Adequate Rate Control Research Articles

Management of Patients With Atrial Fibrillation (Compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS Recommendations)

This document is a compilation of the current American College of Cardiology Foundation/American Heart Association (ACCF/AHA) practice guideline recommendations for atrial fibrillation (AF) from the “ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation),”* the “2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Updating the 2006 Guideline)”† and the “2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Update on Dabigatran).”‡ Updated and new recommendations from 2011 are noted and outdated recommendations have been removed. No new evidence was reviewed, and no recommendations included herein are original to this document. The ACCF/AHA Task Force on Practice Guidelines chooses to republish the recommendations in this format to provide the complete set of practice guideline recommendations in a single resource. ### 1.1. Pharmacological and Nonpharmacological Therapeutic Options #### 1.1.1. Rate Control During AF Class I 1. Measurement of the heart rate at rest and control of the rate using …

Rate control in atrial fibrillation, insight into the RACE II study

Rate control in atrial fibrillation, insight into the RACE II study

Atrial Fibrillation Through the Years

Information about a real patient is presented in stages (boldface type) to an expert clinician (Dr Valentin Fuster), who responds to the information, sharing his reasoning with the reader (regular type). A discussion by the authors follows. A 61-year-old man presents with 2 weeks of exertional dyspnea. Pertinent medical history includes hypertension, nephrolithiasis, and internal hemorrhoids. He takes no medications and has no known drug allergies. His father died after a myocardial infarction at 57 years of age. He formerly smoked 1 pack of cigarettes daily for 15 years but ceased tobacco use 10 years before presentation. He ingests 2 glasses of alcohol weekly and denies illicit drug use. His caffeine intake is limited. He is an architect and is married, with healthy children. On physical examination, his temperature is 98.0°F, blood pressure is 130/85 mm Hg bilaterally, pulse is irregular at 130 beats per minute, and respiratory rate is 18 breaths per minute with an oxygen saturation of 97% while breathing room air. He is a slender white man in no distress. His jugular venous pressure is elevated at 14 cm H 2 O. There is no thyromegaly, and the carotid upstrokes are brisk, without bruits. Cardiovascular examination reveals a rapid and irregular heart rhythm with variation in the intensity of the first heart sound. The point of maximal impulse is not displaced. The remainder of the chest and abdominal examination is within normal limits. The extremities are warm and show mild pitting edema. Laboratory testing is significant for normal renal function and electrolytes, but a hemogram reveals a mild thrombocytopenia of 90 000 platelets/μL. ECG demonstrates atrial fibrillation (AF) with an average ventricular rate of 123 bpm ( Figure 1 ). Figure 1. The 12-lead ECG showing atrial fibrillation with a rapid ventricular rate. Dr Valentin Fuster : This is a …

Irregular Rhythm Adversely Influences Calcium Handling in Ventricular Myocardium

Background— Despite adequate rate control, the combination of atrial fibrillation with heart failure (HF) has been shown, in a number of studies, to hasten HF progression. In this context, we aimed to test the hypothesis that an irregular ventricular rhythm causes an alteration in ventricular cardiomyocyte excitation–contraction coupling which contributes to the progression of HF. Methods and Results— We investigated the effects of electrical field stimulation (average frequency 2 Hz) in an irregular versus regular drive train pattern on the expression of calcium-handling genes and proteins in rat ventricular myocytes. The effect of rhythm on intracellular calcium transients was examined using Fura-2AM fluorescence spectroscopy. In conjunction, calcium-handling protein expression was examined in left ventricular samples obtained from end-stage HF patients, in patients with either persistent atrial fibrillation or sinus rhythm. Compared with regularly paced ventricular cardiomyocytes, in cells paced irregularly for 24 hours, there was a significant reduction in the expression of sarcoplasmic reticulum calcium (Ca 2+ ) ATPase together with reduced serine-16 phosphorylation of phospholamban. These findings were accompanied by a 59% reduction ( P <0.01) in the peak Ca2+ transient in irregulary paced myocytes compared with those with regular pacing. Consistent with these observations, we observed a 54% ( P <0.05) decrease in sarcoplasmic reticulum Ca 2+ ATPase protein expression and an 85% ( P <0.01) reduction in the extent of phosphorylation of phospholamban in the left ventricular myocardium of HF patients in atrial fibrillation compared with those in sinus rhythm. Conclusions— Together, these data demonstrate that ventricular rhythmicity contributes significantly to excitation–contraction coupling by altering the expression and activity of key calcium-handling proteins. These data suggest that control of rhythm may be of benefit in patients with HF.

Atrial Fibrillation in Long Term Care

Increasing age is a potent risk factor for the development of atrial fibrillation (AF), as well as for incident stroke in patients with AF. The prevalence of AF in long term care facilities ranges from 7.5% to 17%, and such patients often present management challenges due to heightened risk for both stroke and bleeding complications related to thromboprophylaxis. This article reviews the diagnosis and management of AF in long term care. In general, patients with minimal symptoms can be managed with rate-control medications and anticoagulation. Patients with persistent symptoms and impaired quality of life despite adequate rate-control should be considered for cardioversion and antiarrhythmic drug therapy aimed at maintaining sinus rhythm. A small percentage of patients who do not respond to rate-control or rhythm-control interventions may be candidates for a catheter-based or surgical ablative procedure. In most older adults, the benefits of systemic anticoagulation in reducing the risk of stroke outweigh the risk of serious bleeding; therefore, anticoagulation is indicated in the majority of older AF patients, including nursing home residents. Although warfarin remains the preferred agent for stroke prophylaxis in the long term care setting, primarily due to very limited experience with the newer agents dabigatran, rivaroxaban, and apixaban, it is likely that the use of these newer drugs will increase as additional data accumulate documenting their safety and efficacy in AF patients of advanced age.

Catheter Ablation of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with significant morbidity and cost.1 AF is seen across a wide spectrum of patients, from lone AF without structural heart disease, to the postoperative setting, to patients with significant left ventricular dysfunction and advanced heart failure. AF is clinically classified as paroxysmal ( 7 days or requiring intervention to restore sinus rhythm), longstanding persistent (>1 year), or permanent, when restoration of sinus rhythm is no longer pursued.2 The presence of AF is associated with increased mortality, and treatment of patients requires symptom relief and prevention of thromboembolism. Optimal antithrombotic therapy is determined on the basis of stroke risk as predicted by the CHADS2 scoring system (a system that awards 1 point each for congestive heart failure, hypertension, age ≥75 years, and diabetes mellitus and 2 points for prior stroke or transient ischemic attack).3,4 More recently, a modified scoring system, CHA2DS-VASC2, has been shown to improve risk prediction for patients previously thought to be at low risk for thromboembolic events.5 Large-scale randomized trials have not shown mortality reduction with a rhythm control strategy compared with a rate control strategy6; however, many patients continue to have symptoms despite adequate rate control. For these patients, 3 therapeutic options are available for AF: (1) Antiarrhythmic drug therapy, (2) catheter ablation, and (3) surgical intervention (Maze procedure). Antiarrhythmic drug therapy has limited efficacy (40%–60%) and important side effects and has been shown to be less effective than catheter ablation in multiple comparative studies.7 In this Clinician Update, we illustrate current ablation strategies used to treat paroxysmal and persistent AF in the electrophysiology laboratory. A 57-year-old man with a history of hypertension presented with palpitations for 2 …

Optimization of pharmacotherapy in chronic heart failure: is heart rate adequately addressed?

The aim of the study is to evaluate the use of beta-blockers in chronic heart failure (CHF) and the extent of heart rate reduction achieved in clinical practice and to determine differences in outcome of patients who fulfilled select inclusion criteria of the SHIFT study according to resting heart rate modulated by beta-blocker therapy. We evaluated an all-comer population of our dedicated CHF outpatient clinic between 2006 and 2010. For inclusion, individually optimized doses of guideline-recommended pharmacotherapy including beta-blockers had to be maintained for at least 3months and routine follow-up performed at our outpatient CHF-clinic thereafter. Treatment dosages of beta-blockers, and demographic and clinical profiles including resting heart rate were assessed. The outcome of patients who fulfilled select inclusion criteria of the SHIFT study (left-ventricular ejection fraction (LVEF) ≤35%, sinus rhythm, NYHA II-IV) and were followed-up for at least 1year was stratified according to resting heart rates:≥75 versus<75bpm and≥70 versus<70bpm. The composite primary endpoint was defined as all-cause death or hospital admission for worsening heart failure during 12-month follow-up. In total, 3,181 patients were assessed in regard to treatment dosages of beta-blockers, and demographic and clinical profiles including resting heart rate. Of the overall studied population, 443 patients fulfilled all inclusion criteria and entered outcome analysis. Median observation time of survivors was 27.5months with 1,039.7 observation-years in total. Up-titration to at least half the evidence-based target dose of beta-blockers was achieved in 69% and full up-titration in 29% of these patients. Patients with increased heart rates were younger, more often male, exhibited a higher NYHA functional class and lower LVEF. The primary endpoint occurred in 21% of patients in the≥70bpm group versus 9% of patients in the group with heart rates<70bpm (p<0.01). Likewise, comparing the groups≥75 and <75bpm, the primary endpoint was significantly increased in the group of patients with heart rates≥75bpm 27 vs. 12.2%; p<0.01). 5-year event-free survival was significantly lower among patients with heart rates ≥70bpm as compared to those with<70bpm (log-rank test p<0.05) and among patients in the≥75bpm group versus<75bpm group (log-rank test p<0.01). In conclusion, in clinical practice, 53% of CHF patients have inadequate heart rate control (heart rates≥75bpm) despite concomitant beta-blocker therapy. In this non-randomized cohort, adequate heart rate control under individually optimized beta-blocker therapy was associated with improved mid- and long-term clinical outcome up to 5years. As further up titration of beta-blockers is not achievable in many patients, the administration of a selective heart rate lowering agent, such as ivabradine adjuvant to beta-blockers may pose an opportunity to further modulate outcome.

A Common β1-Adrenergic Receptor Polymorphism Predicts Favorable Response to Rate-Control Therapy in Atrial Fibrillation

In this study, we evaluated the impact of 2 common β1-adrenergic receptor (β1-AR) polymorphisms (G389R and S49G) in response to ventricular rate control therapy in patients with atrial fibrillation (AF). Randomized studies have shown that ventricular rate control is an acceptable treatment strategy in patients with AF. However, identification of patients who will adequately respond to rate-control therapy remains a challenge. We studied 543 subjects (63% men; age 61.8 ± 14 years) prospectively enrolled in the Vanderbilt AF registry and managed with rate-control strategy. A "responder" displayed adequate ventricular rate control based on the AFFIRM (Atrial Fibrillation Follow-Up Investigation of Rhythm Management) criteria: average heart rate (HR) at rest ≤80 beats/min; and maximum HR during a 6-min walk test ≤110 beats/min or average HR during 24-h Holter ≤100 beats/min. A total of 295 (54.3%) patients met the AFFIRM criteria. Baseline clinical characteristics were similar in responders and nonresponders except for mean resting HR (76 ± 20 beats/min vs. 70 ± 15 beats/min; p < 0.01) and smoking (6% vs. 1%; p < 0.01). Multiple clinical variables (age, gender, hypertension) failed to predict response to rate-control therapy. By contrast, carriers of Gly variant at 389 were more likely to respond favorably to rate-control therapy; 60% versus 51% in the Arg389Arg genotype, p = 0.04. This association persisted after correction for multiple clinical factors (odds ratio: 1.42, 95% confidence interval: 1.00 to 2.03, p < 0.05). Among responders, subjects carrying the Gly389 variant required the lowest doses of rate-control medications; atenolol: 92 mg versus 68 mg; carvedilol: 44 mg versus 20 mg; metoprolol: 80 mg versus 72 mg; diltiazem: 212 mg versus 180 mg, and verapamil: 276 mg versus 200 mg, respectively (p < 0.01 for all comparisons). We have identified a common β1-AR polymorphism, G389R, that is associated with adequate response to rate-control therapy in AF patients. Gly389 is a loss-of-function variant; consequently, for the same adrenergic stimulation, it produces reduced levels of adenyl cyclase, and hence, attenuates the β-adrenergic cascade. Mechanistically, the effect of rate-control drugs will be synergistic with that of the Gly389 variant, which could possibly explain our findings. These findings represent a step forward in the development of a long-term strategy of selecting treatment options in AF based on genotype.

Exercise Heart Rate Acceleration Patterns during Atrial Fibrillation and Sinus Rhythm

Patients with atrial fibrillation sustain a significant lower exercise tolerance compared to those in sinus rhythm, even while seemingly in adequate rate-control. Exercise testing was performed during atrial fibrillation and after electric cardioversion for 30 patients who were initially treated with AV modifying agents and were considered in adequate rate control. Heart rate parameters were obtained during all exercise stages, and a graphic display of heart rate acceleration was obtained. For those patients who remained in sinus rhythm, an additional exercise test was performed after 1 month. During atrial fibrillation, heart rate at the completion of Bruce stage 1 and the peak exercise heart rate were significantly higher when compared to sinus rhythm (120 ± 10 bpm vs. 98 ± 11 bpm and 164 ± 16 bpm vs. 129 ± 11 bpm respectively, p < 0.001 for both). The time to peak exercise heart rate was significantly shorter during atrial fibrillation (3.5 ± 1 min vs. 6.5 ± 1.5 min, p < 0.001), and the total exercise duration was subsequently shorter as well (6 ± 2 min vs. 8.5 ± 2 min, p < 0.001). Treatment with beta-blockers prior to exercise did not affect the earlier peaking of the heart rate. After 1 month, similar time to peak heart rate and similar exercise performance were observed among patients, who remained in sinus rhythm, when compared to to the post-cardioversion exercise test. In patients with atrial fibrillation, exercise heart rate acceleration displays a specific pattern of early peaking. Earlier heart rate peaking occurs regardless of ample rate control while at rest or mild physical activity and contributes to overall lower exercise performance.

Atrioventricular junction ablation and pacemaker implantation for heart failure associated with atrial fibrillation: potential issues and therapies in the setting of acute heart failure syndrome

Atrial fibrillation is the most common arrhythmia and is especially clinically important in patients with heart failure. Prolonged atrial fibrillation with high ventricular rate response may lead to development or worsening of left ventricular function. If adequate heart rate control cannot be obtained medically, often patients will undergo pacemaker implant and catheter ablation of the atrioventricular junction. This intervention can have profound effects on the course of heart failure. This article reviews the technique, complications, outcome data, and alternatives to this management strategy. The potential role of this therapeutic modality in those hospitalized with acute heart failure syndromes is discussed.

Mixed treatment comparisons for atrial fibrillation: evidence network or bewildering entanglement?

This editorial refers to ‘Mixed treatment comparison of dronedarone, amiodarone, sotalol, flecainide, and propafenone, for the management of atrial fibrillation’ by N. Freemantle et al. , on page 329. Atrial fibrillation (AF) imparts significant morbidity and mortality, affecting more than 6 million patients in Europe alone. The impairment in quality of life attributable to AF is similar to the deficits associated with myocardial infarction or heart failure.1 Current clinical practice guidelines advocate antiarrhythmic therapy for patients with debilitating symptoms despite adequate rate control.2,3 Although successive generations of antiarrhythmic drugs have broadened the array of therapeutic options, rates of AF recurrence and toxicity remain frustrating.4 In 2009, dronedarone became the first antiarrhythmic drug in nearly 2 decades to be approved in the European Union for the treatment of AF. Direct comparisons between dronedarone and other antiarrhythmic agents are limited, creating uncertainty for clinicians. Given the paucity of direct, head-to-head data comparing dronedarone and other antiarrhythmic agents for AF, Freemantle et al .5 analysed outcomes from 40 different randomized-controlled trials of currently available guideline recommended class IC and class III agents (amiodarone, dronedarone, flecainide, propafenone, and sotalol).2 In addition to conventional random-effect meta-analysis models that evaluated only the direct comparisons between drugs, the investigators constructed a model that accommodated both the direct and indirect treatment comparisons within the available data. In direct comparisons, amiodarone had the greatest overall efficacy for the prevention of recurrent AF [odds ratio (OR) 0.15, 95% 0.10–0.22] and was superior to both sotalol and dronedarone. In terms of safety, all of the included …

Pharmacological treatment of persistent atrial fibrillation in the older adult: Evidence-based practice

To answer the clinical question: In adults over 65 years of age with persistent atrial fibrillation (AF), do pharmacological rhythm-control agents offer a lower risk of stroke when compared to pharmacological rate-control agents? To address whether or not rhythm control improves quality of life compared to rate control was a secondary outcome question. Comprehensive review of pharmacological treatment of AF on stroke and quality of life outcomes; a meta-analysis of five randomized controlled trials. Research suggests that all AF patients should continue anticoagulant therapy long term, even if they convert to sinus rhythm. Adequate rate control or rhythm control does not appear to reduce the need for lifelong antithrombotic therapy. While an individualized treatment approach to AF is essential, a strong focus in the care of the older adult with AF should be on maintaining therapeutic International Normalized Ratio (INR) levels. Improved quality of life is more dependent on reducing thromboembolic events and subsequent sequelae of stroke.

Restoration of Impaired Cardiac Function in Patients with Dilated Cardiomyopathy after the Radiofrequency Catheter Ablation of Long-Standing Persistent Atrial Fibrillation with Adequate Ventricular Rate Control

Tachycardia induced cardiomyopathy is a well-known form of reversible cardiac dysfunction; however, the effect of maintaining sinus rhythm by a radiofrequency catheter ablation (RFCA) in patients with impaired cardiac function and adequately rate-controlled atrial fibrillation (AF) is unclear. Six patients (54±9 years old, 5 men) with drug-resistant persistent AF (lasting 21±14 months) combined with dilated cardiomyopathy (DCM) had suffered from heart failure for more than one year in spite of an adequate ventricular rate control (<90 bpm) and intensive medications including angiotensin converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, diuretics, and an amiodarone. All patients underwent the RFCA of AF and were maintained in sinus rhythm during a mean follow-up period of 14±19 months. The left ventricular ejection fraction increased from 32±8% to 60±8%, the left atrial diameter decreased from 50±8 mm to 48±10 mm, and the BNP decreased from 302±166 pg/ml to 56±79 pg/ml at the end of the follow-up period. The RFCA of AF may provide a chance to restore an impaired cardiac function in patients who have already diagnosed as DCM with adequately rate-controlled persistent AF.

Rhythm Control for Management of Patients With Atrial Fibrillation: Balancing the Use of Antiarrhythmic Drugs and Catheter Ablation

Antiarrhythmic drug (AAD) therapy may be beneficial for patients with symptoms attributable to atrial fibrillation despite adequate rate control. The limited long-term efficacy of AAD and the relatively large proportion of patients discontinuing therapy because of side effects led to the development of nonpharmacological therapies to achieve rhythm control. Pressing questions remain about the effect of ablation therapy on long-term patient outcomes. Based on recent clinical trials and meta-analyses, ablation appears more effective and possibly safer than AAD for long-term maintenance of sinus rhythm in selected patients, but the evidence is insufficient to recommend ablation in preference to drug therapy as the first AAD therapy for the majority of patients in whom a rhythm control strategy is justified. Herein, we review the most current evidence supporting the use of AAD and catheter ablation in atrial fibrillation.

Rhythm Control Should Be Better for the Management of Patients With Atrial Fibrillation and Heart Failure - Rhythm Control vs. Rate Control: Which Is Better in the Management of Atrial Fibrillation? (Rhythm-Side) -

The incidence of atrial fibrillation (AF) increases with advancing NHYA cardiac functional class, and it significantly affects the cardiac function of a failing heart. In such situations, clinicians should aim to maintain sinus rhythm in these patients with heart failure (HF) in order to improve their prognosis. However, according to various randomized clinical studies demonstrating the non-superiority of rhythm control over rate control, many clinicians seem to prefer to take the line of least resistance (ie, rate control). Curative catheter ablation mainly based on isolation procedure of the pulmonary veins in patients with AF and HF has demonstrated a significant improvement in left ventricular function, even in the presence of adequate ventricular rate control before the ablation. On the other hand, ablation and biventricular pacing therapy, which is an extreme rate control strategy, has not shown any beneficial effects for these patients. Therefore, a regular RR interval with an appropriate cycle length only is not sufficient to improve cardiac performance, and maintenance of sinus rhythm, which restores atrial contraction and the atrioventricular synchrony, is thought to be essential for an improvement in HF. Thoughtful clinicians should do their best to find a way to keep HF patients in sinus rhythm.

Barrier analysis of periocular drug delivery to the posterior segment

Periocular administration is a potential way of delivering drugs to their targets in posterior eye segment (vitreous, neural retina, retinal pigment epithelium (RPE), choroid). Purpose of this study was to evaluate the role of the barriers in periocular drug delivery. Permeation of FITC-dextrans and oligonucleotides in the bovine sclera was assessed with and without Pluronic gel in the donor compartment. Computational model for subconjunctival drug delivery to the choroid and neural retina/vitreous was built based on clearance concept. Kinetic parameters for small hydrophilic and lipophilic drug molecules, and a macromolecule were obtained from published ex vivo and in vivo animal experiments. High negative charge field of oligonucleotides slows down their permeation in the sclera. Pluronic does not provide adequate rate control to modify posterior segment drug delivery. Theoretical calculations for subconjunctival drug administration indicated that local clearance by the blood flow and lymphatics removes most of the drug dose which is in accordance with experimental results. Calculations suggested that choroidal blood flow removes most of the drug that has reached the choroid, but this requires experimental verification. Calculations at steady state using the same subconconjunctival input rate showed that the choroidal and vitreal concentrations of the macromolecule is 2–3 orders of magnitude higher than that of small molecules. The evaluation of the roles of the barriers augments to design new drug delivery strategies for posterior segment of the eye.

Reverse Electrical Remodeling of the Ventricles Following Successful Restoration of Sinus Rhythm in Patients with Persistent Atrial Fibrillation

Atrial fibrillation (AF) has been shown to be associated with reduced survival and increased ventricular arrhythmogenesis. The purpose of this study was to assess the effects of AF with adequate rate control on the electrophysiologic properties of the ventricles. We hypothesized that AF results in increased ventricular arrhythmogenic risk and that reverse remodeling occurs post-successful cardioversion. In nine patients with persistent AF, we recorded 12-lead electrocardiograms (ECGs) and 1-hour high-resolution Holter ECGs (H12+, Mortara Instrument, Inc. Milwaukee, WI, USA; recorders [1000 sps] immediately following cardioversion (Day 1) and after 30 days of maintaining sinus rhythm (Day 30). We measured QTc, QT dispersion, and calculated estimates of mean ventricular action potential duration (RT), diastolic interval (DI), T-wave width (TW), T-wave peak-to-end, and their respective scatter on Day 1 and Day 30. Maintenance of normal sinus rhythm was confirmed with a weekly trans-telephonic ECG transmission. The average QTc interval decreased from 449 ± 28 ms on Day 1 to 422 ± 36 ms on Day 30 (P = 0.04). There was no significant difference in the average QT dispersion. A significant decrease was also noted in DI and TW scatter at Day 30 when compared with Day 1 (P = 0.03 and 0.04, respectively). A decrease in RT scatter was also noted albeit not statistically significant (P = 0.07). Our results suggest a greater propensity to ventricular arrhythmogenesis in the immediate period following restoration of sinus rhythm and reverse electrical remodeling of the ventricles during the first month after successful maintenance of sinus rhythm. (PACE 2010; 33:1198-1202).

Low-dose diltiazem in atrial fibrillation with rapid ventricular response

Objectives Diltiazem is one of the most commonly used medications to control the rapid ventricular response in atrial fibrillation (AF). The recommended starting dose is an intravenous bolus of 0.25 mg/kg over 2 minutes. To avoid hypotension, we have empirically used a lower dose of diltiazem. We compared the efficacy and safety of different doses of diltiazem in rapid AF. Methods A retrospective chart review was undertaken in patients who presented to the emergency department with rapid AF. Patients were divided into 3 groups according to diltiazem dosage: low dose (≤0.2 mg/kg), standard dose (>0.2 and ≤0.3 mg/kg), and high dose (>0.3 mg/kg). We compared the rates of therapeutic response (adequate rate control) and complications (such as hypotension). Multivariate regression analysis was used to determine the effect of diltiazem dose on the occurrence of complications. Results A total of 180 patients were included in the analysis. There were no significant differences in the rates of therapeutic response for the low-, standard-, and high-dose groups (70.5%, 77.1%, and 77.8%; P = .605). The rates of hypotension in the low-, standard-, and high-dose groups were 18%, 34.9%, and 41.7%, respectively. After adjusting confounding variables, the rate of hypotension was significantly lower in the low-dose group in comparison with the standard-dose group (adjusted odds ratio, 0.39; 95% confidence interval, 0.16-0.94). Conclusions Low-dose diltiazem might be as effective as the standard dose in controlling rapid AF and reduce the risk of hypotension.

An unusual presentation of atrial fibrillation

A 66-year-old man with a history of smoking and chronic obstructive pulmonary disease presented to the emergency department with a two-month history of worsening shortness of breath. His electrocardiogram revealed new-onset atrial fibrillation. Adequate rate control was achieved with beta-blockers and digoxin (Figure 1A). Figure 1 A chest x-ray was compatible with chronic obstructive pulmonary disease. A subsequent echocardiogram revealed a mass filling the left atrium and obstructing the mitral orifice (Figure 1B). A cine magnetic resonance imaging sequence showed a pedunculated mass arising from the mid portion of the interatrial septum and measuring 7.8 cm × 4.8 cm in the maximum transverse anteroposterior dimension (Figure 1C). It occupied the entire left atrial cavity and protruded across the mitral valve annulus into the base of the left ventricular (LV) cavity during systole. A coronary angiogram was normal. The patient was taken to the operating room for surgical removal of a large left atrial mass with excision of the site of septal attachment. Bovine pericardial patch repair of the iatrogenic atrial septal defect was performed. Macroscopically (Figure 1D), the mass consisted of white, soft, oblong tissue weighing 109 g. The cut surface of the mass was yellow and glistening, with focal areas of hemorrhage and necrosis. Microscopic pathology (Figure 1E) showed typical histological features of a cardiac myxoma with no atypia or malignancy. Primary tumours of the heart are extremely rare. Cardiac myxomas account for 50% of all primary cardiac tumours. They are more common in the female population, and typically occur between 30 and 60 years of age. Most myxomas originate from the interatrial septum at the fossa ovalis. Myxomas can present with obstructive and constitutional symptoms, electrical disturbances, and emboli. Surgical excision is usually curative. The present patient was discharged home in normal sinus rhythm six days after surgery.

Guidelines' criteria for rate control in atrial fibrillation: Are they useful?

Objectives. The AHA/ACC/ESC Guidelines for management of atrial fibrillation (AF) patients suggest criteria for adequate rate control. We hypothesized that AF patients fulfilling these criteria would have better quality of life (QoL) and exercise capacity compared to the ones not fulfilling the criteria. Design. Heart rate at rest, during moderate exercise and over 24 hours, and peak oxygen uptake (VO2 peak) were measured in patients with permanent AF, all aged 75 years, recruited from two Norwegian municipalities. SF-36 Physical component summary (PCS) and Mental component summary (MCS) QoL scores were assessed. The similar program was also applied to 71 age-matched subjects in sinus rhythm. Results. Twenty-seven AF patients participated. Six (22%) of the AF patients satisfied the Guidelines’ criteria for rate control; their VO2 peak (mean ± SD) was 23.0 ± 6.5 versus 22.6 ± 5.3 ml/kg/min in AF patients not satisfying the criteria, PCS score had median (25th, 75th percentile) 44 (30, 57) versus 41 (31, 47), and MCS score had median 52 (40, 62) versus 56 (43, 60), all p-values > 0.500. When the rate criteria were applied to the group in sinus rhythm, only 45% had heart rates within the ranges recommended by the Guidelines for AF patients. Conclusion. AF patients satisfying the Guidelines' criteria for adequate rate control did not have higher oxygen uptake or report better QoL than AF patients not satisfying the criteria.