Adequate Rate Control Research Articles

Leadless pacemaker implantation and concurrent atrioventricular junction ablation in patients with atrial fibrillation.

Atrioventricular junctional (AVJ) ablation and pacemaker implantation are indicated when pharmacotherapy fails to achieve adequate rate control in atrial fibrillation (AF). The purpose of our study is to assess the feasibility and safety of concurrent Micra leadless transcatheter pacemaker implantation and AVJ ablation. We retrospectively assessed patients who underwent Micra implantation and concurrent AVJ ablation at three institutions between August 2014 and March 2016. All patients and devices were followed at baseline and at 1, 3, 6, and 12 months postimplantion. Twenty-one patients with permanent AF (median age 77 [range: 62-88], female 15 [71.4%]) underwent successful Micra implantation followed by concurrent AVJ ablation. There was no device dislodgement or malfunction during the 12-month follow-up. Complete 12-month electrical performance data were available in 14 patients (67%). Among patients with the complete data set, median pacing thresholds at implant and at 1, 3, 6, and 12 months were 0.5 V (range: 0.25-0.88), 0.44 V (range: 0.25-2.0), 0.5 V (range: 0.25-1.63), 0.5 V (range: 0.25-1.13), and 0.5 V (range: 0.25-1.13) at a pulse width of 0.24 msec, respectively. Two patients died due to noncardiac causes during follow-up. There were no patients with major device-related complications. Concurrent Micra implantation and AVJ ablation is feasible and appears safe. There was no device dislodgement, malfunction, or significant pacing threshold rise requiring device reimplantation during the 12-month follow-up. This combined approach can be considered for patients with AF with suboptimal rate control who have failed AF catheter ablation and/or pharmacotherapy.

2018 Korean Heart Rhythm Society Guidelines for Antiarrhythmic Drug Therapy in Non-valvular Atrial Fibrillation

Rhythm control therapy is the main strategy for restoring and maintaining sinus rhythm in patients with non-valvular atrial fibrillation (NVAF). Sinus rhythm is better restored and maintained with antiarrhythmic drugs than with placebo treatment. In addition, catheter ablation or combination therapy is more effective than antiarrhythmic drugs for treating NVAF. However, in most clinical trials to date, rhythm control therapy has resulted in neutral clinical outcomes compared with rate control therapy. The decision to undergo rhythm control therapy should be based on age, atrial fibrillation (AF)-related symptoms, type of AF, structural heart disease, and underlying comorbidities. For now, rhythm control therapy is indicated to improve symptoms in patients with NVAF who have refractory symptoms after adequate rate control therapy. The Korean Heart Rhythm Society organized the Korean AF Management Guideline Committee and analyzed all available data, including South Korean patients with NVAF. This review article provides general principles and detailed methodology for rhythm control therapy in South Korean patients with NVAF. Keywords: Atrial fibrillation; Anti-arrhythmia agents; Guidelines 중심 단어: 심방세동; í•­ë¶€ì •ë§¥ì œ; 가이드라인

Retrospective Evaluation of the Effect of Heart Rate on Survival in Dogs with Atrial Fibrillation.

BackgroundAtrial fibrillation (AF) usually is associated with a rapid ventricular rate. The optimal heart rate (HR) during AF is unknown.Hypothesis/ObjectivesHeart rate affects survival in dogs with chronic AF.AnimalsForty‐six dogs with AF and 24‐hour ambulatory recordings were evaluated.MethodsRetrospective study. Holter‐derived HR variables were analyzed as follows: mean HR (meanHR, 24‐hour average), minimum HR (minHR, 1‐minute average), maximum HR (maxHR, 1‐minute average). Survival times were recorded from the time of presumed adequate rate control. The primary endpoint was all‐cause mortality. Cox proportional hazards analysis identified variables independently associated with survival; Kaplan‐Meier survival analysis estimated the median survival time of dogs with meanHR <125 bpm versus ≥125 bpm.ResultsAll 46 dogs had structural heart disease; 31 of 46 had congestive heart failure (CHF), 44 of 46 received antiarrhythmic drugs. Of 15 dogs with cardiac death, 14 had CHF. Median time to all‐cause death was 524 days (Interquartile range (IQR), 76–1,037 days). MeanHR was 125 bpm (range, 62–203 bpm), minHR was 82 bpm (range, 37–163 bpm), maxHR was 217 bpm (range, 126–307 bpm). These were significantly correlated with all‐cause and cardiac‐related mortality. For every 10 bpm increase in meanHR, the risk of all‐cause mortality increased by 35% (hazard ratio, 1.35; 95% CI, 1.17–1.55; P < 0.001). Median survival time of dogs with meanHR<125 bpm (n = 23) was significantly longer (1,037 days; range, 524‐open) than meanHR ≥125 bpm (n = 23; 105 days; range, 67–267 days; P = 0.0012). Mean HR was independently associated with all‐cause and cardiovascular mortality (P < 0.003).Conclusions and Clinical ImportanceHolter‐derived meanHR affects survival in dogs with AF. Dogs with meanHR <125 bpm lived longer than those with meanHR ≥ 125 bpm.

Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction: The CAMERA-MRI Study

BackgroundAtrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate control. Existing randomized studies of AF and LVSD of varying etiologies have reported modest benefits with a rhythm control strategy. ObjectivesThe goal of this study was to determine whether catheter ablation (CA) for AF could improve LVSD compared with medical rate control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF. MethodsThis multicenter, randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included pulmonary vein isolation and posterior wall isolation. AF burden post-CA was assessed by using an implanted loop recorder, and adequacy of MRC was assessed by using serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months. ResultsA total of 301 patients were screened; 68 patients were enrolled between November 2013 and October 2016 and randomized with 33 in each arm (accounting for 2 dropouts). The average AF burden post-CA was 1.6 ± 5.0% at 6 months. In the intention-to-treat analysis, absolute LVEF improved by 18 ± 13% in the CA group compared with 4.4 ± 13% in the MRC group (p < 0.0001) and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing CA, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (10.7%; p = 0.0069) and normalization at 6 months (73% vs. 29%; p = 0.0093). ConclusionsAF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of ventricular fibrosis on CMR. This outcome challenges the current treatment paradigm that rate control is the appropriate strategy in patients with AF and LVSD. (Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction [CAMERA-MRI]; ACTRN12613000880741)

Catheter Ablation of Atrial Fibrillation: Where Are We?

Atrial fibrillation (AF) is the commonest cardiac arrhythmia, with significant morbidity and mortality. More than half of patients with AF are still symptomatic despite adequate anticoagulation and rate control. If antiarrhythmic drugs are ineffective or poorly tolerated, AF patients are then typically treated with catheter ablation to restore sinus rhythm. In the past 20 years, AF ablation has developed from a specialized, experimental procedure into a common treatment in the cardiovascular field. Various ablation techniques and mapping technologies have been described and are continuing to evolve for increased safety and efficacy. An incomplete list of such techniques and technologies would include focal and segmental, circumferential and linear, complex fractionated atrial electrogram, ganglionated plexus, focal impulse and rotor modulation, body surface potential mapping–guided, real-time MRI–guided, cryoballoon, visually guided laser balloon, radiofrequency hot balloon, contact force sensing catheter, multielectrode catheter, and hybrid ablations. This review examines the history of invasive AF treatment and its evolution into catheter ablation but mainly focuses on the discussion of various ablation techniques and technologies leading to our current understanding of the ablation therapy of this most common arrhythmia.

Beta-blockers or Digoxin for Atrial Fibrillation and Heart Failure?

In patients with atrial fibrillation (AF) and heart failure (HF) with or without systolic dysfunction, either rhythm control or rate control is an acceptable primary therapeutic option. If a rate control strategy is chosen, treatment with a beta-blocker is almost always required to achieve rate control. Adequate ventricular rate control is usually a resting rate of less than 100 beats per minute, but lower resting rates may be appropriate. Non-dihydropyridine calcium channel blockers are often contraindicated when AF is associated with HF with systolic dysfunction. There have been recent debates on a possible reduced efficacy of beta-blockers as well as safety issues with digoxin when treating HF patients with AF. The benefit of beta-blockers on survival may be lower in patients with HF with reduced ejection fraction when AF is present. Digoxin does not improve survival but may help to obtain satisfactory rate control in combination with a beta-blocker. Digoxin may be useful in the presence of hypotension or an absolute contraindication to beta-blocker treatment.

Rate Control versus Rhythm Control in Atrial Fibrillation: Lessons Learned from Clinical Trials of Atrial Fibrillation

Ample evidence supports the statement that in patients with atrial fibrillation in whom treatment is warranted, either rhythm control or rate control are acceptable primary therapeutic options. If a rhythm control strategy is chosen, it is important to consider that recurrence of atrial fibrillation is not treatment failure per se. Occasional recurrence, with cardioversion if necessary, may be quite acceptable. The latter will depend on the frequency, duration and symptoms associated with recurrence, and may require a change in the rhythm control therapy, e.g., change the antiarrhythmic drug, or initiate or redo atrial fibrillation ablation. And a rhythm control strategy should include careful attention to and treatment of comorbidities (hypertension, heart failure, diabetes, etc.). If a rate control strategy is chosen, treatment with a beta blocker or nondihydropyridine calcium channel blocker is almost always required to achieve adequate rate control. Digoxin is often useful to obtain satisfactory rate control in combination with a beta blocker or nondihydropyridine calcium channel blocker. Digoxin may be useful as primary therapy in the presence of hypotension or heart failure. Satisfactory ventricular rate control is usually a resting rate less than 110 beats per minute, although resting rates below 90 beats per minute are probably wiser. Finally, when pursuing a rhythm control strategy, because recurrence of atrial fibrillation is common, rate control therapy should be a part of the treatment regimen.

Treatment of Atrial Fibrillation.

Atrial fibrillation is a common arrhythmia that affects more than 2.5 million people in the United States and causes substantial morbidity and mortality, especially regarding the increased risk of stroke. To summarize atrial fibrillation treatment exclusive of stroke prevention. An Ovid MEDLINE comprehensive literature search was performed on atrial fibrillation therapy excluding anticoagulation and emphasizing studies published within the last 5 years through April 2015 (N = 5044 references). The 2014 atrial fibrillation guideline from the American Heart Association, the American College of Cardiology, and the Heart Rhythm Society also was reviewed. Reversible causes of atrial fibrillation should be identified. Risk factor modification, including weight loss and treatment of hypertension, diabetes, and obstructive sleep apnea can reduce atrial fibrillation episodes. Appropriate anticoagulation is necessary for patients at substantial stroke risk regardless of rate or rhythm treatment strategy. Sinus rhythm is often needed to control symptoms; however, an alternative strategy for atrial fibrillation is appropriate rate control. Rate control is safe in older patients (those who are about age ≥65 years) followed up for a few years, but no such safety data exist for patients younger than 60 years or for those followed up for longer periods. Thus, selection of therapy is individualized, taking into account present and future medical problems for the patient. Choice of an antiarrhythmic drug is based on safety first vs efficacy. Catheter ablation is an effective nonpharmacological alternative that is often, but not always, the second-line treatment. Reduction of the frequency and duration of atrial fibrillation episodes that result in a significant improvement in quality of life is a good marker of drug treatment success and complete elimination of atrial fibrillation is not required in many patients. Rate control is usually achieved with a β-blocker or non-dihydropyridine calcium channel blockers. It is important to assess adequate rate control during both rest and activity. If the ventricular rate goes uncontrolled for a prolonged period, tachycardia-mediated cardiomyopathy can occur. Therapy for atrial fibrillation includes prevention and modification of inciting causes and appropriate anticoagulation. Rate control is necessary for all patients. Maintenance of sinus rhythm with drugs or catheter ablation should be considered based on the individual needs of each patient.

Sudden Flare of Rheumatoid Arthritis Associated with Newly Diagnosed Atrial Flutter

We present an 89-year-old woman with newly diagnosed atrial flutter associated with a flare of her rheumatoid arthritis (RA). She had a history of diet-controlled type 2 diabetes mellitus, hypertension, and RA and presented with lightheadedness and worsening hand pain. She was found to be in new atrial flutter with rapid ventricular response and to have an active RA flare. In addition to adequate atrial flutter rate control, her RA flare was managed by adding hydroxychloroquine and doubling her existing methotrexate dose.

Cardiac Arrhythmias in the Intensive Care Units

Background: Cardiac arrhythmias in critically ill patients often cause severe hemodynamic impairment or medical complications, precipitating rapid deterioration of patients’ conditions. This manuscript describes common or fatal cardiac arrhythmias occurring in patients hospitalized at intensive care units. Results: Differential diagnosis of wide QRS tachycardias includes ventricular tachycardias (VTs), supraventricular tachycardias with aberrant conduction and noise artifacts. Idiopathic VTs in patients with structurally normal hearts are responsive to antiarrhythmic agents and are cured by catheter ablation. Ventricular tachycardias in structural heart diseases require amiodarone for acute suppression and implantable defibrillator for longterm management. Polymorphic VTs or Torsades de Pointes are effectively suppressed by intravenous infusion of magnesium. Discontinuation of offending agents and, in some refractory cases, installation of temporary pacing is necessary. Atrial fibrillation (AF) is the most commonly observed tachyarrhythmias in intensive care settings. When combined with sepsis or congestive heart failure, AF with rapid ventricular response induces hypotension and sympathetic stimulation, which again aggravates rapid ventricular responses. This viscious cycle continues until adequate rate control measures are initiated. Intravenous amiodarone and anticoagulation are important initial management. In rare cases, electrical noises mimic ventricular tachycardias. Noises are distinguished from true VTs by identification of sharp QRS notches and stable hemodynamics during the events. Conclusion: Proper interpretation of monitoring or standard ECG is crucial for differential diagnosis of cardiac arrhythmias occurring in intensive care units. Management should be tailored based upon arrhythmia characteristics and individual medical conditions. Key Words: Tachycardia; Bradycardia; Intensive care

A Genome-Wide Association Study to Identify Genomic Modulators of Rate Control Therapy in Patients With Atrial Fibrillation

For many patients with atrial fibrillation, ventricular rate control with atrioventricular (AV) nodal blockers is considered first-line therapy, although response to treatment is highly variable. Using an extreme phenotype of failure of rate control necessitating AV nodal ablation and pacemaker implantation, we conducted a genome-wide association study (GWAS) to identify genomic modulators of rate control therapy. Cases included 95 patients who failed rate control therapy. Controls (n= 190) achieved adequate rate control therapy with ≤2 AV nodal blockers using a conventional clinical definition. Genotyping was performed on the Illumina 610-Quad platform, and results were imputed to the 1000 Genomes reference haplotypes. A total of 554,041 single-nucleotide polymorphisms (SNPs) met criteria for minor allele frequency (>0.01), call rate (>95%), and quality control, and 6,055,224 SNPs were available after imputation. No SNP reached the canonical threshold for significance for GWAS of p <5× 10(-8). Sixty-three SNPs with p <10(-5) at 6 genomic loci were genotyped in a validation cohort of 130 cases and 157 controls. These included 6q24.3 (near SAMD5/SASH1, p= 9.36× 10(-8)), 4q12 (IGFBP7, p= 1.75× 10(-7)), 6q22.33 (C6orf174, p= 4.86× 10(-7)), 3p21.31 (CDCP1, p= 1.18× 10(-6)), 12p12.1 (SOX5, p= 1.62× 10(-6)), and 7p11 (LANCL2, p= 6.51× 10(-6)). However, none of these were significant in the replication cohort or in a meta-analysis of both cohorts. In conclusion, we identified several potentially important genomic modulators of rate control therapy in atrial fibrillation, particularly SOX5, which was previously associated with heart rate at rest and PR interval. However, these failed to reach genome-wide significance.

Of hammers and screws: renin-angiotensin-aldosterone system inhibition to prevent atrial fibrillation in patients with hypertension

This editorial refers to ‘Antihypertensive treatment and risk of atrial fibrillation: a nationwide study’[†][1], by S.C.W. Marott et al. , on page 1205 This editorial discusses the observation that monotherapy of uncomplicated hypertension with an ACE inhibitor or a sartan is associated with a lower risk of new-onset atrial fibrillation than treatment with a calcium channel blocker, diuretic, or beta-blocker. This association, found in a Danish nationwide database over a mean follow-up duration of 6–7 years, is put in context with the outcomes of controlled clinical trials testing similar interventions in patients without hypertension. In summary, the data suggest that different types of atrial fibrillation require different forms of preventive treatment, and that such ‘pathophysiological types of atrial fibrillation’ can be differentiated in patients using clinical characteristics supplemented by blood and ECG biomarkers, potentially opening the way towards a more personalized therapy of atrial fibrillation. Although atrial fibrillation (AF) is rarely dangerous in the acute setting, the long-term consequences are grim. Even the most modern forms of management, including adequate stroke prevention and rate control therapy,1 are not sufficient to prevent premature cardiovascular deaths in patients with AF.2,3 Furthermore, the majority of AF patients remain symptomatic,4 and many are hospitalized for AF.5,6 After its manifestation, early rhythm control treatment of AF, i.e. thorough prevention of recurrent AF after the first episode, may be useful.2 Although we do not have formal proof of this concept, preventing the first episode of AF could be an even better way to prevent these complications. The mechanisms by which AF perpetuates itself have been studied in great detail in animal models and in patients in the last … [1]: #fn-2

Clinical Characteristics, Management, and Control of Permanent vs. Nonpermanent Atrial Fibrillation: Insights from the RealiseAF Survey

BackgroundAtrial fibrillation can be categorized into nonpermanent and permanent atrial fibrillation. There is less information on permanent than on nonpermanent atrial fibrillation patients. This analysis aimed to describe the characteristics and current management, including the proportion of patients with successful atrial fibrillation control, of these atrial fibrillation subsets in a large, geographically diverse contemporary sample.Methods and ResultsData from RealiseAF, an international, observational, cross-sectional survey of 10,491 patients with atrial fibrillation, were used to characterize permanent atrial fibrillation (N = 4869) and nonpermanent atrial fibrillation (N = 5622) patients. Permanent atrial fibrillation patients were older, had a longer time since atrial fibrillation diagnosis, a higher symptom burden, and were more likely to be physically inactive. They also had a higher mean (SD) CHADS2 score (2.2 [1.3] vs. 1.7 [1.3], p<0.001), and a higher frequency of CHADS2 score ≥2 (67.3% vs. 53.0%, p<0.001) and comorbidities, most notably heart failure. Physicians indicated using a rate-control strategy in 84.2% of permanent atrial fibrillation patients (vs. 27.5% in nonpermanent atrial fibrillation). Only 50.2% (N = 2262/4508) of permanent atrial fibrillation patients were controlled. These patients had a longer time since atrial fibrillation diagnosis, a lower symptom burden, less obesity and physical inactivity, less severe heart failure, and fewer hospitalizations for acute heart failure than uncontrolled permanent atrial fibrillation patients, but with more arrhythmic events. The most frequent causes of hospitalization in the last 12 months were acute heart failure and stroke.ConclusionPermanent atrial fibrillation is a high-risk subset of atrial fibrillation, representing half of all atrial fibrillation patients, yet rate control is only achieved in around half. Since control is associated with lower symptom burden and heart failure, adequate rate control is an important target for improving the management of permanent atrial fibrillation patients.

Strict heart rate control attenuates prothrombotic state and platelet activity in patients with non-valvular permanent atrial fibrillation

The underlying mechanisms of increased risk of thrombo-embolism in atrial fibrillation (AF) are not completely understood; however, substantial evidence supports that AF is associated with a prothrombotic state. Accordingly, we hypothesized that strict rate control could attenuate platelet activity and thrombotic state in patients with non-valvular AF. Seventy-five patients with non-valvular AF were divided into 2 groups based on heart rate: (1) normal ventricular rate (n = 34, 18 female) and (2) high ventricular rate (n = 39). Thirty-three sex- and age-matched subjects in sinus rhythm were included as control. Thirty patients with high ventricular rate (16 female) were successfully followed. Markers of platelet function were measured at baseline and repeated 1-month after adequate rate control in high ventricular rate group. Serum fibrinogen levels were significantly higher in AF patients with high ventricular rate than that in controls. Mean platelet volume, soluble CD40L and β-Thromboglobulin were significantly higher in AF patients with high ventricular rate than those in both AF patients with normal ventricular rate and controls. Soluble CD40L and β-Thromboglobulin were significantly higher in AF patients with normal ventricular rate than those in controls. One-month after adequate rate control, serum fibrinogen, soluble CD40L and β-Thromboglobulin levels significantly decreased (from 2.26 ± 1.02, 85.01 ± 37.05, 3.10 ± 0.90 to 1.55 ± 1.08, 66.34 ± 33.72, 2.71 ± 0.53; p < 0.001, p = 0.002, p = 0.03, respectively) in high ventricular rate group. AF patients with high ventricular rate had increased indices of platelet activity and thrombotic state. Furthermore, strict rate control significantly decreased indices of thrombotic state and platelet activity in those patients.

Short-term ECG recordings for heart rate assessment in patients with chronic atrial fibrillation.

IntroductionThere is no consensus on the length of ECG tracing that should be recorded to represent adequate rate control in patients with atrial fibrillation (AFib). The purpose of the study was to examine whether heart rate measurements based on short-term ECGs recorded at different periods of the day may correspond to the mean heart rate and rate irregularity analyzed from standard 24-hour Holter monitoring.Material and methodsThe study enrolled 50 consecutive patients with chronic AFib who underwent 24-hour Holter monitoring. Mean heart rate (mHR) and the coefficient of irregularity (CI) were assessed from 5- and 60-minute intervals of Holter recordings in different periods of the day.ResultsThe highest correlation in mean heart rate interval within 24 h was found during a 6-hour sample and in the periods 11.00 AM–12.00 PM, 12 PM–1.00 PM, and 1.00 PM–2.00 PM. With respect to irregularity, only the CI measurements based on a 6-hour interval (7.00 AM–1.00 AM) show a correlation > 0.08 compared to data from the 24-hour recording.ConclusionsOnly long-term (6-hour) recordings provide a high correlation within 24 h in mean heart rate interval and coefficient of irregularity. It seems that the mean heart rate interval in 1-hour periods between 11 AM and 2 PM might be predictive for 24-hour data. Short time recordings of the coefficient of irregularity of heart rate in AFib patients at this moment are not useful in clinical practice for long-term prognosis of ventricular irregularity.

Atrial Tachyarrhythmias Temporally Precede Fluid Accumulation in Implantable Device Patients

The complex relationship between heart failure and atrial tachyarrhythmias (AT/atrial fibrillation [AF]) is not well understood. We examined the temporal association between changes in intrathoracic impedance, suggesting thoracic fluid accumulation, and AT/AF occurrence in cardiac resynchronization therapy-defibrillator and implantable cardioverter defibrillator (ICD) patients. A retrospective analysis was conducted on stored implantable device data to identify patients with automatic monitoring of daily AT/AF burden and intrathoracic impedance. Daily population trends in AT/AF burden before and after a fluid index threshold crossing (FIC) were determined. A total of 73,018 patients (68 ± 12 years, 51% ICD, 75% male) were evaluated over 18.6 ± 11.5 months. Kaplan-Meier analysis indicated a significantly higher probability of FIC events in the first month following the onset of persistent AT/AF when compared to a matched group without persistent AT/AF (hazard ratio [HR] 1.65, 95% confidence interval [CI] [1.58, 1.72], P < 0.001). Conversely, patients were significantly more likely to experience an episode of persistent AF in the first month after the FIC event (HR 1.32, 95% CI [1.08, 1.63], P = 0.008). The probability of a fluid index crossing within 30 days of the onset of persistent AT/AF was significantly lower in a subgroup of patients with adequate rate control (35.8% [34.3-37.4%] vs 42.0% [39.6-44.6%]; HR 1.24 [1.13-1.36]). Thoracic fluid accumulation, as indicated by decreasing intrathoracic impedance, was more likely to occur immediately after the onset of persistent AT/AF, especially in the presence of inadequate rate control. Likewise, the onset of persistent AT/AF was more likely following a decrease in intrathoracic impedance.

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Introduction: The human bocavirus (HBoV) is an emerging parvovirus discovered in 2005. It has been identified in children in different parts of the world. Data suggest that HBoV may be an etiological agent responsible for respiratory tract diseases, especially in children and immunocompromised hosts. It can also cause gastrointestinal symptoms, such as diarrhea and vomiting. HBoV is not confined to the respiratory tract and its presence in respiratory secretions, serum and stool samples suggest that this virus may cause systemic illness, although it seems to be very rare. Currently, HBoV can be detected only by polymerase chain reactions (PCR). Another important feature of this agent is that no specific treatment is known. Case description: Male, 85 years old, pulmonologist physician, admitted to the Intensive Care Unit (ICU) of our hospital with a community-acquired pneumonia without clinical improvement after three days of outpatient treatment with clarithromycin. He was hospitalized for investigation and beggining of intravenous antibiotics. During his second day of hospitalization, he presented an acute atrial fibrillation with rapid ventricular response. During the episode, he was submitted to an echocardiogram (ECHO) that showed left ventricle ejection fraction (LVEF) of 0.50 with mild diffuse hypokinesis; the prior ECHO (4 months before the hospitalization) did not suggest any kind of contraction disfunction. He received amiodarone bolus followed by continuous infusion for 24 hours with adequate heart rate control. The patient evolved with acute respiratory failure after one day, and a new ECHO showed signs of severe systolic heart failure (LVEF .28) with diffuse hypokinesis, and sustained tachycardia; electrocardiogram showed atrial fibrillation again. He was submitted to a transesophageal ECHO followed by electric synchronized cardioversion, with reassignment of sinus rhythm. Antibiotic was scaled and clinical measures for acute heart failure were initiated. During the next 24 hours, ventricular function improved (LVEF .50), and the respiratory symptoms improved, as well. An oropharyngeal swab that was performed during the pneumonia investigation showed a positive polymerase chain reaction (PCR) for bocavirus. No other pathogen was isolated in blood cultures or secretions samples, despite comprehensive investigation. Computed tomography coronary ruled out ischemic event associated and myocardial necrosis markers were negative during all the stay. The patient showed great progress after this events, and was discharged from the ICU 8 days after admission. He left the hospital after finishing the pneumonia treatment, without any respiratory symptoms at all. Discussion: This case report shows the presence of HBoV in respiratory tract of a patient presenting with bronchopneumonia and acute left ventricular dysfunction. Considering the fact that no other etiological agents were identified, and myocardial infarction was ruled out, we can consider the possibility of bocavirus being associated with a myocarditis, causing these symptoms and clinical picture. The ultimate test to confirm that hypothesis, would be a myocardial biopsy, witch was not performed in this case. The bocavirus is a relatively new virus, with most reports focused on respiratory symptoms. Nevertheless, it has been shown the presence of HBoV DNA in heart and other tissues. The pathophysiology and the relationship between the presence of the virus and cardiac dysfunction have not been clearly elucidated, even though it is possible. Conclusion: The full spectrum of disease associated with HBoV remains to be elucidated and probably is not limited to respiratory infections, with other clinical implications. It remains to be seen if respiratory infection due to HBoV in a patient with acute cardiac failure can be a myocarditis caused by bocavirus, or it is just a mere coincidence.

Suboptimal heart rate control in heart failure despite optimal medical and device therapy in the real world

Background: Adequate heart rate control is increasingly recognised as an important risk reduction strategy in management of chronic heart failure. We retrospectively analysed our population of heart failure patients undergoing device therapy for adequacy of heart rate control. Methods: Our specialist heart failure nurse-led service oversees treatment initiation, titration and monitoring of patients with heart failure, as per current NICE guidelines. After established medical therapy, eligible patients underwent biventricular pacemaker (CRT) implantation. Data on resting heart rate and rhythm were retrieved and compared before and after device implantation. All continuous data were reported as mean ± standard deviation, categorical data were reported as percentages. SPSS 18 was used for statistical analysis. Results: In the first six months period of 2012, 58 patients underwent CRT implantation (age 68±13 years, female 21%, 84% had ischaemic heart disease or dilated cardiomyopathy, LVEF 25±8%, QRS 154±30ms, 84% had LBBB). Before CRT, majority patients were in sinus rhythm (67%), some (22%) were in atrial fibrillation and minority were paced from the right ventricle apex (11%). On existing medical therapy (55% beta blocker, 65% ACE inhibitor or ARBs, 28% aldosterone blocker, 7% digoxin), baseline heart rate did not differ from heart rate at 6 months after device implantation (68±14 vs. 69±15, p=0.6269). However, after excluding patients with underlying atrial fibrillation at 6 months, 43% patients had HR≥70bpm and would benefit from further heart rate lowering. Conclusions: Our data suggests that a dedicated heart failure specialist team is essential in management of patients with heart failure. Nonetheless despite optimal medical and device therapy in the real world, a large portion of patients had suboptimal heart rate control.

When 'digoxin use' is not the same as 'digoxin use': lessons from the AFFIRM trial

This statistical viewpoint refers to ‘Increased mortality among patients taking digoxin—analysis from the AFFIRM study’[†][1], by M.G. Whitbeck et al. , on page 1481; and ‘Lack of evidence of increased mortality among patients with atrial fibrillation taking digoxin: findings from post hoc propensity-matched analysis of the AFFIRM trial’[‡][1], by M. Gheorghiade et al., on page 1489 Two reports relating to the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Trial1 explore the association of digoxin use with mortality among patients with atrial fibrillation (AF). The AFFIRM trial randomized 4060 patients with AF and a high risk of stroke or death to rate control vs. rhythm control. In the rate control arm, different therapies were allowed to achieve adequate heart rate control, including digoxin, beta-blockers, calcium channel blockers (verapamil and diltiazem), and combinations of these drugs. In the rhythm control arm, antiarrhythmic drugs included amiodarone, disopyramide, flecainide, moricizine, procainamide, propafenone, quinidine, sotalol, and combinations of these drugs. While the strategy of rate control vs. rhythm control was randomized, the choice of specific agents used was left to the discretion of the treating physician in both arms. During a mean follow-up of 3.5 years, there were 356 deaths (23.8%) in the rhythm control group and 310 deaths (21.3%) among the rate control group, a directionally but not significantly lower mortality with rate control ( P = 0.08). In the article by Whitbeck et al. , digoxin use was assessed at randomization and during follow-up.2 The association of digoxin use with mortality was evaluated treating digoxin as a time-dependent covariate in a Cox proportional hazard model.3 By using digoxin as a time-dependent covariate, patients changed from being in the ‘on-digoxin’ group to the ‘not on-digoxin’ group if their medication use changed over time in the study, and … [1]: #fn-2

New-onset left bundle branch block immediately following noncardiac surgery under combined general and epidural anesthesia

To the Editor: Management of new-onset left bundle branch block (LBBB) in the perioperative period, particularly in a patient with thoracic epidural analgesia, is challenging for clinicians. We recently encountered such a case and believe that there are several important learning points to share with our colleagues. A 57-year-old man with a history of diabetes mellitus, hypertension, and coronary artery disease underwent general anesthesia with endotracheal intubation and thoracic epidural analgesia for an open right partial nephrectomy for resection of a renal tumor. Two bare-metal intracoronary stents had been placed 7 years before surgery. Two years before surgery, routine exercise stress testing revealed excellent exercise capacity. However, maximal stress was accompanied by inferolateral ST segment depressions on electrocardiogram (ECG; Fig. 1a). Subsequent nuclear stress imaging was negative for ischemia. Before surgery, a resting ECG (Fig. 1b) showed sinus bradycardia without stigmata of ischemia. The patient had been active and routinely performed vigorous exercise without difficulty or symptoms. His medications included metformin, atenolol, atorvastatin, quinapril, and aspirin, which was discontinued before surgery. The surgery and anesthesia were of approximately 3 h duration and uneventful. Intraoperative monitoring of ECG leads II and V5 was normal. Upon emergence from general anesthesia, the patient complained of nausea but denied any chest discomfort. Upon arrival to the post-anesthesia care unit, the patient was pain-free and a epidural dermatomal level was not immediately determined. Cardiac telemetry revealed a widened QRS complex with a heart rate of approximately 90 bpm. A 12-lead ECG showed a new-onset LBBB (Fig. 1c). Prompt diagnostic and therapeutic workup was initiated. As this was immediately following major surgery, emergent cardiac catheterization was deferred. Cardiac biomarkers were cycled for three sets and were within normal limits. Despite adequate heart rate control, the LBBB persisted. Pharmacological nuclear stress testing performed on postoperative day 2 showed no evidence of ischemia or infarction. The patient was discharged on postoperative day 3, with ECG showing LBBB. One month after surgery, a repeat ECG (Fig. 1d) showed complete resolution of the LBBB. Current guidelines [1] state that new-onset LBBB in the setting of symptoms should be treated as an acute coronary syndrome equivalent, and immediate intervention should be pursued. However, there is no guideline applicable to the case of a new-onset, non-rate-dependent LBBB without symptoms. Furthermore, cases of new LBBB in the perioperative setting, particularly with epidural analgesia, are quite rare [2]. The symptoms may be masked by adequate analgesia. In the circumstance of new-onset LBBB in the postoperative period, echocardiography may be difficult to M. C. Adams Y. Jiang (&) Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Jackson 422, Boston, MA 02114, USA e-mail: yjiang@partners.org