Search

BACKGROUND: Whether atrial fibrillation (AF) pattern or timing of AF therapy modifies the effectiveness of early rhythm control (ERC) is not known. OBJECTIVES: This study sought to compare clinical characteristics and outcomes in patients presenting with different AF patterns on ERC vs usual care. METHODS: The effects of ERC were compared in first-diagnosed AF (FDAF), paroxysmal AF (paroxAF), and persistent AF (persAF) in this prespecified analysis of the EAST-AFNET 4 (Early treatment of atrial fibrillation for stroke prevention) trial. Associations between AF pattern and primary outcomes (first primary outcome: cardiovascular death, stroke, and hospitalization for heart failure and acute coronary syndrome; second primary outcome: nights spent in hospital per year) were compared over a mean follow-up of 5.1 years. Changes in health-related quality of life were assessed by the EQ-5D. RESULTS: FDAF patients (n = 1,048, enrolled 7 days after diagnosing AF) were slightly older (71 years of age, 48.0% female) than patients with paroxAF (n = 994, 70 years of age, 50.0% female) and persAF (n = 743, 70 years of age, 38.0% female). ERC reduced the primary outcome in all 3 AF patterns. Hospitalizations for acute coronary syndrome were highest in FDAF (incidence rate ratio [IRR]: 1.50; 95% CI: 0.83-2.69; P for interaction = 0.032) compared with paroxAF (IRR: 0.64; 95% CI: 0.32-1.25) and persAF (IRR: 0.50; 95% CI: 0.25-1.00). FDAF patients spent more nights in hospital (IRR: 1.38; 95% CI: 1.12-1.70; P for interaction = 0.004) than paroxAF (IRR: 0.84; 95% CI: 0.67-1.03), and persAF (IRR: 1.02; 95% CI: 0.80-1.30) patients. ERC improved health-related quality of life (EQ-5D score) in patients with paroxAF and persAF but not in patients with FDAF (P = 0.019). CONCLUSIONS: ERC reduces the first primary composite outcome in all AF patterns. Patients with FDAF are at high risk for hospitalization and acute coronary syndrome, particularly on ERC. (Early treatment of atrial fibrillation for stroke prevention trial; ISRCTN04708680; Early Treatment of Atrial Fibrillation for Stroke Prevention Trial [EAST]; NCT01288352; Early treatment of Atrial fibrillation for Stroke prevention Trial [EAST]; EudraCT2010-021258-20).

BACKGROUND: Oral and intravenous flecainide is recommended for cardioversion of atrial fibrillation. In this open-label, dose-escalation study, the feasibility of delivering flecainide via oral inhalation (flecainide acetate inhalation solution) for acute conversion was evaluated. We hypothesized that flecainide delivered by oral inhalation would quickly reach plasma concentrations sufficient to restore sinus rhythm in patients with recent-onset atrial fibrillation. METHODS: Patients (n=101) with symptomatic atrial fibrillation (for ≤48 hours) self administered flecainide acetate inhalation solution using a nebulizer (30 mg [n=10], 60 mg [n=22], 90 mg [n=21], 120 mg [n=19], and 120 mg in a formulation containing saccharin [n=29]). Electrocardiograms and flecainide plasma concentrations were obtained, cardiac rhythm using 4-hour Holter was monitored, and adverse events were recorded. RESULTS: Conversion rates increased with dose and with the maximum plasma concentrations of flecainide. At the highest dose, 48% of patients converted to sinus rhythm within 90 minutes from the start of inhalation. Among patients who achieved a maximum plasma concentration >200 ng/mL, the conversion rate within 90 minutes was 50%; for those who achieved a maximum plasma concentration

of the progress in arrhythmias in 2020. RACE4 and ALL-IN indicated that integrated nurse-led care improves outcomes in AF patients.3,4 The same was reported for early rhythm control therapy15 and cryoablation as initial AF treatment.25,26 Subcutaneous ICD was non-inferior to classical transvenous ICD therapy in PRAETORIAN.54 One mechanistic study showed that autoantibodies against misexpressed actin, keratin, and connexin-43 proteins create a blood-borne biomarker profile enhancing diagnosis of Brugada syndrome.50 Another mechanistic study indicated that transseptal LV pacing yields similar improvement in contractility as His bundle pacing whilst being more easy to execute.44 In PRE-DETERMINE a simple-to-use ECG risk score improved risk prediction in patients with ischemic heart disease possibly enhancing appropriate ICD therapy in high risk patients.58.

BACKGROUND: Adenosine can be used to reveal dormant pulmonary vein (PV) conduction after PV isolation (PVI). This study presents a subanalysis of real-world 1-year follow-up data from the ESC-EHRA EORP Atrial Fibrillation (AF) Ablation Long-Term registry to analyze the usage of adenosine during PVI treatment in terms of rhythm outcome and safety. METHODS: The registry consists of 104 participating centers in 27 countries within the European Society of Cardiology. The registry data was split into an adenosine group (AG) and no-adenosine group (NAG). Procedure characteristics and patient outcome were compared. RESULTS: Adenosine was administered in 10.8% of the 3591 PVI patients included in the registry. Spain, the Netherlands, and Italy included the majority of adenosine cases (48.8%). Adenosine was applied more often in combination with open irrigation radiofrequency (RF) energy (74.7%) and less often in combination with nonirrigated RF energy (1.6%). After 1 year, a higher percentage of the AG was free from AF compared with the NAG (68.9% vs 59.1%, p < 0.001). Adenosine was associated with better rhythm outcome in RF ablation procedures, but not in cryo-ablation procedures (freedom from AF: RF: AG: 70.9%, NAG: 58.1%, p < 0.001, cryo: AG: 63.9%, NAG: 63.8%, p = 0.991). CONCLUSIONS: The use of adenosine was associated with a better rhythm outcome after 1 year follow-up and seems more useful in patients treated with RF energy compared with patients treated with cryo energy. Given the improved rhythm outcome at 1-year follow-up, it seems reasonable to encourage the use of adenosine during RF AF ablation.

BACKGROUND: Previous research showed a significant difference in the presence of subclinical coronary artery disease (CAD) on cardiac CT angiography (CTA) between patients with idiopathic paroxysmal atrial fibrillation (iAF) versus a matched sinus rhythm population (iSR). Here we present 5-year follow-up data and the consequences of subclinical CAD on baseline CTA on the development of cardiovascular disease in iAF. METHODS: In 99 iAF patients (who underwent CTA as part of work-up for pulmonary vein isolation) and 221 matched iSR controls (who underwent CTA for CAD assessment), the incidence of hypertension, diabetes and major cardiovascular events (MACCE) during follow-up was obtained. Multivariable Cox regression analysis was used to reveal predictors of incident cardiovascular disease in the iAF group. RESULTS: During a follow-up of 68±11 months, over one third of patients developed cardiovascular disease, with no difference between iAF and iSR (log-rank p=0.56), and comparable low rates of MACCE (4.0% vs 5.0%,p=0.71). Within the iAF group, age (HR1.12(1.03–1.20);p=0.006), left atrial diameter (HR1.16(1.03–1.31);p=0.01), Segment Involvement Score (total number of coronary segments with atherosclerotic plaque; HR1.43(1.09–1.89);p=0.01) and the number of calcified plaques on CTA (HR0.53(0.30–0.92);p=0.01) were independent predictors of incident cardiovascular disease. CONCLUSIONS: Subclinical coronary disease on CTA may be useful to identify the subset of patients with iAF that harbour concealed cardiovascular risk factors and need intensive clinical follow-up to ensure timely initiation of appropriate therapy once CV disease develops, including anticoagulation and vascular prophylactic therapy.

Quantification of myocardial beta-adrenoceptor density (B-max) is of interest in cardiac diseases in which altered function of the sympathetic nervous system is thought to play a pathophysiological role. PET provides an unrivaled means of taking regional measurements of cardiac microcirculatory function, tissue metabolism and autonomic nervous system activity. Measurements in small regional areas may be biased because of increased noise levels. This study examined the parametric polar map approach for the regional quantification of B-max. Methods: Dynamic PE-T with parametric polar map imaging was performed in 10 healthy volunteers and 4 patients with hypertrophic cardiomyopathy using (S)-[C-11]-(4-(3-tertiarybutylamino-2-hydroxypropoxy)-benzidimazole-2)-o n hydrochloride (CGP)-12177 and a double-injection protocol. Time-activity curves were corrected for partial volume, spill-over and wall motion effects. The mean B-max of the left ventricle was calculated in two ways. First, the average time-activity curve of all segments, having the highest achievable signal-to-noise ratio, was used to calculate B-max(mTAC) (the myocardial beta-adrenoceptor density of the left ventricle calculated using the average time-activity curve). The bias in B-max(mTAC) introduced by noise is minimal. Second, an estimate of whole-heart receptor density was calculated using the polar map method by averaging the values of B-max obtained for 576 individual segments. In these calculations, three different filters (3 x 5, 3 x 9 and 3 x 13 segments) were used to smooth the time-activity curves before calculating B-max. Mean values of whole-left-ventricular receptor density obtained by averaging regional values using the different filters (B-max(PMF1/2/3)) were compared with B-max(mTAC) to assess bias introduced by the polar map approach. Segments with a calculated B-max outside the range 0.1-50 pmol/g were considered unreliable and were excluded from the analysis. Results: The differences between the two methods of calculating B-max were small (7.8%, 4.8% and 3.2%, with the three filters, respectively). Reliable results were obtained in >95% of the segments and in 9 volunteers and all 4 patients. Conclusion: When using PET for the quantification of beta-adrenoceptor density, the regional variation in B-max can be reliably assessed using the parametric polar map approach.

Objectives The purpose of this study was to assess whether management of heart failure (HF) guided by an individualized N-terminal pro-B-type natriuretic peptide (NT-proBNP) target would lead to improved outcome compared with HF management guided by clinical assessment alone. Background Natriuretic peptides may be attractive biomarkers to guide management of heart failure (HF) and help select patients in need of more aggressive therapy. The PRIMA (Can PRo-brain-natriuretic peptide guided therapy of chronic heart failure IMprove heart fAilure morbidity and mortality?) study is, to our knowledge, the first large, prospective randomized study to address whether management of HF guided by an individualized target NT-proBNP level improves outcome. Methods A total of 345 patients hospitalized for decompensated, symptomatic HF with elevated NT-proBNP levels at admission were included. After discharge, patients were randomized to either clinically-guided outpatient management (n = 171), or management guided by an individually set NT-proBNP (n = 174) defined by the lowest level at discharge or 2 weeks thereafter. The primary end point was defined as number of days alive outside the hospital after index admission. Results HF management guided by this individualized NT-proBNP target increased the use of HF medication (p = 0.006), and 64% of HF-related events were preceded by an increase in NT-proBNP. Nevertheless, HF management guided by this individualized NT-proBNP target did not significantly improve the primary end point (685 vs. 664 days, p = 0.49), nor did it significantly improve any of the secondary end points. In the NT-proBNP-guided group mortality was lower, as 46 patients died (26.5%) versus 57 (33.3%) in the clinically-guided group, but this was not statistically significant (p = 0.206). Conclusions Serial NT-proBNP measurement and targeting to an individual NT-proBNP value did result in advanced detection of HF-related events and importantly influenced HF-therapy, but failed to provide significant clinical improvement in terms of mortality and morbidity. (Effect of NT-proBNP Guided Treatment of Chronic Heart Failure [PRIMA]; NCT00149422) (J Am Coll Cardiol 2010;56:2090-100) (C) 2010 by the American College of Cardiology Foundation

Aim Differential drug treatment guided by the underlying heart disease may improve outcome of rhythm control therapy. In the present study we investigated in a well-defined group with either lone atrial. fibrillation (AF) or hypertension whether there were differences in rhythm control outcome between both groups in relation to the use of cardiovascular drugs. Methods and results One hundred sixty-two patients were included after successful cardioversion of persistent AF. None of the patients was given a class I or III antiarrhythmic drug. Patients' heart rhythm was checked 3 times a day, using transtelephonic monitoring for 1 month after cardioversion. One month after cardioversion up to 68% of patients had a recurrence of persistent AF. During the first 3 days almost no recurrences were seen on beta-blocker therapy whereas recurrences peaked on day 2-3 in the absence of beta-blockers. Univariate analysis showed that the use of beta-adrenergic receptor blockers and the presence of hypertension were associated with a lower recurrence rate at 1 month. Multivariate logistic regression analysis demonstrated that beta-blockade was the only statistically significant parameter predicting sinus rhythm at 1 month (OR 0.40, 95% CI 0.19-0.86, P = 0.02). Conclusions Compared with lone AF patients, patients in the setting of hypertension maintain sinus rhythm much better after cardioversion when treated with a beta-blocker. Beta-blockade protects, in particular, against the early subacute recurrences. These findings underscore the importance of a differential approach towards drug prevention of post-cardioversion recurrences depending on the underlying heart disease. (C) 2004 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.

Background: Congestive heart failure (CHF) is characterized by neurohormonal activation, including increased plasma concentrations of atrial natriuretic peptide (ANP) and N-terminal ANP (N-ANP). Onset of atrial fibrillation (AF) further increases these peptides, but it may be hypothesized that concentrations decrease during longstanding AF due to inherent atrial degeneration. Aim: We sought to investigate the relation between neurohormonal activation in patients with CHF and the duration of concomitant AF Methods: The study group comprised 60 patients (age 70+/-8 years) with advanced CHF due to left ventricular systolic dysfunction (left ventricular ejection fraction (LVEF) 0.25 ANP and N-ANP increased along with the duration of AF, whereas in patients with LVEFless than or equal to0.25 an inverse relation between ANP (P=0.02) and N-ANP (P=0.04) and the duration of AF was present, longer-standing AF being associated with lower concentrations. Conclusion: In patients with advanced CHF with low LVEF plasma ANP and N-ANP concentrations decrease during longstanding AF. This finding agrees with the concept that longstanding AF leads to impaired ability of the atria to produce these neurohormones due to inherent degenerative changes. (C) 2002 European Society of Cardiology. Published by Elsevier Science B.V. All rights reserved.

Objective: Atrial fibrillation (AF) is accompanied by electrical. structural and ion-channel protein remodeling. We tested if proteolysis by calpain and proteasome is activated during AF. and studied the relation with the remodeling processes. Methods: Right atrial appendages were obtained from patients with paroxysmal (n = 7) or persistent (n = 10) lone AF and compared to controls (n = 10) in sinus rhythm undergoing coronary artery bypass grafting (CABG). Proteolysis was measured using Suc-Leu-Leu-Val-Tyr-7-amino-4-methyl-coumarin. Protein expression of calpain I and 11 was assessed by Western-blot and calpain I localization by immunohistochemistry. Structural changes were quantified by counting atrial myocytes with contraction bands or hibernation. Results: Calpain activity was significantly increased in paroxysmal AF (2-fold, P

Objectives. To assess the prevalence of microalbuminuria in the general population, especially in nondiabetic and nonhypertensive subjects, and its association with known cardiovascular risk factors and cardiovascular morbidity. Design. Cross-sectional cohort study. Setting. Inhabitants of the city of Groningen, the Netherlands. Subjects. All inhabitants, aged between 28 and 75 years, were send a postal questionnaire and a vial to collect an early morning urine sample (n = 85 421). Of these 40 856 subjects (47.8%) responded. Cardiovascular risk factors and morbidity were validated in a well defined nondiabetic and nonhypertensive group of 5241 subjects. Main outcome measures. Microalbuminuria, self-reported cardiovascular risk and cardiovascular morbidity in the total study cohort, and additionally more detailed measurements in a subset of the total population. Results. Microalbuminuria (20-200 mg L-1) was present in 7.2% of the subjects and independently associated with age, gender, hypertension, diabetes, smoking, previous myocardial infarction and stroke. Some of these associations were already observed at albuminuria levels of 10-20 mg L-1. After exclusion of the diabetic and hypertensive subjects, microalbuminuria was still prevalent in 6.6% of the subjects. Conclusions. Microalbuminuria appears to be common not only in the general population but also in a nondiabetic, nonhypertensive population and is independently associated with increased cardiovascular risk factors and cardio-vascular morbidity. Importantly, some of these associations are present at urinary albumin levels currently considered to be normal. These findings suggest that urinary albumin measurements may be useful in early risk profiling and prevention of cardiovascular disease in the population at large.

Aim: Autonomic impairment is related to the incidence of sudden death in chronic heart failure (CHF). Our objective was to study autonomic profiles in patients with mild CHF due to coronary artery disease, and to investigate the value of add-on P-blockade. Methods and results: Measures of autonomic function (plasma norepinephrine, heart rate [HR] variability, autonomic function testing), and exercise capacity, were compared between 24 patients with mild CHF, and 24 healthy controls. In this mechanistic study, we assessed the effect of 26 weeks metoprolol treatment in a double-blind, randomized, placebo-controlled design. All patients received metoprolol sustained release (200 mg; n = 12) or placebo (n = 12). Assessments were made at baseline and after 10 and 26 weeks' treatment. At baseline, norepinephrine levels were elevated, while HR variability parameters were decreased in patients vs. controls (both P

Aim To assess the value of microalbuminuria as an indicator of increased cardiovascular risk in a non-diabetic population. Methods and Results 7579 non-diabetic subjects were studied with ages ranging from 28 to 75 years selected from a population based cohort. Using computerized Minnesota coding, ischaemic electrocardiographic abnormalities were divided into three categories: infarct patterns, major ischaemia. and minor ischaemia. Urinary albumin excretion was measured as the mean of two 24-h urine collections. Cardiovascular risk indicators were defined as an age above 60 Fears, male sex, hypertension, hypercholesterolaemia, smoking, obesity and a positive cardiovascular family history. Microalbuminuria was associated with age, sea, blood pressure, serum cholesterol, serum glucose, body mass index and all three categories of electrocardiographic abnormalities. In a multivariate model, adjusted for established cardiovascular risk indicators, microalbuminuria was independently associated with infarct patterns (OR [95% CI] 1.61 [1.12-2.32]), major ischaemia (OR 1.43 [1.08-1.91]) and minor ischaemia (OR 1.32 [1.03-1.68]). Conclusions The independent association between microalbuminuria and ischaemic electrocardiographic abnormalities suggests that microalbuminuria has additional value to conventional risk indicators in predicting cardiovascular disease in non-diabetics. Assessment of microalbuminuria could be an instrument to identify those at an increased risk for coronary vascular disease in an early stage. (C) 2000 The European Society of Cardiology.

OBJECTIVES: We sought to investigate the effect of angiotensin-converting enzyme (ACE) inhibition BACKGROUND: The ACE inhibitors reduce mortality after MI. Attenuation of LV dilation has been suggested as an important mechanism. METHODS: The data of 845 patients with three-month echocardiographic follow-up after MI were combined from three randomized, double-blind, placebo-controlled studies. The criteria for these studies included: 1) thrombolytic therapy; 2) ACE inhibition within 6 to 9 h; and 3) evaluation of LV dilation as the primary objective. RESULTS: The ACE inhibitor was started 3.2 +/- 1.7 h after the patients' first (mainly, 85%) anterior MI. After three months, LV dilation was not significantly attenuated by very early treatment with an ACE inhibitor. The diastolic volume index was attenuated by 0.5 ml/m(2) (95% confidence interval [CI] -1.5 to 2.5, p = 0.61), and the systolic volume index by 0.5 ml/m2 (95% CI -1.0 to 1.9, p = 0.50). Subgroup analysis demonstrated that LV dilation was significantly attenuated by ACE inhibitor treatment for patients in whom reperfusion failed. In contrast, LV dilation was almost unaffected by ACE inhibitor treatment in successfully reperfused patients. CONCLUSIONS: We could not demonstrate attenuation of LV dilation in patients receiving thrombolysis by ACE inhibitor treatment within 6 to 9 h after MI. We speculate that very early treatment with an ACE inhibitor has a beneficial effect on LV remodeling only in patients in whom reperfusion failed. Other mechanisms may be responsible for the beneficial effects of ACE inhibitors in successfully reperfused patients after MI. (C) 2000 by the American College of Cardiology.

1 We evaluated the role of SH-groups in improvement of endothelial dysfunction with ACE-inhibitors in experimental heart failure. To this end, we compared the vasoprotective effect of chronic treatment with zofenopril (plus SH-group) versus lisinopril (no SH-group), or N-acetylcysteine (only SH-group) in myocardial infarcted (MI) heart failure rats. 2 After 11 weeks of treatment, aortas were obtained and studied as ring preparations for endothelium-dependent and -independent dilatation in continuous presence of indomethacin to avoid interference of vasoactive prostanoids, and the selective presence of the NOS-inhibitor L-NMMA to determine NO-contribution. 3 Total dilatation after receptor-dependent stimulation with acetylcholine (ACh) was attenuated (-49%, P

Aims To examine whether the presence, or development, of atrial fibrillation in patients with advanced chronic heart failure, is associated with a poorer prognosis, compared to patients with sinus rhythm and chronic heart failure. Methods and Results We examined 409 patients with moderate to severe chronic heart failure, and compared patients with sinus rhythm (n=325) to those with atrial fibrillation (n=84). At baseline, the two groups were similar regarding most indices of severity of chronic heart failure, such as left ventricular ejection fraction (0.23) and New York Heart Association (NYHA) functional class, while they were different for age (70 years for atrial fibrillation vs 67 rears for sinus rhythm patients), aetiology of chronic heart failure, blood pressure, concomitant treatment, and plasma neurohormones (all P Conclusions The present data do not support the concept that the presence, or the development of atrial fibrillation in patients with advanced chronic heart failure is independently related to an adverse outcome during long-term follow-zip. The generally observed higher mortality in patients with atrial fibrillation thus seems to be related to other factors, associated with atrial fibrillation. (Eur Heart J 2000; 21: 1238-1245) (C) 2000 The European Society of Cardiology.

Objective-To investigate the occurrence of heart failure complications, and to identify variables that predict heart failure in patients with (recurrent) persistent atrial fibrillation, treated aggressively with serial electrical cardioversion and antiarrhythmic drugs to maintain sinus rhythm. Design-Non-randomised controlled trial; cohort; case series; mean (SD) follow up duration 3.4 (1.6) years. Setting-Tertiary care centre. Subjects-Consecutive sampling of 342 patients with persistent atrial fibrillation (defined as > 24 hours duration) considered eligible for electrical cardioversion. Interventions-Serial electrical cardioversions and serial antiarrhythmic drug treatment, after identification and treatment of underlying cardiovascular disease. Main outcome measures-heart failure complications: development or progression of heart failure requiring the institution or addition of drug treatment, hospital admission, or death from heart failure. Results-Development or progression of heart failure occurred in 38 patients (11%), and 22 patients (6%) died from heart failure. These complications were related to the presence of coronary artery disease (p

Objective-To investigate left ventricular dysfunction in patients who had been treated with anthracycline based chemotherapy. Methods-Autonomic function was compared with left ventricular diastolic function in 20 asymptomatic women with normal systolic function (left ventricular ejection fraction (LVEF) > 0.50) treated for breast cancer with high dose anthracycline based chemotherapy, and 20 age matched healthy controls. Left ventricular diastolic function was assessed echocardiographically by measuring the early peak flow velocity to atrial peak flow velocity ratio, isovolumic relaxation time, and deceleration time. Heart rate variability analysis was assessed for time domain and frequency domain parameters. Results-The mean (SD) age of the patients was 45 (7) years and the mean LVEF was 0.59 (0.06). The time interval after the end of chemotherapy was 29 (27) months. One or more diastolic variables were abnormal in 50% of the patients. Heart rate variability was abnormal in 85% of patients. Mean values of both time domain and frequency domain parameters were decreased (p

Background-The long-term efficacy of atrial fibrillation (AF) detection and R-wave synchronization are critical safety requirements for the development of an implantable atrial defibrillator (LAD) for treatment of AF. Methods and Results The long-term efficacy of the Metrix IAD for AF detection and R-wave synchronization was tested in 51 patients. The mean duration of follow-up was 259 +/- 138 days (72 to 613 days), AF detection tests were performed 2240 times during observed operation with 100% specificity and 92.3% sensitivity for differentiation between sinus rhythm and AF; 2219 episodes and their electrograms stored in the device during AF detection were analyzed. The positive predictive value of the AF detection algorithm was 97.4% (lower 95% confidence limit [CL], 94.5%) in the out-of-hospital setting. A total of 242 435 R waves were analyzed for R-wave synchronization. Of these, 49% were marked for synchronized shock delivery, 82% of sinus rhythm and 36% of AF R waves, respectively. All shock markers were properly synchronized and within the R wave (overall synchronization accuracy, 100%; lower 95% CL, 99.999%). Overall, 3719 shocks have been delivered via the LAD with no instance of unsynchronized shock delivery or any episode of proarrhythmia. The observed proarrhythmic risk was 0%, with an estimated maximum proarrhythmic risk of 0.084% per shock (95% upper CL). Conclusions-The Metrix IAD can appropriately detect AF with a high specificity and sensitivity and reliably synchronize within a suitable R wave for shock delivery to minimize the risk of ventricular proarrhythmia.

Background Prolonged periods of atrial fibrillation or rapid atrial pacing induce shortening of the atrial effective refractory period (AERP), which is thought to be related to the lower success rates of various antifibrillatory treatments when the arrhythmia has lasted for a longer period of time. Methods and Results To investigate whether an increase in intracellular calcium could be the stimulus for electrical remodeling, the effects of verapamil on shortening of the AERP in response to 24 hours of rapid atrial pacing (300 bpm) were studied in five chronically instrumented conscious goats during infusion of saline or verapamil. During rapid atrial pacing, the ventricular rate was kept constant by ventricular pacing (150 bpm). The AERP was measured by programmed electrical stimulation at basic cycle lengths of 430, 300, and 200 ms. Verapamil had no effects on the AERP before rapid atrial pacing. However, in the course of 24 hours of rapid atrial pacing, the AERP shortened significantly less (27% to 58%) in the presence of verapamil compared with control (at 430, 300, and 200 ms, P Conclusions Electrical remodeling of the atrium during rapid atrial pacing was significantly attenuated by verapamil. This suggests that electrical remodeling of the atrium is triggered by the high calcium influx during rapid atrial pacing rates.

Extensive myocardial bridging in the left anterior descending coronary artery was found in a 46 year old survivor of sudden cardiac near-death. Positron emission tomography and dobutamine stress echocardiography revealed ischaemia in the myocardium distal to the bridging. Spasm was excluded as cause of the ischaemia by intracoronary infusion of acetylcholine. Further evaluation of the haemodynamic importance of the bridging using intracoronary Doppler flow velocity measurements revealed an abnormal flow reserve. Dobutamine stress during coronary angiography caused increased mechanical compression during diastole. This was accompanied by multiple premature ventricular contractions. After a debridging operation the flow velocity reserve was normal. The abnormalities found during dobutamine stress had disappeared. Unexpectedly, a spasm was inducible. This may have been due to local oedema or scar formation after the operation. For the evaluation of the haemodynamic importance of myocardial bridging, intracoronary Doppler flow velocity measurements and angiography during dobutamine stress may be helpful in clinical decision making.

Two cases of amiodarone-induced pulmonary toxicity during a relatively short period of low-dose amiodarone treatment are reported. The toxicity risk of amiodarone is determined by cumulative factors in individual patients.

Objective-To determine she long-term outcome of serial electrical cardioversion therapy in patients with chronic atrial flutter. Design-Prospective study, case series. Setting-University hospital. Patients-50 consecutive patients with chronic (> 24 hours) atrial flutter without a previous relapse on antiarrhythmic drugs. Interventions-Elective electrical cardioversion therapy, if necessary repeated, to obtain and keep patients in sinus rhythm. Hf the first cardioversion resulted in sinus rhythm, patients were not given antiarrhythmic drugs. Relapses were managed by repeated cardioversions then antiarrhythmic drugs were used serially in a set sequence. Main outcome measure-Maintenance of sinus rhythm. Results-Mean (SD) follow up was 3.5 (1.7) years. The first cardioversion was successful in 48 patients (96%). After a single shock and without antiarrhythmic drugs being used, 42% of the patients maintained sinus rhythm in the longterm. Only left atrial size was inversely related to the efficacy of one shock (P = 0.025). With serial cardioversion 90% of the patients were kept in sinus rhythm for 5 years. Univariate analysis showed that a long duration of arrhythmia impaired cardiac function were related to poor outcome, During follow up 3 patients died of progression of heart failure and another 5 died suddenly. None of these 5 patients was on antiarrhythmic drugs. Conclusions-Electrical cardioversion was an effective and safe method of converting chronic atrial flutter to sinus rhythm. To maintain sinus rhythm, more than half of the patients required multiple shocks and prophylactic antiarrhythmic drugs. Sudden death was relatively frequent in the study population; the limited data available from this study suggest that such deaths were caused by the the underlying disease and not drug related proarrhythmia.