Catheter Ablation vs Antiarrhythmic Drug Therapy for Treatment of Premature Ventricular Complexes: A Systematic Review.

There is variability in treatment modalities for premature ventricular complexes (PVCs), including use of antiarrhythmic drug (AAD) therapy or catheter ablation (CA). This study reviewed evidence comparing CA vs AADs for the treatment of PVCs. A systematic review was performed from the Medline, Embase, and Cochrane Library databases, as well as the Australian and New Zealand Clinical Trials Registry, U.S. National Library of Medicine ClinicalTrials database, and the European Union Clinical Trials Register. Five studies (1 randomized controlled trial) enrolling 1,113 patients (57.9% female) were analyzed. Four of five studies recruited mainly patients with outflow tract PVCs. There was significant heterogeneity in AAD choice. Electroanatomic mapping was used in 3 of 5 studies. No studies documented intracardiac echocardiography or contact force-sensing catheter use. Acute procedural endpoints varied (2 of 5 targeted elimination of all PVCs). All studies had significant potential for bias. CA seemed superior to AADs for PVC recurrence, frequency, and burden. One study reported long-term symptoms (CA superior). Quality of life or cost-effectiveness was not reported. Complication and adverse event rates were 0% to 5.6% for CA and 9.5% to 21% for AADs. Future randomized controlled trials will assess CA vs AADs for patients with PVCs without structural heart disease (ECTOPIA [Elimination of Ventricular Premature Beats with Catheter Ablation versus Optimal Antiarrhythmic Drug Treatment]), with impaired LVEF (PAPS [Prospective Assessment of Premature Ventricular Contractions Suppression in Cardiomyopathy] Pilot), and with structural heart disease (CAT-PVC [Catheter Ablation Versus Amiodarone for Therapy of Premature Ventricular Contractions in Patients With Structural Heart Disease]). In conclusion, CA seems to reduce recurrence, burden, and frequency of PVCs compared with AADs. There is a lack of data on patient- and health care-specific outcomes such as symptoms, quality of life, and cost-effectiveness. Several upcoming trials will offer important insights for management of PVCs.

A Prospective, Multicentre Randomised Controlled Trial Comparing Catheter Ablation Versus Antiarrhythmic Drugs in Patients With Structural Heart Disease Related Ventricular Tachycardia: The CAAD-VT Trial Protocol.

IMPORTANCE: Randomised trials have shown that catheter ablation (CA) is superior to medical therapy for ventricular tachycardia (VT) largely in patients with ischaemic heart disease. Whether this translates to patients with all forms and stages of structural heart disease (SHD-e.g., non-ischaemic heart disease) is unclear. This trial will help clarify whether catheter ablation offers superior outcomes compared to medical therapy for VT in all patients with SHD. OBJECTIVE: To determine in patients with SHD and spontaneous or inducible VT, if catheter ablation is more efficacious than medical therapy in control of VT during follow-up. DESIGN: Randomised controlled trial including 162 patients, with an allocation ratio of 1:1, stratified by left ventricular ejection fraction (LVEF) and geographical region of site, with a median follow-up of 18-months and a minimum follow-up of 1 year. SETTING: Multicentre study performed in centres across Australia. PARTICIPANTS: Structural heart disease patients with sustained VT or inducible VT (n=162). INTERVENTION: Early treatment, within 30 days of randomisation, with catheter ablation (intervention) or initial treatment with antiarrhythmic drugs only (control). MAIN OUTCOMES, MEASURES, AND RESULTS: Primary endpoint will be a composite of recurrent VT, VT storm (≥3 VT episodes in 24 hrs or incessant VT), or death. Secondary outcomes will include each of the individual primary endpoints, VT burden (number of VT episodes in the 6 months preceding intervention compared to the 6 months after intervention), cardiovascular hospitalisation, mortality (including all-cause mortality, cardiac death, and non-cardiac death) and LVEF (assessed by transthoracic echocardiography from baseline to 6-, 12-, 24- and 36-months post intervention). CONCLUSIONS AND RELEVANCE: The Catheter Ablation versus Anti-arrhythmic Drugs for Ventricular Tachycardia (CAAD-VT) trial will help determine whether catheter ablation is superior to antiarrhythmic drug therapy alone, in patients with SHD-related VT. TRIAL REGISTRY: Australian New Zealand Clinical Trials Registry (ANZCTR) TRIAL REGISTRATION ID: ACTRN12620000045910 TRIAL REGISTRATION URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377617&isReview=true.

Early Catheter Ablation Versus Initial Medical Therapy for Ventricular Tachycardia Storm.

BACKGROUND: Ventricular tachycardia (VT) storm is associated with significantly increased morbidity, mortality, and exponential healthcare utilization. Although catheter ablation (CA) may be curative, there are limited data directly comparing outcomes of early CA with initial medical therapy. METHODS: We compared outcomes of patients presenting with VT storm treated with initial CA versus those treated with initial medical therapy during their first storm presentation in an observational study. Retrospective data from the host institution from January 2014 to April 2020 of 129 patients with their first VT storm presentation were analyzed (58 underwent initial CA, 71 underwent treatment with initial medical therapy). Outcomes were compared in follow-up. RESULTS: Median time to initial CA was 6 days. Over a median follow-up of 702 days, patients who underwent initial CA compared with those treated with initial medical therapy had significantly less: (i) VA recurrence (43% versus 92%; P=0.002); (ii) VT storm recurrence (28% versus 73%; P<0.001); (iii) composite end point of death, heart transplant, VT storm recurrence, and VT-related hospitalization (47% versus 89%; P=0.002); (iv) iatrogenic complications (at 12 months: 17% versus 45%; P<0.001); (v) cardiovascular-related hospitalizations (50% versus 89%; P=0.01); (vi) total number of hospitalizations (median 1 versus 4; P<0.001); and (vi) cumulative days in hospital (median 0.5 versus 18; P<0.001). There were no intraprocedural deaths in patients treated with early CA. CONCLUSION: In an observational setting in which patients presenting with storm, early CA appears superior to initial medical therapy in terms of VT recurrence, storm recurrence, iatrogenic complications, cardiovascular hospitalizations, and cumulative days in hospital in follow-up.

Axillary vein access using ultrasound guidance, Venography or Cephalic Cutdown-What is the optimal access technique for insertion of pacing leads?

We reviewed the different approaches used for central vein access during insertion of cardiac implantable electronic devices. The benefits and hazards of each approach (cephalic vein cutdown, axillary vein cannulation using venography and ultrasound) are discussed. Each approach has its advantages and hazards that need to be considered for the individual patient and balanced against the skills of the operator. The benefits of ultrasound guided venous access in reducing radiation exposure to the patient and implanter, avoiding the need for angiographic contrast and in minimizing the risk of pneumothorax and inadvertent arterial puncture are highlighted. Trainees should be taught each approach to deal with patient variability. Ultrasound guidance should be considered as a mainstream option for most patients.

Clinician-Created Educational Video Resources for Shared Decision-making in the Outpatient Management of Chronic Disease: Development and Evaluation Study.

BACKGROUND: The provision of reliable patient education is essential for shared decision-making. However, many clinicians are reluctant to use commonly available resources, as they are generic and may contain information of insufficient quality. Clinician-created educational materials, accessed during the waiting time prior to consultation, can potentially benefit clinical practice if developed in a time- and resource-efficient manner. OBJECTIVE: The aim of this study is to evaluate the utility of educational videos in improving patient decision-making, as well as consultation satisfaction and anxiety, within the outpatient management of chronic disease (represented by atrial fibrillation). The approach involves clinicians creating audiovisual patient education in a time- and resource-efficient manner for opportunistic delivery, using mobile smart devices with internet access, during waiting time before consultation. METHODS: We implemented this educational approach in outpatient clinics and collected patient responses through an electronic survey. The educational module was a web-based combination of 4 short videos viewed sequentially, followed by a patient experience survey using 5-point Likert scales and 0-100 visual analogue scales. The clinician developed the audiovisual module over a 2-day span while performing usual clinical tasks, using existing hardware and software resources (laptop and tablet). Patients presenting for the outpatient management of atrial fibrillation accessed the module during waiting time before their consultation using either a URL or Quick Response (QR) code on a provided tablet or their own mobile smart devices. The primary outcome of the study was the module's utility in improving patient decision-making ability, as measured on a 0-100 visual analogue scale. Secondary outcomes were the level of patient satisfaction with the videos, measured with 5-point Likert scales, in addition to the patient's value for clinician narration and the module's utility in improving anxiety and long-term treatment adherence, as represented on 0-100 visual analogue scales. RESULTS: This study enrolled 116 patients presenting for the outpatient management of atrial fibrillation. The proportion of responses that were "very satisfied" with the educational video content across the 4 videos ranged from 93% (86/92) to 96.3% (104/108) and this was between 98% (90/92) and 99.1% (107/108) for "satisfied" or "very satisfied." There were no reports of dissatisfaction for the first 3 videos, and only 1% (1/92) of responders reported dissatisfaction for the fourth video. The median reported scores (on 0-100 visual analogue scales) were 90 (IQR 82.5-97) for improving patient decision-making, 89 (IQR 81-95) for reducing consultation anxiety, 90 (IQR 81-97) for improving treatment adherence, and 82 (IQR 70-90) for the clinician's narration adding benefit to the patient experience. CONCLUSIONS: Clinician-created educational videos for chronic disease management resulted in improvements in patient-reported informed decision-making ability and expected long-term treatment adherence, as well as anxiety reduction. This form of patient education was also time efficient as it used the sunk time cost of waiting time to provide education without requiring additional clinician input.

Quantitative spectral assessment of intracardiac electrogram characteristics associated with post infarct fibrosis and ventricular tachycardia.

BACKGROUND: Post-myocardial infarction (MI) remodeling contributes to increased electrophysiological and structural heterogeneity and arrhythmogenesis. Utilising the post-infarct ovine model our aim was to determine unipolar electrogram frequency characteristics consequent to this remodeling and the development of Ventricular Tachycardia (VT). METHODS AND RESULTS: Mapping studies were performed on 14 sheep at >1 month post-MI induction. Sheep were divided into VT inducible (n = 7) and non-inducible (n = 7) groups. Multielectrode needles (n = 20) were deployed within and surrounding ventricular scar for electrophysiological assessment of electrogram amplitude and width. Spectral analysis of electrograms was undertaken using wavelet and fast fourier transformations (WFFT) to calculate root mean square (RMS) power intervals spanning 0-300Hz in 20Hz intervals. Quantitative assessment between electrophysiological and histological parameters including collagen density, and structural organization of the myocardium was performed. Increasing myocardial scar density resulted in attenuation of electrogram amplitude and RMS values. (all p<0.01). Between groups there were no differences in electrogram amplitude (p = 0.37), however WFFT analysis revealed significantly higher RMS values in the VT group (p<0.05) in association with high frequency fractional components of the electrogram. As scar density increased, greater between-group differences in RMS were observed spanning this high frequency (200-280Hz) spectrum and which were proportionally dependent on the degree of structural disorganisation of the myocardium (p<0.001) and number of extrastimuli required to induce VT (p<0.05). CONCLUSION: High frequency unipolar electrogram spectral characteristics were quantitatively co-influenced by the presence of fibrosis and degree of myocardial structural dissorganisation and were associated with the propensity for development of VT.

Importance of the Interventricular Septum as Part of the Ventricular Tachycardia Substrate in Nonischemic Cardiomyopathy.

OBJECTIVES: This study sought to characterize septal substrate in patients with nonischemic left ventricular cardiomyopathy (NILVCM) undergoing ventricular tachycardia (VT) ablation. BACKGROUND: The interventricular septum is an important site of VT substrate in NILVCM. METHODS: The authors studied 95 patients with NILVCM and VT. Electroanatomic mapping using standard bipolar (<1.5 mV) and unipolar (<8.3 mV) low-voltage criteria identified septal scar location and size. Analysis of unipolar voltage was performed and scars quantified using graded unipolar cutoffs from 4 to 8.3 mV were correlated with delayed gadolinium-enhanced cardiac magnetic resonance (DE-CMR), performed in 57 patients. RESULTS: Detailed LV endocardial mapping (mean 262 ± 138 points) showed septal bipolar and unipolar voltage abnormalities (VAs) in 44 (46%) and 79 (83%) patients, most commonly with basal anteroseptal involvement. Of the 59 patients in whom the septum was targeted, bipolar and unipolar septal VAs were seen in 36 (61%) and 54 (92%). Of the 35 with CMR-defined septal scar, bipolar and unipolar septal VAs were seen in 18 (51%) and 31 (89%). In 12 patients without CMR septal scar, 6 (50%) had isolated unipolar septal VAs on electroanatomic mapping, a subset of whom the septum was targeted for ablation (44%). In the graded unipolar analysis, the optimal cutoff associated with magnetic resonance imaging septal scar was 4.8 mV (sensitivity 75%, specificity 70%; area under the curve: 0.75; 95% confidence interval: 0.60 to 0.90). CONCLUSIONS: Septal substrate by unipolar or bipolar voltage mapping in patients with NILVCM and VT is common. A unipolar voltage cutoff of 4.8 mV provides the best correlation with DE-CMR. A subset of patients with septal VT had normal DE-CMR or endocardial bipolar voltage with abnormal unipolar voltage.

Influence of Intramyocardial Adipose Tissue on the Accuracy of Endocardial Contact Mapping of the Chronic Myocardial Infarction Substrate.

BACKGROUND: Recent studies have demonstrated that intramyocardial adipose tissue (IMAT) may contribute to ventricular electrophysiological remodeling in patients with chronic myocardial infarction. Using an ovine model of myocardial infarction, we aimed to determine the influence of IMAT on scar tissue identification during endocardial contact mapping and optimal voltage-based mapping criteria for defining IMAT dense regions. METHOD AND RESULTS: In 7 sheep, left ventricular endocardial and transmural mapping was performed 84 weeks (15-111 weeks) post-myocardial infarction. Spearman rank correlation coefficient was used to assess the relationship between endocardial contact electrogram amplitude and histological composition of myocardium. Receiver operator characteristic curves were used to derive optimal electrogram thresholds for IMAT delineation during endocardial mapping and to describe the use of endocardial mapping for delineation of IMAT dense regions within scar. Endocardial electrogram amplitude correlated significantly with IMAT (unipolar r=-0.48±0.12, P<0.001; bipolar r=-0.45±0.22, P=0.04) but not collagen (unipolar r=-0.36±0.24, P=0.13; bipolar r=-0.43±0.31, P=0.16). IMAT dense regions of myocardium reliably identified using endocardial mapping with thresholds of <3.7 and <0.6 mV, respectively, for unipolar, bipolar, and combined modalities (single modality area under the curve=0.80, P<0.001; combined modality area under the curve=0.84, P<0.001). Unipolar mapping using optimal thresholding remained significantly reliable (area under the curve=0.76, P<0.001) during mapping of IMAT, confined to putative scar border zones (bipolar amplitude, 0.5-1.5 mV). CONCLUSIONS: These novel findings enhance our understanding of the confounding influence of IMAT on endocardial scar mapping. Combined bipolar and unipolar voltage mapping using optimal thresholds may be useful for delineating IMAT dense regions of myocardium, in postinfarct cardiomyopathy.

Successful treatment of Listeria monocytogenes prosthetic valve endocarditis using rifampicin and benzylpenicillin in combination with valve replacement.

Introduction.Listeria monocytogenes is an uncommon cause of prosthetic valve endocarditis (PVE). Recommended antimicrobial therapy typically includes intravenous ß-lactams with or without synergistic aminoglycosides. In vitro studies have previously identified antagonism when rifampicin has been used in combination with ß-lactams. However, in vivo data of rifampicin use are limited despite its enhanced anti-biofilm activity. Case presentation. A 63-year-old male presented with fever and back pain. L. monocytogenes bacteraemia and bioprosthetic aortic valve endocarditis was confirmed, along with spinal discitis and osteomyelitis. He was successfully treated with benzylpenicillin and rifampicin, in conjunction with valve replacement. Conclusion. Rifampicin remains an alternate agent to use, when there are contraindications to traditional aminoglycoside therapy. Further data on rifampicin use in L. monocytogenes PVE are awaited.

Transcatheter non-contact microwave ablation may enable circumferential renal artery denervation while sparing the vessel intima and media.

AIMS: Trials of transcatheter renal artery denervation (RDN) have failed to show consistent antihypertensive efficacy. Procedural factors and limitations of radiofrequency ablation can lead to incomplete denervation. The aim of the study was to show that non-contact microwave catheter ablation could produce deep circumferential perivascular heating while avoiding injury to the renal artery intima and media. METHODS AND RESULTS: A novel microwave catheter was designed and tested in a renal artery model consisting of layers of phantom materials embedded with a thermochromic liquid crystal sheet, colour range 50-78°C. Ablations were performed at 140 W for 180 sec and 120 W for 210 sec, delivering 25,200 J with renal arterial flow at 0.5 L/min and 0.1 L/min. Transcatheter microwave ablations 100-160 W for 180 sec were then performed in the renal arteries of five sheep. In vitro, ablations at 140 W and 0.5 L/min flow produced circumferential lesions 5.9±0.2 mm deep and 19.2±1.5 mm long with subendothelial sparing depth of 1.0±0.1 mm. In vivo, transcatheter microwave ablation was feasible with no collateral visceral thermal injury. There was histological evidence of preferential outer media and adventitial ablation. CONCLUSIONS: Transcatheter microwave ablation for RDN appears feasible and provides a heating pattern that may enable more complete denervation while sparing the renal arterial intima and media.

Catheter Ablation in the Right Ventricular Outflow Tract Associated With Occlusion of Left Anterior Descending Coronary Artery.

Major vessel injury during right ventricular outflow tract ablation is not something widely recognized, and routine evaluation of the left anterior descending (LAD) artery location in relation to the septal right ventricle is not routinely performed. In the present article, we report a case of acute LAD occlusion after right ventricular outflow tract ablation and then illustrate the intimately close relationship of the LAD artery to the anterior septal site of the RVOT (approximately 2-3 cm under the pulmonic valve), using a combination of intracardiac echocardiography and 3-dimensional electroanatomical mapping recorded during a second case, in order to specifically point to the area at risk.

Recovery of renal dysfunction after catheter ablation of outflow tract ventricular arrhythmias in patients with ventricular premature depolarization-mediated cardiomyopathy.

PURPOSE: Frequent ventricular premature depolarizations (VPDs) may cause cardiomyopathy (VPDCM), which often improves after VPD suppression. This study aimed to evaluate whether ablation of outflow tract ventricular arrhythmias (OT VAs) in patients with VPDCM improves renal in addition to left ventricular (LV) function. METHODS: We retrospectively evaluated 153 patients with OT VAs and examined VPD burden and LV ejection fraction (LVEF), as well as estimated glomerular filtration rate (eGFR) pre- and post-ablation. LV dysfunction was defined as LVEF <50 % and impaired renal function was defined as eGFR of <60 mL/min/1.73m2. RESULTS: Fifty-five patients had VPDCM. During mean follow-up of 14 months, 140 (92 %) were free from arrhythmia. In patients with VPDCM, patients with baseline LVEF 40-50 % had greater improvement in the post-ablation LVEF compared to patients with baseline LVEF <40 % (p < 0.01). At baseline, 36 (72 %) patients had renal dysfunction, 29 (81 %) of whom had improvement in eGFR from baseline after successful ablation from eGFR 51 to 57 mL/min/1.73m2. There was a significant association between cardiac (ΔLVEF ≥10 %) and renal (ΔeGFR ≥10 %) improvement (r = 0.54, p = 0.04). Using logistic regression analysis, procedural success was an independent predictor of improvement of cardiac (odds ratio [OR] = 13.7, p = 0.03) and renal function (OR = 21.0, p = 0.047). CONCLUSIONS: Successful catheter ablation of OT VA reduces VPD burden and is associated with improved cardiac and renal function in patients with VPDCM.

Five seconds of 50-60 W radio frequency atrial ablations were transmural and safe: an in vitro mechanistic assessment and force-controlled in vivo validation.

AIMS: Longer procedural time is associated with complications in radiofrequency atrial fibrillation ablation. We sought to reduce ablation time and thereby potentially reduce complications. The aim was to compare the dimensions and complications of 40 W/30 s setting to that of high-power ablations (50-80 W) for 5 s in the in vitro and in vivo models. METHODS AND RESULTS: In vitro ablations-40 W/30 s were compared with 40-80 W powers for 5 s. In vivo ablations-40 W/30 s were compared with 50-80 W powers for 5 s. All in vivo ablations were performed with 10 g contact force and 30 mL/min irrigation rate. Steam pops and depth of lung lesions identified post-mortem were noted as complications. A total of 72 lesions on the non-trabeculated part of right atrium were performed in 10 Ovine. All in vitro ablations except for the 40 W/5 s setting achieved the critical lesion depth of 2 mm. For in vivo ablations, all lesions were transmural, and the lesion depths for the settings of 40 W/30 s, 50 W/5 s, 60 W/5 s, 70 W/5 s, and 80 W/5 s were 2.2 ± 0.5, 2.3 ± 0.5, 2.1 ± 0.4, 2.0 ± 0.3, and 2.3 ± 0.7 mm, respectively. The lesion depths of short-duration ablations were similar to that of the conventional ablation. Steam pops occurred in the ablation settings of 40 W/30 s and 80 W/5 s in 8 and 11% of ablations, respectively. Complications were absent in short-duration ablations of 50 and 60 W. CONCLUSION: High-power, short-duration atrial ablation was as safe and effective as the conventional ablation. Compared with the conventional 40 W/30 s setting, 50 and 60 W ablation for 5 s achieved transmurality and had fewer complications.

Ninety Seconds Could be the Optimal Duration for Ventricular Radiofrequency Ablation - Results From a Myocardial Phantom Model.

BACKGROUND: Shallow lesions could be the predominant factor affecting the efficacy of ventricular radiofrequency (RF) ablations. The objective of this study was to assess lesion dimensions and overheating in extended RF ablations up to 180seconds and compare with that of conventional 30seconds ablations. METHODS: The Navistar Thermocool irrigated catheter (Biosense Webster, CA, USA) was used in a previously validated myocardial phantom. Ablations were performed with 20W, 30W, 40W and 50W powers for 180seconds. The volume of lesion and overheating were measured at 530C and 800C isotherms respectively. RESULTS: A total of 110 RF lesions were analysed. The lesion depth increment when ablation was extended from the conventional 30seconds to 90seconds were 31.2±0.2, 33.6±0.6, 36.3±1.8% of that at 30seconds, respectively for powers 30W, 40W and 50W. During 30W ablations, at 90seconds the lesion width and depth were 95.4±1.2%, 91.8±1.6% respectively of the final dimensions at 180seconds. Similar proportions were observed for 40W and 50W. During 40W ablations, the volume of overheating was 113±6% and 184±11% higher at 90seconds and 180seconds respectively compared to that at 30seconds and was 142±9% and 194±9% for 50W ablations. CONCLUSION: Extending RF ablations up to 90seconds significantly increased the lesion depth (30-40%), however, overheating was present at 40W and 50W powers. Ablations beyond 90seconds provided little incremental value.

Recurrent atrial arrhythmias in the setting of chronic pulmonary vein isolation.

BACKGROUND: Atrial arrhythmias may still occur in patients after durable pulmonary vein isolation (PVI). OBJECTIVE: The purpose of this study was to examine the incidence of patients undergoing ablation for recurrent arrhythmia despite chronic PVI and their clinical outcomes. METHODS: Patients undergoing repeat left atrial ablation procedures were selected from a prospective registry. From this population, we identified patients with chronic PVI. Clinical characteristics, ablation strategies, and outcomes were analyzed. RESULTS: Between January 2003 and December 2013, 1045 patients underwent 1298 repeat left atrial procedures. Of these, 900 patients had atrial fibrillation (AF) and 145 had atrial flutter (AFL)/atrial tachycardia (AT). Fifty-two patients (5.0%; 27 with AF and 25 with AFL/AT) had chronic PVI and were included in the study. Patients were followed for 19.7 ± 5.6 months. In patients with AF, 11 (41%) had a non-PV trigger identified. Ablation strategies included non-PV trigger ablation (n = 11), empiric trigger-site ablation (n = 3), provoked arrhythmia ablation (n = 9), complex fractionated atrial electrogram ablation (n = 2), and linear ablation (n = 2). During follow-up, 9 (33%) had no recurrence, 7 (26%) had rare AF (≤2 episodes during follow-up ≥1 year), and 11 (41%) had AF recurrence. In patients with AFL/AT, 12 (48%) had no recurrence, 4 (16%) had rare recurrence (≤2 episodes during follow-up ≥1 year), and 9 (36%) had recurrence. CONCLUSION: In patients with PVI undergoing a repeat procedure during the time period studied, only a small portion had chronic PVI. A strategy of targeting non-PV triggers for AF and linear/focal ablation for AFL/AT may achieve long-term arrhythmia control in the majority of patients.

Atrial fibrillation ablation by single ring isolation versus wide antral isolation: Effects on left atrial size and function.

BACKGROUND: Pulmonary vein isolation (PVI) by single ring isolation (SRI) has been demonstrated to reduce recurrence of atrial fibrillation (AF) compared to the standard technique of wide antral isolation (WAI). In this study, we examine the differential effect of these techniques on left atrial size and function. METHODS: We examined left atrial (LA) size (LA maximum and LA minimum volumes) and function (LA emptying fraction and LA expansion index) over a period of 6 months following PVI as measured by transthoracic echocardiography in 187 patients that were enrolled in a randomised controlled trial of SRI vs WAI. RESULTS: Compared to pre-ablation, at 6 months post-PVI, there was a small decrease in the LA maximum volume in the WAI group (67.3 vs 62.7 mL, p=0.02). The LA size did not change significantly over 6 months in the SRI group. Patients who underwent SRI had a small reduction in the LA expansion index at 6 months post-PVI compared to baseline (80.6 vs 66.6%, p=0.02). LA function did not change significantly over 6 months in the WAI group. However, at 6 months, there was no difference in any measure of LA size or function between the SRI and WAI groups. CONCLUSIONS: SRI, whilst previously demonstrated to be more effective than WAI in preventing AF recurrence, is associated with minimal adverse effects on left atrial function at medium term follow-up despite the isolation of a larger region of LA myocardium.