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Introduction Successful pulmonary vein isolation (PVI) for atrial fibrillation (AF) depends on the formation of durable transmural lesions. Recently, novel indices have emerged to guide lesion delivery. The aim of the systematic review of literature was to determine AF recurrence following ablation guided by indices incorporating force, power and time, and compare acute procedural outcomes and 12-month AF recurrence with ablation guided by contact force (CF) guided only. Methods PubMed, EMBASE, and Web of Science Core Collection databases were searched on 27 January 2020 using the keywords; catheter ablation, ablation index (AI), lesion size index (LSI), contact force, atrial fibrillation. Results After exclusions, seven studies were included in the analysis. AI-guided catheter ablation was associated with a 91% (n=5, 0.91 95% CI; 0.88–0.93) and 80% (n=5, 0.80, 95% CI; 0.77–0.84) freedom from AF at 12 months with and without the use of anti-arhythmic drugs respectively. As compared to CF guided ablation, AI-guided catheter ablation was associated with a 49% increase in successful first pass isolation (n=3; RR: 1.49, 95% CI; 1.38, 1.61), a 50% decrease in number of acute reconnections (n=4; RR: 0.50, 95% CI; 0.39–0.65) and a 22% (n=4, RR: 1.22, 95% CI; 1.10–1.35) increase in AF freedom without anti-arrhythmic drugs at 12 months. Conclusions Radiofrequency ablation guided by AI was associated with higher successful first pass isolation and lower rates of acute reconnection which translates to greater freedom from AF at 12 months [CRD42019131469].

Patients with non-valvular atrial fibrillation (NVAF) are at an increased risk of ischemic stroke due to the risks of thrombus formation. The left atrial appendage (LAA) is shown to be “the culprit” of thromboembolic events in NVAF and is currently a therapeutic target to prevent stroke. The absolute benefit of oral anticoagulation in the management of NVAF to improve cardiovascular outcomes has been well established. However, some patients are not good long-term candidates for oral anticoagulation for many reasons, including risks of bleeding, noncompliant to oral anticoagulation (OAC). Left atrial appendage occlusion (LAAO) provides an attractive alternative to reduce the risk of stroke for those who are contraindicated to OAC therapy.

Despite being the most common supraventricular tachycardia in clinical practice, atrioventricular nodal reentrant tachycardia (AVNRT) still often imposes challenges both conceptually but also from a procedural standpoint. The anatomic substrate for AVNRT is still not fully understood and controversy remains as to whether the reentrant circuit involves part of the atrium.1 The model of a reentrant circuit with a slow pathway in the right atrial inferoseptal region and a more anteriorly located fast pathway in the apex of the Koch triangle has served as a simplistic conceptual framework, which, however, has been challenged. The notion of an upper common pathway localized between the upper turnaround point within the atrioventricular (AV) node upper junction of fast and slow pathways and the atria as a separate anatomical entity has also been disputed.2,3 This controversy stems predominantly from the lack of any supportive histological evidence. It has been long recognized, however, that unlike the AV reentrant tachycardia, the atrium is not an obligate part of the concept circuit, as evidenced by the fact that the atria can dissociate from the tachycardia during AVNRT and also during pacing maneuvers. Nonetheless, more recent evidence suggests that perinodal atrial tissue may be part of the tachycardia circuit. We report a case of typical AVNRT that persisted with various degrees of ventriculoatrial (VA) block as well as during sustained atrial fibrillation (AF), suggestive of the presence of an upper common pathway.

BackgroundMicrovascular angina (MVA) is increasingly recognized as an endotype of ischaemia with no obstructive coronary artery disease (INOCA), but assessment remains difficult while validated diagnostic investigation is invasive. This pilot study assessed the correlation between left ventricular contractile reserve (CR), measured via speckle-tracking imaging on low dose dobutamine stress echocardiography (DSE) and the invasive coronary microvascular function in patients with INOCA.MethodsForty-two patients with INOCA and abnormal coronary vasomotor dysfunction were prospectively screened at a single tertiary centre covering the Northern metropolitan area of South Australia, from February 2018 to December 2020 (ACTRN12618000149268). Forty patients were invited into to the DSE study after coronary angiography demonstrated NOCAD and abnormal coronary epicardial and microvascular function (n = 40).Results: Of the 40 participants undergoing DSE study, 30 were suitable to be included in the final analysis. Average age of 54.8 ± 10.8 years old and more female (76.2%) than male recruited. 92.1% of patients were of Caucasian ethnicity. 65.8% were considered obese. The study cohort demonstrating a degree of angina burden, with 73.7% experiencing > once angina in a week. Weak positive association between CR with hyperaemic microvascular resistance (HMR); at 5mcg/kg/min, CR(absolute) (r=0.427, p-value=0.019); between 5 and 10 mcg/kg/min, CR(absolute) (r = 0.481, p-value = 0.007). The relationship between CR and HMR showed a trend of increase in CR at a DSE of 5mcg/kg/min, but a blunted response at the higher doses of 10 and 20mcg/kg/min (p=0.400). Weak positive association between CR with coronary flow reserve (CFR); at 5mcg/kg/min, CR(absolute) (r = 0.442, p-value = 0.015). The relationship between CR and CFR showed a trend of increase in CR at a DSE of 5mcg/kg/min, but a blunted response at the higher doses of 10 and 20mcg/kg/min (p=0.393).Conclusion:This pilot study has provided the possible utility of speckle tracking technique in assessment of INOCA with a MVA endotype.

Obstructive sleep apnea (OSA) is increasingly recognized to be a risk factor for cardiovascular disease. This pilot study assessed the association of OSA and invasive coronary microvascular function in patients with ischemia with no obstructive coronary artery disease (INOCA). Forty-two patients with angina, were prospectively screened at a single tertiary centre covering the northern metropolitan area of South Australia, from February 2018 to December 2020 (ACTRN12618000149268). Forty patients were invited into to this observational study after coronary angiography demonstrated INOCA and functional coronary vasomotor disorder (n = 40). Twenty one participants subsequently underwent a sleep study for OSA diagnosis while 9 participants had prior formal diagnosis of OSA (ACTRN12618000227291). Of the 30 participants with OSA data, 87% (n = 26) had a diagnosis of OSA. Accordingly, 11 with mild severity, 7 with moderate severity and 8 with severe OSA. No OSA was observed in 4 participants. Participants with OSA were older [61.4±8.7 vs 49.9±9.7, P = 0.002] with similar clinical characteristics for the pattern and severity of angina and other co-morbidities. 73.3% (n = 22) had abnormal functional disorders of the epicardial coronary arteries and/or coronary microcirculation. On multivariate analysis, OSA was the only statistically significant association with functional coronary microvascular disorders [OR 53.95, 1.41 -2065.01, P = 0.032]. This study provided an observation of a significant correlation between INOCA with abnormal coronary vasomotor function and OSA in an Australian cohort. This correlation supports a possible pathophysiological interplay between these two conditions that needs to be further evaluated. The benefit of treatment of OSA in this subset remains unknown.

A 60-year old male with paroxysmal atrial fibrillation underwent a combined procedure of left atrial appendage occlusion and pulmonary vein isolation. However, an acute intraprocedural 24-mm Watchman device dislodgement occurred, and thus a decision for urgent surgery was made. However, it was noted during the surgery that the device had migrated further to the descending aorta, just distal to the left subclavian artery. Since a right sternotomy access for retrieval was not feasible, a percutaneous approach was justified. A homemade snare was created using a combination of a long sheath, J-wire, and a regular snare, and the device was successfully retrieved without significant difficulty.

Background Atrial fibrillation (AF) is common after pacemaker implantation. However, the impact of pacemaker algorithms in AF prevention is not well understood. Objective The purpose of this study was to evaluate the role of pacing algorithms in preventing AF progression. Methods A systematic search of articles using the PubMed and Embase databases resulted in a total of 754 references. After exclusions, 21 randomized controlled trials (8336 patients) were analyzed, comprising studies reporting ventricular pacing percentage (VP%) (AAI vs DDD, n=1; reducing ventricular pacing [RedVP] algorithms, n=2); and atrial pacing therapies (atrial preference pacing [APP], n=14; atrial antitachycardia pacing [aATP]+APP, n=3; RedVP+APP+aATP, n=1). Results Low VP% ( 10%). APP algorithm reduced premature atrial complexes (PAC) burden (mean difference [MD] –1117.74; 95% CI –1852.36 to –383.11; P = .003; I2 = 67%) but did not decrease AF burden (MD 8.20; 95% CI –5.39 to 21.80; P = .24; I2 = 17%) or AF episodes (MD 0.00; 95% CI –0.24 to 0.25; P = .98; I2 = 0%). Similarly, aATP+APP programming showed no significant difference in AF progression (odds ratio 0.65; 95% CI 0.36–1.14; P = .13; I2 = 61%). No serious adverse events related to algorithm were reported. Conclusion This meta-analysis of randomized controlled trials demonstrated that algorithms to reduce VP% can be considered safe. Low burden VP% did not significantly suppress AF progression. The atrial pacing therapy algorithms could suppress PAC burden but did not prevent AF progression.

INTRODUCTION The evidence on the association between obesity and atrial fibrillation (AF) recurrence was equivocal. We aimed to evaluate the dose-response relationship between body mass index (BMI) and AF recurrence and adverse events. METHODS A systematic literature search was conducted using PubMed, Europe PMC, EBSCO, ProQuest and Cochrane Library. Obesity was defined as BMI ≥28 kg/m2 . The primary outcome was AF recurrence, and the secondary outcome was adverse events. Adverse events were defined as procedure-related complications and cardio-cerebrovascular events. RESULTS There were a total of 52,771 patients from 20 studies. Obesity was associated with higher AF recurrence (Odds ratio [OR] 1.30 [95% confidence interval [CI] 1.16-1.47], P

BACKGROUND Medical technology has made significant advances over the last few decades with smaller and more dynamic pacemakers. However, technical failures leading to premature replacement is a cause of concern. We present a series of Medtronic EnRhythm devices that reached premature elective replacement indicator (ERI). METHODS The database of Centre of Heart Rhythm Disorders was searched for EnRhythm device implantation from 2006 to 2011. Battery depletion

Background: The posterior left atrium is an arrhythmogenic substrate that contributes to the initiation and maintenance of atrial fibrillation (AF); however, the feasibility, safety, and efficacy of posterior wall isolation (PWI) as an AF ablation strategy has not been widely reported. Methods: We undertook a systematic review and meta-analysis of studies performing PWI to assess (1) acute procedural success including the ability to achieve PWI and the number of procedure-related complications, (2) Long-term, clinical success including rates of arrhythmia recurrence and posterior wall reconnection, and (3) The efficacy of PWI compared with pulmonary vein isolation on preventing arrhythmia recurrence. MEDLINE, EMBASE, and Web of Science databases were searched in May 2018 to retrieve relevant studies. Results were pooled using a random effects model. Results: Seventeen studies (13 box isolation, 3 single ring isolation, and 1 debulking ablation) comprising 1643 patients (31.3% paroxysmal AF, left atrial diameter 41±3.1 mm) were included in the final analysis. In studies focusing specifically on PWI, the acute procedural success rate for achieving PWI was 94.1% (95% CI, 87.2%–99.3%). Single-procedure 12-month freedom from atrial arrhythmia was 65.3% (95% CI, 57.7%–73.9%) overall and 61.9% (54.2%–70.8%) for persistent AF. Randomized control trials comparing PWI to pulmonary vein isolation (3 studies, 444 patients) yielded conflicting results and could not confirm an incremental benefit to PWI. Fifteen major complications (0.1%), including 2 atrio-esophageal fistulas, were reported. Conclusions: PWI as an end point of AF ablation can be achieved in a large proportion of cases with good rates of 12-month freedom from atrial arrhythmia. Although the procedure-related complication rate is low, it did not eliminate the risk of atrio-esophageal fistula. Registration: URL: http://www.crd.york.ac.uk/prospero . PROSPERO registration number: CRD42018107212.

ObjectiveThe aim of the meta-analysis was to determine the association of obesity and heart failure (HF) and the cardiac impact of intentional weight loss following bariatric surgery on cardiac structure and myocardial function in obese subjects.MethodsMEDLINE, Embase and Web of Science were searched up to 3 April 2018. Studies reporting association and prognostic impact of obesity in HF and the impact of intentional weight loss following bariatric surgery on cardiac structure and myocardial function in obesity were included in the meta-analysis.Results4959 citations were reviewed. After exclusions, 29 studies were analysed. A ‘J curve’ relationship was observed between body mass index (BMI) and risk of HF with maximum risk in the morbidly obese (1.73 (95% CI 1.30 to 2.31), pConclusionsDespite the increased risk of HF with obesity, an ‘obesity paradox’ is observed for all-cause mortality. However, the nadir for CV mortality is observed in the overweight group. Importantly, intentional weight loss was associated with improvement in indices of cardiac structure and myocardial function in obese patients.Trial registration numberAPP 74412.

Aims Several techniques have been utilized for the ablation of persistent (P) and long-standing persistent (LsP) atrial fibrillation (AF); however, the best approach of substrate ablation remains poorly defined. This study aims to examine the impact of ablation approach on outcomes associated with P or LsP AF ablation by conducting a meta-analysis and regression on contemporary literature. Methods and results A systematic literature review was conducted up to 29 July 2015 for scientific literature reporting on outcomes associated with P or LsP AF ablation. One hundred and thirteen studies reported outcomes in a total of 18 657 patients undergoing various ablation approaches for the treatment of P-LsP AF between 2001 and 2015. The point efficacy estimate of a single-AF ablation procedure without the use of anti-arrhythmic drugs was 43% (95% CI; 39-47%). Multiple procedures and/or the use of anti-arrhythmic drugs increase success to 69% (95% CI; 66-71%). Meta-regression revealed that ablation technique (P

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Background Insertable cardiac monitors (ICMs) are increasingly utilized for diagnosis of unexplained syncope and arrhythmia monitoring. The Reveal LINQ is a novel miniaturized ICM with improved algorithms. The feasibility and safety of insertion outside the traditional electrophysiology laboratory is unknown. Here we compare outcomes of Reveal LINQ insertion in different environments. Methods We report on a prospective, single-centre, non-randomized, observational experience of consecutive Reveal LINQ implantation in the electrophysiology laboratory or a procedure room between October 2013 and October 2015. Results Of 178 consecutive patients who underwent LINQ device insertion, 80 were implanted in the electrophysiology laboratory and 98 in a procedure room. There were no significant differences in baseline patient characteristics. All implants were performed in the recommended manufacturer method with the exception of 1 which required suture closure. Only a minority received peri-procedural antibiotics with a greater number in the electrophysiology laboratory group (11 [14%] versus 1 [1%], p=0.007). Overall, there were 3 (1.7%) complications with no significant difference between the electrophysiology laboratory and the procedure room groups (2 [3%] versus 1 [1%], p=0.45). There was 1 superficial infection in the procedure room group and 1 superficial infection with device extrusion and 1 traumatic extrusion in the electrophysiology laboratory group. Procedure room implantation subjectively improved laboratory efficiency and patient flow. Conclusion Reveal LINQ insertion can be safely performed outside of the cardiac laboratory provided a sterile technique is followed by the operator using manufacturer recommendations for insertion. These findings have significant resource implications for hospitals undertaking such procedures.

Reel syndrome is a variant form of twiddler's syndrome. We describe a 53 years old woman who was referred to our hospital because of symptomatic sinus bradycardia. Subsequently she underwent dual chamber pacemaker implantation and was sent back to the previous hospital on the following day. She was referred again because of sudden syncope due to low heart rate 2 weeks following implantation. Chest X-ray revealed leads had pulled out of the heart and coiled up around the pacemaker generator; a diagnosis of reel syndrome was made. The difference between the two syndromes, risk factors and preventive measures were discussed.

Although coronary artery bypass graft (CABG) surgery has had major advances in surgical techniques and will minimize patients’ clinical symptoms and improve survival, vein grafts continue to have high failure rates. If graft failure occurs, it will lead to worsening outcomes such as recurrent myocardial infarction (MI) and heart failure (HF). It has been shown that in select HF patients, cardiac resynchronization therapy (CRT) would lead left ventricular reverse remodeling and improve patients’ symptoms, quality of life, exercise tolerance, and finally improve survival. Most heart failures in patients following CABG are due to graft failures, which are related to occurring ischemia burden or scar tissue due to myocardial infarction. Therefore, in select patients, CRT may also have a beneficial effect, such as in non-CABG heart failure patients. Wider QRS complex with left bundle branch block morphology, low ejection fraction and New York Heart Association (NYHA) functional class II or higher are the only criteria for patient selection as recommended by many guidelines. If the ischemia burden is significant, then its management should be discussed with the local Heart Team (including intervention cardiologist and cardiac surgeon) whether additional percutaneous coronary intervention (PCI) or redo CABG should be performed despite CRT or CRT defibrillator (CRT-D) implantation. The complications related with CRT implantation are left ventricle (LV) lead dislodgement, phrenic nerve stimulation (PNS), and coronary sinus dissection. Although the complication rate is quite low, the implanter should take into consideration these potential complications. New techniques and devices for CRT implantation are now widely used and new advanced LV lead technology is commencing; hence the implantation technique will become easier and safer. The proper follow-up, especially for atrio-ventricular (AV) and ventriculo-ventricular (VV) optimization, is also important and needed besides successful CRT or CRT-D implantation.