimicrobial agents or anticoagulation without thrombolytic agents are employed. The unique features of coronary embolism highlighted in this historical study justify further examination in contemporary patient populations.

Paroxysmal atrial fibrillation presenting as anterior wall STEMI in an elderly woman

A 77-year-old woman without traditional risk factors for coronary artery disease (CAD) underwent coronary CT-angiography for evaluation of palpitations after negative Holter monitoring and non-diagnostic ECG exercise stress test. Coronary artery calcium score was reported zero; 1 day later, she was admitted with anterior-wall ST elevation myocardial infarction. Acute left anterior descending artery thrombus was treated with mechanical thrombectomy and Percutaneous Coronary Intervention (PCI). Interestingly, the coronary arteries were angiographically normal. During hospitalisation, paroxysmal atrial fibrillation was noted followed by initiation of anticoagulation. Echocardiogram did not show thrombus or atrial shunt. Cardioversion with Sotalol was successful. Myocardial infraction was most likely cardioembolic secondary to paroxysmal atrial fibrillation-consistent with longstanding history of palpitations. Accounting for 3% of acute coronary syndromes, coronary embolism is treated with therapeutic anticoagulation for at least 3 months irrespective of cause and carries a higher risk of adverse cardiovascular events.

The Novel CHA2DS2-VASC-FSH Score is Predictive of Severe Coronary Artery Disease on Coronary Angiography in Patients with Atrial Fibrillation and Unstable Symptoms

Objective

AF may create confusion about the presence of severe or unstable coronary artery disease in cases with unstable symptoms. Novel scores and markers are needed to determine severe coronary artery disease in such patients. We aimed to test the newly developed CHA₂DS₂-VASc-FSH score, developed by adding family history for coronary artery disease, hyperlipidemia, and smoking to the original CHA₂DS₂-VASc score, in the prediction of severe CAD in patients with AF and unstable symptoms.

Materials and Methods

We retrospectively analyzed 72 patients presenting to Başkent Universtiy School of Medicine Hospital between April 2011 and January 2016. The CHA₂DS₂VASc-FSH score was assessed for the prediction of severe CAD.

Results

Seventy-two patients aged 65.7±11.2 years were enrolled. Thirty-five (48.6%) patients had severe CAD and 11 (15.3%) had unstable CAD. patients with severe coronary artery disease had a significantly greater CHA₂DS₂VASC-FSH score (5 (1-8) vs 3(0-7); p<0.05). The CHA₂DS₂VASC-FSH score independently predicted severe CAD, with a CHA₂DS₂VASc-FSH score of 3 or greater having a sensitivity of 77.1% and a specificity of 56.8% for severe CAD.

Conclusion

Among patients with AF and unstable symptoms, the CHA₂DS₂VASc-FSH score independently predicts severe CAD.

California Study of Ablation for Atrial Fibrillation:Re-hospitalization for Cardiac Events (CAABL-CE)

Background

Catheter ablation (ABL) for non-valvular (NV) atrial fibrillation (AF) improves rhythm control. Our aim was to compare re-hospitalization for heart failure (HF), acute coronary syndrome (ACS), or recurrent AF among patients with NVAF who underwent ABL versus controls.

Methods

From the Office of Statewide Planning and Development (OSHPD) database, we identified all patients who had at least one hospitalization for AF between 2005-2013. Patients who subsequently underwent ABL were compared to controls (up to fivematched controls by age, sex and duration of AF between diagnosis and time of ABL). Cases with valve disease, open maze, other arrhythmias, or implanted cardiac devices were excluded. Pre-specified clinical outcomes including readmission for HF, ACS, severe or simple AF (severe = with HF or ACS; simple= without HF or ACS)were assessed using a weighted proportional hazard model adjusting for number of hospital admissions with AF before the ABL, calendar year of ABL, and presence of chronic comorbidities.

Results

The study population constituted 8338 cases and controls, with mean 3.5+ 1 patient-year follow up. In the ABL cohort, there was lower risk of re-hospitalizations for HF, HR=0.55(95%CI: 0.43-0.69,); ACS,HR=0.5(95%CI: 0.35-0.72,); severe AF [HR=0.86 (CI:0.74-0.99), and higher for simple AF, HR=1.25 (CI:1.18-1.33).

Conclusions

In patients with NVAF,although ABL is associated with increased risk of re-hospitalization for simple AF, ABL was associated with a significant reduction in the risk of re-hospitalization for HF, ACS and severe AF. These findingsrequireconfirmation in a prospective clinical trial.

A fluttering coronary event

Acute coronary syndrome (ACS) is a term used to describe a spectrum of diseases associated with sudden reduced blood flow to the heart. Coronary artery thromboembolism is recognized as an important nonatherosclerotic cause of acute myocardial infarctions in 2.9% of ACS cases, with a long-term outcome indicating that coronary embolism patients represent a high-risk subpopulation. There are various risk factors for developing a coronary thromboembolism, with atrial fibrillation being the most frequently reported cause. Herein, we are presenting a case of a 65-year-old female patient who presented to the emergency department with sudden-onset pressure-like chest pain diagnosed as ACS due to nonatherosclerotic thromboembolism secondary to atrial flutter.

Electrocardiogram modeling during paroxysmal atrial fibrillation: application to the detection of brief episodes

OBJECTIVE

A model for simulating multi-lead ECG signals during paroxysmal atrial fibrillation (AF) is proposed.

SIGNIFICANCE

The model is of particular significance when evaluating detection performance in the presence of brief AF episodes, especially since annotated databases with such episodes are lacking.

APPROACH

The proposed model accounts for important characteristics such as switching between sinus rhythm and AF, varying P-wave morphology, repetition rate of f-waves, presence of atrial premature beats, and various types of noise.

MAIN RESULTS

Two expert cardiologists assessed the realism of simulated signals relative to real ECG signals, both in sinus rhythm and AF. The cardiologists identified the correct rhythm in all cases, and considered two-thirds of the simulated signals as realistic. The proposed model was also investigated by evaluating the performance of two AF detectors which explored either rhythm only or both rhythm and morphology. The results show that detection performance is strongly dependent on AF episode duration, and, consequently, demonstrate that the model can play a significant role in the investigation of detector properties.

Predictive value of CHADS2 and CHA2DS2-VASc scores for acute myocardial infarction in patients with atrial fibrillation

The presence of acute myocardial infarction (AMI) confers a poor prognosis in atrial fibrillation (AF), associated with increased mortality dramatically. This study aimed to evaluate the predictive value of CHADS₂ and CHA₂DS₂-VASc scores for AMI in patients with AF. This retrospective study enrolled 5140 consecutive nonvalvular AF patients, 300 patients with AMI and 4840 patients without AMI. We identified the optimal cut-off values of the CHADS₂ and CHA₂DS₂-VASc scores each based on receiver operating characteristic curves to predict the risk of AMI. Both CHADS₂ score and CHA₂DS₂-VASc score were associated with an increased odds ratio of the prevalence of AMI in patients with AF, after adjustment for hyperlipidaemia, hyperuricemia, hyperthyroidism, hypothyroidism and obstructive sleep apnea. The present results showed that the area under the curve (AUC) for CHADS₂ score was 0.787 with a similar accuracy of the CHA₂DS₂-VASc score (AUC 0.750) in predicting “high-risk” AF patients who developed AMI. However, the predictive accuracy of the two clinical-based risk scores was fair. The CHA₂DS₂-VASc score has fair predictive value for identifying high-risk patients with AF and is not significantly superior to CHADS₂ in predicting patients who develop AMI.

Atrial fibrillation is associated with an increased risk of myocardial infarction: Insights from a meta-analysis

BACKGROUND AND AIMS

The presence of atrial fibrillation (AF) markedly increases the risk of stroke and mortality in patients. Whether AF is a risk factor for myocardial infarction (MI) is discrepant from current studies. The aim of this meta-analysis was to ascertain the association of AF with incident MI.

METHODS

Studies were identified through PubMed, CENTRAL, EMBASE, reviews and reference lists of relevant papers. Results of the MI outcome were presented as hazard ratio (HR) and 95% confidence interval (CI). Statistical analyses were performed with Stata 12.0 (Stata Corp LP, College Station, Texas, USA).

RESULTS

Twelve studies, with a total of 169,306 patients, were included in the analysis. AF was associated with a 47% increased risk of MI (HR:1.47; 95% CI: 1.21-1.80; p = 0.000; I² = 84.1%), while in patients free of coronary heart disease at baseline the risk could be increased by 71% (HR:1.71; 95% CI: 1.36-2.14; p = 0.000; I² = 83.1%). Moreover, patients with AF had higher MI risk in the studies with lower mean age (<60 years) (HR:1.66; 95% CI: 1.26-2.20; p = 0.000; I² = 82.9%) than in the studies with higher mean age (≥60 years) (HR:1.35; 95% CI: 1.00-1.82; p = 0.000; I² = 84.9%). Sex difference also existed, and the association between AF and MI was stronger in women (HR:2.02; 95% CI: 1.60-2.56; p = 0.017; I² = 61.0%) than in men (HR:1.44; 95% CI: 1.13-1.84; p = 0.000; I² = 76.1%).

CONCLUSIONS

AF is associated with an increased risk of incident MI, especially in patients free of coronary heart disease at baseline, young patients and women. The findings need confirmation in well-designed observational trials.

Atrial Fibrillation and Myocardial Infarction: A Systematic Review and Appraisal of Pathophysiologic Mechanisms

BACKGROUND

A growing body of evidence suggests that atrial fibrillation (AF) is associated with myocardial infarction (MI). However, incidence and management of MI in AF is still undefined.

METHODS AND RESULTS

We searched MEDLINE via PubMed and Cochrane database between 1965 and 2015. All observational clinical studies and interventional trials reporting 1-year incidence of MI in AF were included. We also discussed pathophysiological mechanisms, predictors, and therapeutic approaches to reduce the risk of MI in AF. Twenty-one observational studies and 10 clinical trials were included. The annual rate of MI in observational studies including AF patients ranged from 0.4% to 2.5%. Higher rates of MI were reported in AF patients with stable coronary artery disease (11.5%/year), vascular disease (4.47%/year), heart failure (2.9%/year), and in those undergoing coronary artery interventions (6.3%/year). However, lower annual rates have been described in AF patients from Eastern countries (0.2-0.3%/year), and in those enrolled in clinical trials (from 0.4 to 1.3%/year).

CONCLUSIONS

AF patients had a significant residual risk of MI despite anticoagulant treatment. Coexistence of atherosclerotic risk factors and platelet activation account for the increased risk of MI in AF. Identification of high-risk AF patients is a needed first step to develop cost-effective approaches for prevention. A new score, the 2MACE score, has been recently developed to stratify MI risk in AF, and may help not only in allocating resources to high-risk groups, but also in design of studies examining novel therapies for prevention of MI in AF.