Atrial fibrillation : Clinical managements with special emphasis on cardioversion

Atrial fibrillation (AF) is the most common arrhythmia of clinical importance. It often decreases quality of life and is related to significant morbidity, as well as decreases longevity. This thesis covers three main issues of importance in the management of patients with AF: · Knowledge of and adherence to published guidelines. · Symptomatology of paroxysmal and persistent AF. · Aspects of electrical cardioversion of AF. Knowledge of and proneness to adhere to Swedish guidelines were studied by asking 728 physicians to respond to a questionnaire focusing on relevant issues when handling patients with AF. In parallel, 200 records from patients hospitalized for AF were reviewed to verify actual compliance to the guidelines. Only 40% of the patients with persistent AF and risk factors for stroke, received warfarin, although they did not have any contraindication to such treatment. Several discrepancies were detected, regarding the prescription of antiarrhythmic therapy. In conclusion, there was a lack of compliance between management as recommended by the guidelines and actual practice concerning several important aspects, some of which exposed patients to unnecessary risk. A structured medical history, two-dimensional echocardiography and 24-h Holter-ECG were obtained from 282 consecutive patients with persistent AF in order to investigate the differences between patients with and without symptoms and the prevalence of left ventricular dysfunction. Apart from the presence of valvular heart disease, symptomatic and asymptomatic subjects did not differ. Approximately 20% in this group had an impaired left ventricular function, this was more prevalent among those with high ventricular rate, ischemic heart disease and male gender. Episodes of paroxysmal AF are often asymptomatic. It is not known whether such episodes differ from symptomatic episodes. In a group of twenty-one patients with an implanted atrial def ibrillator, symptomatic episodes that caused the patient to attend hospital for cardioversion were compared with episodes that did not lead the patient to a hospital visit. Episodes ending with cardioversion were characterized by a high initial ventricular rate and longer duration than those that were unnoted. To test the hypotheses that one high-energy shock is more efficacious than incremental shocks, 120 consecutive patients referred for a first elective cardioversion were randomized to one shock of 360 J or incremental shocks starting at 100 J with a stepwise increase to 360 J. There were no differences in efficacy, sinus rhythm being obtained in 87 and 91 % in the two groups respectively. One single shock of 360 J caused less chest discomfort than the strategy based on incremental energy shocks. Neither of the two groups revealed any signs of myocardial injury. There are theoretical reasons to believe that rapid atrial pacing prior to the delivery of a cardioversion shock may lower the atrial defibrillation threshold (ADFT). This hypothesis was tested in 11 patients by pre-shock atrial pacing during internal cardioversion of AF. The ADFT was recorded in a randomized design, applying a step-up protocol starting at 100 V At each energy level the shock preceded by pacing was compared to a shock given without pacing until a level when sinus rhythm was restored by either of the two modes. Subsequently the step-up protocol was repeated applying the inverse sequence of the modes. The hypothesis could not be confirmed since rapid atrial pacing, did not influence the internal ADFT, at least not according to the protocol used. In conclusion, AF is associated with an increased morbidity and mortality. Through careful patient management the risks can be minimized and the need for medical care reduced. The described studies increase the understanding of the symptomatology and electrophysiological mechanisms and may hopefully contribute to improve patient care in this large group of people

Effects of yoga in patients with paroxysmal atrial fibrillation - a randomized controlled study.

BACKGROUND: Patients with atrial fibrillation often have an impaired quality of life (QoL). Practising yoga may decrease stress and have positive effects on mental and physical health. The aim of this study was to investigate whether yoga can improve QoL and decrease blood pressure and heart rate in patients with paroxysmal atrial fibrillation (PAF). METHODS: In this pilot study, 80 patients diagnosed with PAF were randomized to standard treatment (control group, n=40) or standard treatment in combination with yoga (yoga group, n=40) during a 12-week period. QoL, blood pressure and heart rate were evaluated at baseline and at the end of the study (12 (+2) weeks). EuroQoL-5D (EQ-5D) Visual Analogue Scale (VAS) and the two dimensions in Short-Form Health Survey (SF-36) were used to evaluate QoL. RESULTS: At baseline there was a significant difference in QoL between the groups in EQ-5D VAS- scale (p=0.02) and SF-36 mental health score (p<0.001) in which the control group had higher scores. At the end of the study, the yoga group averaged higher SF-36 mental health scores. There was a significant difference between the two groups (p=0.016), but no differences in EQ-5D VAS- scale and physiological health score was seen between the two groups. At the end of the study, the yoga group had significantly lower heart rate (p=0.024) and systolic (p=0.033) and diastolic blood pressure (p<0.001) compared to the control group. CONCLUSIONS: Yoga with light movements and deep breathing may lead to improved QoL, lower blood pressure and lower heart rate in patients with PAF compared to a control group. Yoga could be a complementary treatment method to standard therapy

Prognostic impact of morphology and duration of premature ventricular contractions in a population without structural heart disease

Abstract Background Premature ventricular contractions (PVCs) are a common form of arrhythmia associated with an unfavorable prognosis in patients with structural heart disease. It is unclear whether PVCs site of origin and QRS‐width has a prognostic significance in patients without structural heart disease. The aim of this study was to assess the prognostic importance of PVCs morphology and duration in this patient group. Methods We included 511 consecutive patients without a history of previous heart disease. They were examined with echocardiography and exercise test with normal findings. We categorized the PVCs from a 12 lead ECG according to morphology and width of the QRS‐complex and analyzed the outcome in terms of a composite endpoint of total mortality and cardiovascular morbidity. Results During a median follow‐up time of 5.3 years, 19 patients (3.5%) died and 61 (11.3%) met the composite outcome. Patients with PVCs originating from the outflow tracts had a significantly lower risk for the composite outcome compared to patients with non‐OT‐PVCs. Similarly, patients with PVC originating from the right ventricle had a better outcome than patients with left ventricular PCVs. No difference in outcome depending on QRS‐width during PVCs was noticed. Conclusion In our cohort of consecutively included PVC patients without structural heart disease PVCs from the outflow tracts were associated with a better prognostic outcome than non‐OT PVCs; the same was true for right ventricular PVCs when compared to left ventricular ones. The classification of the origin of the PVCs was based on 12‐lead ECG morphology. QRS‐width during PVC did not seem to have prognostic significance

Anticoagulation control in Sweden: reports of time in therapeutic range, major bleeding, and thrombo-embolic complications from the national quality registry AuriculA.

Aims In anticoagulation treatment with warfarin, the risk of thrombo-embolic events must be weighed against the risk of bleeding. Time in therapeutic range (TTR) is an important tool to assess the quality of anticoagulation treatment, and has been shown to correlate with less bleeding and thrombo-embolic complications. AuriculA, the Swedish national quality registry for atrial fibrillation and anticoagulation, is used for follow-up and dosage control of warfarin. This is the first report of TTR in AuriculA and, in a subgroup of two centres, bleeding and thrombo-embolic complications during 2008. Methods and results Prothrombin complex (International normalized ratio) values from 18 391 patients in 67 different centres were analysed. The mean (SD) age was 70 (12) years. The main indications for warfarin treatment were: atrial fibrillation (64%), venous thromboembolism (19%), and heart valve dysfunction (13%). Time in therapeutic range for all patients was 76.2%. The mean weekly dose of warfarin decreased with age and TTR increased with age. In 4273 patients from two centres in AuriculA, the frequency of major bleedings and venous/arterial thrombo-embolism were 2.6 and 1.7% and for atrial fibrillation, 2.6 and 1.4%, per treatment year, respectively. A correlation between age and the risk of major bleeding (P< 0.001), but not thrombo-embolic complications (P= 0.147), was seen. Conclusion Compared with prospective randomized trials of warfarin treatment, TTR in the AuriculA population was higher. Complications were low, probably due to the organization of anticoagulation treatment in Sweden. Use of the AuriculA dosing programme could have contributed to the results by keeping dosing regimens consistent over all centres

Safe automatic one-lead electrocardiogram analysis in screening for atrial fibrillation

Aims Screening for atrial fibrillation (AF) using intermittent electrocardiogram (ECG) recordings can identify individuals at risk of AF-related morbidity in particular stroke. We aimed to validate the performance of an AF screening algorithm compared with manual ECG analysis by specially trained nurses and physicians (gold standard) in 30 s intermittent one-lead ECG recordings. Methods and results The STROKESTOP study is a mass-screening study for AF using intermittent ECG recordings. All individuals in the study without known AF registered a 30-s ECG recording in Lead I two times daily for 2 weeks, and all ECGs were manually interpreted. A computerized algorithm was used to analyse 80 149 ECG recordings in 3209 individuals. The computerized algorithm annotated 87.1% (n = 69 789) of the recordings as sinus rhythm/minor rhythm disturbances. The manual interpretation (gold standard) was that 69 758 ECGs were normal, making the negative predictive value of the algorithm 99.9%. The number of ECGs requiring manual interpretation in order to find one pathological ECG was reduced from 288 to 35. Atrial fibrillation was diagnosed in 84 patients by manual interpretation, in all of whom the algorithm indicated pathology. On an ECG level, 278 ECGs were manually interpreted as AF, and of these the algorithm annotated 272 ECGs as pathological (sensitivity 97.8%). Conclusion Automatic ECG screening using a computerized algorithm safely identifies normal ECGs in Lead I and reduces the need for manual evaluation of individual ECGs with >85% with 100% sensitivity on an individual basis

Clinical risk profile score predicts all cause mortality but not implantable cardioverter defibrillator intervention rate in a large unselected cohort of patients with congestive heart failure

BACKGROUND: Primary prophylactic implantable cardioverter defibrillator (ICD) therapy is indicated for patients with reduced left ventricular ejection fraction (LVEF). We aimed to determine if preoperative clinical risk profiling can predict long-term benefit, and if clinical risk scores can be applied and improved in a patient cohort outside the clinical trial setting.METHODS: Using registry data, 789 patients with reduced LVEF who received ICDs for primary prevention during 2006-2011 were identified (age 64 ± 11 years, 82% men, 63% ischemic etiology, 52% cardiac resynchronization therapy with defibrillator). The patients were divided into three risk groups, based on the presence of baseline clinical risk factors (age >70, QRS duration >120 ms, New York Heart Association class III-IV, atrial fibrillation history, or creatinine >106 μmol/L). Endpoints were all-cause mortality and survival free of adequate ICD therapy.RESULTS: Mean follow-up was 39 ± 18 months. Annual mortality was 7.6%, and increased with risk group (p < .001). Rates of appropriate antitachycardia pacing and shock therapy were not statistically different between the groups, and ranged from 11%-16% and 6%-14%, respectively. By combining the previous risk score with data on diabetes, a better independent prediction of mortality was achieved; mortality rates then ranged from 11% (low-risk) to 46% (high-risk) (p < .0001).CONCLUSIONS: Implantable cardioverter defibrillator therapies occur across the spectrum of comorbidities in a population with systolic heart failure. However, all-cause mortality is considerably higher in the group of patients with accumulated risk factors, and using the proposed scoring system can be helpful for the evaluation and risk stratification of the patient prior to making a decision for a primary prophylactic ICD implantation

Stepwise mass screening for atrial fibrillation using N-terminal B-type natriuretic peptide : the STROKESTOP II study

Aims: To study the prevalence of unknown atrial fibrillation (AF) in a high-risk, 75/76-year-old, population using N-terminal B-type natriuretic peptide (NT-proBNP) and handheld electrocardiogram (ECG) recordings in a stepwise screening procedure. Methods and results: The STROKESTOP II study is a population-based cohort study in which all 75/76-year-old in the Stockholm region (n = 28 712) were randomized 1:1 to be invited to an AF screening programme or to serve as the control group. Participants without known AF had NT-proBNP analysed and were stratified into low-risk (NT-proBNP &lt;125 ng/L) and high-risk (NT-proBNP &gt;= 125 ng/L) groups. The high-risk group was offered extended ECG-screening, whereas the low-risk group performed only one single-lead ECG recording. In total, 6868 individuals accepted the screening invitation of which 6315 (91.9%) did not have previously known AF. New AF was detected in 2.6% [95% confidence interval (CI) 2.2-3.0] of all participants without previous AF. In the high-risk group (n = 3766/6315, 59.6%), AF was diagnosed in 4.4% (95% CI 3.7-5.1) of the participants. Out of these, 18% had AF on their index-ECG. In the low-risk group, one participant was diagnosed with AF on index-ECG. The screening procedure resulted in an increase in known prevalence from 8.1% to 10.5% among participants. Oral anticoagulant treatment was initiated in 94.5% of the participants with newly diagnosed AF. Conclusion: N-terminal B-type natriuretic peptide-stratified systematic screening for AF identified 4.4% of the high-risk participants with new AF. Oral anticoagulant treatment initiation was well accepted in the group diagnosed with new AF

Cost-effectiveness of population screening for atrial fibrillation : the STROKESTOP study

Aims Previous studies on the cost-effectiveness of screening for atrial fibrillation (AF) are based on assumptions of long-term clinical effects. The STROKESTOP study, which randomised 27 975 persons aged 75/76 years into a screening invitation group and a control group, has a median follow-up time of 6.9 years. The aim of this study was to estimate the cost-effectiveness of population-based screening for AF using clinical outcomes. Methods and results The analysis is based on a Markov cohort model. The prevalence of AF, the use of oral anticoagulation, clinical event data, and all-cause mortality were taken from the STROKESTOP study. The cost for clinical events, age-specific utilities, utility decrement due to stroke, and stroke death was taken from the literature. Uncertainty in the model was considered in a probabilistic sensitivity analysis. Per 1000 individuals invited to the screening, there were 77 gained life years and 65 gained quality-adjusted life years. The incremental cost was euro1.77 million lower in the screening invitation group. Gained quality-adjusted life years to a lower cost means that the screening strategy was dominant. The result from 10 000 Monte Carlo simulations showed that the AF screening strategy was cost-effective in 99.2% and cost-saving in 92.7% of the simulations. In the base-case scenario, screening of 1000 individuals resulted in 10.6 [95% confidence interval (CI): -22.5 to 1.4] fewer strokes (8.4 ischaemic and 2.2 haemorrhagic strokes), 1.0 (95% CI: -1.9 to 4.1) more cases of systemic embolism, and 2.9 (95% CI: -18.2 to 13.1) fewer bleedings associated with hospitalization. Conclusion Based on the STROKESTOP study, this analysis shows that a broad AF screening strategy in an elderly population is cost-effective. Efforts should be made to increase screening participation.Funding Agencies|Swedish Heart and Lung foundation; Stockholm County Council; Tornspiran Foundation; King Gustav V and Queen Victorias Freemasons Foundation; Klebergska Foundation; Scientific Council of Halland Region; Southern Regional Healthcare Committee; Swedish stroke Foundation; Carl Bennet AB; Boehringer Ingelheim; Bayer; Bristol-Myers Squibb-Pfizer</p