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Hybrid ablation combines thoracoscopic epicardial ablation with percutaneous catheter based endocardial ablation for the treatment of AF. The purpose of this study was to evaluate the safety and efficacy of hybrid ablation surgery for the treatment of atrial fibrillation (AF), and to compare outcomes of unilateral vs bilateral thoracoscopic epicardial ablation. Patients with documented AF who underwent hybrid ablation were followed post-operatively for major events. Major events were classified into 2 categories consisting of (1) safety, comprising all-cause mortality and major morbidities, and (2) efficacy, which included recurrence of atrial arrhythmia, cessation of antiarrhythmic drugs (AAD), and completeness of lesion set. A total of 84 consecutive patients were consented for hybrid ablation. Patients presented with an average AF duration of 85.9 months before hybrid ablation. 80 patients underwent successful thoracoscopic epicardial ablation. At 1-year, 87% (60/69) of patients were free from AF and 73% (50/69) were free from AF and off AAD. 63 patients completed both epicardial and endocardial hybrid ablation with posterior wall isolation achieved in 89% (56/63) of patients. Unilateral epicardial ablation was associated with significantly shorter hospital length of stay compared to bilateral surgical approached (3.9 vs 6.7 days, p = 0.002) with no difference in freedom from AF between groups at 1 year. Hybrid ablation for atrial fibrillation is effective for patients at high risk for recurrence after catheter ablation. The unilateral surgical approach may be associated with shorter hospital stay with no appreciable effect on procedure success rates. [Display omitted] [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ahj.2009.08.002 Byline: Marco V. Perez (a), Frederick E. Dewey (a), Rachel Marcus (a), Euan A. Ashley (a), Amin A. Al-Ahmad (a), Paul J. Wang (a), Victor F. Froelicher (a)(b) Abstract: Atrial fibrillation (AF) is the most prevalent arrhythmia in the United States and accounts for more than 750,000 strokes per year. Noninvasive predictors of AF may help identify patients at risk of developing AF. Our objective was to identify the electrocardiographic characteristics associated with onset of AF. Author Affiliation: (a) Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA (b) Cardiovascular Medicine, Palo Alto Veterans Affairs Health Care System, Stanford, CA Article History: Received 26 May 2009; Accepted 6 August 2009

Introduction: Shared decision making (SDM) may result in treatment plans that best reflect the goals and wishes of patients, increasing patient satisfaction with the decision-making process. There is a knowledge gap to support the use of decision aids in SDM for anticoagulation therapy in patients with atrial fibrillation (AF). We describe the development and testing of a new decision aid, including a multicenter, randomized, controlled, 2-arm, open-label ENHANCE-AF clinical trial (Engaging Patients to Help Achieve Increased Patient Choice and Engagement for AF Stroke Prevention) to evaluate its effectiveness in 1,200 participants.Methods: Participants will be randomized to either usual care or to a SDM pathway incorporating a digital tool designed to simplify the complex concepts surrounding AF in conjunction with a clinician tool and a non-clinician navigator to guide the participants through each step of the tool. The participant-determined primary outcome for this study is the Decisional Conflict Scale, measured at 1 month after the index visit during which a decision was made regarding anticoagulation use. Secondary outcomes at both 1 and 6 months will include other decision making related scales as well as participant and clinician satisfaction, oral anticoagulation adherence, and a composite rate of major bleeding, death, stroke, or transient ischemic attack. The study will be conducted at four sites selected for their ability to enroll participants of varying racial and ethnic backgrounds, health literacy, and language skills. Participants will be followed in the study for 6 months.Conclusions: The results of the ENHANCE-AF trial will determine whether a decision aid facilitates high quality shared decision making in anticoagulation discussions for stroke reduction in AF. An improved shared decision-making experience may allow patients to make decisions better aligned with their personal values and preferences, while improving overall AF care. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) has presented substantial challenges to patient care and impacted health care delivery, including cardiac electrophysiology practice throughout the globe. Based upon the undetermined course and regional variability of the pandemic, there is uncertainty as to how and when to resume and deliver electrophysiology services for arrhythmia patients. This joint document from representatives of the Heart Rhythm Society, American Heart Association, and American College of Cardiology seeks to provide guidance for clinicians and institutions reestablishing safe electrophysiological care. To achieve this aim, we address regional and local COVID-19 disease status, the role of viral screening and serologic testing, return-to-work considerations for exposed or infected health care workers, risk stratification and management strategies based on COVID-19 disease burden, institutional preparedness for resumption of elective procedures, patient preparation and communication, prioritization of procedures, and development of outpatient and periprocedural care pathways. [ABSTRACT FROM AUTHOR]

Background: Approaches, tools, and technologies for atrial fibrillation (AF) ablation have evolved significantly since its inception. We sought to characterize secular trends in AF ablation success rates.Methods: We performed a systematic review and meta-analysis of AF ablation from January 1, 1990, to August 1, 2016, searching PubMed, Scopus, and Cochrane databases. Major exclusion criteria were insufficient outcome reporting and ablation strategies that were not prespecified and uniform. We stratified treatment arms by AF type (paroxysmal AF; nonparoxysmal AF) and analyzed single-procedure outcomes. Multivariate meta-regressions analyzed effects of study, patient, and procedure characteristics on success rate trends. Registered in PROSPERO (CRD42016036549).Results: A total of 180 trials and observational studies with 28,118 patients met inclusion. For paroxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 73.1% in 2003 to 77.1% in 2016, increasing by 0.9%/year (95% CI 0.4%-1.4%; P = .001; I2 = 90%). After controlling for study design and patient demographics, rate of improvement in success rate summary estimate increased (1.6%/year; 95% CI 0.9%-2.2%; P = .001; I2 = 87%). For nonparoxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 70.0% in 2010 to 64.3% in 2016 (1.1%/year; 95% CI -1.3% to 3.5%; P = .37; I2 = 85%), with no improvement in multivariate analyses.Conclusions: Despite substantial research investment and health care expenditure, improvements in AF ablation success rates have been incremental. Meaningful improvements may require major paradigm or technology changes, and evaluation of clinical outcomes such as mortality and quality of life may prove to be important going forward. [ABSTRACT FROM AUTHOR]

Background: There are limited data on the prognostic importance of declining activity level in patients with heart failure.Objective: We aimed to assess the association of reduced activity level with adverse cardiovascular outcomes in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT).Methods: Final device interrogations from patients enrolled in the MADIT-CRT with cardiac resynchronization devices capable of recording percent daily activity level were assessed. To determine temporal change, standardized activity levels (SALs) comparing each week to the monthly activity 3 months prior were obtained. Death, heart failure events (HFEs)/death, and ventricular tachyarrhythmias (VTAs)/death were the primary end points of this study.Results: The average absolute activity level and SAL of the final week prior to death or end of study were significantly lower in patients who died compared with those in patients who did not. The total cohort (N = 1008) was further randomized into 2 subgroups to identify (group 1) and validate an optimal threshold (group 2). Patients with >40% reduced SAL had a significantly increased 77-day short-term cumulative incidence of death (P = .0006), HFE/death (P < .0001), or VTA/death (P = .0248). After adjustment for clinical covariates, these patients remained at an increased risk for death (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.5-4.9; P = .001), HFE/death (HR, 2.7; 95% CI, 1.8-3.9; P ≤ .001) and VTA/death (HR, 1.9; 95% CI, 1.31-2.6; P = .001). A decline in SAL following a nonfatal VTA and HFE was also associated with an increased probability of death.Conclusions: Decline in activity level is a short-term predictor for adverse cardiovascular events in patients with mild to moderate heart failure undergoing cardiac resynchronization. [ABSTRACT FROM AUTHOR]

Background: During ablation for atrial fibrillation (AF), it is challenging to anticipate transitions to organized tachycardia (AT). Defining indices of this transition may help to understand fibrillatory conduction and help track therapy.Objective: To determine the timescale over which atrial fibrillation (AF) organizes en route to atrial tachycardia (AT) using the ECG referenced to intracardiac electrograms.Methods: In 17 AF patients at ablation (58.7±9.6years; 53% persistent AF) we analyzed spatial loops of atrial activity on the ECG and intracardiac electrograms over successive timepoints. Loops were tracked at precisely 15, 10, 5, 3 and 1min prior to defined transitions of AF to AT.Results: Organizational indices reliably quantified changes from AF to AT. Spatiotemporal AF organization on the ECG was identifiable at least 15min before AT was established (p=0.02).Conclusions: AF shows anticipatory global organization on the ECG minutes before AT is clinically evident. These results offer a foundation to establish when AF therapy is on an effective path, and for a quantitative classification separating AT from AF. [ABSTRACT FROM AUTHOR]

Background: There are limited data on the significance of left ventricular (LV) lead pacing polarity to predict clinical outcomes.Objectives: We aimed to determine the association between the LV lead pacing polarity for heart failure (HF) or death and ventricular tachyarrhythmias (VTA) in patients enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy), receiving a cardiac resynchronization therapy device with implanted cardioverter-defibrillator (CRT-D).Methods: We retrospectively analyzed LV pacing polarity. Patients with LV bipolar leads paced between LV ring and LV tip were identified as True Bipolar, while those with LV bipolar leads paced between LV tip or LV ring and right ventricular coil or unipolar leads were identified as Unipolar/Extended Bipolar. Kaplan-Meier survival analyses and multivariate Cox proportional hazards regression models were used.Results: Of the 969 patients, 421 had True Bipolar pacing while the remainder (n = 548) had Unipolar/Extended Bipolar pacing. Among patients with left bundle branch block (LBBB), True Bipolar pacing was associated with lower cumulative incidence of death (P = .022) and HF/death (P = .046) compared to those with Unipolar/Extended Bipolar LV pacing. After adjustment for clinical covariates, bipolar LV pacing in LBBB patients was associated with 54% lower risk for death (HR: 0.46; 95% CI: 0.24-0.88; P = .020) and 32% lower risk for HF/death (HR: 0.68; 95% CI: 0.46-1.00; P = .048) compared to Unipolar/Extended Bipolar LV pacing, but not in those with non-LBBB. No association was seen with risk of ventricular tachyarrhythmia.Conclusion: True Bipolar LV pacing configuration is associated with a significantly lower risk of HF/death and all-cause mortality in CRT-D patients with LBBB. [ABSTRACT FROM AUTHOR]

Background: There are limited data about the correlation between brain natriuretic peptide (BNP) levels and arrhythmic risk assessment in patients who receive device therapy for the treatment of heart failure (HF) or for the prevention of sudden cardiac death. Objectives: We aimed to investigate the association between BNP levels and the risk of ventricular tachyarrhythmias among mildly symptomatic HF patients who receive an intracardiac defibrillator (ICD) with or without cardiac resynchronization therapy (respectively, CRT-D or CRT). Methods: The study population involved 1197 patients enrolled in MADIT-CRT. Plasma BNP was measured in a core laboratory at baseline and after 1-year follow-up. Ventricular tachycardia/fibrillation (VT/VF) events were identified from ICD/CRT-D interrogations. Results: Multivariate Cox hazards regression modeling showed that elevated baseline (> median = 72 ng/L) and 1-year BNP were associated with a significant increase in the risk of VT/VF (HR = 1.36, P = .026; and HR = 1.79, P < .001, respectively); and VT/VF or death (HR = 1.37, P = .008; and HR = 1.84, P < .0001, respectively) during follow-up. At 1 year post device implantation, BNP levels were significantly lower among study patients treated with CRT-D as compared with those who received ICD only (P = .014). CRT-D patients who had greater than median reductions in BNP levels (greater than one-third reduction of initial value) experienced a significantly lower risk of subsequent VT/VF (HR = 0.61, P = .021) and VT/VF or death (HR = 0.45, P < .0001) as compared to patients without such reductions. Conclusions: In MADIT-CRT, elevated baseline and follow-up BNP levels were independent predictors of increased risk for subsequent ventricular tachyarrhythmias, whereas BNP reductions following CRT-D implantation identified patients with a lower incidence of VT/VF during follow-up. [ABSTRACT FROM AUTHOR]

Background: Previous observations have reported that the number of pacing stimuli required to entrain a tachycardia varies on the basis of arrhythmia type and location, but a quantitative formulation of the number needed to entrain (NNE) that unifies these observations has not been characterized.Objective: We sought to investigate the relationship between the number of pacing stimulations, the tachycardia cycle length (TCL), the overdrive pacing cycle length (PCL), and the postpacing interval (PPI) to accurately estimate the timing of tachycardia entrainment.Methods: First, we detailed a mathematical derivation unifying electrophysiological parameters with empirical confirmation in 2 patients undergoing catheter ablation of typical atrial flutter. Second, we validated our formula in 44 patients who underwent various catheter ablation procedures. For accuracy, we corrected for rate-related changes in conduction velocity.Results: We derived the equations NNE = |(PPI - TCL)/(TCL - PCL)| + 1 and Tachycardia advancement = (NNE - 1) × (TCL - PCL) - (PPI - TCL), which state that the NNE and the amount of tachycardia advancement on the first resetting stimulation are determined using regularly measured intracardiac parameters. In the retrospective cohort, the observed PPI - TCL highly correlated with the predicted PPI - TCL (mean difference 5.8 ms; r = 0.97; P < .001), calculated as PPI - TCL = (NNE - 1) × (TCL - PCL) - tachycardia advancement.Conclusion: The number of pacing stimulations required to entrain a reentrant tachycardia is predictable at any PCL after correcting for cycle length-dependent changes in conduction velocity. This relationship unifies established empirically derived diagnostic and mapping criteria for supraventricular tachycardia and ventricular tachycardia. This relationship may help elucidate when antitachycardia pacing episodes are ineffective or proarrhythmic and could potentially serve as a theoretical basis to customize antitachycardia pacing settings for improved safety and effectiveness. [ABSTRACT FROM AUTHOR]

Background: There are no prior studies assessing the relationship between left atrial volume (LAV) and inappropriate implantable cardioverter-defibrillator (ICD) therapy following treatment with cardiac resynchronization therapy. Objective: The purpose of this study was to investigate the hypothesis that patients randomized to cardiac resynchronization therapy with defibrillator (CRT-D) in the Multicenter Automatic Defibrillator Trial–Cardiac Resynchronization Therapy (MADIT-CRT) who had significant LAV reductions would have reduced risks of inappropriate ICD therapy. Methods: Cardiac resynchronization remodeling was assessed by measuring LAV change between baseline and 12-month echocardiograms in 751 CRT-D treated patients. Patients were stratified into quartiles based on percent reduction of LAV change. High LAV responders were those in the highest 3 quartiles of LAV reduction (LAV reduction ≥21%). Low LAV responders were those in the lowest quartile of LAV reduction (LAV reduction <21%). Clinical factors associated with ≥21% reduction in LAV were evaluated by linear regression analysis. Results: In Cox proportional hazards regression analyses, high LAV responders had a 39% reduction in the risk of inappropriate therapy (hazard ratio 0.61, P = .04) and left bundle branch block patients exhibited an even greater risk reduction in inappropriate therapy (hazard ratio 0.51, P = .02) compared to low LAV responders during follow-up extending up to 3 years after the 12-month echocardiogram. High LAV responders also had a significantly lower risk of heart failure or death during follow-up than did low LAV responders. Conclusion: A ≥21% reduction in LAV with cardiac resynchronization therapy is associated with significant reductions in inappropriate ICD therapy and in heart failure or death during a 3-year follow-up. [Copyright &y& Elsevier]

Background: Data on the outcome of cardiac resynchronization therapy with defibrillator (CRT-D) in patients developing ventricular arrhythmias are limited. Objective: To evaluate the prognostic value of ventricular tachycardia (VT) or ventricular fibrillation (VF) episodes by heart rate in patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy trial. Methods: Slow VT was defined as VTs with heart rate < 200 beats/min. Fast VT with a heart rate ≥200 beats/min and VF (>250 beats/min) were considered as a combined category. Primary end point was heart failure (HF) or death. Secondary end point included all-cause mortality. Results: There were 228 (12.7%) patients with slow VT and 198 (11.1%) with fast VT/VF. In time-dependent analysis, slow VT was associated with an increased risk of HF/death in CRT-D patients with left branch bundle block (LBBB; hazard ratio [HR] 3.19; 95% confidence interval [CI] 1.83–5.55; P < .001), but not in patients with implantable cardioverter-defibrillator (ICD) (HR 1.03; 95% CI 0.52–2.19; P = .867; interaction P value = .017). CRT-D patients with LBBB and fast VT/VF doubled their risk of HF/death compared to ICD patients (interaction P value = .06). Slow VT events were also predictive of death in CRT-D patients with LBBB (HR 3.48; 95% CI 1.66–7.28; P < .001), but not in ICD patients (interaction P value = .06). Slow VTs were highly predictive of subsequent fast VT/VF (HR 4.33; 95% CI 3.01–6.24; P < .001). Conclusions: Slow VT episodes are predictive of subsequent fast VT/VF. Slow VT and fast VT/VF episodes in CRT-D patients are associated with an increased risk of subsequent HF/death. CRT-D-treated LBBB patients with slow VTs have a significantly higher risk of mortality. [Copyright &y& Elsevier]

Objectives: The aim of our study was to evaluate the relationship between left ventricular (LV) dyssynchrony and the risk of ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients enrolled in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial—Cardiac Resynchronization Therapy) trial. Background: Intraventricular mechanical dyssynchrony might be an important factor in ventricular arrhythmogenesis by enhancing electrical heterogeneity in heart failure patients. The effects of dyssynchrony have not yet been evaluated in a large cohort of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy with defibrillator (CRT-D) patients. Methods: LV dyssynchrony was measured at baseline and at 12-months by speckle-tracking echocardiography, defined as the standard deviation of time to peak systolic strain in 12 LV myocardial segments. The endpoint was the first VT/VF/death or VT/VF. LV dyssynchrony was evaluated in 764 left bundle branch block (LBBB) patients and in 312 non-LBBB patients. Results: Baseline LV dyssynchrony was not predictive of VT/VF/death or VT/VF in LBBB or non-LBBB patients in either treatment arm. In CRT-D patients with LBBB, improvement in LV dyssynchrony over a year was associated with significantly lower incidence of VT/VF/death (p < 0.001) and VT/VF (p < 0.001) compared to ICD patients and to CRT-D patients with unchanged or worsening dyssynchrony. Among LBBB patients, 15% decrease in LV dyssynchrony was associated with lower risk of VT/VF/death (hazard ratio: 0.49, 95% confidence interval: 0.24 to 0.99, p = 0.049) and VT/VF (hazard ratio: 0.30, 95% confidence interval: 0.12 to 0.77, p = 0.009) as compared to ICD patients. Patients without LBBB receiving CRT-D did not show reduction in VT/VF/death or in VT/VF in relation to improving dyssynchrony when evaluating cumulative event rates or risk of events. Conclusions: Baseline LV dyssynchrony did not predict VT/VF/death or VT/VF in mild heart failure patients with or without LBBB. CRT-induced improvement of LV dyssynchrony was associated with significant reduction of ventricular arrhythmias in patients with LBBB. (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271) [Copyright &y& Elsevier]

Background: The effect of cardiac resynchronization therapy (CRT) on left ventricular wall thickness and left ventricular mass (LVM) is unknown. Objectives: To evaluate the effects of CRT on septal and posterior wall thickness (SWT and PWT) and LVM in patients with left bundle branch block (LBBB) and non-LBBB vs implantable cardioverter-defibrillator patients and to assess the relationship between CRT-induced changes and cardiac events. Methods: We investigated 843 patients with LBBB and 366 patients with non-LBBB enrolled in the Multicenter Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy (MADIT-CRT) trial to analyze changes in SWT, PWT, and LVM at 12 months and subsequent outcome. The primary end point was heart failure or death; secondary end points included ventricular tachycardia, ventricular fibrillation, or death. Results: In LBBB patients, reduction in SWT, PWT, and LVM was more pronounced in CRT defibrillator (CRT-D) than in implantable cardioverter-defibrillator (SWT:−6.7%±4.4% vs−1.0%±1.9%; PWT:−6.4%±4.3% vs−0.8%±1.9%; LVM:−23.6%±9.9% vs−5.1%±5.1%; P<.001 for all). In CRT-D patients with non-LBBB, LVM reduction was less pronounced; however, changes in SWT and PWT were comparable. Changes in LVM correlated with changes in left ventricular end-diastolic volume. In CRT-D patients with LBBB, reduction in SWT and LVM was associated with reduction in heart failure/death (SWT: hazard ratio 0.94; 95% confidence interval 0.89–0.99 per percent change; P = .03) and ventricular tachycardia/ventricular fibrillation/death (SWT: hazard ratio 0.95; 95% confidence interval 0.91–1.00; P = .04). CRT-D patients with non-LBBB did not show favorable reduction in clinical or arrhythmic end points related to changes in SWT, PWT, or LVM. Conclusions: CRT-D was associated with significant reduction in SWT, PWT, and LVM in patients with LBBB along with left ventricular volume changes and associated favorable clinical and arrhythmia outcomes. [Copyright &y& Elsevier]

Background: Prior studies have indicated that the magnitude of risk association of microvolt T-wave alternans (MTWA) testing appears to vary with the population studied. We performed a meta-analysis to determine the ability of MTWA to modify risk assessment of ventricular tachyarrhythmic events (VTEs) and sudden cardiac death (SCD) across a series of patient risk profiles using likelihood ratio (LR) testing, a measure of test performance independent of disease prevalence. Methods: We identified original research articles published from January 1990 to January 2011 that investigate spectrally derived MTWA. Ventricular tachyarrhythmic event was defined as the total and arrhythmic mortality and nonfatal sustained or implantable cardioverter-defibrillator–treated ventricular tachyarrhythmias. Summary estimates were created for positive and nonnegative MTWA results using a random-effects model and were expressed as positive (LR+) and negative (LR−) LRs. Results: Of 1,534 articles, 20 prospective cohort studies met our inclusion criteria, consisting of 5,945 subjects predominantly with prior myocardial infarction or left ventricular dysfunction. Although there was a modest association between positive MTWA and VTE (relative risk 2.45, 1.58-3.79) and nonnegative MTWA and VTE (3.68, 2.23-6.07), test performance was poor (positive MTWA: LR+ 1.78, LR− 0.43; nonnegative MTWA: LR+ 1.38, LR− 0.56). Subgroup analyses of subjects classified as prior VTE, post–myocardial infarction, SCD-HeFT type, and MADIT-II type had a similar poor test performance. A negative MTWA result would decrease the annualized risk of VTE from 8.85% to 6.37% in MADIT-II–type patients and from 5.91% to 2.60% in SCD-HeFT–type patients. Conclusions: Despite a modest association, results of spectrally derived MTWA testing do not sufficiently modify the risk of VTE to change clinical decisions. [Copyright &y& Elsevier]

Rationale and Objectives: During radiofrequency catheter ablation for atrial fibrillation, the esophagus is at risk for thermal injury. In this study, C-arm computed tomography (CT) was compared to clinical CT, without the administration of oral contrast, to visualize the esophagus and its relationship to the left atrium and the ostia of the pulmonary veins (PVs) during the radiofrequency ablation procedure. Materials and Methods: Sixteen subjects underwent both cardiac clinical CT and C-arm CT. Computed tomographic scans were performed on a multidetector scanner using a standard electrocardiographically gated protocol. C-arm computed tomographic scans were obtained using either a multisweep protocol with retrospective electrocardiographic gating or a non-gated single-sweep protocol. C-arm and clinical computed tomographic scans were analyzed in a random order and then compared for the following criteria: (1) visualization of the esophagus (yes or no), (2) relationship of esophageal position to the four PVs, and (3) direct contact or absence of a fat pad between the esophagus and the PV antrum. Results: The esophagus was identified in all C-arm and clinical computed tomographic scans. In four cases, orthogonal planes were needed on C-arm CT (inferior PV level). In six patients, the esophageal location on C-arm CT was different from that on CT. Direct contact was reported in 19 of 64 of the segments (30%) examined on CT and in 26 of 64 (41%) on C-arm CT. In five of 64 segments (8%), C-arm CT overestimated a direct contact of the esophagus to the left atrium. Conclusions: C-arm computed tomographic image quality without the administration of oral contrast agents was shown to be sufficient for visualization of the esophagus location during a radiofrequency catheter ablation procedure for atrial fibrillation. [Copyright &y& Elsevier]

Objectives: We aimed to evaluate the relationship between echocardiographic response to cardiac resynchronization therapy (CRT) and the risk of subsequent ventricular tachyarrhythmias (VTAs). Background: Current data regarding the effect of CRT on the risk of VTA are limited and conflicting. Methods: The risk of a first appropriate implantable cardioverter-defibrillator (ICD) therapy for VTA (including ventricular tachycardia, ventricular fibrillation, and ventricular flutter) was compared between high- and low-echocardiographic responders to CRT defibrillator (CRT-D) therapy (defined as ≥25% and <25% reductions, respectively, in left ventricular end-systolic volume [LVESV] at 1 year compared with baseline) and ICD-only patients enrolled in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy). Results: The cumulative probability of a first VTA at 2 years after assessment of echocardiographic response was highest among low responders to CRT-D (28%), intermediate among ICD-only patients (21%), and lowest among high responders to CRT-D (12%), with p < 0.001 for the overall difference during follow-up. Multivariate analysis showed that high responders to CRT-D experienced a significant 55% reduction in the risk of VTA compared with ICD-only patients (p < 0.001), whereas the risk of VTA was not significantly different between low responders and ICD-only patients (hazard ratio [HR]: 1.26; p = 0.21). Consistently, assessment of response to CRT-D as a continuous measure showed that incremental 10% reductions in left ventricular end-systolic volume were associated with corresponding reductions in the risk of subsequent VTA (HR: 0.80; p < 0.001), VTA/death (HR: 0.79; p < 0.001), ventricular tachycardia (HR: 0.80; p < 0.001), and ventricular fibrillation/ventricular flutter (HR: 0.75; p = 0.044). Conclusions: In patients with left ventricular dysfunction enrolled in the MADIT-CRT trial, reverse remodeling was associated with a significant reduction in the risk of subsequent life-threatening VTAs. (Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271) [Copyright &y& Elsevier]

Background: Coronary revascularization (CR) may confer electrical stability in patients with ischemic cardiomyopathy. However, data regarding the effect of CR on the development of ventricular tachyarrhythmias in this population are limited. Objective: The purpose of this study was to evaluate the association between CR and arrhythmic risk in postmyocardial infarction (post-MI) patients with left ventricular dysfunction. Methods: The risk for life-threatening ventricular tachyarrhythmias (defined as a first appropriate defibrillator therapy for ventricular tachycardia [VT]/ventricular fibrillation [VF] or death) was compared between post-MI patients with and those without prior CR (n = 612 and 147, respectively) enrolled in the Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy (MADIT-CRT). Results: The 3-year cumulative rate of VT/VF or death was significantly higher among patients without prior CR (42%) than in patients who underwent prior CR (32%, P = .02). Multivariate analysis demonstrated that patients without prior CR had 48% increased risk (P = .01) for VT/VF or death. Risk reduction associated with CR was related to elapsed time from CR, assessed both as a categorical variable (tertiles for time from CR: ≥7 years, hazard ratio [HR] = 1.93, P = .001; 1.5–7 years, HR = 1.70, P = .01 vs <1.5 years) and as a continuous measure (4%, P = .002, increased risk for VT/VF or death per 1-year increment of elapsed time from CR). The effect of CR on arrhythmic risk was similar in patients treated with a defibrillator alone or when combined with cardiac resynchronization therapy. Conclusion: Post-MI patients with left ventricular dysfunction who undergo CR experience a time-dependent reduction in the risk for subsequent life-threatening ventricular tachyarrhythmias. [ABSTRACT FROM AUTHOR]

Background: Cardiac computed tomography (CT) is commonly used to visualize left atrial (LA) anatomy for ablation of atrial fibrillation. We have developed a new imaging technique that allows acquisition and visualization of three-dimensional (3D) cardiac images in the catheter lab. Objective: We sought to compare LA and pulmonary vein (PV) dimensions acquired using gated multisweep rotational fluoroscopy (C-arm CT) system and multislice computed tomography (MSCT) in an in vivo porcine model. Methods: A Siemens AXIOM Artis dTA C-arm system (Siemens AG, Medical Solutions) was modified to allow acquisition of four bidirectional sweeps during synchronized acquisition of the electrocardiogram signal to allow retrospective gating. C-arm CT image volumes were then reconstructed. Gated MSCT (SOMATOM Sensation 16 and 64, Siemens AG, Medical Solutions) and C-arm CT images were acquired in six animals. The two main PV diameters were measured in orthogonal axes. LA volumes were calculated. C-arm CT measurements were compared with the MSCT measurements. Results: The average PV diameters using the C-arm CT were 2.24 x 1.35 cm, versus 2.27 x 1.38 cm for CT. The average difference was 0.034 cm (1.9%) between the C-arm CT and standard CT. The average LA volume using MSCT was 49.1 +/- 12.7 cm(3), as compared with 51.0 +/- 8.7 cm(3) obtained by the C-arm CT. The average difference between the C-arm CT and the MSCT was 1.9 cm(3) (3.7%). There were no significant differences in either the PV or LA measurements. Conclusions: Visualization of 3D cardiac anatomy during ablation procedures is possible and highly accurate. The 3D cardiac reconstructions acquired during ablation procedures will be valuable for procedural planning and guidance. [ABSTRACT FROM AUTHOR]

Abstract: The goal of the present study was to determine if there are global or regionally specific decreases in callosal area in early Alzheimer''s disease (AD) and mild cognitive impairment (MCI). In addition, this study examined the corpus callosum of healthy older adults who have subjective cognitive complaints (CC) but perform within normal limits on neuropsychological tests. We used a semi-automated procedure to examine the total and regional areas of the corpus callosum in 22 patients with early AD, 28 patients with amnestic MCI, 28 healthy older adults with cognitive complaints, and 50 demographically matched healthy controls (HC). The AD, MCI, and CC groups all showed a significant reduction of the posterior region (isthmus and splenium) relative to healthy controls. The AD group also had a significantly smaller overall callosum than the controls. The demonstration of callosal atrophy in older adults with cognitive complaints suggests that callosal changes occur very early in the dementing process, and that these earliest changes may be too subtle for detection by neuropsychological assessments, including memory tests. [Copyright &y& Elsevier]

Background: Despite improvements in cardiac resynchronization therapy (CRT) implantation techniques, a significant minority of CRT attempts are unsuccessful. Inability to cannulate the coronary sinus (CS) because of difficult anatomy is a major reason for unsuccessful CRT implantation. Direct visualization of intracardiac structures during the implant may facilitate access into the CS. The present study describes CRT implantation with the aid of an endocardial visualization catheter (EVC).Methods: Fifty-eight consecutive patients (mean age 72 +/- 12 years; ejection fraction 26.2% +/- 7.0%; New York Heart Association [NYHA] class 2.9) underwent CRT implantation using a steerable fiberoptic EVC (Acumen Medical, Inc., Sunnyvale, CA).Results: The EVC was able to visualize the CS ostium in all cases. The CS was successfully cannulated in 57 (98.3%) of 58 patients. The time from vascular access to CS visualization was 6 +/- 5 minutes, and the total time to CS access was 8 +/- 6 minutes. Successful left ventricle (LV) lead implantation was accomplished in 55 (94.8%) of 58 patients. Three patients who had a previous history of failed LV lead implantation were successfully implanted using the EVC.Conclusion: Fiberoptic imaging of intracardiac structures during CRT implantation may be performed rapidly in a wide range of patients with an EVC. The ability to visualize right atrial anatomy may aid CS access and LV lead implantation. [ABSTRACT FROM AUTHOR]

Background: Facilitation is an important physiologic property of the atrioventricular (AV) node. Previous studies demonstrated abnormal AV conduction in connexin (Cx)40-deficient mice. Objectives: We hypothesize that Cx40-deficient mice display altered patterns of AV nodal facilitation compared with wild-type mice. Methods: Sixteen 36-week-old mice (eight Cx40−/− mice and eight Cx40+/+ controls) underwent in vivo closed chest electrophysiologic study. A 2Fr octapolar catheter was advanced into the right ventricle to record a His-bundle electrogram. A special facilitation stimulation protocol was performed in each mouse to evaluate facilitation. Following atrial drive pacing (S1S1) at 150 ms, a facilitating beat S2 was delivered prior to the test beat S3. S3H3 was measured for varying S1S2 values at fixed H2S3 intervals. Results: Progressive shortening of S1S2 (from 150 ms to 130, 110, and 90 ms) resulted in gradual prolongation of S2H2. The prolongation was more pronounced in Cx40−/− mice for each S1S2 compared with wild-type mice (P <.001). In each wild-type mouse, for a given H2S3 interval, this gradual increase in S2H2 produced progressive shortening of S3H3, so-called AV nodal facilitation phenomenon. However, in each Cx40−/− mouse, facilitation was seen only at S1S2 of 130 ms (P <.001 vs S1S2 of 150 ms). Evidence of reverse facilitation was documented at S1S2 of 110 and 90 ms. Conclusion: Facilitation is observed in wild-type mice. With similar S1S2 intervals in Cx40-deficient mice, facilitation is seen only at longer S1S2 intervals, whereas reverse facilitation is seen at shorter S1S2 intervals, suggesting that Cx40 is involved in the generation of AV nodal facilitation. [Copyright &y& Elsevier]