Ablation versus anti-arrhythmic therapy for reducing all hospital episodes from recurrent atrial fibrillation: a prospective, randomized, multi-centre, open label trial.

AIMS: There is rising healthcare utilization related to the increasing incidence and prevalence of atrial fibrillation (AF) worldwide. Simplifying therapy and reducing hospital episodes would be a valuable development. The efficacy of a streamlined AF ablation approach was compared to drug therapy and a conventional catheter ablation technique for symptom control in paroxysmal AF. METHODS AND RESULTS: We recruited 321 patients with symptomatic paroxysmal AF to a prospective randomized, multi-centre, open label trial at 13 UK hospitals. Patients were randomized 1:1:1 to cryo-balloon ablation without electrical mapping with patients discharged same day [Ablation Versus Anti-arrhythmic Therapy for Reducing All Hospital Episodes from Recurrent (AVATAR) protocol]; optimization of drug therapy; or cryo-balloon ablation with confirmation of pulmonary vein isolation and overnight hospitalization. The primary endpoint was time to any hospital episode related to treatment for atrial arrhythmia. Secondary endpoints included complications of treatment and quality-of-life measures. The hazard ratio (HR) for a primary endpoint event occurring when comparing AVATAR protocol arm to drug therapy was 0.156 (95% CI, 0.097-0.250; P < 0.0001 by Cox regression). Twenty-three patients (21%) recorded an endpoint event in the AVATAR arm compared to 76 patients (74%) within the drug therapy arm. Comparing AVATAR and conventional ablation arms resulted in a non-significant HR of 1.173 (95% CI, 0.639-2.154; P = 0.61 by Cox regression) with 23 patients (21%) and 19 patients (18%), respectively, recording primary endpoint events (P = 0.61 by log-rank test). CONCLUSION: The AVATAR protocol was superior to drug therapy for avoiding hospital episodes related to AF treatment, but conventional cryoablation was not superior to the AVATAR protocol. This could have wide-ranging implications on how demand for AF symptom control is met. TRIAL REGISTRATION: Clinical Trials Registration: NCT02459574.

A real-world experience of subcutaneous and transvenous implantable cardiac defibrillators-comparison with the PRAETORIAN study.

Background: PRAETORIAN is the first randomized controlled trial that demonstrated the noninferiority of subcutaneous ICD (S-ICD) in comparison with transvenous ICD (TV-ICD). We retrospectively reviewed electronic records of patients with ICD implanted over the past 6 years, with the primary objective to compare our real-world single tertiary center experience with the randomized data from the PRAETORIAN study. Methods: Seventy S-ICD patients were compared with 197 TV-ICD patients, from July 2014 to June 2020 retrospectively, over a median period of 1304 days (296-2451 days). Primary composite endpoints included inappropriate shocks and device-related malfunctions. Results: Patients with S-ICD implantation were younger than those who received TV-ICD (mean, 49.7 years vs 63.9 years, p < .001). About 31.4% of S-ICDs were implanted for secondary prevention, and 58.6% of S-ICD patients had ischemic cardiomyopathy (ICM) with a median left ventricular ejection fraction of 32.5% (range: 10-67%). S-ICDs and TV-ICD had statistically similar inappropriate shocks (4.3% vs 4.6%, p = .78), device-related complications (11.4% vs 9.1%, p = .93), and the overall primary endpoints (15.7% vs 13.7%, p = .68). The findings remained the same even after age and gender adjustments and time-dependent analysis. Conclusion: Although single-center experience with a small number of S-ICD patients, results of the PRAETORIAN study has been replicated in our real-world experience of S-ICD and TV-ICD implantations across diverse etiologies, indications, and age groups confirming the comparable performance of S-ICD and TV-ICD when implanted in selected patients.

Meta-analysis comparing outcomes of high-power short-duration and low-power long-duration radiofrequency ablation for atrial fibrillation.

OBJECTIVE: High power short duration (HPSD) ablation strategy is proposed to be more effective than low power long duration (LPLD) for radiofrequency ablation of atrial fibrillation. Although small trials abound, data from a large cohort are lacking. This meta-analysis compares all the existing studies comparing these two approaches to evaluate perceived advantages of one over the other. METHODS: A systematic search of PubMed, EMBASE, and Cochrane databases identified studies comparing HPSD to LPLD ablation. All the analyses used the random-effects model. RESULTS: Ablation settings varied widely across 20 studies comprising 2,136 patients who underwent HPSD and 1,753 patients who underwent LPLD. The pooled incidence of atrial arrhythmia recurrence after HPSD ablation was 20% [95% confidence interval (CI): 0.16-0.25; I2=88%]. Atrial arrhythmia recurrences were significantly less frequent with HPSD ablation (incidence risk ratio=0.66; 95% CI: 0.49-0.88; I2=72%; p=0.004). Procedural, fluoroscopy, and ablation times were significantly shorter with HPSD ablation. First-pass pulmonary vein isolations (PVIs) were significantly more [odds ratio (OR)=2.94; 95% CI: 1.50-5.77; I2=89%; p=0.002), and acute pulmonary vein reconnections (PVRs) were significantly lesser (OR=0.41; 95% CI: 0.28-0.62; I2=62%; p<0.001) in the HPSD group. Although radiofrequency energy was significantly higher, esophageal thermal injuries (ETI) were lower with HPSD ablation. Acute complications, including steam-pops, were rare and statistically similar in both the groups. CONCLUSION: HPSD ablation enables faster first-pass PVI with fewer PVRs, similar ETI rates, rare collateral damage, and lower recurrence of atrial arrhythmia in the long term than LPLD. Randomized controlled studies with a larger cohort are indicated both to confirm the benefit of HPSD ablation and standardize the ablation protocol.

Burden of recurrent syncope and injuries and the usefulness of implantable cardiac monitors: insights from a nationwide longitudinal cohort analysis.

Aim: The study assesses the burden and costs of recurring unexplained syncope and injuries and the effectiveness of implantable loop recorders. Methods: The English national hospital database (Hospital Episode Statistics) was retrospectively analyzed. Results: 12,002 patients were identified with repeated syncope hospitalizations. 25% of patients were hospitalized at least once again for syncope, 9% of the patients were hospitalized at least once for an injury, causing substantial costs. In the second analysis: 10,902 patients implanted with an implantable cardiac monitor were tracked. By year 3, hospitalizations due to syncope had dropped by 60% versus pre-implantable cardiac monitor (ICM) levels. Conclusion: This study shows a high rate of recurrent syncope admissions and a parallel burden of hospitalizations for injuries. Use of an ICM appears to reduce syncope hospitalizations.

Tilt testing is more cost-effective than implantable loop recorder monitoring as a means of directing pacing therapy in people with recurrent episodes of suspected vasovagal syncope that affect their quality of life or present a high risk of injury.

OBJECTIVE: To assess the cost-effectiveness of implantable loop recorders (ILRs) and tilt testing (TT) to direct pacing therapy in people with recurrent episodes of transient loss of consciousness that are adversely affecting their quality of life or represent a high risk of injury and are suspected to be vasovagal. DESIGN: Decision analytical modelling was used to estimate the costs and benefits of diagnostic testing including the costs and benefits of treatment for several clinically important arrhythmias following diagnosis. SETTING: A UK National Health Service and personal social services perspective was taken. PATIENTS: People with recurrent episodes of transient loss of consciousness that are adversely affecting their quality of life or represent a high risk of injury and which are suspected to be vasovagal. INTERVENTIONS: The diagnostic test strategies compared were TT alone, TT followed by ILR (if TT 'negative'), ILR alone and no further testing. MAIN OUTCOME MEASURES: Benefits measured using quality-adjusted life years and incremental cost-effectiveness ratios (ICER) are reported. RESULTS: The ICERs for TT alone, ILR alone and TT followed by ILR were £5960, £24 620 and £19 110, respectively, compared with no testing. ILR alone was extendedly dominated by the other strategies, meaning that it is never the most cost-effective option. Sensitivity analysis found that the cost-effectiveness estimates were robust despite the areas of uncertainty identified in the evidence and assumptions used to inform the model. CONCLUSIONS: TT alone is likely to be the most cost-effective strategy in this population.

Prolonged implantable electrocardiographic monitoring indicates a high rate of misdiagnosis of epilepsy--REVISE study.

AIMS: Syncope, epilepsy, and psychogenic pseudo-syncope are the most common causes of transient loss of consciousness (T-LOC or blackout). All can present with similar features, including abnormal limb movements. It is reported that somewhere between 13 and 42% of patients with 'epilepsy' may be misdiagnosed. A UK Parliamentary working group found that at least 74 000 English patients are misdiagnosed with epilepsy, and taking antiepileptic drugs. The likely alternative diagnosis is 'convulsive' syncope, mimicking an epileptic seizure. We hypothesized that many patients misdiagnosed with epilepsy have convulsive reflex syncope, and that prolonged electrocardiographic (ECG) monitoring with an implantable ECG recorder (ILR) would show reflex cardioinhibition during T-LOC. This would respond to permanent pacing and allow antiepileptic drugs to be withdrawn. We also aimed to evaluate tilt testing and other tests done in these patients. METHODS AND RESULTS: We included patients previously diagnosed with epilepsy, but considered to have a definite or likely misdiagnosis of epilepsy after specialist neurological review. All received an ILR (Reveal Plus(®)/Reveal DX(®), Medtronic Inc.), and tilt-table testing. One hundred and three patients were included, mean age of 46 ± 17 years, with 58 of 103 (56%) female patients. A diagnosis of epilepsy was previously made by a neurologist in 69%, but definite tonic-clonic seizures were only noted in the history in 4%. In 22 patients (21%), the ILR recorded profound bradyarrhythmia or asystole with convulsive features, and they were offered pacemaker implantation. After pacing and withdrawal of antiepileptic drugs, 60% of these patients were asymptomatic. Only 14% of patients had a positive tilt-table test. In these, there was no correlation with the ECG findings of a spontaneous blackout during ILR recording. CONCLUSION: This study shows a high incidence of the cardioinhibition of reflex syncope in patients with convulsive T-LOC previously diagnosed as epilepsy and treated with antiepileptic drugs. We believe that reflex syncope with convulsive features mimics generalized epilepsy, leading to a misdiagnosis. This may be a widespread problem accounting for many wrong diagnoses of epilepsy. There was also poor correlation in ECG findings between tilt testing and ILR recording.

Significance of exercise induced U wave inversion as a marker for coronary artery disease.

Exercise stress testing for detecting inducible ischaemia was first introduced in the 1950s and remained one of the only methods of stressing the heart for years to come. The presence of inducible ischaemia was assessed by ECG changes during exercise apart from other factors, namely, duration of exercise, blood pressure and heart rate response, metabolic equivalents achieved, etc. With the emergence of other tests to look for inducible ischaemia, for example, dobutamine stress echocardiography and myocardial perfusion scanning and also as the threshold for invasive evaluation has decreased, unusual and infrequently encountered ECG changes are not looked for during exercise stressing with the same degree of diligence. The authors describe below the case of a 49-year-old male whose left anterior descending artery stenosis was diagnosed on exercise stress test on the basis of a negative U wave.

Implantable loop recorders are cost-effective when used to investigate transient loss of consciousness which is either suspected to be arrhythmic or remains unexplained.

AIMS: To assess the cost-effectiveness of implantable loop recorders (ILRs) in people with transient loss of consciousness (TLoC), which, after initial assessment and specialist cardiovascular assessment, is either suspected to be arrhythmic in origin or remains unexplained. This analysis was conducted to inform clinical guideline recommendations made by the National Institute for Health and Clinical Excellence (NICE) on the management of TLoC. METHODS AND RESULTS: Decision analytic modelling was used to estimate the costs and benefits of using ILRs compared with a strategy of no further diagnostic testing. Diagnostic outcomes were estimated from a systematic review and used to populate a decision tree model. To capture the main consequences of diagnosis, the costs and benefits of treatment for several clinically significant arrhythmias were estimated within the model. We used a cost-utility approach, in which benefits are measured using quality adjusted life years (QALYs), and took a UK National Health Service (NHS) and personal social services perspective. The cost per QALY was £17,400 in patients with unexplained syncope and £16,400 in patients with suspected arrhythmic syncope. Sensitivity analysis found that the cost-effectiveness estimates are fairly robust despite the areas of uncertainty identified in the evidence and assumptions used to inform the model. CONCLUSIONS: Implantable loop recorder monitoring is likely to be a cost-effective strategy in people presenting to the UK NHS who are experiencing infrequent episodes of TLoC which either remain unexplained or are suspected to be arrhythmic after initial assessment and specialist cardiovascular assessment. Implantable loop recorder monitoring has been recommended by NICE for these populations.

Atrial fibrillation is under-recognized in chronic heart failure: insights from a heart failure cohort treated with cardiac resynchronization therapy.

AIMS: Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with chronic heart failure (CHF). Under-detection of asymptomatic paroxysmal AF (PAF) underestimates the true burden of AF in patients with CHF. We retrospectively studied the prevalence of asymptomatic PAF in 162 CHF patients through analysis of cardiac resynchronization therapy (CRT) device downloads to determine whether these episodes are associated with adverse outcomes. METHODS AND RESULTS: An episode of AF was defined by mode switching on CRT devices with an atrial rate >200 for at least 30 s. Of the 101 patients thought to be persistently in sinus rhythm (SR), 27% were found to have significant paroxysms of AF, with the cumulative percentage of time in the 'mode-switch mode' (i.e. the AF burden) of 1.6 +/- 0.9%. Mortality was 19.2% in patients with newly identified PAF with hospitalization and thrombo-embolism rates of 42.3 and 2.1%, respectively, compared with mortality of 10.4% with hospitalization and thrombo-embolism rates of 41.8 and 1.9%, respectively, in patients persistently in SR (P= NS). CONCLUSION: Analysis of data from CRT devices in a population of CHF patients with severe left ventricular dysfunction shows that a significant proportion of those perceived to be persistently in SR have undiagnosed paroxysms of AF but with relatively low burden. These episodes appear to be associated with a trend towards increased mortality but no effects on hospitalization or thrombo-embolism rates.

Cardiac resynchronization therapy in chronic heart failure.

Cardiac resynchronization devices are used with increasing frequency in the treatment of chronic heart failure. This review focuses on the pathophysiological basis of cardiac dyssynchrony, and the rationale for resynchronization therapy.

Management of atrial arrhythmias 3: paroxysmal atrial fibrillation.

This is the third in a series of four practical articles highlighting the important management steps for non-cardiologists and non-cardiac electrophysiologists dealing with patients with atrial fibrillation and common atrial flutter. This article will deal with care pathways and management principles for paroxysmal atrial fibrillation.