Introduction: Early Diagnosis and Appropriate Treatment of Atrial Fibrillation.

Atrial fibrillation (AF), the most common sustained arrhythmia, represents a significant burden to patients and healthcare systems. Many patients with AF are asymptomatic and often undiagnosed. Improved detection methods and surveillance have resulted in recognition of asymptomatic and subclinical AF, providing earlier diagnosis. The recent EAST-AFNET 4 and Korean studies have demonstrated early rhythm control (ERC) with antiarrhythmic drugs (AADs) or ablation in patients with AF improves outcomes. The EARLY AF and STOP AF First studies have shown that ERC using ablation can slow AF progression. In the following videos, the authors discuss the evolving AF landscape, with an emphasis on the benefits of early diagnosis and treatment. Historic rate versus rhythm control studies and their limitations are reviewed, followed by recent studies that support the use of ERC alongside usual care including rate control. Discussion of ERC treatment includes the selection of appropriate AADs based on safety, when to choose ablation as first-line therapy, and the complementary use of ablation and AADs. The authors summarize the current guidelines for the use of AADs to treat AF, highlighting the importance of concordance with those guidelines. Patient cases are used to relate the contents of the videos to clinical practice and are supplemented with discussion of the importance of shared decision-making involving the patient in treatment decisions. It is anticipated that this digital publication will enable cardiologists and primary care providers to recognize when early treatment of AF will improve patient outcomes, and to empower them to initiate that treatment accordingly.

Chapter 3: Evidence for the Use of Early Rhythm Control to Prevent Atrial Fibrillation Progression.

This chapter reviews atrial fibrillation (AF) progression and its associated mechanisms, including comorbidities and AF as contributors to atrial myopathy, and atrial myopathy as a contributing factor to AF progression. In addition, the chapter discusses the concept of comorbidities and atrial myopathy as synergistic contributors to adverse outcomes, the notion of "AF begets AF," and the consequences of AF burden if left untreated. Clinical trials evaluating outcomes with antiarrhythmic drugs (AADs) compared with placebo have demonstrated efficacy, but also reveal a possible proarrhythmic and mortality risk if AAD selection is not appropriate and patients are not correctly identified based on risk factors and comorbidities. Data from ATHENA, the first and only trial to demonstrate that an AAD (dronedarone) can reduce cardiovascular (CV) hospitalizations in people with AF, are reviewed, along with studies reporting on the use of catheter ablation versus AADs for AF rhythm control. Finally, recent data showing a reduction in major adverse outcomes if rhythm control is initiated early are summarized, including results from the EAST-AFNET 4 trial, as well as confirmatory results from several large "real-world" trials. Chapter 3 is summarized as follows.

Chapter 4: Evidence for the Early Use of Ablation and AADs Post-Ablation.

Both catheter ablation and antiarrhythmic drugs (AADs) are effective treatments for atrial fibrillation (AF) and can be used individually or as complementary treatments. This chapter discusses the use of ablation for early rhythm control in AF, and the use of AADs post-ablation. Decisions on which therapeutic approach to pursue should be based on shared decision-making with the patient. The chapter reviews data from the CABANA trial, in which the intent-to-treat (ITT) analysis failed to show superiority for ablation versus AADs. Statistical significance was achieved, however, when using the pre-specified per-protocol and pre-treatment analyses. The discussion addresses the fact that data analysis was complicated by several factors: (1) not all members of the group assigned to ablation actually received ablation; (2) the AAD arm included rate control treatment without the use of AADs; (3) there were a large number of crossovers from the AAD arm to the ablation arm; and (4) many ablation-treated participants also used AADs. Results from the CABANA trial showed that ablation was better at preventing AF recurrence than AADs alone. Data from the STOP AF and EARLY AF trials that support the observation of ablation being superior to AADs alone for the reduction of recurrent AF are also reviewed. Many patients who undergo catheter ablation for AF either continue to use or need to restart AADs following ablation. This combination therapy is used by up to 40-50% of people at 1-year post ablation, as is clearly demonstrated by the results from the trials discussed above, in addition to those from the 5A trial, the POWDER AF trial, the AMIO-CAT trial, and a substantial meta-analysis. All these trials are reviewed in this chapter, noting that a variety of differences exist between the randomized clinical trials, including in ablation procedures, follow-up periods, physician experience, and AADs. Chapter 4 is summarized as follows.

Chapter 5: Guideline Recommendations: Which AAD and for Whom?

This chapter discusses the American College of Cardiology/American Heart Association/ Heart Rhythm Society (AHA/ACC/HRS) and European Society of Cardiology (ESC) guidelines for atrial fibrillation (AF) management with particular focus on antiarrhythmic drug (AAD) selection and the identification of individuals for whom AAD treatment is appropriate. Discussion includes AAD indications, when to start an AAD, choosing among AADs, how to minimize proarrhythmic risk, how to determine efficacy, and the use of adjuvant interventions. The indications for all AADs are based on safety; the current AHA/ACC/HRS and ESC guidelines state that the choice of AAD is based on the presence or absence of structural heart disease (SHD), coronary artery disease, or heart failure (HF), with further recommendations in the ESC guidelines based on HF type (e.g., HF with reduced ejection fraction [HFrEF] versus HF with preserved ejection fraction [HFpEF]). The chapter closes with a discussion of the lack of consistent use of guideline-directed care, with a review of supportive data from the recently reported AIM-AF survey-a multinational survey on AF management that involved both cardiologists and electrophysiologists. In AIM-AF, inappropriate drug selection in terms of suitable candidate selection and drug choice occurred with all types of drugs and in most patient groups. Most notable was the overuse of amiodarone in patients without SHD, and the widespread use of sotalol, including its use in patients with HFrEF. Chapter 5 is summarized as follows.

Chapter 6: AAD Use in Different Patient Populations, and a Patient-Centric Approach to Optimal Patient Management.

Associated with longer life expectancy, greater survival of patients with cardiovascular disorders, and increased use of wearable and insertable/implantable devices capable of detection, the frequency of atrial fibrillation (AF) diagnosis is increasing. This chapter describes two representative patient cases that were used to enable a discussion of the evaluation and management of AF in different scenarios. One patient is young and healthy with paroxysmal AF but no major comorbidities (though there is a family history of AF). The other is older with multiple complicating comorbidities. These cases sparked an active discussion among the panelists that demonstrated not only the multitude of considerations when choosing the optimal therapy for each individual, but also the individualistic differences in biases and styles that can exist between experts in the field. The results of these discussions revealed agreement that.

Chapter 1: The Evolving Atrial Fibrillation Landscape: Importance of Early Diagnosis and Treatment.

Chapter 1 begins with data that show the rising prevalence of atrial fibrillation (AF), which is increasing in tandem with the growing number of older adults, increased survival of people who have cardiovascular (CV) disorders, and the expanding use of wearable and insertable/implantable devices capable of detection. Together, these increases will result in healthcare providers seeing more patients with AF who present at earlier stages of the disease. The panel discussion covers information regarding symptoms that are common to patients with AF as well as information about the important adverse outcomes that may occur in patients with AF, including heart failure, hospitalization, thromboembolism, and death. Notably, these events may reflect either the comorbidities commonly underlying AF, AF itself, or a combination of these conditions. The chapter also introduces the four pillars of therapy-"upstream therapy," rate control, rhythm control, and embolic prevention-with an emphasis on early rhythm control as being optimal. Chapter 1 is summarized as follows.

Chapter 2: Rate Versus Rhythm Control.

Atrial fibrillation (AF) is a potentially serious health risk, both because of its symptoms and because of its association with an increased risk for heart failure, hospitalization, thromboembolism, and death. Chapter 2 discusses selection of appropriate treatments and when to initiate these therapies. Older trials focused on comparing rate versus rhythm control treatment options for AF. It is now recognized that both rate and rhythm control are important and can be used together. This chapter reviews the historical, pivotal rate versus rhythm control trials that failed to show any overall survival benefit of rhythm over rate control, as well as the trials' now-recognized limitations with respect to modern therapy. In addition, an in-depth discussion of the more recent trials of antiarrhythmic drugs (AAD) and ablation techniques (which have become available since the original rate versus rhythm trials were performed) is included. These updated trials show that when applied to patient- and disease-specific situations, rhythm control can reduce the risk for mortality and hospitalization. The chapter also reviews the guidelines that have been developed to achieve these goals. Chapter 2 is summarized as follows: (1) Rate control is needed (at rest and during exertion) to reduce rate-related symptoms when rhythm control is ineffective or incomplete and to prevent a tachycardia-induced cardiomyopathy. (2) Previous trials with pharmacological therapy alone comparing rate versus rhythm control using the AADs available at that time failed to show any overall survival benefit of rhythm control over rate control. (3) These earlier trials had many methodological limitations and enrolled participants who did not have access to modern therapies. (4) Newer therapies, including those for stroke prevention, dronedarone (the latest approved AAD), and AF ablation, have improved the safety and efficacy of rhythm control strategies.

Racial/Ethnic Disparities in Atrial Fibrillation Treatment and Outcomes among Dialysis Patients in the United States.

BACKGROUND: Because stroke prevention is a major goal in the management of ESKD hemodialysis patients with atrial fibrillation, investigating racial/ethnic disparities in stroke among such patients is important to those who could benefit from strategies to maximize preventive measures. METHODS: We used the United States Renal Data System to identify ESKD patients who initiated hemodialysis from 2006 to 2013 and then identified those with a subsequent atrial fibrillation diagnosis and Medicare Part A/B/D. Patients were followed for 1 year for all-cause stroke, mortality, prescription medications, and cardiovascular disease procedures. The survival mediational g-formula quantified the percentage of excess strokes attributable to lower use of atrial fibrillation treatments by race/ethnicity. RESULTS: The study included 56,587 ESKD hemodialysis patients with atrial fibrillation. Black, white, Hispanic, and Asian patients accounted for 19%, 69%, 8%, and 3% of the population, respectively. Compared with white patients, black, Hispanic, or Asian patients were more likely to experience stroke (13%, 15%, and 16%, respectively) but less likely to fill a warfarin prescription (10%, 17%, and 28%, respectively). Warfarin prescription was associated with decreased stroke rates. Analyses suggested that equalizing the warfarin distribution to that in the white population would prevent 7%, 10%, and 12% of excess strokes among black, Hispanic, and Asian patients, respectively. We found no racial/ethnic disparities in all-cause mortality or use of cardiovascular disease procedures. CONCLUSIONS: Racial/ethnic disparities in all-cause stroke among hemodialysis patients with atrial fibrillation are partially mediated by lower use of anticoagulants among black, Hispanic, and Asian patients. The reasons for these disparities are unknown, but strategies to maximize stroke prevention in minority hemodialysis populations should be further investigated.

Outcomes of Acute Conduction Abnormalities Following Transcatheter Aortic Valve Implantation With a Balloon Expandable Valve and Predictors of Delayed Conduction System Abnormalities in Follow-up.

Transcatheter aortic valve implantation (TAVI) is an acceptable treatment for severe aortic stenosis in high or intermediate risk patients. Conduction abnormalities are a known complication of TAVI. Most abnormalities occur perioperatively but can develop later. The predictors of delayed conduction abnormalities are unknown. Patients who underwent TAVI at our institution were reviewed. Patients with a pre-existing pacemaker were excluded. Baseline, in-hospital, and 30-day follow-up ECGs were reviewed. Patient and procedural characteristics were analyzed to look for predictors of acute and delayed abnormalities. Ninety-eight patients were included. All valves implanted were balloon expandable, most commonly SAPIEN S3 (78%). Thirty-seven (37.7%) patients developed abnormalities before discharge. Of these patients, 20 (57.1%) had complete resolution at 30-day follow-up. No patients with new conduction abnormalities during hospitalization had additional abnormalities at 30-day follow-up. Five (5.1%) patients developed new conduction abnormalities following discharge. Overall, 22 (22.4%) patients had conduction abnormalities at 30-day follow-up which were not present at baseline. Predilatation (p = 0.003), higher ratios of balloon (p = 0.03) or valve (p = 0.05) size to left ventricular outflow tract, and previous myocardial infarction (p = 0.034) were predictive of acute conduction abnormalities. Baseline right bundle branch block (p = 0.002), longer baseline (p <0.001) and discharge (p = 0.004) QRS duration, moderate, or severe aortic insufficiency (p = 0.002) and atrial fibrillation (p = 0.031) were predictors of new conduction abnormalities after discharge. In conclusion, most new in-hospital conduction abnormalities resolve by 30-day follow-up. In-hospital conduction abnormalities are related to technical aspects of TAVI while delayed conduction abnormalities are related to baseline conduction system disease.

Percutaneous management of ostial stenosis of the left internal mammary artery graft.

A 61-year-old man, who had undergone coronary artery bypass surgery 10 years earlier, presented with a non-ST segment elevation myocardial infarction. He was treated with medical therapy and taken to the Cardiac Catheterization Laboratory. A left heart catheterization demonstrated an ostial stenosis in the left internal mammary artery graft, which was felt to be the culprit lesion. This was successfully repaired with a drug eluting stent. This case is presented as an unusual location for a de novo coronary stenosis. The pathophysiology of these lesions is not well understood.

Clozapine-induced myocarditis.

Approved in 1989 for the management of treatment-resistant schizophrenia, Clozapine is a last-line atypical antipsychotic drug used with increasing frequency. In addition to its well-known side effect of agranulocytosis, this drug also carries with it rare but serious adverse cardiovascular risk of myocarditis. We present a patient on Clozapine who was admitted to the cardiology service with chest pain, ST segment elevations and elevated troponin concerning for acute myocardial infarction. Evaluation with imaging revealed decreased left ventricular function, however, no coronary artery disease was present on catheterization; findings consistent with a diagnosis of myocarditis. Subsequent discontinuation of the patient's Clozapine and initiation of brief supportive medical therapy resulted in full recovery of systolic left ventricular function. Given the potential cardiovascular mortality risk, it is important for physicians on cardiology services caring for psychiatric patients to be aware of the presentation of symptoms, diagnostic findings and management of Clozapine induced myocarditis.

Does CHA2DS2-VASc improve stroke risk stratification in postmenopausal women with atrial fibrillation?

BACKGROUND: Risk stratification of atrial fibrillation patients with a congestive heart failure (C), hypertension (H), age ≥ 75 (A), diabetes (D), stroke or transient ischemic attack (TIA) (S2) (CHADS2) score of <2 remains imprecise, particularly in women. Our objectives were to validate the CHADS2 and congestive heart failure (C), hypertension (H), age ≥ 75 (A2), diabetes (D), stroke, TIA or prior thromboembolic disease (S2)- vascular disease (V), age 65-74 (A), female gender (S) (CHA2DS2-VASc) stroke risk scores in a healthy cohort of American women with atrial fibrillation and to determine whether CHA2DS2-VASc further risk-stratifies individuals with a CHADS2 score of <2. METHODS: We identified a cohort of 5981 women with atrial fibrillation not on warfarin at baseline (mean age 65.9 ± 7.2 years) enrolled in the Women's Health Initiative and followed for a median of 11.8 years. Univariate and multivariate proportional hazards analyses were used to examine these 2 risk scores, with main outcome measures being annualized event rates of ischemic stroke or transient ischemic attack stratified by risk score. RESULTS: Annualized stroke/transient ischemic attack rates ranged from 0.36% to 2.43% with increasing CHADS2 score (0-4+) (hazard ratio [HR] 1.57; 95% confidence interval [CI], 1.45-1.71 for each 1-point increase) and 0.20%-2.02% with increasing CHA2DS2-VASc score (1-6+) (HR 1.50; 95% CI, 1.41-1.60 for each 1-point increase). CHA2DS2-VASc had a higher c statistic than CHADS2: 0.67 (95% CI, 0.65-0.69) versus 0.65 (95% CI, 0.62-0.67), P <.01. For CHADS2 scores <2, stroke risk almost doubled with every additional CHA2DS2-VASc point. CONCLUSIONS: Although both CHADS2, and CHA2DS2-VASc are predictive of stroke risk in postmenopausal women with atrial fibrillation, CHA2DS2-VASc further risk-stratifies patients with a CHADS2 score <2.

Impact of ancestry and common genetic variants on QT interval in African Americans.

BACKGROUND: Ethnic differences in cardiac arrhythmia incidence have been reported, with a particularly high incidence of sudden cardiac death and low incidence of atrial fibrillation in individuals of African ancestry. We tested the hypotheses that African ancestry and common genetic variants are associated with prolonged duration of cardiac repolarization, a central pathophysiological determinant of arrhythmia, as measured by the electrocardiographic QT interval. METHODS AND RESULTS: First, individual estimates of African and European ancestry were inferred from genome-wide single-nucleotide polymorphism (SNP) data in 7 population-based cohorts of African Americans (n=12,097) and regressed on measured QT interval from ECGs. Second, imputation was performed for 2.8 million SNPs, and a genome-wide association study of QT interval was performed in 10 cohorts (n=13,105). There was no evidence of association between genetic ancestry and QT interval (P=0.94). Genome-wide significant associations (P<2.5 × 10(-8)) were identified with SNPs at 2 loci, upstream of the genes NOS1AP (rs12143842, P=2 × 10(-15)) and ATP1B1 (rs1320976, P=2 × 10(-10)). The most significant SNP in NOS1AP was the same as the strongest SNP previously associated with QT interval in individuals of European ancestry. Low probability values (P<10(-5)) were observed for SNPs at several other loci previously identified in genome-wide association studies in individuals of European ancestry, including KCNQ1, KCNH2, LITAF, and PLN. CONCLUSIONS: We observed no difference in duration of cardiac repolarization with global genetic indices of African American ancestry. In addition, our genome-wide association study extends the association of polymorphisms at several loci associated with repolarization in individuals of European ancestry to include individuals of African ancestry.

Risk factors for sudden cardiac death in post-menopausal women.

OBJECTIVES: The aim of this study was to estimate the annual incidence rate of sudden cardiac death (SCD) and to identify risk factors for SCD in post-menopausal women. BACKGROUND: With the aging U.S. population, post-menopausal women now have the greatest population burden of cardiovascular disease including SCD. METHODS: We examined 161,808 women who participated in the Women's Health Initiative clinical trials and observational study. The women were recruited at 40 clinical sites across the United States, enrolled between 1993 and 1998, and followed until August 2009. Our primary endpoint is incident SCD, defined as death occurring within 1 h of symptom onset or within 1 h after the participant was last seen without symptoms and death that occurred in the absence of a potentially lethal non-coronary disease process. RESULTS: Four hundred eighteen women experienced adjudicated SCD. The incidence rate of SCD was 2.4/10,000 women/year (95% confidence interval: 2.2 to 2.7). We identified the following independent risk factors for SCD: older age, African-American race, tobacco use, higher pulse, higher waist-to-hip ratio, elevated white blood cell count, history of heart failure, diabetes, history of myocardial infarction, previous carotid artery disease, and hypertension. Population-attributable fractions were greatest for hypertension, waist-to-hip ratio, and myocardial infarction. CONCLUSIONS: Besides traditional risk factors for coronary heart disease, risk factors for sudden cardiac death in post-menopausal women include African-American race, higher pulse, higher waist-to-hip ratio, elevated white blood cell count, and heart failure. Nearly one-half of women who experienced sudden cardiac death had no previous diagnosis of coronary heart disease.