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

Background and Purpose: Weight loss in morbidly obese patients reduces atrial fibrillation (AF); however, it is unknown whether similar benefits are maintained in patients with obstructive sleep apnea (OSA). We sought to determine whether incident AF and stroke rates are affected by OSA after weight loss and to identify predictors of AF and stroke. Methods: Differences in laparoscopic adjustable gastric banding­induced weight loss on incident AF and stroke events in those with and without OSA in the entire and in propensity-matched cohorts were determined longitudinally, and independent predictors of AF and stroke were identified. Results: Of 827 morbidly obese patients who underwent laparoscopic adjustable gastric banding (mean age, 44±11 years; mean body mass index, 49±8 kg/m2), incident AF was documented in 4.96% and stroke in 5.44% of patients during a mean 6.0±3.2-year follow-up. Despite a similar reduction in body weight (19.6% and 21% in 3 years), new-onset AF was significantly higher in patients with OSA than without OSA in the entire (1.7% versus 0.5% per year; P<0.001) and propensity-matched cohorts. Incident stroke was higher in the OSA than in the non-OSA group (2.10% versus 0.47% per year; P<0.001), but only 20% of patients with stroke had documented AF. On multivariate analysis, OSA (hazard ratio, 2.88 [95% CI, 1.45­5.73]), age, and hypertension were independent predictors of new-onset AF, and OSA (hazard ratio, 5.84 [95% CI, 3.02­11.30]), depression, and body mass index were for stroke events. Conclusions: In morbidly obese patients who underwent laparoscopic adjustable gastric banding, despite similar weight loss, patients with OSA had a higher incidence of AF and stroke than patients without OSA. Both non-AF and AF-related factors were involved in increasing stroke risk. Further investigation is warranted into whether OSA treatment helps reduce AF or stroke events in this population.

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.

Comparative Effectiveness of Hybrid Ablation Versus Endocardial Catheter Ablation Alone in Patients With Persistent Atrial Fibrillation.

OBJECTIVES: The outcomes of hybrid ablation versus endocardial catheter ablation alone were evaluated in patients with persistent and long-standing persistent atrial fibrillation (AF). BACKGROUND: Variable outcomes exist following endocardial catheter ablation in medically refractory patients with persistent AF. A hybrid epicardial-endocardial approach has emerged as an alternative to endocardial ablation. METHODS: In 133 consecutive patients, 69 received endocardial ablation alone (pulmonary vein isolation and radiofrequency catheter ablation [endo group]) and 64 received endocardial catheter ablation and epicardial ablation (hybrid group). Recurrence was defined as any arrhythmia following the 3-month blanking period. RESULTS: Patients were followed for a median of 16 months. The hybrid and endo groups were similar in age (61 ± 10 years vs. 62 ± 8 years), body mass index (35 ± 6 kg/m2 vs. 35 ± 7 kg/m2), CHA2D2-VASc score (2 ± 1 vs. 2 ± 1), and ejection fraction (54 ± 11% vs. 53 ± 8%). The hybrid group had longer AF duration (median [interquartile range (IQR)] (12 months [IQR: 8 to 28 months] vs. 7 months [IQR: 5 to 12 months]; p < 0.001) and more previous ablations (58% vs. 25%; p < 0.001). Both groups had similar antiarrhythmic drug use at follow-up (55% vs. 48%). The hybrid group was less likely to have recurrence (37% vs. 58%; p = 0.013) and repeat ablation (9% vs. 26%; p = 0.012), and had an AF-free survival of 72% versus 51% (p = 0.01). CONCLUSIONS: Among patients with persistent AF, hybrid ablation is associated with less AF recurrence and fewer re-do ablations. Prospective large-scale randomized trials are needed to validate these results.

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.

Circulating Biomarkers Predictive of Postoperative Atrial Fibrillation.

Postoperative atrial fibrillation (PoAF), a common complication of cardiac surgery, contributes significantly to morbidity, mortality, and increasing healthcare costs. Despite advances in surgical and medical management, the overall incidence of PoAF has not changed significantly, partly because of the limited understanding of mechanisms underlying acute surgery-related factors, such as myocardial injury, inflammation, sympathetic activation, and oxidative stress, which play an important role in the initiation of PoAF, whereas a preexisting atrial substrate appears to be more important in the maintenance of this dysrhythmia. Thus, in a majority of patients, PoAF becomes a manifestation of an underlying arrhythmogenic substrate that is unmasked after acute surgical stress. As such, the ability to identify which patients have this proarrhythmic substrate and are, therefore, at high risk for developing AF postoperatively, is important for the improved selection for prophylactic interventions, closer monitoring for complications, and establishing the probability of AF in the long term. This review highlights the role of the underlying substrate in promoting PoAF, proposed mechanisms, and the potential role of serum biomarkers to identify patients at risk for PoAF.

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.

Left atrial laceration with epicardial ligation device.

Many new devices and techniques are being developed to attempt a reduction in embolic stroke risk for patients with atrial fibrillation who are either unable or unwilling to maintain long-term anticoagulation. One of these new devices (LARIAT®, SentreHEART Inc., Redwood City, California, USA) employs delivery of an epicardial suture to ligate the left atrial appendage after percutaneous pericardial and transseptal access. This series presents three clinical cases that demonstrate a serious and recurrent complication of left atrial laceration and cardiac tamponade shortly following delivery of an epicardial suture ligation to the left atrial appendage. Three clinical cases are described in detail with pre- and postprocedure angiography and echocardiography as well as illustrations reflecting the surgeon's findings on direct visualization of the left atrial lacerations postligation. Potential hypotheses of each injury are examined in light of the case timelines and findings at sternotomy. There was no suggestion that tamponade was related to pericardial or transseptal access, but rather a complication with device delivery. These three patients quickly progressed to clinical cardiac tamponade despite attempted drainage, stressing the importance of cardiovascular surgery backup, including a cardiopulmonary bypass pump, when delivering novel, percutaneous ligation devices for the left atrial appendage.

Novel anticoagulants for stroke prevention in atrial fibrillation: safety issues in the elderly.

Vitamin K antagonists (VKAs) are the most widely used anticoagulants for stroke prevention in patients with atrial fibrillation (AF). Recently, the US FDA approved three novel anticoagulants that work through inhibition of coagulation cascade independent of Vitamin K-dependent enzymatic reactions and, therefore, should have less food-drug interactions. Since AF is a disease of the aging heart, it is important to assess safety and efficacy of these new anticoagulants in elderly patients. We reviewed age-related changes in pharmacokinetics and pharmacodynamics observed with senescence and the effects of these changes on novel anticoagulants, known and anticipated drug and food interactions, and challenges related to bleeding complications and temporary discontinuation prior to surgery or interventional procedure. Although advantageous to VKA in age groups represented in trials, there are lack of data on VKA usage in older-elderly patients; additional research and post-marketing analysis in older-elderly patients are needed.

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.

Mapping techniques for atrial fibrillation ablation.

Atrial fibrillation (AF) is a common arrhythmia. Although significant work still needs to be done, recent advances in understanding the mechanism of AF have led to the development of elegant catheter mapping techniques for ablation of AF. These improved mapping techniques are complemented by an evolution in various imaging and navigational technologies, several of which can now be combined in a process called registration, so that the physician no longer needs to rely solely on a mental image of the anatomy of the left atrium and the pulmonary vein while attempting to ablate the region. Ongoing advances in mapping technique will increase safety and efficacy and it is likely that AF ablation will become the first-line therapy in most patients with this complicated arrhythmia.

Computed tomography-fluoroscopy image integration-guided catheter ablation of atrial fibrillation.

INTRODUCTION: This study examines the feasibility of atrial fibrillation (AF) ablation using registered three-dimensional computed tomography (CT) images of the left atrium with fluoroscopy. METHODS AND RESULTS: A total of 50 consecutive patients with symptomatic AF refractory to medical therapy (32 paroxysmal, 18 persistent, age 55 +/- 10 years) were randomized to undergo a catheter-based AF ablation procedure with or without the CT-fluoroscopy guidance system. All patients underwent preprocedural contrast-enhanced CT imaging and segmentation of the left atrium. For the CT-fluoroscopy group, circumferential lesions encompassing the pulmonary vein (PV) antrum and linear lesions along the roof of the left atrium between the superior PVs and the mitral isthmus were created on the CT image, which was registered with real-time fluoroscopy. The registered images were then used to navigate the ablation catheters to the sites of planned ablation. After the ablation sites were completed, any remaining PV potentials were isolated with electrophysiological guidance. In the control patients, the same technique was performed without using the CT-fluoro guidance system. CT scans were accurately registered to fluoroscopic images with minimal manual correction. Operators could navigate catheters on the registered images to preplanned, extraostial sites for ablation. CT-fluoroscopy guidance decreased procedure duration and fluoro times (P < 0.05). At a mean follow-up of 9 +/- 2 months, 21 patients (84%) in the CT-fluoro guidance group and 16 patients (64%) in the control group have had no recurrence of AF. CONCLUSION: CT-fluoroscopic-guided left atrial ablation is feasible and allows appropriate catheter manipulation in the left atrium.

Radiofrequency ablation of atrial fibrillation during mitral valve surgery.

Twenty-three patients underwent endocardial radiofrequency ablation of atrial fibrillation (AF) during mitral valve procedures with a previously described left atrial lesion pattern. A temperature-controlled 7-coil surgical probe delivered 60-second lesions at 80 degrees C. The left atrial appendage was oversewn after ablation. Ages ranged from 28 to 88 years. Nineteen patients had chronic AF that was present for over 1 year in 74%; 12 patients had rheumatic mitral stenosis. Mean left atrial diameter was 5.4 +/- 0.7 cm. There was 1 operative death unrelated to the ablation, and no strokes or ablation-related complications were observed. At mean follow-up of 32.5 weeks, 86% of the 22 survivors were in sinus rhythm. All 18 patients with left atrial diameter <6 cm are in sinus rhythm. All postoperative atrial flutter was transient, and no patients required subsequent transcatheter ablation. This lesion pattern is safe and effective when applied in the method described here. It appears to be a reasonable alternative to the complete Maze 3 lesion pattern in patients with mitral valve disease.

Validation of a left atrial lesion pattern for intraoperative ablation of atrial fibrillation.

BACKGROUND: Evidence that atrial fibrillation may begin in early stages from triggers or reentry circuits primarily in the left atrium suggests that the entire Maze 3 lesion pattern may be unnecessary. In the present study we describe a new left atrial lesion pattern for intraoperative linear ablation of chronic atrial fibrillation. METHODS: Endocardial radiofrequency ablation was performed on 12 dogs with chronic atrial fibrillation. Lesions to isolate pulmonary veins in pairs, the left atrial appendage, and connecting lesions between these structures were administered in a randomized approach. RESULTS: Twelve dogs were in chronic atrial fibrillation for 31 +/- 21 days before ablation. Atrial fibrillation was successfully ablated and rendered noninducible in all 12 dogs. All treatment failures observed with less than the full lesion pattern became a success when the remaining lesions were given. CONCLUSIONS: Atrial fibrillation ablation using this left atrial lesion pattern is highly successful in this model. This approach may have significant utility as a concomitant procedure for patients with atrial fibrillation undergoing mitral valve procedures.