Swallowing-induced Supraventricular Tachyarrhythmia.

Swallowing-induced supraventricular tachyarrhythmia is an extremely rare entity with unclear pathophysiology. A 55-year-old man presented with a 2-year history of worsening presyncopal symptoms triggered only by drinking liquids of any temperature. Results of a physical examination were unremarkable except for reproducible atrial tachycardias to 180 to 210 beats/minute documented on rhythm strips when the patient was given water to drink. He underwent radiofrequency ablation with complete resolution of symptoms. We reviewed all 43 published cases of swallowing-induced supraventricular tachyarrhythmia in the English-language medical literature. We found only one other reported case induced only by drinking liquids. Radiofrequency ablation appears to be the treatment of choice.

Effect of botulinum toxin on inducibility and maintenance of atrial fibrillation in ovine myocardial tissue.

BACKGROUND: Aberrant vagal stimulation may promote the generation and propagation of atrial fibrillation (AF). Researchers have suggested that botulinum toxin (BTX), a neurotoxin that decreases neural vagal stimulation, may decrease the incidence of postoperative AF. The exact electrophysiologic mechanism underlying the observations and histopathologic alterations associated with BTX are unclear. OBJECTIVE: To investigate the electrophysiologic, functional, and histopathologic effects of BTX on fibrillation induction in ovine atria. METHODS: Eight sheep underwent BTX injections into their pulmonary veins, atrial fat pads, and ventricular walls. Electrophysiology with pacing was performed at baseline and 7 days after injection to evaluate the atrial effective refractory period (ERP) and vulnerability to AF with and without vagal stimulation. Echocardiography was performed at baseline and day 7. After euthanasia, histopathologic analysis was performed. RESULTS: Seven sheep completed the study. For both atria, there was significant shortening in the ERP with vagal stimulation versus no stimulation on day 0 but not on day 7. More aggressive pacing was required to induce AF in the left atrium on day 7 than on day 0. Echocardiography on day 7 showed no significant changes in ejection fraction or new wall-motion abnormalities of the left and right ventricle. Histopathologic analysis showed no significant adverse effects. CONCLUSION: The subacute BTX effect reduced the vulnerability of atrial tissue to AF induction and reduced the vagal influence on atrial ERP shortening compared to baseline levels. Direct BTX injection did not cause myocardial dysfunction or histologic adverse effects.

Cryoballoon pressure waveform change during balloon inflation is not a reliable predictor of adequate pulmonary vein occlusion.

BACKGROUND: Cryoballoon ablation of pulmonary veins (PVs) is widely used to treat atrial fibrillation (AF). Successful ablation requires occluding the PVs by cryoballoon. Angiography is a standard method of assessing PV occlusion. To decrease contrast doses and overcome potential contraindications (e.g., allergy to contrast, renal disease), alternative methods have been tested, including intracardiac echocardiography, transesophageal echocardiography-color flow Doppler, and distal cryoballoon pressure monitoring. OBJECTIVE: We evaluated pressure monitoring's accuracy in detecting PV occlusion during cryoballoon ablation. METHODS: We studied 72 PVs in 18 nonconsecutive patients (mean age 68 ± 8 years; 13 male) who underwent cryoballoon ablation for paroxysmal AF. In 67 PVs, we documented the point at which the recorded pressure waveform at the distal tip of the inflated cryoballoon transformed from a left atrial into a pulmonary arterial pressure waveform. PV occlusion was confirmed by concurrent PV angiography through the distal balloon channel. Occlusion was rated on a I­IV scale in which I indicated poor occlusion with major leakage and IV indicated complete occlusion without leakage. RESULTS: In 43 of 67 PVs (64%), the change in the pressure waveform from left atrial to pulmonary arterial was associated with complete PV occlusion (grade IV), confirmed by angiography. In the other 24 PVs, complete occlusion was achieved by further movement of the cryoballoon under intracardiac echocardiographic guidance and angiographic confirmation. All 67 PVs were electrically isolated with cryoballoon. CONCLUSIONS: The change in pressure waveforms at the distal tip of inflated cryoballoon is not a reliable predictor of complete PV occlusion during cryoballoon ablation.

Contact-force recovery can predict cardiac perforation during radiofrequency ablation.

BACKGROUND: During radiofrequency ablation (RFA), the ability to know whether a steam pop has led to cardiac perforation (CP) would be of profound clinical significance. We aimed to determine whether catheter contact-force characteristics can predict whether a steam pop during RFA causes CP. METHODS: We used a 7.5F Thermocool® Smarttouch™ force-sensing catheter (Biosense Webster Inc., Diamond Bar, CA, USA) to perform open-chest left atrial RFA under direct visualization in four sheep. We measured the contact force and its direction every 50 ms during RFA. At each steam pop, we noted whether CP occurred. We then analyzed the contact-force signals to determine whether specific features predicted the presence (+) or absence (-) of CP. RESULTS: A total of 24 steam pops occurred; 10 were CP+ and 14 were CP-. At the time of CP+ and CP- events, the contact force was 50 ± 25 and 40 ± 15 g, respectively (P = 0.146). All steam-pop events were associated with a rapid drop-off in contact force, but 10 of the 14 CP- events showed an immediate contact-force rebound, whereas none of the CP+ events did. This rebound presumably occurred as the catheter tip resumed contact with the left atrial wall. The average contact-force rebound equaled 80-100% of the contact-force drop-off. CONCLUSIONS: The ability to measure catheter contact force during RFA is a valuable asset, as contact-force recovery may be used to predict CP. Further studies are warranted to validate our findings in the clinical setting.

Sustainable colonization of Mars using shape optimized structures and in situ concrete.

The major obstacle to Martian colonization is the mission cost which requires significant reduction. From the structural engineering point of view, importing materials and structural elements from Earth or massive excavations on the surface of Mars require an enormous amount of energy; thus, inflatable and under-surface structures as the main options for Martian colonization seem unrealistically expensive. Construction of affordable buildings onsite using only in situ sources may represent an ideal solution for Martian colonization. On the other hand, solar energy, at the early stage of colonization, would be the only available, practical, and low-cost energy source on Mars. Though, for sustainable and broad colonization, the energy required for construction and the construction cost should be minimized. Here, we propose three types of simple (relatively optimized), perforated, and algorithmic shape-optimized Martian structures to minimize the material and energy required for construction as well as the construction cost using only in situ resources. These structural forms can be considered remarkable steps towards sustainable structural construction and colonization on Mars. Also, these innovative structures were designed to minimize the tensile stress (maximize the compressive stress) and enable the use of in situ concrete. Our data indicate that compared to our previous study, the material and energy required for construction as well as the construction cost can be reduced by more than 50%. Acceptance criteria and limitations appropriate to the Martian environment, and desirable structural and material behaviors were defined to evaluate whether or not the behavior of a structure under the applied loads and conditions will be acceptable. To detect potential issues for onsite construction and evaluate the geometry of the models, a 1:200 3D model of the best structural form was printed.

Martian buildings: structural forms using in-place sources.

On Mars, structural loads and the low tensile strength of in-place Martian binders make existing solutions for Martian structures uneconomical because they are based on the terrestrial sources like inflatable units. Here we address this issue by introducing and analyzing three innovative structural forms in accordance with the structural engineering point of view using symmetric optimum parabolic rotated arch shapes and in-place waterless sulfur-based concrete. These forms minimize the tensile stresses under Martian structural loads. Probable Martian structural loads, including gravity, wind, marsquakes, asteroid and meteoroid impact loads and their effects have been investigated and calculated. The proposed models were analyzed under Martian structural loads using the implicit finite element method and the results were compared to two concrete structural forms from previous studies. The proposed models could tolerate Martian structural loads with complete elastic behavior and would significantly decrease the Martian colonization cost due to using Martian resources and reduce element importing from Earth.

Lobectomy for pulmonary vein occlusion secondary to radiofrequency ablation.

Pulmonary vein stenosis, a recognized complication of transcatheter radiofrequency ablation in the left atrium, is often asymptomatic. Significant stenosis is commonly treated with percutaneous balloon dilation with or without stenting. We encountered a case of complete pulmonary vein occlusion that caused lobar thrombosis, pleuritic pain, and persistent cough. Imaging studies revealed virtually no perfusion to the affected lobe. A lobectomy was performed, resolving the persistent cough and pain. Pulmonary vein occlusion should be suspected in patients who present with pulmonary symptoms after having undergone ablative procedures for atrial fibrillation. This condition may necessitate surgical intervention if interventions such as balloon dilation or stenting are not possible or are ineffective.

Programming antitachycardia pacing for primary prevention in patients with implantable cardioverter defibrillators: results from the PROVE trial.

OBJECTIVES: the PROVE trial was designed to determine if antitachycardia pacing (ATP) is clinically beneficial for primary prevention in patients who have implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds). BACKGROUND: use of ICDs and CRT-Ds reduces mortality in patients with ventricular dysfunction and mild to moderate heart failure. However, in studies of the primary prevention population, shock-only ICDs are predominantly used, without ATP programming for less painful termination of ventricular tachycardia (VT). METHODS: we conducted a prospective, nonrandomized, multicenter study using market-released ICDs and CRT-Ds. Patients received devices programmed to deliver ATP for VT cycle lengths of 270-330 ms. Follow-up evaluation was performed at 3, 6, and 12 months. The incidence of VT and the rate of successful termination by ATP were analyzed. RESULTS: of 830 patients in the study population (men, 73%; mean age, 67.3 ± 12 years), 32% received single-chamber ICDs, 44% dual-chamber ICDs, and 24% CRT-Ds. ATP was attempted for 112 VT episodes in 71 patients, and 103 (92%) of the VT episodes were successfully terminated. Three VT episodes were accelerated by ATP and required termination by ICD shock; 6 episodes terminated spontaneously or by ICD shock. CONCLUSIONS: VT is common in patients without a history of this arrhythmia who have received ICDs or CRT-Ds for primary prevention indications. Programming ICDs for ATP therapy at the time of implantation could potentially terminate most VT episodes and reduce the number of painful shocks for these patients.

Cardiac resynchronization therapy in patients with right ventricular pacing-induced cardiomyopathy.

BACKGROUND: It is not known whether patients with normal baseline left ventricular (LV) function who develop right ventricular (RV) pacing-induced cardiomyopathy as a result of dual-chamber pacing can benefit from cardiac resynchronization therapy (CRT). We retrospectively assessed the effect of a CRT upgrade on RV pacing-induced cardiomyopathy. METHODS AND RESULTS: We reviewed the charts of patients who received a CRT device for RV pacing-induced cardiomyopathy. We assessed the effects of CRT on LV function, recovery, and other response parameters. From September 2005 through February 2009, 21 patients (13 men; aged 63 + or - 9 years) underwent a treatment upgrade to a CRT system. Before the dual-chamber pacemaker was implanted, the LV ejection fraction (LVEF) was 53 + or - 2.3%. After pacing, the LVEF was 31.2 + or - 3.8%, the LV end-diastolic dimension (LVEDD) was 5.8 + or - 0.5 cm, and B-type natriuretic peptide (BNP) levels were 426 + or - 149 pg/mL. The duration of pacing before documentation of pacing-induced cardiomyopathy was 3.8 + or - 1.5 months. All the patients had been on a stable medical regimen for at least 2 months. After the upgrade to CRT, the follow-up time was 4.9 + or - 0.9 months. Sixteen patients (76%) reported a significant improvement in their symptoms. After the CRT upgrade, the LVEF increased to 37.4 + or - 9.0% (P < 0.01 vs pre-CRT). The LVEDD decreased to 5.0 + or - 1.0 cm (P = 0.03 vs pre-CRT), and BNP levels decreased to 139 + or - 92 pg/mL (P = 0.08 vs pre-CRT). CONCLUSION: A CRT upgrade is an effective treatment for RV pacing-induced cardiomyopathy and should be implemented as soon as the diagnosis is established. Unfortunately, about 24% of our patients did not respond to the upgrade.

Variability in postpacing intervals predicts global ventricular activation pattern during tachycardia.

INTRODUCTION: Assessment of ventricular activation pattern is critical to the successful ablation of ventricular tachycardia (VT). We have previously shown that the global atrial activation pattern during tachycardia can be rapidly and accurately assessed by calculating the postpacing interval variability (PPIV); PPIV was minimal in circuitous tachycardias and highly variable in centrifugal tachycardias. In the present study, we use the PPIV to determine the ventricular global activation pattern during VT. METHODS: Patients with mappable VT were included. We defined global ventricular activation as either centrifugal (arising from a focus with radial expansion) or circuitous (gross macro-reentrant circuit), based on the findings of electroanatomic mapping. PPIV was calculated as the difference in postpacing interval with right ventricular apical overdrive pacing during tachycardia at cycle lengths (CL) 10 ms and 30-ms shorter than tachycardia, regardless of the origin of the tachycardia. We studied 20 patients with 23 VTs (11 centrifugal, mean CL 390 +/- 36.1 ms; 12 circuitous, mean CL 418 +/- 75.7 ms). RESULTS: The mean PPIV was 45 +/- 16 ms for patients with centrifugal VT and 6.7 +/- 4.1 ms for patients with circuitous VT. Rank sum analysis of PPIV showed a significant difference between the two groups (P < 0.05). CONCLUSIONS: Our data suggest that the global ventricular activation pattern during VT can be rapidly and accurately defined by assessing the PPIV. This technique allows for a rapid confirmation of the tachycardia activation and significantly facilitates mapping and ablation.

Cardiac resynchronization therapy may improve symptoms of congestive heart failure in patients without electrical or mechanical dyssynchrony.

AIMS: Cardiac resynchronization therapy (CRT) has reportedly not been effective in the absence of electrical or mechanical dyssynchrony. We present six patients with severe left ventricular (LV) dilation, mitral regurgitation (MR), and non-ischaemic cardiomyopathy who underwent CRT. We assessed the effects of CRT on LV ejection fraction (EF), LV dimensions, mitral valve regurgitant fraction (RF), pulmonary arterial pressures (PAP), and serum levels of B-natriuretic peptide (BNP). METHODS AND RESULTS: All patients had severe LV dilation (>/=6.8 cm) and no electrical or mechanical dyssynchrony. All patients underwent CRT-D (with defibrillator) without complications. Average echocardiographic follow-up was 4.6 months. Mean LVEF increased significantly from 20.8 +/- 3.4 to 28.3 +/- 2.9% after CRT (P < 0.01). Mean LV end-diastolic dimension decreased significantly from 6.9 +/- 0.15 to 6.45 +/- 0.33 cm after CRT (P = 0.03); mean BNP serum level decreased from 1738 +/- 526 to 1040 +/- 768 pg/mL (P = 0.07). Baseline RF decreased from 45 +/- 12.2 to 20 +/- 10.9% after CRT-D (P = 0.009). Mean PAP decreased from 48.5 +/- 5.8 to 42.6 +/- 5.2 (P = 0.03). In five patients, New York Heart Association class symptoms improved by at least one level. No patients required assist devices or transplantation. One patient was hospitalized during follow-up. CONCLUSION: We describe six patients with severe LV dilation without evidence of electrical or mechanical dyssynchrony who improved with CRT, possibly due to improvement in MR.

Variability in post-pacing intervals predicts global atrial activation pattern during tachycardia.

INTRODUCTION: Knowledge of the global atrial activation pattern is critical to ablation of an atrial arrhythmia. We hypothesized that the variability in post-pacing intervals (PPIs) with pacing at different cycle lengths (CLs) from the same pacing site, regardless of distance to the circuit, can be used to identify atrial activation patterns during tachycardia. METHODS AND RESULTS: Consecutive patients referred for ablation of organized atrial arrhythmias were included (n = 28, 31 total tachycardias). The variability in PPIs (PPIV) was calculated by comparing the difference in PPIs after overdrive pacing with 5-second trains 10, 20, and 30 ms shorter than the tachycardia cycle length (TCL). The global activation pattern was defined as circuitous (macroreentrant atrial circuit) or centrifugal (focal origin with centrifugal radiation) by electroanatomic mapping. Except for one case, all pacing was performed from the proximal coronary sinus bipole. Circuitous tachycardias (n = 17, all macro-reentrant) exhibited minimal variability with pacing at 10 ms and 30 ms shorter than TCL (6.0 +/- 2.5 ms), whereas centrifugal tachycardias (n = 14, 8 microreentrant) displayed a high degree of variability (56.5 +/- 20.6 ms). Rank sum analysis of PPIV suggests that the two groups are indeed distinct (P < 0.001). Using PPIV cutoffs of or=30 ms, circuitous and centrifugal activation patterns could be distinguished with a high degree of sensitivity (94% circuitous, 92.8% centrifugal) and 100% specificity. CONCLUSIONS: Our data support the use of PPIV to rapidly and accurately predict the global activation pattern during atrial arrhythmia.

Organized incessant atrial arrhythmias in the setting of severe, isolated biatrial scarring.

INTRODUCTION: Diffuse transmural fibrosis and scarring limited to the area without atrial dilation or significant structural heart or other systemic disease has not been reported. We present three cases of a syndrome characterized by refractory organized atrial arrhythmias, diffuse atrial scarring with electrical silence, and mechanical paralysis in the absence of atrial dilation or any systemic or neurodegenerative disorders. METHODS: Patients referred for electrophysiology study of atrial arrhythmias were included. Electroanatomic mapping with the Carto system (Biosense Webster, Diamond Bar, CA, USA) and magnetic resonance imaging (MRI) with scar sequencing were performed. RESULTS: There was no family or personal history of cardiac, muscular, or developmental diseases. All patients had organized atrial arrhythmias. Echocardiograms showed atrial standstill with normal atrial and ventricular dimensions. No other structural abnormalities were noted. Carto mapping revealed severe biatrial diffuse scarring. The left atrial (LA) was less affected than the right atrial (RA). MRI findings confirmed biatrial scarring. During tachycardia, islands of dissociated electrical activity could be seen in the right atria. Entrainment mapping was not performed in the atria as high-output pacing could not capture the atria. Coronary sinus entrainment demonstrated the coronary sinus(CS) not to be critical to the tachycardia. Ablation was targeted toward channels of low voltage but was not successful in any cases. All required atrioventricular (AV) nodal ablation with pacing. CONCLUSION: An association between biatrial cardiomyopathy and scarring with normal atrial dimensions has been described. Since severe scarring has not been reported with organized arrhythmias this may represent a new syndrome.

Dual-chamber versus single-chamber detection enhancements for implantable defibrillator rhythm diagnosis: the detect supraventricular tachycardia study.

BACKGROUND: Delivery of inappropriate shocks caused by misdetection of supraventricular tachycardia (SVT) remains a substantial complication of implanted cardioverter/defibrillator (ICD) therapy. Whether use of optimally programmed dual-chamber ICDs lowers this risk compared with that in single-chamber ICDs is not clear. METHODS AND RESULTS: Subjects with a clinical indication for ICD (n=400) at 27 participating centers received dual-chamber ICDs and were randomly assigned to strictly defined optimal single- or dual-chamber detection in a single-blind manner. Programming minimized ventricular pacing. The primary end point was the proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study. On a per-episode basis, 42% of the episodes in the single-chamber arm and 69% of the episodes in the dual-chamber arm were due to SVT. Mortality (3.5% in both groups) and early study withdrawal (14% single-chamber, 11% dual-chamber) were similar in both groups. The rate of inappropriate detection of SVT was 39.5% in the single-chamber detection arm compared with 30.9% in the dual-chamber arm. The odds of inappropriate detection were decreased by almost half with the use of the dual-chamber detection enhancements (odds ratio, 0.53; 95% confidence interval, 0.30 to 0.94; P=0.03). CONCLUSIONS: Dual-chamber ICDs, programmed to optimize detection enhancements and to minimize ventricular pacing, significantly decrease inappropriate detection.

Interatrial conduction measured during biventricular pacemaker implantation accurately predicts optimal paced atrioventricular intervals.

BACKGROUND: Optimizing atrioventricular (AV) delay during biventricular (BiV) pacemaker implantation can require substantial resources. Hence, a simpler method is desirable. We hypothesized that interatrial conduction time (IACT), measured at the time of BiV device implant, could be a surrogate value for the optimal AV delay. OBJECTIVE: This study determined the relationship between paced IACT and the optimal paced AV delay (PAV), as determined by echocardiography. METHODS: Consecutive subjects (N = 25; age = 66 +/- 10 years; M/F: 17/8) undergoing BiV pacemaker implantation and in sinus rhythm were included. Cannulation of the coronary sinus (CS) was at the operator's discretion. A quadripolar electrophysiology catheter was inserted via the guiding sheath into the inferiolateral CS to measure left atrial depolarization. The IACT was calculated as the interval between right atrial stimulation artifact and earliest deflection on the coronary sinus catheter electrogram. Subsequently, during atrial pacing the PAV was determined using transmitral pulsed wave Doppler echocardiography (iterative method). The relationship between paced IACT and PAV was then determined. RESULTS: The mean +/- SD paced IACT and PAV were 126 +/- 25 msec and 157 +/- 23 msec, respectively. There was a strong positive correlation between the paced IACT and PAV (r = 0.73, P < 0.001). The equation describing the relationship was PAV = 0.68 * (IACT + 104) msec. CONCLUSIONS: The paced IACT has a strong correlation with the echo derived optimal PAV. This method may be used to program PAV intervals without need for echocardiography in patients undergoing BiV pacemaker implantation.

Inherited arrhythmic disorders: long QT and Brugada syndromes.

Inherited arrhythmic disorders comprise a group of syndromes with unique genetic abnormalities and presentations but with very similar clinical outcomes and complications, the most terrifying of which are life-threatening arrhythmias and sudden cardiac death. Advances in molecular biology have enabled us to define and pinpoint many such disorders, which were previously labeled as idiopathic, to specific genes on various chromosomes. The current trend in the management of these potentially deadly disorders is to use pharmacotherapy (antiarrhythmic agents) and defibrillators for the prevention of sudden death; however, targeted therapy at a molecular level appears to be the path of the future. Herein, we review long QT and Brugada syndromes and focus on the genetics, pathophysiology, and clinical manifestations of these inherited arrhythmogenic disorders that affect patients with structurally normal hearts.

Comparative Efficacy of Nebivolol and Metoprolol to Prevent Tachycardia-Induced Cardiomyopathy in a Porcine Model.

Chronic tachycardia is a well-known cause of nonischemic cardiomyopathy. We hypothesized that nebivolol, a ß-blocker with nitric oxide activity, would be superior to a pure ß-blocker in preventing tachycardia-induced cardiomyopathy in a porcine model. Fifteen healthy Yucatan pigs were randomly assigned to receive nebivolol, metoprolol, or placebo once a day. All pigs underwent dual-chamber pacemaker implantation. The medication was started the day after the pacemaker implantation. On day 7 after implantation, each pacemaker was set at atrioventricular pace (rate, 170 beats/min), and the pigs were observed for another 7 weeks. Transthoracic echocardiograms, serum catecholamine levels, and blood chemistry data were obtained at baseline and at the end of the study. At the end of week 8, the pigs were euthanized, and complete histopathologic studies were performed. All the pigs developed left ventricular cardiomyopathy but remained hemodynamically stable and survived to the end of the study. The mean left ventricular ejection fraction decreased from baseline by 34%, 20%, and 20% in the nebivolol, metoprolol, and placebo groups, respectively. These changes did not differ significantly among the 3 groups (P =0.51). Histopathologic analysis revealed mild left ventricular perivascular fibrosis with cardiomyocyte hypertrophy in 14 of the 15 pigs. Both nebivolol and metoprolol failed to prevent cardiomyopathy in our animal model of persistent tachycardia and a high catecholamine state.

Postoperative atrial fibrillation and mortality after coronary artery bypass surgery.

OBJECTIVES: We sought to determine if the occurrence of postoperative atrial fibrillation (AF) affects early or late mortality following coronary artery bypass surgery (CABG). BACKGROUND: Atrial fibrillation is the most common arrhythmia seen following CABG. METHODS: The Texas Heart Institute Cardiovascular Research Database was used to identify all patients that developed AF after isolated initial CABG from January 1993 to December 1999 (n = 994). This population was compared with patients who underwent CABG during the same period but did not develop AF (n = 5,481). In-hospital end points were adjusted using logistic regression models to account for baseline differences. Long-term survival was evaluated using a retrospective cohort design, where Cox proportional hazards methods were used to adjust for baseline differences, and with case-matched populations (n = 390, 195 per arm). RESULTS: Atrial fibrillation was diagnosed in 16% of the population. Postoperative AF was associated with greater in-hospital mortality (odds ratio [OR] 1.7, p = 0.0001), more strokes (OR 2.02, p = 0.001), prolonged hospital stays (14 vs. 10 days, p < 0.0001), and a reduced incidence of myocardial infarction (OR 0.62, p = 0.01). At four to five years, survival was worse in patients who developed postoperative AF (74% vs. 87%, p < 0.0001 in the retrospective cohort; 80% vs. 93%, p = 0.003 in the case-matched population). On multivariate analysis, postoperative AF was an independent predictor of long-term mortality (adjusted OR 1.5, p < 0.001 in the retrospective cohort; OR 3.4, p = 0.0018 in the case-matched population). CONCLUSIONS: The occurrence of AF following CABG identifies a subset of patients who have a reduced survival probability following CABG. The impact of various strategies, such as antiarrhythmics and warfarin, aimed at reducing AF and its complications deserves further study.

A Review of the LARIAT Suture Delivery Device for Left Atrial Appendage Closure.

The prevalence of atrial fibrillation (AF) is 1-2 % in the general population, and the risk of embolic stroke in AF patients is 4-5 times higher than that in the general population. AF-related strokes are often severe, and the rate of permanent disability is much higher among individuals who have AF-related strokes than in those who have strokes unrelated to AF. In patients with AF, more than 90 % of thrombi originate from the left atrial appendage (LAA). The purpose of this paper is to review the efficacy and safety of performing the LAA closure with the LARIAT Suture Delivery Device to prevent AF-related stroke in patients with contraindications to oral anticoagulant therapy.

Safety and effectiveness of compassionate use of LARIAT® device for epicardial ligation of anatomically complex left atrial appendages.

BACKGROUND: Percutaneous left atrial appendage (LAA) ligation using an epicardial suture system (LARIAT®, SentreHEART, Palo Alto, CA) has been used in patients with nonvalvular atrial fibrillation (AF) and contraindication to oral anticoagulation. However, complex LAA anatomy may preclude its use. We report the safety and effectiveness of compassionate use of first-generation LARIAT® device for epicardial ligation of large, complex left atrial appendages. METHODS: Between January 2010 and March 2013, 93 patients with AF, high CHADS2 score, and contraindication(s) for oral anticoagulation therapy were evaluated for LAA ligation. Complex anatomy detected by 3D cardiac computed tomography CT angiography led to preclusion of 25 patients (27%). Of these, nine patients who opted for epicardial LAA ligation on compassionate grounds were studied. RESULTS: Mean age was 68.1 ± 8.2 years, four females, all with large LAA width (>40 mm, 45-58 mm) and additional anatomic complexities such as bilobed (two), long C-shaped-like (two), goose neck-like (one), multilobed cauliflower-like (two), cactus-like (one), and chicken wing-like (one) LAA. LAA ligation with LARIAT® was successfully performed with surgical standby in all patients. Seven patients (78%) were safely treated percutaneously and only two patients required minimally invasive thoracotomy (one due to inability to release the epicardial snare from long C-shaped LAA and other due to preexisting adhesions precluding pericardial entry). There were no major complications. Repeat trans-esophageal echocardiography at 3 months showed no remnant flow and none had stroke off Coumadin at 19.3 ± 8.2 months of follow-up. CONCLUSIONS: Despite a high preclusion rate, percutaneous LAA ligation may be safely and effectively performed on compassionate grounds using the first-generation LARIAT® device with surgical standby in patients with large and complex LAA.