Five-year results of Amaze: a randomized controlled trial of adjunct surgery for atrial fibrillation.

OBJECTIVES: The Amaze trial showed that adding atrial fibrillation (AF) surgery to cardiac operations increased return to sinus rhythm (SR) without impact on quality of life or survival at 2 years. We report outcomes to 5 years. METHODS: In a multicentre, phase III, pragmatic, double-blind, randomized controlled superiority trial, cardiac surgery patients with >3 months of AF were randomized 1:1 to adjunct AF surgery or control. Primary outcomes of 1-year SR restoration and 2-year quality-adjusted survival were already reported. This study reports on rhythm, survival, quality-adjusted survival, stroke, medication and safety to 5 years. RESULTS: Between 2009 and 2014, 352 patients were randomized. By 5 years 79 died, 58 withdrew, 34 were lost to follow-up and the remaining 182 provided data. AF surgery significantly increased the odds of remaining in SR at 5 years {odds ratio = 2.98 [95% confidence interval (CI) 1.23, 7.17], P = 0.015}. There was a non-significant decrease in stroke incidence [odds ratio = 0.605 (95% CI 0.284, 1.287), P = 0.19], but no improved survival [5-year survival: AF surgery 77.3% (95% CI 71.1%, 83.5%), controls 77.8% (95% CI 71.7%, 84.0%), P = 0.85]. Quality-adjusted survival difference was negligible (-0.03; 95% CI -0.33, 0.27, P = 0.85). The composite of survival free of stroke and AF was better in the AF surgery group [odds ratio = 2.34 (95% CI 1.03, 5.31)]. There were no other differences. CONCLUSIONS: Adjunct AF surgery confers a higher rate of SR to 5 years and a better composite outcome of survival free of stroke and AF but has no impact on overall or quality-adjusted survival or other clinical outcomes. CLINICAL TRIAL REGISTRATION NUMBER: ISRCTN82731440.

Ultra-High-Density Activation Mapping to Aid Isthmus Identification of Atrial Tachycardias in Congenital Heart Disease.

OBJECTIVES: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD). BACKGROUND: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit. METHODS: Mapping and ablation data of 61 patients with CHD (35 males, age 45 ± 14 years) from 8 tertiary centers were reviewed. RESULTS: Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricular physiology (Fontans) (n = 8); Tetralogy of Fallot (n = 10); atrial septal defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septal resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 ± 8 months, 7 patients had recurrence. CONCLUSIONS: We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra-high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set.

Ablation of Complex Fractionated Electrograms Improves Outcome in Persistent Atrial Fibrillation of Over 2 Year's Duration.

AIM: There is controversy and sparse data on whether substrate based techniques in addition to pulmonary vein isolation (PVI) confer benefit in the catheter ablation of persistent atrial fibrillation (AF), especially if long standing. We performed an observational study to assess whether substrate based ablation improved freedom from atrial arrhythmia. METHODS: A total of 286 patients undergoing first ablation procedures for persistent AF with PVI only(n = 79), PVI plus linear ablation(n = 85), or PVI plus complex fractionated electrogram (CFAE) and linear ablation(n = 107) were followed. Primary end point was freedom from atrial arrhythmia at one year. RESULTS: Mean duration of pre-procedure time in AF was 28+/-27 months.There were no differences in baseline characteristics between groups except a higher proportion of patients with a severely dilated LA in those receiving PVI+CFAEs+lines. Freedom from atrial arrhythmia was higher with a PVI+CFAE+lines strategy then for PVI alone (HR 1.56, 95% CI: 1.04-2.34, p=0.032) but was not higher with PVI+lines. Benefit of substrate modification was conferred for preprocedure times in AF of over 30 months. The occurrence of atrial tachycardia was higher when lines were added to the ablation strategy (HR 0.08, 95% CI: 0.01-0.59, p=0.014). Freedom from atrial arrhythmia at 1 year was higher with lower patient age, use of general anaesthetic (GA), normal or mildly dilated left atrium and decreasing time in AF. CONCLUSIONS: In patients with long standing persistent AF of over 30 months duration,CFAE ablation resulted in improved freedom from atrial arrhythmia. Increased freedom from atrial arrhythmia occurs in patients who are younger and have smaller atria, and with GA procedures. Linear ablation did not improve outcome and resulted in a higher incidence of atrial tachycardia.

Association of catheter ablation for atrial fibrillation with mortality and stroke: A systematic review and meta-analysis.

BACKGROUND: Maintenance of sinus rhythm has been associated with lower mortality, but whether atrial fibrillation (AF) ablation per se benefits hard outcomes such as mortality and stroke is still debated. OBJECTIVE: To determine whether AF ablation is associated with a reduction in all-cause mortality and stroke compared with medical therapy alone. METHODS: Literature search looking for both randomized and observational studies comparing AF catheter ablation vs. medical management. Data pooled using random-effects. Risk ratios (RR) with 95% confidence intervals (CI) used as a measure of treatment effect. The primary and secondary outcomes were all-cause mortality and occurrence of cerebrovascular events during follow-up, respectively. RESULTS: Thirty studies were eligible for inclusion, comprising 78,966 patients (25,129 receiving AF ablation and 53,837 on medical treatment) and 233,990patient-years of follow-up. The pooled data of studies revealed that ablation was associated with lower risk of all-cause mortality: 5.7% vs. 17.9%; RR=0.44, 95% CI 0.32-0.62, p<0.001. In a sensitivity analysis by study design, a survival benefit of AF ablation was seen in randomized studies, with no heterogeneity (mortality risk 4.2% vs. 8.9%; RR=0.55, 95% CI 0.39-0.79, p=0.001, I2=0%), and also in observational studies, but with marked heterogeneity (6.1% vs. 18.3%; RR=0.39, 95% CI 0.26-0.59, p<0.001, I2=95%). The mortality benefit in randomized studies was mainly driven by trials performed in patients with left ventricular (LV) dysfunction and heart failure. The pooled risk of a cerebrovascular event was lower in patients receiving AF ablation (2.3% vs. 5.5%; RR=0.57, 95% CI 0.46-0.70, p<0.001, I2=62%), but no difference was seen in randomized trials (2.2% vs. 2.1%; RR=0.94, 95% CI 0.46-1.94, p=0.87, I2=0%). CONCLUSIONS: Ablation of atrial fibrillation associates with a survival benefit compared with medical treatment alone, although evidence is restricted to the setting of heart failure and LV systolic dysfunction.

Amaze: a double-blind, multicentre randomised controlled trial to investigate the clinical effectiveness and cost-effectiveness of adding an ablation device-based maze procedure as an adjunct to routine cardiac surgery for patients with pre-existing atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) can be treated using a maze procedure during planned cardiac surgery, but the effect on clinical patient outcomes, and the cost-effectiveness compared with surgery alone, are uncertain. OBJECTIVES: To determine whether or not the maze procedure is safe, improves clinical and patient outcomes and is cost-effective for the NHS in patients with AF. DESIGN: Multicentre, Phase III, pragmatic, double-blind, parallel-arm randomised controlled trial. Patients were randomised on a 1 : 1 basis using random permuted blocks, stratified for surgeon and planned procedure. SETTING: Eleven acute NHS specialist cardiac surgical centres. PARTICIPANTS: Patients aged ≥ 18 years, scheduled for elective or in-house urgent cardiac surgery, with a documented history (> 3 months) of AF. INTERVENTIONS: Routine cardiac surgery with or without an adjunct maze procedure administered by an AF ablation device. MAIN OUTCOME MEASURES: The primary outcomes were return to sinus rhythm (SR) at 12 months and quality-adjusted life-years (QALYs) over 2 years after randomisation. Secondary outcomes included return to SR at 2 years, overall and stroke-free survival, drug use, quality of life (QoL), cost-effectiveness and safety. RESULTS: Between 25 February 2009 and 6 March 2014, 352 patients were randomised to the control (n = 176) or experimental (n = 176) arms. The odds ratio (OR) for return to SR at 12 months was 2.06 [95% confidence interval (CI) 1.20 to 3.54; p = 0.0091]. The mean difference (95% CI) in QALYs at 2 years between the two trial arms (maze/control) was -0.025 (95% CI 0.129 to 0.078; p = 0.6319). The OR for SR at 2 years was 3.24 (95% CI 1.76 to 5.96). The number of patients requiring anticoagulant drug use was significantly lower in the maze arm from 6 months after the procedure. There were no significant differences between the two arms in operative or overall survival, stroke-free survival, need for cardioversion or permanent pacemaker implants, New York Heart Association Functional Classification (for heart failure), EuroQol-5 Dimensions, three-level version score and Short Form questionnaire-36 items score at any time point. Sixty per cent of patients in each trial arm had a serious adverse event (p = 1.000); most events were mild, but 71 patients (42.5%) in the maze arm and 84 patients (45.5%) in the control arm had moderately severe events; 31 patients (18.6%) in the maze arm and 38 patients (20.5%) in the control arm had severe events. The mean additional cost of the maze procedure was £3533 (95% CI £1321 to £5746); the mean difference in QALYs was -0.022 (95% CI -0.1231 to 0.0791). The maze procedure was not cost-effective at £30,000 per QALY over 2 years in any analysis. In a small substudy, the active left atrial ejection fraction was smaller than that of the control patients (mean difference of -8.03, 95% CI -12.43 to -3.62), but within the predefined clinically equivalent range. LIMITATIONS: Low recruitment, early release of trial summaries and intermittent resource-use collection may have introduced bias and imprecise estimates. CONCLUSIONS: Ablation can be practised safely in routine NHS cardiac surgical settings and increases return to SR rates, but not survival or QoL up to 2 years after surgery. Lower anticoagulant drug use and recovery of left atrial function support anticoagulant drug withdrawal provided that good atrial function is confirmed. FURTHER WORK: Continued follow-up and long-term clinical effectiveness and cost-effectiveness analysis. Comparison of ablation methods. TRIAL REGISTRATION: Current Controlled Trials ISRCTN82731440. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 19. See the NIHR Journals Library website for further project information.

Amaze: a randomized controlled trial of adjunct surgery for atrial fibrillation.

OBJECTIVES: Atrial fibrillation (AF) reduces survival and quality of life (QoL). It can be treated at the time of major cardiac surgery using ablation procedures ranging from simple pulmonary vein isolation to a full maze procedure. The aim of this study is to evaluate the impact of adjunct AF surgery as currently performed on sinus rhythm (SR) restoration, survival, QoL and cost-effectiveness. METHODS: In a multicentre, Phase III, pragmatic, double-blinded, parallel-armed randomized controlled trial, 352 cardiac surgery patients with >3 months of documented AF were randomized to surgery with or without adjunct maze or similar AF ablation between 2009 and 2014. Primary outcomes were SR restoration at 1 year and quality-adjusted life years at 2 years. Secondary outcomes included SR at 2 years, overall and stroke-free survival, medication, QoL, cost-effectiveness and safety. RESULTS: More ablation patients were in SR at 1 year [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.20-3.54; P = 0.009]. At 2 years, the OR increased to 3.24 (95% CI 1.76-5.96). Quality-adjusted life years were similar at 2 years (ablation - control -0.025, P = 0.6319). Significantly fewer ablation patients were anticoagulated from 6 months postoperatively. Stroke rates were 5.7% (ablation) and 9.1% (control) (P = 0.3083). There was no significant difference in stroke-free survival [hazard ratio (HR) = 0.99, 95% CI 0.64-1.53; P = 0.949] nor in serious adverse events, operative or overall survival, cardioversion, pacemaker implantation, New York Heart Association, EQ-5D-3L and SF-36. The mean additional ablation cost per patient was £3533 (95% CI £1321-£5746). Cost-effectiveness was not demonstrated at 2 years. CONCLUSIONS: Adjunct AF surgery is safe and increases SR restoration and costs but not survival or QoL up to 2 years. A continued follow-up will provide information on these outcomes in the longer term. Study registration: ISRCTN82731440 (project number 07/01/34).

Improved outcome and cost effectiveness in ablation of persistent atrial fibrillation under general anaesthetic.

Aims: Outcome of persistent atrial fibrillation (AF) ablation remains suboptimal. Techniques employed to reduce arrhythmia recurrence rate are more likely to be embraced if cost-effectiveness can be demonstrated. A single-centre observational study assessed whether use of general anaesthesia (GA) in persistent AF ablation improved outcome and was cost-effective. Methods and results: Two hundred and ninety two patients undergoing first ablation procedures for persistent AF under conscious sedation or GA were followed. End points were freedom from listing for repeat ablation at 18 months and freedom from recurrence of atrial arrhythmia at 1 year. Freedom from atrial arrhythmia was higher in patients who underwent ablation under GA rather than sedation (63.9% vs. 42.3%, hazard ratio (HR) 1.87, 95% confidence interval (CI): 1.23-2.86, P = 0.002). Significantly fewer GA patients were listed for repeat procedures (29.2% vs. 42.7%, HR 1.62, 95% CI: 1.01-2.60, P = 0.044). Despite GA procedures costing slightly more, a saving of £177 can be made per patient in our centre for a maximum of two procedures if all persistent AF ablations are performed under GA. Conclusions: In patients with persistent AF, it is both clinical and economically more effective to perform ablation under GA rather than sedation.

Patients upgraded to cardiac resynchronization therapy due to pacing-induced cardiomyopathy are at low risk of life-threatening ventricular arrhythmias: a long-term cause-of-death analysis.

Aims: Upgrade to cardiac resynchronization therapy (CRT) should be offered to patients who have developed pacing-induced cardiomyopathy with conventional right ventricular pacing. The extent to which these patients would also benefit from defibrillator back-up at the time of CRT upgrade is, however, unknown. Methods and results: Retrospective observational cohort study of 199 patients with pacing-induced cardiomyopathy and no history of sustained ventricular arrhythmia, including 104 upgraded to CRT-Pacemaker (CRT-P) and 95 upgraded to CRT-Defibrillator (CRT-D). The incidence of ventricular arrhythmias and the risk of sudden arrhythmic death obtained through a cause-of-death analysis based on clinical data and necropsy results were assessed and compared between the two groups. During a mean follow-up of 66 ± 24 months, 40 (38.5%) CRT-P patients died: three from primary arrhythmic death, while the remaining died of different causes (especially progressive heart failure), giving an incidence of 6.2 sudden arrhythmic deaths per 1000 patient-years. No episode of sustained VT was observed in the study group. There were no sudden arrhythmic deaths in the CRT-D group during a shorter follow-up, but the small and non-significant difference in all-cause mortality between CRT-Pacemaker (CRT-P) and CRT-D groups was mostly accounted for by an increase in non-sudden death. Women upgraded to CRT were at particularly low risk of all-cause mortality compared with men (HR 0.232, P = 0.048). Conclusion: Our findings suggest that patients who develop pacing-induced cardiomyopathy and are upgraded to CRT may not derive any significant benefit from the addition of the defibrillator in the absence of a history of ventricular arrhythmias.

Acute and sub-acute sinus node dysfunction following pulmonary vein isolation: a case series.

Six patients submitted to paroxysmal atrial fibrillation (AF) ablation presented with long post-reversion sinus pauses between a few hours to 2 months after their procedures, causing recurrent syncope or pre-syncope. Five patients required urgent pacemaker implantation. None of these patients had previous symptoms suggestive of sick sinus syndrome (SSS) or a history of symptomatic bradycardia. Acute or sub-acute sinus node dysfunction (SND) has only recently been suggested as a potential complication of AF ablation. In three of our patients, the sinus node artery (SNA) was exclusively left-sided, running along the high anterior left atrium in close proximity to the ostia of the left and right superior pulmonary veins. In a fourth case, the SNA originated from the right coronary artery and coursed along the high anterior left atrium close to the ostium of the right superior pulmonary vein. In the remaining two cases, a pre-procedural assessment of the SNA was not possible, although a post-procedural CT scan performed in one of these did not reveal any signs of the SNA. Overdrive suppression of the sinus node exacerbated by thermal injury to the SNA may have been implicated. This was supported by (i) the lack of symptoms/signs suggestive of SSS pre-ablation, (ii) post-ablation acute/sub-acute pronounced post-AF reversion sinus pauses, and (iii) the observation that the SNA coursed along areas typically ablated during an AF ablation. Although this case series is hypothesis-generating only, we hope it will raise the awareness for the occurrence of acute/sub-acute SND as a potential complication of AF ablation.

Adding Defibrillation Therapy to Cardiac Resynchronization on the Basis of the Myocardial Substrate.

BACKGROUND: Patients with nonischemic dilated cardiomyopathy (DCM) may be at lower risk for ventricular arrhythmias compared with those with ischemic cardiomyopathy (ICM). In addition, DCM has been identified as a predictor of positive response to cardiac resynchronization therapy (CRT). OBJECTIVES: The aim of this study was to investigate the impact of an additional implantable cardioverter-defibrillator over CRT, according to underlying heart disease, in a large study group of primary prevention patients with heart failure. METHODS: This was an observational, multicenter, European cohort study of 5,307 consecutive patients with DCM or ICM, no history of sustained ventricular arrhythmias, who underwent CRT implantation with (n = 4,037) or without (n = 1,270) a defibrillator. Propensity-score and cause-of-death analyses were used to compare outcomes. RESULTS: After a mean follow-up period of 41.4 ± 29.0 months, patients with ICM had better survival when receiving CRT with a defibrillator compared with those who received CRT without a defibrillator (hazard ratio for mortality adjusted on propensity score and all mortality predictors: 0.76; 95% confidence interval [CI]: 0.62 to 0.92; p = 0.005), whereas in patients with DCM, no such difference was observed (hazard ratio: 0.92; 95% CI: 0.73 to 1.16; p = 0.49). Compared with recipients of defibrillators, the excess mortality in patients who did not receive defibrillators was related to sudden cardiac death in 8.0% among those with ICM but in only 0.4% of those with DCM. CONCLUSIONS: Among patients with heart failure with indications for CRT, those with DCM may not benefit from additional primary prevention implantable cardioverter-defibrillator therapy, as opposed to those with ICM.

Implantable cardioverter-defibrillator elective generator replacement: a procedure for all?

PURPOSE: Six risk stratification scores have been developed to estimate mortality risk in patients receiving an implantable cardioverter-defibrillator (ICD). This study aims at validating and comparing these risk scores in patients having elective ICD generator replacement (GR) and assessing the outcome of patients submitted to this procedure. METHODS: Two hundred twenty three consecutive patients with ischaemic or non-ischaemic dilated cardiomyopathy submitted to elective ICD GR and followed-up for 44 ± 19 months were included. We evaluated which of six previously developed risk scores could predict post-discharge all-cause mortality risk in this context with the highest efficacy. Comparisons between these scores were made using receiver-operating characteristic curves and the integrated discrimination improvement (IDI) index. We further assessed risk of appropriate ICD therapies and all-cause mortality following ICD GR. RESULTS: The prognostic utility of the six scores was assessed by calculating the AUC for follow-up all-cause mortality prediction: Goldenberg - 0.758 ± 0.042, p < 0.001; Parkash - 0.754 ± 0.042, p < 0.001; Bilchick - 0.813 ± 0.038, p < 0.001; Kraaier - 0.721 ± 0.043, p < 0.001; REPLACE DARE - 0.746 ± 0.048, p < 0.001; Providencia - 0.739 ± 0.043, p < 0.001. Through measures of risk reclassification (IDI and relative IDI), the score by Bilchick et al. was shown to outperform all other scores. Binary logistic regression identified pre-GR-appropriate ICD therapy as an independent predictor of post-GR ICD therapy (OR 6.2, CI 95% 3.0-12.7, p < 0.001), along with male gender (OR 6.6, CI 95% 0.8-55, p = 0.082) and history of atrial fibrillation (OR 2.28, CI 95% 1.1-4.5, p = 0.019). CONCLUSIONS: Current prediction scores are useful in predicting mortality risk of patients considered for ICD generator replacement and can potentially help identify patients who may not benefit from continuous ICD treatment due to high mortality rates regardless of the ICD.

Diagnostic yield of molecular autopsy in patients with sudden arrhythmic death syndrome using targeted exome sequencing.

AIMS: The targeted genetic screening of Sudden Arrhythmic Death Syndrome (SADS) probands in a molecular autopsy has a diagnostic yield of up to 35%. Exome sequencing has the potential to improve this yield. The primary aim of this study is to examine the feasibility and diagnostic utility of targeted exome screening in SADS victims, utilizing familial clinical screening whenever possible. METHODS AND RESULTS: To determine the feasibility and diagnostic yield of targeted exome sequencing deoxyribonucleic acid (DNA) was isolated from 59 SADS victims (mean age 25 years, range 1-51 years). Targeted exome sequencing of 135 genes associated with cardiomyopathies and ion channelopathies was performed on the Illumina HiSeq2000 platform. Non-synonymous, loss-of-function, and splice-site variants with a minor allele frequency <0.02% in the NHLBI exome sequencing project and an internal set of control exomes were prioritized for analysis followed by <0.5% frequency threshold secondary analysis. First-degree relatives were offered clinical screening for inherited cardiac conditions. Seven probands (12%) carried very rare (<0.02%) or novel non-sense candidate mutations and 10 probands (17%) had previously published rare (0.02-0.5%) candidate mutations-a total yield of 29%. Co-segregation fully confirmed two private SCN5A Na channel mutations. Variants of unknown significance were detected in a further 34% of probands. CONCLUSION: Molecular autopsy using targeted exome sequencing has a relatively low diagnostic yield of very rare potentially disease causing mutations. Candidate pathogenic variants with a higher frequency in control populations are relatively common and should be interpreted with caution.

A minimal or maximal ablation strategy to achieve pulmonary vein isolation for paroxysmal atrial fibrillation: a prospective multi-centre randomized controlled trial (the Minimax study).

AIMS: Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal). METHODS AND RESULTS: Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 ± 14.6 vs. 41.5 ± 13.1 min; P < 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 ± 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P = 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P < 0.01). CONCLUSION: There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033).

Cardioverter-defibrillator implantation and generator replacement in the octogenarian.

AIMS: Increase in life expectancy has led to increased rate of implantable cardioverter-defibrillator (ICD) implantation in patients in their 80s, but there are no current formal recommendations to guide physicians when elderly patients with ICDs require elective unit replacement (EUR). This study aims at assessing survival and rates of ICD therapies in patients who have had ICD implantation or EUR above the age of 80, focusing on the latter. METHODS AND RESULTS: Retrospective analysis of a prospectively kept database of all ICD-related procedures carried out in a single tertiary centre. Patients 80 years of age or older submitted to ICD implantation (n = 42) or EUR (n = 34) between November 1991 and May 2012 were included. Using collected baseline and outcome data from this cohort, we assessed survival of these patients and the rates of ICD therapies. Median additional years of life after ICD implantation and ICD EUR in patients who died before data retrieval was 2.5 and 1.2, respectively, and while 65% of deceased patients after ICD implantation died in the first 3 years after the procedure, 50% of deceased post-ICD EUR patients died within the first year. Mortality rates at 1 and 2 years post-EUR were 23.1 and 38.1%, respectively. Furthermore, ventricular tachycardia occurred in a small minority of patients after EUR (16.7%) and no ventricular fibrillation-triggered ICD therapies were reported in both groups. CONCLUSION: In octogenarians who are due for an ICD EUR, careful thought should be given to the current clinical status, comorbidities, and general frailty prior to considering them for the procedure. A survival benefit from ICD EUR in this age stratum is not likely.

Untreated atrial fibrillation in the United Kingdom: Understanding the barriers and treatment options.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major preventable cause of stroke and hospitalization. Its prevalence is on the rise worldwide and experts believe it will continue to rise for the foreseeable future, due to the ageing population and increased survival from conditions associated with AF. Despite the fact that oral anticoagulation is effective in preventing strokes due to AF, there is extensive evidence suggesting this therapy remains underused. Barriers to the prescription of anticoagulation include patients' age per se, comorbidities, inadequate risk stratification, perceived risk of falls and bleeding, and the difficulty in achieving a stable international normalized ratio (INR) on warfarin. Also, asymptomatic patients with AF may not be identified and therefore not be candidates for anticoagulation. Physicians need continued better education on the identification of patients at risk of stroke and management of oral anticoagulation. This article reviews the barriers to anticoagulation in patients with AF in the United Kingdom and considers how those barriers may be overcome.

P wave morphology in guiding the ablation strategy of focal atrial tachycardias and atrial flutter.

Focal atrial tachycardias arise preferentially from specific locations within the atria. Careful analysis of the P wave can provide useful information about the chamber and likely site of origin within that chamber. Macro-reentrant atrial flutter also tends to occur over a limited number of potential circuits. In this case, the ECG usually gives a guide to the chamber of origin, but unless it shows a specific morphology it is less useful in delineating the circuit involved. Nonetheless, prior knowledge of the likely chamber of origin helps to plan the ablation strategy.

Cardiac resynchronisation therapy: pacemaker versus internal cardioverter-defibrillator in patients with impaired left ventricular function.

OBJECTIVE: Studies have shown beneficial effects of cardiac resynchronisation therapy (CRT) on mortality among patients with heart failure. However the incremental benefits in survival from CRT with a defibrillator (CRT-D) are unclear. The choice of appropriate device remains unanswered. METHOD: This is a single-centre observational study in a tertiary cardiac centre. Patients (n=500) implanted with a CRT device with pacing alone (CRT-P) (n=354) and CRT-D (n=146) were followed for at least 2 years (mean 29 months, SD 14 months). The primary end point was all-cause mortality. RESULTS: A total of 116 deaths (23.2%) were recorded: 88 (24.8%) and 28 (19.2%), in the CRT-P and CRT-D groups, respectively. At 1 year there was a trend favouring CRT-D (HR 0.54, 95% CI 0.27 to 1.07, p=0.08) but this was attenuated by the 2nd year and became insignificant at the end of follow-up (HR 0.76, 95% CI 0.50 to 1.170, p=0.21). There was no survival benefit from having an internal cardioverter-defibrillator if patients were deemed non-responders to CRT. 27% of the CRT-P patients with ischaemic cardiomyopathy met indications for potential internal cardioverter-defibrillator implantation for primary prevention. These were older patients with poorer baseline function in comparison with CRT-D patients with devices for primary prevention. Once these differences were adjusted for, there was no difference in outcome between the groups. CONCLUSIONS: CRT-D did not offer additional survival advantage over CRT-P at longer-term follow-up, as the clinical benefit of a defibrillator attenuated with time. Further work is needed to define which subset of patients benefit from CRT-D.

Mechanisms of atrial mitral regurgitation: insights using 3D transoesophageal echo.

AIMS: Functional mitral regurgitation (FMR) is a consequence of mitral annular enlargement, leaflet tethering and reduced co-aptation. The importance of the left atrium (LA) as a cause of mitral regurgitation (MR) is less clear. We applied a co-aptation index using three-dimensional (3D) transoesophageal echocardiography to FMR and MR secondary to LA dilatation (atrial mitral regurgitation, AMR). METHODS AND RESULTS: Seventy-two patients underwent comprehensive 3D echo studies: FMR (n = 19); AMR (n = 33); and 20 controls. We recorded: LV size and function; LA dimensions; mitral annular area (MVA); and leaflet area in early and late systole. MVA fractional change was defined: (MVA late systole - MVA early systole)/MVA late systole × 100%; the co-aptation index was defined: (leaflet area early systole - leaflet area late systole)/leaflet area early systole × 100%. Despite normal LV size and function in AMR, MVA was increased similarly to FMR (AMR 12.86 cm(2) vs. FMR 12.33 cm(2), P = ns; both P < 0.01 vs. controls 8.83 cm(2)), and MVA fractional change similarly reduced (AMR 5.1% vs. FMR 6.3%; P = ns; both P < 0.001 vs. controls 14.6%). The co-aptation index was reduced in both MR groups (FMR 6.6% vs. AMR 7.0%, P = ns; both P < 0.001 vs. controls 19.6%). After multivariate analysis, the co-aptation index (χ(2) = 41.2) and MVA fractional change (χ(2) = 22.1) remained the strongest predictors of MR (both P < 0.001 for the model). A co-aptation index of ≤13% was 96% sensitive and 90% specific for the presence of MR. CONCLUSION: LA dilatation leads to MVA enlargement, reduced leaflet co-aptation and MR even without LV dilatation. A co-aptation index describes this in vivo. This work provides insights into the mechanism of AMR.