Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the American Heart Association.

Acute atrial fibrillation is defined as atrial fibrillation detected in the setting of acute care or acute illness; atrial fibrillation may be detected or managed for the first time during acute hospitalization for another condition. Atrial fibrillation after cardiothoracic surgery is a distinct type of acute atrial fibrillation. Acute atrial fibrillation is associated with high risk of long-term atrial fibrillation recurrence, warranting clinical attention during acute hospitalization and over long-term follow-up. A framework of substrates and triggers can be useful for evaluating and managing acute atrial fibrillation. Acute management requires a multipronged approach with interdisciplinary care collaboration, tailoring treatments to the patient's underlying substrate and acute condition. Key components of acute management include identification and treatment of triggers, selection and implementation of rate/rhythm control, and management of anticoagulation. Acute rate or rhythm control strategy should be individualized with consideration of the patient's capacity to tolerate rapid rates or atrioventricular dyssynchrony, and the patient's ability to tolerate the risk of the therapeutic strategy. Given the high risks of atrial fibrillation recurrence in patients with acute atrial fibrillation, clinical follow-up and heart rhythm monitoring are warranted. Long-term management is guided by patient substrate, with implications for intensity of heart rhythm monitoring, anticoagulation, and considerations for rhythm management strategies. Overall management of acute atrial fibrillation addresses substrates and triggers. The 3As of acute management are acute triggers, atrial fibrillation rate/rhythm management, and anticoagulation. The 2As and 2Ms of long-term management include monitoring of heart rhythm and modification of lifestyle and risk factors, in addition to considerations for atrial fibrillation rate/rhythm management and anticoagulation. Several gaps in knowledge related to acute atrial fibrillation exist and warrant future research.

Acute alcohol exposure and electrocardiographic changes: Finding from the HOLIDAY trial.

BACKGROUND: Alcohol consumption is associated with a higher increased risk of atrial fibrillation (AF), but the acute effects on cardiac electrophysiology in humans remain poorly understood. The HOw ALcohol InDuces Atrial TachYarrhythmias (HOLIDAY) Trial revealed that alcohol shortened pulmonary vein atrial effective refractory periods, but more global electrophysiologic changes gleaned from the surface ECG have not yet been reported. METHODS: This was a secondary analysis of the HOLIDAY Trial. During AF ablation procedures, 100 adults were randomized to intravenous alcohol titrated to 0.08% blood alcohol concentration versus a volume and osmolarity-matched, masked, placebo. Intervals measured from 12­lead ECGs were compared between pre infusion and at infusion steady state (20 min). RESULTS: The average age was 60 years and 11% were female. No significant differences in the P-wave duration, PR, QRS or QT intervals, were present between alcohol and placebo arms. However, infusion of alcohol was associated with a statistically significant relative shortening of the JT interval (r: -14.73, p = 0.048) after multivariable adjustment. CONCLUSION: Acute exposure to alcohol was associated with a relative reduction in the JT interval, reflecting shortening of ventricular repolarization. These acute changes may reflect a more global shortening of refractoriness, suggesting immediate proarrhythmic effects pertinent to the atria and ventricles.

Device Therapy and Arrhythmia Management in Left Ventricular Assist Device Recipients: A Scientific Statement From the American Heart Association.

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure with reduced ejection fraction. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common, predispose these patients to additional risk, and complicate patient management. However, there is no consensus on best practices for the medical management of these arrhythmias or on the optimal timing for procedural interventions in patients with refractory arrhythmias. Although the vast majority of these patients have preexisting cardiovascular implantable electronic devices or cardiac resynchronization therapy, given the natural history of heart failure, it is common practice to maintain cardiovascular implantable electronic device detection and therapies after LVAD implantation. Available data, however, are conflicting on the efficacy of and optimal device programming after LVAD implantation. Therefore, the primary objective of this scientific statement is to review the available evidence and to provide guidance on the management of atrial and ventricular arrhythmias in this unique patient population, as well as procedural interventions and cardiovascular implantable electronic device and cardiac resynchronization therapy programming strategies, on the basis of a comprehensive literature review by electrophysiologists, heart failure cardiologists, cardiac surgeons, and cardiovascular nurse specialists with expertise in managing these patients. The structure and design of commercially available LVADs are briefly reviewed, as well as clinical indications for device implantation. The relevant physiological effects of long-term exposure to continuous-flow circulatory support are highlighted, as well as the mechanisms and clinical significance of arrhythmias in the setting of LVAD support.

The QT Interval as a Noninvasive Marker of Atrial Refractoriness.

BACKGROUND: Atrial refractoriness may be an important determinant of atrial fibrillation (AF) risk, but its measurement is not clinically accessible. Because the QT interval predicts incident AF and the atrium and ventricle share repolarizing ion currents, we investigated the association between an individual's QT interval and atrial effective refractory period (AERP). METHODS: In paroxysmal AF patients presenting for catheter ablation, the QT interval was measured from the surface 12-lead electrocardiogram. The AERP was defined as the longest S1-S2 coupling interval without atrial capture using a 600-ms drive cycle length. RESULTS: In 28 patients, there was a positive correlation between QTc and mean AERP. After multivariate adjustment, a 1-ms increase in QTc predicted a 0.70-ms increase in AERP. CONCLUSIONS: The QTc interval reflects the AERP, suggesting that the QTc interval may be used as a marker of atrial refractoriness relevant to assessing AF risk and mechanism-specific therapeutic strategies.

The effect of antiarrhythmic medication management on atrial fibrillation ablation outcomes.

BACKGROUND: Patients commonly present for atrial fibrillation (AF) ablation while taking antiarrhythmic (AA) medications. It is unknown if AA use at the time of ablation affects procedural outcome. This study compares the AF ablation outcomes of patients who underwent ablation while on AA medications to those who were not on AA medications. METHODS AND RESULTS: A total of 180 consecutive patients who underwent their first catheter ablation of AF were identified from the Johns Hopkins Hospital AF registry and divided into 2 cohorts: those On AA at the time of ablation (127 patients, mean follow-up 24.6 months) and those Off AA at the time of ablation (53 patients, mean follow-up 20.3 months). Follow-up was performed to identify recurrent AF. There was no statistically significant difference in the percentage of patients without a recurrence of symptomatic AF (single procedure success rate) in the On and Off AA groups at 6 months postablation (53.5% vs 50.1%, P = 0.75), or by the end of follow-up (37.8% vs 41.5%, P = 0.64). For those patients who had symptomatic AF recurrence, the average time to recurrence was 6.2 ± 9.0 months in the On AA group and 4.2 ± 7.2 months in the Off AA group (P = 0.27). CONCLUSIONS: There was no statistically significant difference in the rate of symptomatic AF recurrence between the On AA and Off AA groups in this study. The use of AA medications at the time of ablation does not appear to affect procedural outcomes in this population.

Increased thrombosis susceptibility and altered fibrin formation in STAT5-deficient mice.

To explore the effect(s) of growth hormone signaling on thrombosis, we studied signal transduction and transcription factor 5 (STAT5)-deficient mice and found markedly reduced survival in an in vivo thrombosis model. These findings were not explained by a compensatory increase in growth hormone secretion. There was a modest increase in the activity of several procoagulant factors, but there was no difference in the rate or magnitude of thrombin generation in STAT5-deficient mice relative to control. However, thrombin-triggered clot times were markedly shorter, and fibrin polymerization occurred more rapidly in plasma from STAT5-deficient mice. Fibrinogen depletion and mixing studies indicated that the effect on fibrin polymerization was not due to intrinsic changes in fibrinogen, but resulted from changes in the concentration of a circulating plasma inhibitor. While thrombin-triggered clot times were significantly shorter in STAT5-deficient animals, reptilase-triggered clot times were unchanged. Accordingly, while the rate of thrombin-catalyzed release of fibrinopeptide A was similar, the release of fibrinopeptide B was accelerated in STAT5-deficient plasma versus control. Taken together, these studies demonstrated that the loss of STAT5 resulted in a decrease in the concentration of a plasma inhibitor affecting thrombin-triggered cleavage of fibrinopeptide B. This ultimately resulted in accelerated fibrin polymerization and greater thrombosis susceptibility in STAT5-deficient animals.

Drug Interactions Affecting Antiarrhythmic Drug Use.

Antiarrhythmic drugs (AAD) play an important role in the management of arrhythmias. Drug interactions involving AAD are common in clinical practice. As AADs have a narrow therapeutic window, both pharmacokinetic as well as pharmacodynamic interactions involving AAD can result in serious adverse drug reactions ranging from arrhythmia recurrence, failure of device-based therapy, and heart failure, to death. Pharmacokinetic drug interactions frequently involve the inhibition of key metabolic pathways, resulting in accumulation of a substrate drug. Additionally, over the past 2 decades, the P-gp (permeability glycoprotein) has been increasingly cited as a significant source of drug interactions. Pharmacodynamic drug interactions involving AADs commonly involve additive QT prolongation. Amiodarone, quinidine, and dofetilide are AADs with numerous and clinically significant drug interactions. Recent studies have also demonstrated increased morbidity and mortality with the use of digoxin and other AAD which interact with P-gp. QT prolongation is an important pharmacodynamic interaction involving mainly Vaughan-Williams class III AAD as many commonly used drug classes, such as macrolide antibiotics, fluoroquinolone antibiotics, antipsychotics, and antiemetics prolong the QT interval. Whenever possible, serious drug-drug interactions involving AAD should be avoided. If unavoidable, patients will require closer monitoring and the concomitant use of interacting agents should be minimized. Increasing awareness of drug interactions among clinicians will significantly improve patient safety for patients with arrhythmias.

A Randomized, Double-Blind, Placebo-Controlled Trial of Intravenous Alcohol to Assess Changes in Atrial Electrophysiology.

OBJECTIVES: This study sought to identify acute changes in human atrial electrophysiology during alcohol exposure. BACKGROUND: The mechanism by which a discrete episode of atrial fibrillation (AF) occurs remains unknown. Alcohol appears to increase the risk for AF, providing an opportunity to study electrophysiologic effects that may render the heart prone to arrhythmia. METHODS: In this randomized, double-blinded, placebo-controlled trial, intravenous alcohol titrated to 0.08% blood alcohol concentration was compared with a volume and osmolarity-matched, masked, placebo in patients undergoing AF ablation procedures. Right, left, and pulmonary vein atrial effective refractory periods (AERPs) and conduction times were measured pre- and post-infusion. Isoproterenol infusions and burst atrial pacing were used to assess AF inducibility. RESULTS: Of 100 participants (50 in each group), placebo recipients were more likely to be diabetic (22% vs. 4%; p = 0.007) and to have undergone a prior AF ablation (36% vs. 22%; p = 0.005). Pulmonary vein AERPs decreased an average of 12 ms (95% confidence interval: 1 to 22 ms; p = 0.026) in the alcohol group, with no change in the placebo group (p = 0.98). Whereas no statistically significant differences in continuously assessed AERPs were observed, the proportion of AERP sites tested that decreased with alcohol (median: 0.5; interquartile range: 0.6 to 0.6) was larger than with placebo (median: 0.4; interquartile range: 0.2 to 0.6; p = 0.0043). No statistically significant differences in conduction times or in the proportion with inducible AF were observed. CONCLUSIONS: Acute exposure to alcohol reduces AERP, particularly in the pulmonary veins. These data demonstrate a direct mechanistic link between alcohol, a common lifestyle exposure, and immediate proarrhythmic effects in human atria. (How Alcohol Induces Atrial Tachyarrhythmias Study [HOLIDAY]; NCT01996943).

Relation Between Ventricular Premature Complexes and Incident Heart Failure.

Ventricular premature complexes (VPCs) may represent a reversible cause of heart failure (HF); however, the type of patients most prone remains unknown. This study leverages a large population-based database to examine interactions that might prove clinically useful in risk-stratifying patients with VPCs. We used the California Healthcare Cost and Utilization Project to identify patients with VPCs and incident systolic HF from January 1, 2005, to December 31, 2009. We calculated hazard ratios for predictors of incident systolic HF using multivariable Cox proportional hazard models. Interactions with known risk factors were studied. Of the 16.8 million patients experiencing 48.1 million hospitalizations, 35,817 (0.2%) had a VPC diagnosis and 198,818 (1.2%) developed systolic HF. Incidence of systolic HF was 62.8 per 1,000 patient-years (95% confidence interval [CI] 61.2 to 64.4) in those with and 6.1 per 1,000 patient-years (95% CI 6.1 to 6.2) in those without VPCs (p <0.001). After adjusting for potential confounders, VPCs were associated with a nearly twofold risk of systolic HF (HR 1.8, 95% CI 1.8 to 1.9, p <0.001). Interaction analyses revealed a stronger relation between VPCs and HF among those with fewer cardiovascular risk factors. A VPC diagnosis in younger patients (<65 years) without coronary artery disease, hypertension, diabetes, or atrial fibrillation exhibited a sixfold increased risk of systolic HF (HR 6.5, 95% CI 5.5 to 7.7, p <0.001). In conclusion, these results suggest that a diagnosis of VPCs independently predicts incident systolic HF. This effect is most pronounced in younger patients without co-morbidities, suggesting that VPCs may be an important cause of "idiopathic" HF.

Alcohol Abuse and Cardiac Disease.

BACKGROUND: Understanding the relationship between alcohol abuse, a common and theoretically modifiable condition, and the most common cause of death in the world, cardiovascular disease, may inform potential prevention strategies. OBJECTIVES: The study sought to investigate the associations among alcohol abuse and atrial fibrillation (AF), myocardial infarction (MI), and congestive heart failure (CHF). METHODS: Using the Healthcare Cost and Utilization Project database, we performed a longitudinal analysis of California residents ≥21 years of age who received ambulatory surgery, emergency, or inpatient medical care in California between 2005 and 2009. We determined the risk of an alcohol abuse diagnosis on incident AF, MI, and CHF. Patient characteristics modifying the associations and population-attributable risks were determined. RESULTS: Among 14,727,591 patients, 268,084 (1.8%) had alcohol abuse. After multivariable adjustment, alcohol abuse was associated with an increased risk of incident AF (hazard ratio [HR]: 2.14; 95% confidence interval [CI]: 2.08 to 2.19; p < 0.0001), MI (HR: 1.45; 95% CI: 1.40 to 1.51; p < 0.0001), and CHF (HR: 2.34; 95% CI: 2.29 to 2.39; p < 0.0001). In interaction analyses, individuals without conventional risk factors for cardiovascular disease exhibited a disproportionately enhanced risk of each outcome. The population-attributable risk of alcohol abuse on each outcome was of similar magnitude to other well-recognized modifiable risk factors. CONCLUSIONS: Alcohol abuse increased the risk of AF, MI, and CHF to a similar degree as other well-established risk factors. Those without traditional cardiovascular risk factors are disproportionately prone to these cardiac diseases in the setting of alcohol abuse. Thus, efforts to mitigate alcohol abuse might result in meaningful reductions of cardiovascular disease.

Ectopy on a Single 12-Lead ECG, Incident Cardiac Myopathy, and Death in the Community.

BACKGROUND: Atrial fibrillation and heart failure are 2 of the most common diseases, yet ready means to identify individuals at risk are lacking. The 12-lead ECG is one of the most accessible tests in medicine. Our objective was to determine whether a premature atrial contraction observed on a standard 12-lead ECG would predict atrial fibrillation and mortality and whether a premature ventricular contraction would predict heart failure and mortality. METHODS AND RESULTS: We utilized the CHS (Cardiovascular Health) Study, which followed 5577 participants for a median of 12 years, as the primary cohort. The ARIC (Atherosclerosis Risk in Communities Study), the replication cohort, captured data from 15 792 participants over a median of 22 years. In the CHS, multivariable analyses revealed that a baseline 12-lead ECG premature atrial contraction predicted a 60% increased risk of atrial fibrillation (hazard ratio, 1.6; 95% CI, 1.3-2.0; P<0.001) and a premature ventricular contraction predicted a 30% increased risk of heart failure (hazard ratio, 1.3; 95% CI, 1.0-1.6; P=0.021). In the negative control analyses, neither predicted incident myocardial infarction. A premature atrial contraction was associated with a 30% increased risk of death (hazard ratio, 1.3; 95% CI, 1.1-1.5; P=0.008) and a premature ventricular contraction was associated with a 20% increased risk of death (hazard ratio, 1.2; 95% CI, 1.0-1.3; P=0.044). Similarly statistically significant results for each analysis were also observed in ARIC. CONCLUSIONS: Based on a single standard ECG, a premature atrial contraction predicted incident atrial fibrillation and death and a premature ventricular contraction predicted incident heart failure and death, suggesting that this commonly used test may predict future disease.

Inappropriate Implantable Cardioverter-Defibrillator Shock from QRS Double Counting in the Setting of Hyperkalemia.

This case shows the complexity of arrhythmia management in patients with implantable cardioverter-defibrillators (ICDs) who present with hyperkalemia. In order to prevent inappropriate ICD shock, consideration should be given to the suspension of ICD therapies while intensive care treatment of extreme electrolyte derangements is being pursued. Patients in these setting should be closely monitored until their electrocardiograms have normalized, after which the device can safely be reactivated.

Access to alcohol and heart disease among patients in hospital: observational cohort study using differences in alcohol sales laws.

OBJECTIVE:  To investigate the relation between alcohol consumption and heart disease by using differences in county level alcohol sales laws as a natural experiment. DESIGN:  Observational cohort study using differences in alcohol sales laws. SETTING:  Hospital based healthcare encounters in Texas, USA. POPULATION:  1 106 968 patients aged 21 or older who were residents of "wet" (no alcohol restrictions) and "dry" (complete prohibition of alcohol sales) counties and admitted to hospital between 2005 and 2010, identified using the Texas Inpatient Research Data File. OUTCOME MEASURES:  Prevalent and incident alcohol misuse and alcoholic liver disease were used for validation analyses. The main cardiovascular outcomes were atrial fibrillation, acute myocardial infarction, and congestive heart failure. RESULTS:  Residents of wet counties had a greater prevalence and incidence of alcohol misuse and alcoholic liver disease. After multivariable adjustment, wet county residents had a greater prevalence (odds ratio 1.05, 95% confidence interval 1.01 to 1.09; P=0.007) and incidence (hazard ratio 1.07, 1.01 to 1.13; P=0.014) of atrial fibrillation, a lower prevalence (odds ratio 0.83, 0.79 to 0.87; P<0.001) and incidence (hazard ratio 0.91, 0.87 to 0.99; P=0.019) of myocardial infarction, and a lower prevalence (odds ratio 0.87, 0.84 to 0.90; P<0.001) of congestive heart failure. Conversion of counties from dry to wet resulted in statistically significantly higher rates of alcohol misuse, alcoholic liver disease, atrial fibrillation, and congestive heart failure, with no detectable difference in myocardial infarction. CONCLUSIONS:  Greater access to alcohol was associated with more atrial fibrillation and less myocardial infarction and congestive heart failure, although an increased risk of congestive heart failure was seen shortly after alcohol sales were liberalized.

Consumption of Caffeinated Products and Cardiac Ectopy.

BACKGROUND: Premature cardiac contractions are associated with increased morbidity and mortality. Though experts associate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) with caffeine, there are no data to support this relationship in the general population. As certain caffeinated products may have cardiovascular benefits, recommendations against them may be detrimental. METHODS AND RESULTS: We studied Cardiovascular Health Study participants with a baseline food frequency assessment, 24-hour ambulatory electrocardiography (Holter) monitoring, and without persistent atrial fibrillation. Frequencies of habitual coffee, tea, and chocolate consumption were assessed using a picture-sort food frequency survey. The main outcomes were PACs/h and PVCs/hour. Among 1388 participants (46% male, mean age 72 years), 840 (61%) consumed ≥1 caffeinated product per day. The median numbers of PACs and PVCs/h and interquartile ranges were 3 (1-12) and 1 (0-7), respectively. There were no differences in the number of PACs or PVCs/h across levels of coffee, tea, and chocolate consumption. After adjustment for potential confounders, more frequent consumption of these products was not associated with ectopy. In examining combined dietary intake of coffee, tea, and chocolate as a continuous measure, no relationships were observed after multivariable adjustment: 0.48% fewer PACs/h (95% CI -4.60 to 3.64) and 2.87% fewer PVCs/h (95% CI -8.18 to 2.43) per 1-serving/week increase in consumption. CONCLUSIONS: In the largest study to evaluate dietary patterns and quantify cardiac ectopy using 24-hour Holter monitoring, we found no relationship between chronic consumption of caffeinated products and ectopy.

Ventricular Ectopy as a Predictor of Heart Failure and Death.

BACKGROUND: Studies of patients presenting for catheter ablation suggest that premature ventricular contractions (PVCs) are a modifiable risk factor for congestive heart failure (CHF). The relationship among PVC frequency, incident CHF, and mortality in the general population remains unknown. OBJECTIVES: The goal of this study was to determine whether PVC frequency ascertained using a 24-h Holter monitor is a predictor of a decrease in the left ventricular ejection fraction (LVEF), incident CHF, and death in a population-based cohort. METHODS: We studied 1,139 Cardiovascular Health Study (CHS) participants who were randomly assigned to 24-h ambulatory electrocardiography (Holter) monitoring and who had a normal LVEF and no history of CHF. PVC frequency was quantified using Holter studies, and LVEF was measured from baseline and 5-year echocardiograms. Participants were followed for incident CHF and death. RESULTS: Those in the upper quartile versus the lowest quartile of PVC frequency had a multivariable-adjusted, 3-fold greater odds of a 5-year decrease in LVEF (odds ratio [OR]: 3.10; 95% confidence interval [CI]: 1.42 to 6.77; p = 0.005), a 48% increased risk of incident CHF (HR: 1.48; 95% CI: 1.08 to 2.04; p = 0.02), and a 31% increased risk of death (HR: 1.31; 95% CI: 1.06 to 1.63; p = 0.01) during a median follow-up of >13 years. Similar statistically significant results were observed for PVCs analyzed as a continuous variable. The specificity for the 15-year risk of CHF exceeded 90% when PVCs included at least 0.7% of ventricular beats. The population-level risk for incident CHF attributed to PVCs was 8.1% (95% CI: 1.2% to 14.9%). CONCLUSIONS: In a population-based sample, a higher frequency of PVCs was associated with a decrease in LVEF, an increase in incident CHF, and increased mortality. Because of the capacity to prevent PVCs through medical or ablation therapy, PVCs may represent a modifiable risk factor for CHF and death.

Paraneoplastic leukemoid reaction as marker for transitional cell carcinoma recurrence.

A case of a 78-year-old man with transitional cell carcinoma and a paraneoplastic leukemoid reaction. The leukocytosis was present at the diagnosis of carcinoma. It dissipated with complete tumor resection, was absent when a surveillance computed tomography scan showed no evidence of recurrence at 6 months, and had returned with tumor recurrence at 8 months. This case demonstrates that a paraneoplastic leukemoid reaction can be used as a tumor marker in cases of transitional cell carcinoma when a leukemoid reaction is found at presentation.