Age-Based Trends in the Outcomes of Percutaneous Left Atrial Appendage Occlusion: Insights from a Real-World Database

The age-based trends in-hospital outcomes in patients with percutaneous left atrial appendage occlusion (LAAO) are unknown. Using the National Readmission Database from 2016 to 2019, patients who underwent LAAO were divided into 2 age groups: 60 to 79 and ≥80 years. The primary objective was to evaluate the age-based trends in the outcomes related to LAAO. The secondary objectives were to evaluate the mean cost and total cumulative cost of readmissions in both age groups in 2019. We identified 58,818 patients who underwent LAAO, of whom 36,964 (63%) were aged 60 to 79 years, and 21,854 (37%) were ≥80 years. The hospital mortality, pericardial complications, acute kidney injury, and in-hospital cardiac arrest did not change over time. The risk-adjusted postoperative stroke and bleeding requiring blood transfusion decreased in patients aged ≥80 years (p trend 0.03 for both outcomes). The length of stay decreased, and early discharge rates increased over time in both the unadjusted and risk-adjusted models in both age groups. The risk-adjusted 90-day readmission rates also decreased in patients aged ≥80 years. The inflation-adjusted cost did not change over time on the unadjusted and adjusted analyses. The total cumulative all-cause 90-readmission cost for both groups in 2019 was $31.7 million. Most outcomes after LAAO either improved or did not change from 2016 to 2019. Hospital mortality has remained <0.5% consistently since 2016. The risk-adjusted postoperative stroke, bleeding, and 90-day readmission rates improved in elderly vulnerable patients aged ≥80 years. The inflation-adjusted cost did not improve despite the decreasing length of stay and improving early discharge rates.

Risk of Atrial Fibrillation and Stroke After Bariatric Surgery in Patients With Morbid Obesity With or Without Obstructive Sleep Apnea

[Figure: see text].

Characterizing Recurrence Following Hybrid Ablation in Patients With Persistent Atrial Fibrillation

Purpose

It is widely accepted that atrial fibrillation (AF) accounts for half of arrhythmia recurrences following endocardial catheter ablation of AF. An epicardial-endocardial approach (hybrid) has emerged as an alternative to endocardial ablation alone for the treatment of AF, yet recurrence after a hybrid procedure has not been well characterized. This retrospective study is aimed at characterizing recurrence following hybrid ablation for patients with persistent AF.

Methods

Patients with persistent AF (N=108) received both endocardial and epicardial ablation of the posterior left atrial wall using catheter ablation and a small midline surgical approach (hybrid). Presence of atrial flutter or AF was determined with ambulatory monitoring (n=22) or electrocardiogram analysis (n=86) at each follow-up visit. Recurrence mode was confirmed by electrophysiology study for those patients undergoing subsequent catheter ablation after hybrid ablation.

Results

Patients were followed for a mean ± standard deviation of 25 ± 14 months. Of patients who had a recurrence, 53% (n=33) were in atrial flutter and 47% (n=29) were in AF. Of those who had a recurrence with atrial flutter, 14 received repeat ablation for either left (n=11) or left/right (n=3) atrial flutter and 3 received AF ablation. Half of ablations for atrial flutter recurrence following the hybrid procedure involved the mitral isthmus.

Conclusions

Atrial flutter accounts for about half of arrhythmia recurrences post-hybrid ablation. If catheter ablation of the mitral isthmus is considered during the hybrid procedure to prevent subsequent occurrence of perimitral flutter, bidirectional block must be performed to ensure a complete line of block.

P5658Incorporation of severity of left atrial enlargement in clinical risk factors improves identification of patients at risk for development of atrial fibrillation

Background

Early identification of patients at risk for atrial fibrillation (AF) is desirable to prevent its development and complications. Clinical predictors have been recognized but need refinement to improve predictability. We evaluated whether severity of left atrial enlargement (LAE) added to a scoring system (CHA2DS2VASC) in an unselected non-AF population improves risk stratification for incident AF.

Purpose

To assess the incremental benefit of LAE severity added to CHA2DS2VASc in predicting future AF in non-AF patients.

Methods

From 2012–2017, consecutive adult patients with an echocardiogram and no prior AF were identified. CHA2DS2VASc was used to define baseline AF risk, and the incremental risk of AF with addition of LAE was assessed through increased LA volume index (LAVI; moderate 42–48 ml/m2, severe >48 ml/m2). To quantify improvement in risk prediction, logistic regression model was fitted and odds ratios (OR) and ROC curves obtained.

Results

Out of 155,597 patients with no prior AF, 13.8% developed AF over 1.5±1.3 years. OR for AF with CHA2DS2VASc was 1.68 (95% CI 1.66–1.69). With addition of moderately or severely increased LAVI to the model, OR for AF increased to 2.3 (2.2–2.5) and 3.8 (3.6–4.0), respectively. ROC analysis showed c-statistics of 0.66 with CHA2DS2VASc, 0.63 with LAVI, and 0.71 with incorporation of both (Fig).

AF CHAD score

Conclusion(s)

In non-AF patients, predictability for future AF can be improved by using clinical factors (CHA2DS2VASc) and increased LAVI. This information may guide closer monitoring and initiation of therapies to prevent progression to AF or stroke.

Acknowledgement/Funding

None

The beneficial effect of weight reduction on adverse cardiovascular outcomes following bariatric surgery is attenuated in patients with obstructive sleep apnea

Weight loss after bariatric surgery is associated with reduction in adverse cardiovascular outcomes; however, the impact of obstructive sleep apnea (OSA) on reduction of cardiovascular outcomes after bariatric surgery in morbidly obese patients is not known. We retrospectively assessed differences in cardiovascular events after laparoscopic adjustable gastric banding (LAGB)-induced weight loss in patients with and without OSA before and after propensity score matching for age, sex, body mass index (BMI), and major comorbidities between the two groups and determined predictors of poor outcomes. OSA was present in 222 out of 830 patients (27 per cent) who underwent LAGB between 2001 and 2011. Despite a similar reduction in BMI (20.0 and 20.8 per cent), a significantly higher percentage of cardiovascular events were observed in patients with than without OSA (35.6 vs 6.9 per cent; p < 0.001) at 3 years (mean follow-up 6.0 ± 3.2; range: 0.5 to 13 years). The differences in the cumulative endpoint of new onset stroke, heart failure, myocardial infarction, venous thrombosis, and pulmonary embolism between the OSA and non-OSA groups were maintained after propensity matching. Patients with OSA treated with continuous positive airway pressure (CPAP) during sleep [n = 66] had lower cardiovascular event rates at 30 months compared with those not treated (p < 0.041). OSA (hazard ratio: 6.92, 95% CI: 3.39-14.13, p < 0.001) remained an independent predictor of cardiovascular events after multivariate analysis. Thus, patients with OSA, despite a similar initial weight loss after LAGB, had a higher incidence of cardiovascular events compared with a propensity-matched group without OSA. Treatment with CPAP appears to reduce such events.

Abstract 270: Peroxisome Proliferator Activated Receptor- α is a Connecting Link Between Cardiac Fibrosis and Oxidative Stress in Atrial Fibrillation

Background: AF, a common sustained arrhythmia that predisposes heart failure and stroke, is associated with cardiac fibrosis and oxidative stress. Peroxisome proliferator-activated receptor (PPAR)-α, important for ROS and lipid degradation, is reported to negatively correlate with kidney, liver, and lung fibrosis, but its role in cardiac fibrosis is less clear. We hypothesize that reduced expression of PPARα in AF contributes to oxidative stress and interferes with TGFβ signaling, a cytokine implicated in cardiac fibrosis.

Methods: Myocardial fibrosis was detected (Masson trichrome) in right atrial appendages of AF and non-AF patients. Levels of 4-hydroxynonenal (4-HNE) (ELISA) and superoxide production (MitoSOX) were assayed in patients’ atrial tissue homogenates and cardiac myofibers respectively. Using atrial fibroblasts (hAF) from AF and non-AF patients, α-SMA, COL1A1 and c-Jun/c-Fos expressions were determined (RT-PCR and/or Western Blot) in the absence and presence of TGF-β (5 ng) with or without ciprofibrate (200 μM), a PPARα agonist.

Results: Increased atrial fibrosis, levels of 4-HNE (101.7 vs 7.4 ng/mg protein; p=0.02(n=6)) and oxidative stress (8.7 fold; p=0.04) correlated with reduced PPAR-α mRNA (2.1 fold; p<0.01) in AF patients. Activation of PPARα by ciprofibrate reduced TGFβ1-induced increased expression of α-SMA and COL1A1 by repressing AP-1 signaling in hAF.

Conclusion: Reduced expression of PPARα is associated with impaired cardiac mitochondrial metabolism and promotes TGFβ-induced profibrotic pathway. Preliminary data suggest PPARα agonist might confer therapeutic benefits for patients with cardiac fibrosis and oxidative stress in AF.

Identifying the third dimension in 2D fluoroscopy to create 3D cardiac maps

Three-dimensional cardiac mapping is important for optimal visualization of the heart during cardiac ablation for the treatment of certain arrhythmias. However, many hospitals and clinics worldwide cannot afford the high cost of the current mapping systems. We set out to determine if, using predefined algorithms, comparable 3D cardiac maps could be created by a new device that relies on data generated from single-plane fluoroscopy and patient recording and monitoring systems, without the need for costly equipment, infrastructure changes, or specialized catheters. The study included phantom and animal experiments to compare the prototype test device, Navik 3D, with the existing CARTO 3 System. The primary endpoint directly compared: (a) the 3D distance between the Navik 3D-simulated ablation location and the back-projected ground truth location of the pacing and mapping catheter electrode, and (b) the same distance for CARTO. The study's primary objective was considered met if the 95% confidence lower limit was greater than 0.75% for the Navik 3D-CARTO difference between the 2 distances, or less than or equal to 2 mm. Study results showed that the Navik 3D performance was equivalent to the CARTO system, and that accurate 3D cardiac maps can be created using data from equipment that already exists in all electrophysiology labs.

Outcomes of In-Hospital Cardiopulmonary Resuscitation in Morbidly Obese Patients

OBJECTIVES

This study sought to assess the impact of morbid obesity on outcomes in patients with in-hospital cardiac arrest (IHCA).

BACKGROUND

Obesity is associated with increased risk of out-of-hospital cardiac arrest; however, little is known about survival of morbidly obese patients with IHCA.

METHODS

Using the Nationwide Inpatient Sample database from 2001 to 2008, we identified adult patients undergoing resuscitation for IHCA, including those with morbid obesity (body mass index ≥40 kg/m²) by using International Classification of Diseases 9th edition codes and clinical outcomes. Outcomes including in-hospital mortality, length of stay, and discharge dispositions were identified. Logistic regression model was used to examine the independent association of morbid obesity with mortality.

RESULTS

Of 1,293,071 IHCA cases, 27,469 cases (2.1%) were morbidly obese. The overall mortality was significantly higher for the morbidly obese group than for the nonobese group experiencing in-hospital non-ventricular fibrillation (non-VF) (77% vs. 73%, respectively; p = 0.006) or VF (65% vs. 58%, respectively; p = 0.01) arrest particularly if cardiac arrest happened late (>7 days) after hospitalization. Discharge to home was significantly lower in the morbidly obese group (21% vs. 31%, respectively; p = 0.04). After we adjusted for baseline variables, morbid obesity remained an independent predictor of increased mortality. Other independent predictors of mortality were age and severe sepsis for non-VF and VF group and venous thromboembolism, cirrhosis, stroke, malignancy, and rheumatologic conditions for non-VF group.

CONCLUSIONS

The overall mortality of morbidly obese patients after IHCA is worse than that for nonobese patients, especially if IHCA occurs after 7 days of hospitalization and survivors are more likely to be transferred to a skilled nursing facility.

Selective downregulation of mitochondrial electron transport chain activity and increased oxidative stress in human atrial fibrillation

Mitochondria are critical for maintaining normal cardiac function, and a deficit in mitochondrial energetics can lead to the development of the substrate that promotes atrial fibrillation (AF) and its progression. However, the link between mitochondrial dysfunction and AF in humans is still not fully defined. The aim of this study was to elucidate differences in the functional activity of mitochondrial oxidative phosphorylation (OXPHOS) complexes and oxidative stress in right atrial tissue from patients without (non-AF) and with AF (AF) who were undergoing open-heart surgery and were not significantly different for age, sex, major comorbidities, and medications. The overall functional activity of the electron transport chain (ETC), NADH:O2 oxidoreductase activity, was reduced by 30% in atrial tissue from AF compared with non-AF patients. This was predominantly due to a selective reduction in complex I (0.06 ± 0.007 vs. 0.09 ± 0.006 nmol·min(-1)·citrate synthase activity(-1), P = 0.02) and II (0.11 ± 0.012 vs. 0.16 ± 0.012 nmol·min(-1)·citrate synthase activity(-1), P = 0.003) functional activity in AF patients. Conversely, complex V activity was significantly increased in AF patients (0.21 ± 0.027 vs. 0.12 ± 0.01 nmol·min(-1)·citrate synthase activity(-1), P = 0.005). In addition, AF patients exhibited a higher oxidative stress with increased production of mitochondrial superoxide (73 ± 17 vs. 11 ± 2 arbitrary units, P = 0.03) and 4-hydroxynonenal level (77.64 ± 30.2 vs. 9.83 ± 2.83 ng·mg(-1) protein, P = 0.048). Our findings suggest that AF is associated with selective downregulation of ETC activity and increased oxidative stress that can contribute to the progression of the substrate for AF.

Preexcitation Syndromes

The classic electrocardiogram in Wolff-Parkinson-White (WPW) syndrome is characterized by a short PR interval and prolonged QRS duration in the presence of sinus rhythm with initial slurring. The clinical syndrome associated with above electrocardiogram finding and the history of paroxysmal supraventricular tachycardia is referred to as Wolff-Parkinson-White syndrome. Various eponyms describing accessory or anomalous conduction pathways in addition to the normal pathway are collectively referred to as preexcitation syndromes. The latter form and associated eponyms are frequently used in literature despite controversy and disagreements over their actual anatomical existence and electrophysiological significance. This communication highlights inherent deficiencies in the knowledge that has existed since the use of such eponyms began. With the advent of curative ablation, initially surgical, and then catheter based, the knowledge gaps have been mostly filled with better delineation of the anatomic and electrophysiological properties of anomalous atrioventricular pathways. It seems reasonable, therefore, to revisit the clinical and electrophysiologic role of preexcitation syndromes in current practice.

Pharmacological strategies for prevention of postoperative atrial fibrillation

Atrial fibrillation (AF) complicating cardiac surgery continues to be a major problem that increases the postoperative risk of stroke, myocardial infarction, heart failure and costs and can affect long-term survival. The incidence of AF after surgery has not significantly changed over the last two decades, despite improvement in medical and surgical techniques. The mechanism and pathophysiology underlying postoperative AF (PoAF) is incompletely understood and results from a combination of acute and chronic factors, superimposed on an underlying abnormal atrial substrate with increased interstitial fibrosis. Several anti-arrhythmic and non-anti-arrhythmic medications have been used for the prevention of PoAF, but the effectiveness of these strategies has been limited due to a poor understanding of the basis for the increased susceptibility of the atria to AF in the postoperative setting. In this review, we summarize the pathophysiology underlying the development of PoAF and evidence behind pharmacological approaches used for its prevention in the postoperative setting.

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

Diabetes mellitus is a major risk factor for arrhythmogenesis and is associated with a two-fold increase in all-cause mortality and a four-fold increase in cardiovascular mortality including sudden cardiac death when compared with nondiabetics. Implantable cardioverter defibrillators (ICD) have been shown to effectively reduce arrhythmic death and all-cause mortality in patients with severe myocardial dysfunction. With a high competing risk of nonarrhythmic cardiac and noncardiac death, survival benefit of ICD in patients with diabetes mellitus could be reduced, but the subanalysis of diabetic patients in randomized clinical trials provides reassurance regarding a similar beneficial survival effect of ICD and cardiac resynchronization therapy in diabetics, as observed in the overall population with advanced heart disease. In this article, the authors highlight some of the clinical issues related to diabetes, summarize the data on the efficacy of ICD in diabetics when compared with nondiabetics and discuss concerns related to ICD implantation in patients with diabetes.

Utility of unipolar recordings for complex Wolff–Parkinson–White ablation

Radiofrequency ablation has been shown to be a safe and effective treatment strategy for the management of symptomatic patients with Wolff–Parkinson–White syndrome. It is supported by a success rate of 95% and a recurrence rate of less than 5%. However, ablation of accessory pathways can be challenging at times. The causes for failure can be grouped into three categories – unusual location of the pathway, technical difficulties in delivering the ablation and localization error [1]. In this case report we are reporting a case of a young male who presented to us with symptomatic Wolff–Parkinson–White syndrome with two failed prior ablations at another institution. This case illustrates the importance of knowing accurate localization and course of the accessory pathway by utilizing the unipolar and bipolar electrograms simultaneously during radiofrequency ablation.

Abstract 198: Noninvasive Approach Assessing Atrial Mechanics and Serum Biomarkers of Collagen Turnover Provides a Surrogate for Fibrosis and Atrial Fibrillation

Introduction: Atrial fibrosis alters myocardial electrophysiological properties, increasing susceptibility to postoperative atrial fibrillation (PoAF); however, its estimation is problematic. We hypothesized that a noninvasive approach using history of AF (HxAF), LA mechanics and serum biomarkers of collagen turnover provides a surrogate for the extent of interstitial atrial fibrosis to identify patients at risk for PoAF.

Methods: In patients undergoing cardiac surgery from April-Dec 2013, concentrations of biomarkers reflecting collagen synthesis/degradation and extracellular matrix remodeling were determined in serum from preoperative blood using an enzyme-linked immunosorbent assay, and echocardiographic evaluation was performed using M-mode, 2D, Doppler and 3D speckle tracking.

Results: Of 66 patients (68 ±11 y, 67% men), 15 had HxAF and 11 of 51 with no HxAF (22%) developed new onset PoAF. In patients with HxAF, biomarkers for collagen turnover were elevated (Fig A) and correlated with a reduction in LA ejection fraction and global and regional relaxation of the LA wall (p=0.01, Fig B). In patients with no HxAF, procollagen type III (PIIINP) was significantly different in those who developed PoAF (p=0.01) and correlated with reduction in contractility in the posterior LA roof (p=<0.001) with a prolonged time to peak end-diastolic volume (p=0.03). LA size or ventricular structure and function were not different between groups.

Conclusion: Surrogate serum and imaging biomarkers correlate with the substrate abnormality that promotes AF. These results need to be validated in larger cohorts to assess the power of these parameters in predicting new onset PoAF.

Polymorphic ventricular tachycardia--part II: the channelopathies

In this article, we explore the clinical and cellular phenomena of primary electrical diseases of the heart, that is, conditions purely related to ion channel dysfunction and not structural heart disease or reversible acquired causes. This growing classification of conditions, once considered together as "idiopathic ventricular fibrillation," continues to evolve and segregate into diseases that are phenotypically, molecularly, and genetically unique.

Abstract 038: A Novel Histology Based Classification System to Identify Patients at Risk for Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (PoAF) is a common complication in up to 40% of patients after cardiac surgery, increasing morbidity, hospital stay and costs. The myocardial substrate underlying PoAF is not fully characterized. The objective was to assess the impact of atrial fibrosis on incident AF and define the fibrosis threshold level predictive of PoAF.

Methods: Right atrial appendages removed from patients undergoing elective CABG with no history of AF or class III/IV heart failure were used to characterize the ratio of collagen to myocardium (Masson’s trichrome; NIH ImageJ software; Fig A), which was correlated with incident AF. Percentage burden of fibrosis predictive of PoAF with high sensitivity and specificity was determined by ROC curve.

Results: Of 28 patients (67±10 years, 64% males), 15 had PoAF. There were no age, gender or comorbidity differences between groups. Compared to the group that remained in sinus rhythm, patients with PoAF had a significantly higher ratio of extracellular collagen to myocardium (45±16% vs. 5±4%, p <0.001; Fig B). A threshold ratio of 12.7% collagen to myocardium (ROC area under the curve 0.997; z statistic 137; P<0.0001) with 96% sensitivity and 97% specificity identified those with PoAF (Fig C). A classification system based on histological extent of atrial fibrosis is proposed for identifying patients at risk for PoAF (Fig D).

Conclusion: Ongoing studies will confirm the predictive value of this new classification system for identifying the atrial substrate predisposing PoAF and correlate with preoperative cardiac imaging and circulatory serum biomarkers to provide a novel noninvasive tool to stratify patients at risk for PoAF.

Left Atrial Anatomy in Patients Undergoing Ablation for Atrial Fibrillation

Background: Left atrial anatomy is highly variable, asymmetric, irregular and three-dimensionally unique. This variability can affect the outcome of atrial ablation. A catalog of anatomic varieties may aid patient selection and ablation approach and provide better tools for left atrial ablation. Methods: We analyzed computed tomography scans from 514 patients undergoing left atrial ablation. Images were processed on Advantage Windows with CardEP™ software (GE Healthcare, Waukesha, WI). Measurements of pulmonary vein (PV) ostial size along the long and short axes were made using double oblique cuts, and area of the ostia was calculated. Results: Patients with 2 left (LPV) and 2 right PVs (RPV) (62.6%), 2 LPVs and 3 RPVs (17.3%) and 1 LPV and 2 RPVs (14.2%) made up the three most common variants. In the 2-LPV/2-RPV anatomy, the ostial size and area of the RPVs were larger than their corresponding LPVs (p<0.001), and the ostial size and area of the superior PVs were larger than their corresponding inferior PVs (p<0.001). In the 2-LPV/3-RPV anatomy, the total area of the RPVs was larger than the total area of the LPVs (p<0.001). In the 1-LPV/2-RPV anatomy, the ostial size of the left common PV was larger than either right PV (p<0.007). However, the total area of the RPVs was larger than the area of the left common PV (p<0.002). The left common PV was also larger than any of the left veins in any of the other anatomies. The total PV area between the three most common anatomies was not significantly different. Conclusions: More than 37% of patients have a left atrial anatomy other than 2 left and 2 right PVs. This data may help in designing approaches for left atrial ablation, tailoring the procedure to individual patients and improving ablation tools.

Repolarization syndromes

Repolarization syndromes, including early repolarization, Brugada, and short and long QT, have been implicated increasingly as causes of sudden cardiac death (SCD) despite no obvious mechanical cardiac abnormalities. So-called idiopathic ventricular fibrillation is now often reassigned to one of the aforementioned entities. Underlying causes are diverse; genetic mutation has been proven in many but not all cases. Although high-risk individuals generally can be identified, most of the potential victim pool is still unknown and cannot be discovered at this time. Awareness of these entities' existence, knowledge of family history, and 12-lead electrocardiography are the initial steps toward preventing SCD in this population. Underlying mechanisms for ventricular tachycardia/fibrillation in such individuals include phase 2 reentry, early after depolarization, and vortex reentry. For the time-being, although most forms of long QT syndrome can be treated with β-blockers, an implantable cardioverter-defibrillator remains the only definitive therapy for the prevention of arrhythmic death among high-risk populations.

Left ventricular pacing in right ventricular cardiomyopathy: blessing or blunder?

Arrhythmogenic right ventricular dysplasia (ARVD) predominantly involves the right ventricle, and myocardium is progressively replaced by fat and fibrous tissue in the apex, base, and outflow tract regions. This pathology, and the progressive nature of the disease, poses special challenges for implant and subsequent appropriate functioning of an implantable cardioverter-defibrillator. This case report describes a solution to problems during lead placement in patients with ARVD.

A Prospective Comparison of Cardiac Imaging Using Intracardiac Echocardiography With Transesophageal Echocardiography in Patients With Atrial Fibrillation

Background—

The Intracardiac Echocardiography Guided Cardioversion Helps Interventional Procedures study evaluated the concordance of intracardiac echocardiography (ICE) with transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF).

Methods and Results—

Patients with AF undergoing right heart catheterization underwent left atrium (LA) and interatrial septal (IAS) imaging by TEE and ICE. A blinded comparison of the 2 modalities was performed at a core laboratory. Ninety-five patients aged 58±12 years completed the study. The LA was profiled in all patients with both techniques, and concordance for image quality was 96%. LA appendage (LAA) imaging was achieved in 85% with ICE and 96% with TEE. There was no difference in the presence of spontaneous echo contrast between ICE and TEE during LA imaging, but there was a trend toward a greater incidence in the LAA with TEE ( P =0.109). Intracardiac thrombus was uncommonly seen (TEE, 6.9%; ICE, 5.2%). The concordance for the presence or absence of thrombus was 97% in the LA and 92% in the LAA, but the latter was detected more frequently with TEE. IAS imaging was achieved in 91% with ICE and in 97% with TEE ( P =0.177). Concordance for patent foramen ovale and atrial septal aneurysms was 100% and 96%, respectively. A negative ICE examination was associated with absence of dense echo contrast or thrombus on TEE in 86%.

Conclusions—

This study provides validation for the use of ICE for LA and IAS imaging. ICE imaging was less sensitive compared to TEE for LAA thrombus identification.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00281073.

A case of flecainide-induced hyponatremia

We present a case of flecainide-induced hyponatremia in a 67-year-old woman who was treated for paroxysmal atrial tachycardia. She developed dizziness after starting flecainide and was found to be hyponatremic with a sodium level of 122 mmol/L (decreased from 136 mmol/L). Work-up failed to reveal other causes of hyponatremia. She was not on diuretics, laxatives, or herbal medications. After discontinuation of flecainide, her symptoms and sodium levels improved. Hyponatremia is a previously unrecognized entity as an adverse effect of flecainide. We will discuss the clinical presentation, lab findings, and a possible explanation for this patient's unusual reaction to flecainide.

Incessant interfascicular reentrant ventricular tachycardia as a result of catheter ablation of the right bundle branch: case report and review of the literature

A 72-year-old woman developed incessant interfascicular (IF) ventricular tachycardia immediately after successful right bundle branch (RBB) catheter ablation for the treatment of sustained bundle branch reentrant tachycardia. Catheter ablation of the left bundle branch and the left anterior fascicle was successful in eliminating the tachycardia (in 2 different sessions). This report discusses the direct link between the creation of an RBB block and the development of IF tachycardia, in our case, and in prior cases of IF reentry reported in the literature.

Pacing lead implantation without live fluoroscopy: feasibility of acute success in the live canine model

INTRODUCTION

Fluoroscopic visualization for transvenous pacing lead placement necessitates lead shielding to minimize radiation exposure. An electromagnetic (EM) navigation system that integrates real-time intracardiac tracking within an anatomic navigation environment may provide an effective alternative for lead delivery that obviates live fluoroscopy. We assessed feasibility of pacing lead implantation with electromagnetic tracking guided solely by radiographic virtual navigation and compared this to fluoroscopy-guided implants in a canine model.

METHODS

Seven mongrel dogs with normal hearts were randomized to 47 pacing lead placements in the right atrium (RA) or right ventricle (RV) guided by single-plane fluoroscopy, or an experimental EM navigation system guided by registered fluoroscopic snapshots obtained before implant (EMN). Ability to achieve successful lead delivery acutely was assessed, and pacing parameters as well as fluoroscopy and implant times were measured. Means were compared using a paired t-test.

RESULTS

All lead delivery attempts were acutely successful. One atrial lead dislodged with EMN, resulting in 46 successful pacing attempts. There was no statistical difference in pacing parameters and time for lead placement between the approaches (EMN vs fluoroscopic navigation [mean +/- SD]: RA threshold 1.15 V +/- 0.98 V vs 1.95 V +/- 0.98 V [P = NS], RV threshold 1.18 V +/- 0.58 V vs 1.42 V +/- 0.63 V [P = NS], implant time 4:38 +/- 2:37 minutes vs 4:44 +/- 2:38 minutes [P = NS]). No live fluoroscopy was required for EMN implants.

CONCLUSION

Pacing lead placement with an EM system guided by preprocedural fluoroscopic views is feasible and comparable to fluoroscopic navigation, and avoids the use of live fluoroscopy.