Fluoroless Catheter Ablation of Atrial Fibrillation: Integration of Intracardiac Echocardiography and Cartosound Module.

OBJECTIVE: To evaluate the feasibility, safety, and clinical efficacy of non-fluoroscopic radiofrequency catheter ablation of atrial fibrillation (AF) in comparison to traditional fluoroscopy-guided ablation in a local Canadian community cohort. METHODS: We retrospectively studied consecutive patients with paroxysmal and persistent AF undergoing pulmonary vein isolation (PVI) guided by intracardiac echocardiography (ICE) and Carto system (CartoSound module). ICE-guided PVI without fluoroscopy (Zero-fluoro group) was performed in 116 patients, and conventional fluoroscopy-guided PVI (Traditional group) was performed in 131 patients. RESULTS: Two hundred and forty-seven patients with AF (60.7% male; mean age: 62.2 ± 10.6 years; paroxysmal AF =63.1%) who underwent PVI were studied. Mean procedure times were similar between both groups (136.8±33.4 minutes in the zero-fluoro group vs. 144.3±44.9 minutes in the traditional group; p=0.2). Acute PVI was achieved in all patients. Survival from early AF recurrence was 85% and 81% in the zero-fluoro and traditional groups, respectively (p = 0.06). Survival from late AF recurrence (12-months) between the zero-fluoro and traditional groups was also similar (p=0.1). Moreover, there were no significant differences between complication rates, including hematoma (p = 0.2) and tamponade (p = 1),between both groups. CONCLUSIONS: Zero-fluoroscopy ICE and CartoSound-guided AF ablation may be safe and feasible in patients undergoing PVI compared to conventional fluoroscopy-guided ablation.

Safety and feasibility of left bundle branch area pacing following valvular interventions: Multicenter study.

OBJECTIVES: To evaluate the safety and feasibility of left bundle branch area pacing (LBBAP) in patients with valvular interventions. METHODS: Eighty-four patients were included in this study. All patients underwent recent surgical or percutaneous valvular interventions. LBBAP was attempted in all patients. Implant success rates, peri- and postprocedure electrocardiogram, pacing parameters, and complications were assessed at implant, and during follow-up. RESULTS: LBBAP implantation was successful in 80/84 (95%) patients. Mean age was 74.1 ± 13.8 years and 56% patients were male. Prior valvular replacements included: percutaneous aortic (26), surgical aortic (36), combined surgical aortic plus mitral (6), MVR (10), tricuspid (1), and pulmonic (1). Average LVEF was 52.6 ± 11%. Majority of patients underwent LBBAP due to atrioventricular block (76%) and sinus node disease (13%). Total procedure duration was 74.1 ± 12.5 min and fluoroscopic duration was 9.7 ± 6.8 min. Pacing parameters were stable during follow-up period of 10.0 ± 6.3 months. Pacing QRS duration was significantly narrower than baseline QRS duration (131.5 ± 31.4 ms vs. 114.3 ± 13.7 ms, p < .001, respectively). No acute complications were observed. Mean follow-up was 10.0 ± 6.3 months (median: 8.4 months, min: 1 and max: 24 months). During follow-up, there were three device infections and two patients had loss of LBBA capture within 1 month of implant. CONCLUSIONS: LBBAP is a feasible and safe pacing modality in patients with prior interventions for valvular heart disease.

Acute care nurses' perceptions of leadership, teamwork, turnover intention and patient safety - a mixed methods study.

BACKGROUND: This study contributes to a small but growing body of literature on how context influences perceptions of patient safety in healthcare settings. We examine the impact of senior leadership support for safety, supervisory leadership support for safety, teamwork, and turnover intention on overall patient safety grade. Interaction effects of predictors on perceptions of patient safety are also examined. METHODS: In this mixed methods study, cross-sectional survey data (N = 185) were collected from nurses and non-physician healthcare professionals. Semi-structured interview data (N = 15) were collected from nurses. The study participants worked in intensive care, general medicine, mental health, or the emergency department of a large community hospital in Southern Ontario. RESULTS: Hierarchical regression analyses showed that staff perceptions of senior leadership (p < 0.001), teamwork (p < 0.01), and turnover intention (p < 0.01) were significantly associated with overall patient safety grade. The interactive effect of teamwork and turnover intention on overall patient safety grade was also found to be significant (p < 0.05). The qualitative findings corroborated the survey results but also helped expand the characteristics of the study's key concepts (e.g., teamwork within and across professional boundaries) and why certain statistical relationships were found to be non-significant (e.g., nurse interviewees perceived the safety specific responsibilities of frontline supervisors much more broadly compared to the narrower conceptualization of the construct in the survey). CONCLUSIONS: The results of the current study suggest that senior leadership, teamwork, and turnover intention significantly impact nursing staff perceptions of patient safety. Leadership is a modifiable contextual factor and resources should be dedicated to strengthen relational competencies of healthcare leaders. Healthcare organizations must also proactively foster inter and intra-professional collaboration by providing teamwork educational workshops or other on-site learning opportunities (e.g., simulation training). Healthcare organizations would benefit by considering the interactive effect of contextual factors as another lever for patient safety improvement, e.g., lowering staff turnover intentions would maximize the positive impact of teamwork improvement initiatives on patient safety.

Turnover intention of hospital staff in Ontario, Canada: exploring the role of frontline supervisors, teamwork, and mindful organizing.

BACKGROUND: This study contributes to a small but growing body of literature on how context influences employee turnover intention. We examine the impact of staff perceptions of supervisory leadership support for safety, teamwork, and mindful organizing on turnover intention. Interaction effects of safety-specific constructs on turnover intention are also examined. METHODS: Cross-sectional survey data were collected from nurses, allied health professionals, and unit clerks working in intensive care, general medicine, mental health, or the emergency department of a large community hospital in Southern Ontario. RESULTS: Hierarchical regression analyses showed that staff perceptions of teamwork were significantly associated with turnover intention (p < 0.001). Direct associations of supervisory leadership support for safety and mindful organizing with turnover intention were non-significant; however, when staff perceived lower levels of mindful organizing at the frontlines, the positive effect of supervisory leadership on turnover intention was significant (p < 0.01). CONCLUSIONS: Our results suggest that, in addition to teamwork perceptions positively affecting turnover intentions, safety-conscious supportive supervisors can help alleviate the negative impact of poor mindful organizing on frontline staff turnover intention. Healthcare organizations should recruit and retain individuals in supervisory roles who prioritize safety and possess adequate relational competencies. They should further dedicate resources to build and strengthen the relational capacities of their supervisory leadership. Moreover, it is important to provide on-site workshops on topics (e.g., conflict management) that can improve the quality of teamwork and consequently reduce employees' intention to leave their unit/organization.

Risk of Stroke and Recurrence After AF Ablation in Patients With an Initial Event-Free Period of 12 Months.

INTRODUCTION: Because of the unclear prognostic effects of ablation of atrial fibrillation (AF), oral anticoagulation (OAC) is often continued after ablation even in asymptomatic patients. We sought to determine the frequency of stroke and AF recurrence in patients on and off therapeutic OAC 1 year after a successful AF ablation. METHODS AND RESULTS: Patients that underwent AF ablation and were free of AF 12 months after ablation were selected from our AF database. During follow-up (FU), patients were screened for recurrence of AF, changes in OAC or antiarrhythmic medication, and the occurrence of stroke or transient ischemic attack (TIA). A total of 398 patients (median age 60.7 years [50.8, 66.8], 25% female) were investigated. The median duration of FU was 529 (373, 111,3.5) days. OAC was discontinued in 276 patients (69.3%). During FU, 4 patients (1%) suffered from stroke and 55 patients (13.8%) experienced a recurrence of AF. Persistent AF was significantly associated with a greater chance of AF recurrence (49.1% vs. 26.8%; P = 0.001). Neither CHADS2 nor CHA2DS2-VASc-Score nor recurrence of AF were significantly different in patients with or without stroke. There was a trend toward a higher percentage of coronary artery disease among patients that experienced stroke (50% vs. 10%; P = 0.057). CONCLUSION: The overall risk of stroke and AF recurrence is low in patients with a recurrence free interval of at least 12 months after AF ablation. Of note, recurrence of AF was not associated with a higher risk of stroke in our study population.

Predictors for Progression of Atrial Fibrillation in Patients Awaiting Atrial Fibrillation Ablation.

BACKGROUND: Success rates of atrial fibrillation (AF) ablation have been shown to be significantly lower for patients with persistent AF. However, little is known about the risk factors predicting progression to persistent AF in patients awaiting AF ablation. METHODS: We performed a retrospective, single-centre investigation of patients with paroxysmal AF at the time of placement on the ablation waiting list. Patients were defined as having progressed if they had developed self-reported or electrocardiogram-recorded AF durations more than 7 days while awaiting ablation. After ablation, clinical visits at 3, 6, 9, 12, and 18 months were performed with a minimum of a 48-hour-Holter and electrocardiogram. Baseline characteristics including left atrial diameter (LA) and the HATCH score were analyzed by univariable and multivariable analysis for predicting progression to persistent AF. RESULTS: During a median waiting time of 9.7 (6.1, 14.2) months, 60 of 564 patients (11%) progressed to persistent AF. In patients who progressed, ablation took longer (180 [150, 249] minutes vs 157 [125, 210] minutes; P = 0.009) and was associated with a higher rate of recurrence after a median of 12 months (53.3% vs 39.1%; P < 0.001). The HATCH score was a poor predictor of AF progression (area under the curve 0.54), whereas an LA diameter of more than 45 mm (odds ratio 3.46, P < 0.001) and heart failure (odds ratio 3.11, P = 0.036) were strong and independent predictors of AF progression in multivariable analysis. CONCLUSIONS: Patients with an increased LA diameter or heart failure have a significantly increased risk of progression to persistent AF. These characteristics may define patients who should undergo earlier catheter ablation to optimize outcome.

The Impact of Duration of Atrial Fibrillation Recurrences on Measures of Health-Related Quality of Life and Symptoms.

BACKGROUND: Little is known about the relationship between daily atrial fibrillation (AF) burden and quality of life (QOL). We sought to determine the influence of atrial tachycardia (AT) or AF burden on measures of QOL and symptoms. METHODS AND RESULTS: We retrospectively analyzed patients with dual-chamber pacemakers from the Atrial Septal Pacing Efficacy Clinical Trial (ASPECT), Atrial Therapy Efficacy and Safety Trial (ATTEST), and aTRial arrhythmias dEtected by implaNted Device diagnostics Study (TRENDS) trials. All patients underwent at least one QOL evaluation. We predefined four AF burden groups: no AT/AF (group 1), ≤30 minutes (group 2), 30 minutes-2 hours (group 3), and >2 hours (group 4) per day. We compared QOL measures using the 12-item Short-Form Health Survey (SF-12; standard 4 week recall) and the AF Symptom Checklist (SC) severity and frequency between groups 2-4 to those in group 1. A total of 798 patients were analyzed (age 72 ± 11 years, 447 male [56%]). SC frequency and severity and SF-12 physical and mental scores worsened significantly when patients in group 4 were compared to patients with no AF. There were no statistically significant differences for any of the measures when comparing group 2 or 3 patients to group 1. By linear regression, only the 2-hour-cutoff had a significant impact on QOL as measured by SC frequency (+3.15, P < 0.001), severity (+3.23, P < 0.001), SF-12 physical score (-2.42, P = 0.013), and SF-12 mental score (-2.11, P = 0.021). CONCLUSION: A daily AT/AF burden of more than 2 hours had significant impact on QOL. This might influence the choice of appropriate cut-off points to determine the success of an AF treatment.

Sleep Disruption is Associated with Increased Ventricular Ectopy and Cardiac Arrest in Hospitalized Adults.

STUDY OBJECTIVES: To determine whether sleep disruption increases ventricular ectopy and the risk of cardiac arrest in hospitalized patients. METHODS: Hospital emergency codes (HEC) trigger multiple hospital-wide overhead announcements. In 2014 an electronic "code white" program was instituted to protect staff from violent patients. This resulted in an increase in nocturnal HEC. Telemetry data was examined between September 14 and October 2, 2014. The frequency of nocturnal announcements was correlated with changes in frequency of premature ventricular complexes per hour (PVC/h). Cardiac arrest data were examined over a 3-y period. All HEC were assumed to have triggered announcements. The relationship between nocturnal HEC and the incidence of subsequent cardiac arrest was examined. RESULTS: 2,603 hours of telemetry were analyzed in 87 patients. During nights with two or fewer announcements, PVC/h decreased 33% and remained 30% lower the next day. On nights with four or more announcements, PVC/h increased 23% (P < 0.001) and further increased 85% the next day (P = 0.001). In 2014, following the introduction of the code white program, the frequency of all HEC increased from 1.1/day to 6.2/day (P < 0.05). The frequency of cardiac arrest/24 h rose from 0.46/day in 2012-2013 to 0.62/day in 2014 (P = 0.001). During daytime hours (06:00-22:00), from 2012 through 2014, the frequency of cardiac arrest following zero, one or at least two nocturnal HEC were 0.331 ± 0.03, 0.396 ± 0.04 and 0.471 ± 0.09 respectively (R(2) = 0.99, P = 0.03). CONCLUSIONS: Sleep disruption is associated with increased ventricular ectopy and increased frequency of cardiac arrest.

Incidence, predictors, and procedural results of upgrade to resynchronization therapy: the RAFT upgrade substudy.

BACKGROUND: The resynchronization-defibrillation for ambulatory heart failure trial (RAFT) study demonstrated that adding cardiac resynchronization therapy (CRT) in selected patients requiring de novo implantable cardiac defibrillators (ICD) reduced mortality as compared with ICD therapy alone, despite an increase in procedure-related adverse events. Data are lacking regarding the management of patients with ICD therapy who develop an indication for CRT upgrade. METHODS AND RESULTS: Participating RAFT centers provided data regarding de novo CRT-D (CRT with ICD) implant, upgrade to CRT-D during RAFT (study upgrade), and upgrade within 6 months after presentation of study results (substudy). Substudy centers enrolled 1346 (74.9%) patients in RAFT, including 644 de novo, 80 study upgrade, and 60 substudy CRT attempts. The success rate (initial plus repeat attempts) was 95.2% for de novo versus 96.3% for study upgrade and 90.0% for substudy CRT attempts (P=0.402). Acute complications occurred among 26.2% of de novo versus 18.8% of study upgrade and 3.4% of substudy CRT implantation attempts (P<0.001). The most common complication was left ventricular lead dislodgement. The principal reasons for not yet attempting upgrade in the substudy were patient preference (31.9%), New York Heart Association Class I (17.0%), and a QRS<150 ms (13.1%). CONCLUSIONS: Among a broad group of implant physicians, CRT upgrades were performed in patients with an ICD in situ with no difference in implant success rate and a reduced acute complication rate as compared with a de novo CRT implant. Decisions to upgrade were influenced by predictors of benefit in subgroup analyses of the RAFT study and other trials.

Substrate-guided ablation of haemodynamically tolerated and untolerated ventricular tachycardia in patients with structural heart disease: effect of cardiomyopathy type and acute success on long-term outcome.

AIMS: The purpose of this study was to evaluate the outcomes of purely substrate-guided ventricular tachycardia (VT) ablation in patients with non-ischaemic dilated cardiomyopathy (NIDCM) and ischaemic cardiomyopathy (ICM) and the impact of acute procedural success on long-term outcome. METHODS AND RESULTS: One hundred and forty-two patients (65 ± 12 years old, 72% male) with ICM (n = 87) and with NIDCM (n = 55) underwent substrate-guided VT ablation. The ablation approach involved eliminating all LP regions and ablating all scar border zone regions with 10 or more out of 12 pace-matching. All patients were followed with regular implantable defibrillator interrogations for mean 641 ± 301 days. Complete acute success (no inducible VT) was achieved in 60 patients with ICM (69%) and in 29 patients with NIDCM (53%) (P = 0.03). Partial success (elimination of clinical VT only) was obtained in nine patients with ICM (10%) and in four patients with NIDCM (7%) (P = 0.14). Procedural failure (clinical VT still inducible) occurred in 18 patients within the ICM group (21%) and in 22 patients of the NIDCM (40%) (P = 0.04). Overall, 51 patients presented with recurrence of ventricular arrhythmias: 23 in the group with ICM (26%) and 28 in the group with NIDCM (51%) (P = 0.03). Long-term success was related to acute procedural outcome. CONCLUSIONS: Substrate-guided ablation is an effective approach in the treatment of VT with long-term outcome directly related to acute procedural success. Success rates are significantly lower in patients with NIDCM compared with those with ICM.

Comparison of outcomes after cardioversion or atrial fibrillation ablation in patients with differing periprocedural anticoagulation regimens.

BACKGROUND: There is a paucity of data that compare traditional vitamin K antagonist (VKA) with novel oral anticoagulant regimens in periprocedural management of cardioversion or ablation of atrial fibrillation (AF). We sought to compare outcomes of use of VKA, dabigatran (DABI), and rivaroxaban (RIVA) anticoagulation around the time of intervention. METHODS: We studied consecutive patients undergoing cardioversion or ablation of AF at our centre from October 2010 to October 2013. There were 3 different anticoagulation groups: warfarin (VKA), DABI, and RIVA. Safety was assessed according to number of strokes, transient ischemic attacks (TIAs), and clinically important and not important bleeding events. RESULTS: Baseline characteristics were well balanced between the groups. Average follow-up was 6 months (± 4 months). A total of 901 patients who underwent cardioversion were studied (VKA [n = 471], DABI [n = 288] and RIVA [n = 141]). In these patients there were no strokes seen during follow-up and 2 TIAs in the DABI group. Bleeding rates were low, with no significant difference between the 3 groups. A total of 680 patients who underwent ablation were studied (VKA [n = 319], DABI [n = 220] and RIVA [n = 171]). There were no strokes reported during follow-up and 3 TIAs: 2 in the VKA group and 1 in the DABI group not resulting in a significant difference between the groups. Bleeding rates were low, with no significant difference between the groups. CONCLUSIONS: Overall, there was a low incidence of adverse events for all anticoagulation regimens. Warfarin, DABI, and RIVA use around the time of the procedure are safe and reasonable options for patients who undergo cardioversion or AF ablation.

Point-by-point pulmonary vein antrum isolation guided by intracardiac echocardiography and 3D mapping and duty-cycled multipolar AF ablation: effect of multipolar ablation on procedure duration and fluoroscopy time.

PURPOSE: Pulmonary vein antrum isolation (PVAI) guided by intracardiac echocardiography and a roaming circular mapping catheter is an effective treatment modality for atrial fibrillation. Unfortunately, the complexity of this technique leads to long procedure times and high fluoroscopy exposure. Single-catheter multipolar ablation holds the promise to reduce these parameters. This study examined the effect of the conventional point-by-point PVAI with that of single-catheter multipolar ablation on the procedural characteristics and clinical outcomes of atrial fibrillation ablation. METHODS: Referred patients underwent PVAI guided by a magnetic-based 3D mapping (CARTO 3(®) System; group 1) or duty-cycled multipolar AF ablation using the pulmonary vein ablation catheter (PVAC, group 2) between June 2010 and May 2011. RESULTS: Data were analyzed from 19 patients in group 1 and 31 patients in group 2. There was no significant difference in the length of the procedure between the two groups (135 ± 26 vs 125 ± 25 min, P = 0.20). Patients who underwent ablation using PVAC spent significantly less time in the procedure room pre- and post-procedure than those who underwent conventional PVAI (205 ± 38 vs 179 ± 30 min, P = 0.02) and had a significantly shorter fluoroscopy exposure (50 ± 16 vs 36 ± 14 min, P = 0.003) and radiofrequency energy delivery time (54 ± 26 vs 32 ± 33 min, P = 0.02). No differences in safety and efficacy were seen between the groups. CONCLUSIONS: Single-catheter multipolar AF ablation was associated with significantly lower fluoroscopy duration, radiofrequency energy delivery time, and the time the patient spent in the procedure room before and after ablation, although measured short-term clinical outcomes were similar.

Left atrial 'sludge' during vagally mediated pause triggered by pulmonary vein antral ablation.

We report a case of a patient with long-standing persistent atrial fibrillation (AF) who had rapid formation of spontaneous echo-contrast in the left atrium during pulmonary vein antrum isolation set off by a vagally mediated pause despite standard anticoagulation protocol. Spontaneous echo contrast resolved with ventricular pacing, representing visual evidence for dependence of some AF patients with poor atrial transport function on ventricular emptying with potential greater risk of thromboembolism related to a long ventricular pause.

Relationship between complex fractionated electrograms (CFE) and dominant frequency (DF) sites and prospective assessment of adding DF-guided ablation to pulmonary vein isolation in persistent atrial fibrillation (AF).

BACKGROUND: Sites of high DF are potential targets for AF ablation, but it is unknown if addition of DF ablation can improve procedural outcome. OBJECTIVES: We sought to (1) examine the relationship between DF sites and complex fractionated electrograms (CFE) and (2) prospectively assess the long-term outcome of adding DF ablation to pulmonary vein antral isolation (PVAI) for persistent AF. METHODS: First, 20 patients with persistent AF who underwent previous CFE-guided ablation and who had AF terminate during ablation were studied retrospectively (group I). Bipolar, 8-second electrograms were collected by a circular catheter (288 ± 86 points/map). The EnSite NavX system allows for automated display of both CFE and DF maps. Electrograms with cycle length <120 ms were considered CFE and were compared to DF sites > 8 Hz (direct inverse relationship). Sites of AF termination were related to CFE and DF sites. Based on these observations, 30 different patients (group II) with persistent AF prospectively underwent DF-guided ablation plus PVAI. They were followed every 3 months for 1 year (visit, Holter, ECG). These patients were compared to case-matched controls undergoing PVAI alone (group III). RESULTS: In group I, there was a significant, inverse correlation between DF and CFE values at each point (r =-0.24, P < 0.001). DF surface area was less than CFE area (27 ± 5 cm(2) vs 34 ± 4 cm(2) , P = 0.03). CFE sites overlapped 48 ± 27% with the DF surface area. Nonoverlapping CFE sites were contiguous to DF sites. AF termination occurred where DF and CFE overlapped, and at these sites, DF was always greater than the mean DF for the map. In group II, all DF sites above the mean value were prospectively ablated during AF. AF termination was noted in only 2/30 (7%) patients. After DF ablation, PVAI was performed and termination increased to 4/30 patients (14%). At 1 year, freedom from atrial arrhythmia > 30 seconds occurred in 57% of DF+PVAI compared to 60% in patients receiving PVAI alone (P = 0.18). CONCLUSIONS: DF and CFE regions overlap only about 50%. AF termination retrospectively occurred on overlapping CFE/DF sites where DF was above the mean. However, prospective ablation of DF sites plus PVAI resulted in low AF termination rates, and did not improve 1 year success over PVAI alone.

Clinical predictors of arrhythmia recurrences following pulmonary vein antrum isolation for atrial fibrillation: predicting arrhythmia recurrence post-PVAI.

INTRODUCTION: Pulmonary vein antrum isolation (PVAI) is an accepted treatment for atrial fibrillation (AF) refractory to medical therapy. The purpose of this study was to identify the patient, procedural, and follow-up factors associated with arrhythmia recurrences following PVAI. METHODS AND RESULTS: Clinical data were prospectively collected on all 385 consecutive patients who had 530 PVAI (age 58 ± 11 years, 63% paroxysmal AF-PAF, follow-up 2.8 ± 1.2 years) between February 2004 and March 2009. ECGs were recorded at each follow-up visit with Holter monitoring 1, 3, 6, and 12 months following PVAI and every 6 months thereafter. Recurrences < 3 months post-PVAI were defined as early, 3 months-1 year post-PVAI as late, and > 1 year post-PVAI as very late. Relationship between predictor variables and outcomes was modeled using Cox proportional hazards analysis. Late recurrences occurred in 42% with a lower rate among PAF versus non-PAF patients (39% vs 56%, P = 0.001). Of the 256 patients with ≥ 1-year follow-up, 121 (47%) had no arrhythmia off antiarrhythmic drugs (AADs) 1 year post-PVAI; 36 (30%) of these had a very late recurrence. In multivariate analysis, non-PAF, hypertension, and prior AAD failure predicted recurrence. When entered into the model, early recurrences remained the only predictor of late recurrences. CONCLUSION: Patients with non-PAF, hypertension, and prior failure of multiple AAD were more likely to experience arrhythmia recurrence post-PVAI. Early recurrences were the strongest predictor of late recurrences. Late and very late recurrences following PVAI were common and should be considered when planning long-term AF patient management.

CARTO-guided vs. NavX-guided pulmonary vein antrum isolation and pulmonary vein antrum isolation performed without 3-D mapping: effect of the 3-D mapping system on procedure duration and fluoroscopy time.

PURPOSE: Pulmonary vein antrum isolation (PVAI) guided by intracardiac echocardiography and a roaming circular mapping catheter is an effective treatment modality for atrial fibrillation. Unfortunately, the complexity of this technique leads to long procedure times and high fluoroscopy exposure. This study examined the effect of two different mapping systems on the procedural characteristics and clinical outcomes of PVAI for atrial fibrillation. METHODS: Referred patients underwent PVAI using a magnetic-based 3-dimensional (3-D) mapping (CARTO® System; group 1), a current-based system (EnSite NavX™; group 2), or fluoroscopy without 3-D mapping (group 3) between February 2004 and November 2009. RESULTS: Data were analyzed from 71 patients in group 1, 165 patients in group 2, and 197 patients in group 3. Baseline characteristics and measured long-term outcomes did not differ between the groups. Although patients in group 1 were more likely to undergo a concurrent flutter ablation (P = 0.01), they had significantly shorter procedure time, fluoroscopy time, and radiofrequency energy delivery time compared with group 2 and 3 patients. No difference was detected among the groups with respect to recurrence, mean time to recurrence, or number of PVAI procedures. CONCLUSIONS: Use of a magnetic-based 3-D mapping system, which allows precise spatial localization of the ablation catheter, was associated with significantly lower procedure time, fluoroscopy duration, and radiofrequency energy delivery time during catheter ablation for atrial fibrillation compared with a current-based system and ablation performed without 3-D mapping, although measured short- and long-term clinical outcomes were similar.

Incidence of very high defibrillation thresholds (DFT) and efficacy of subcutaneous (SQ) array insertion during implantable cardioverter defibrillator (ICD) implantation.

BACKGROUND: The incidence, risk factors, and management of very high defibrillation thresholds (DFTs) during present-day implantable cardioverter defibrillator (ICD) testing are not well known. OBJECTIVES: The purpose of this study was to assess (1) the incidence of very high DFTs and (2) the efficacy/safety of routinely adding a subcutaneous (SQ) array for these patients. METHODS: The study evaluated patients undergoing first-time ICD implantation at Southlake Regional Healthcare Centre from January 2006 to December 2007. All implanted ICDs had a maximal output of 35 J. Patients with DFTs greater than a 10-J safety margin from maximum output were considered to have very high readings and underwent SQ array insertion after other attempts at lowering DFT (group I). These patients were compared with the rest of the patients who had acceptable DFTs (group II) using both univariate and multivariate logistic regression analysis. Outcomes of array insertion were also assessed. RESULTS: A total of 313 patients underwent first-time ICD implantation during the analysis period. Of those, 16 (5.1%) had very high DFTs (group I). By univariate analysis, advanced New York Heart Association class (3 or 4), congestive heart failure hospitalization, non-ischemic cardiomyopathy, amiodarone use, implant of a biventricular device, and highest quartile of left ventricular (LV) chamber enlargement were all significant predictors of very high DFTs (p < 0.05). By multivariate analysis, only amiodarone use [odds ratio (OR) = 10.3, 95% confidence interval (95% CI) = 3.7-32.6] and being in the highest quartile for LV diastolic diameter [OR = 5.4, 95% CI = 1.4-20.8] predicted very high DFT. In all 16 cases, other methods to lower DFT prior to array insertion were attempted but failed for all patients: reversing shock polarity (n = 15), removing the superior vena cava coil (n = 14), reprogramming shock waveform (n = 9), and repositioning right ventricular lead (n = 9). Addition of the array successfully decreased DFT to within safety margin for all patients (33 ± 2 vs 21 ± 5 J, p = 0.02). Complication due to array insertion occurred in one patient (pneumothorax). CONCLUSIONS: Very high DFTs occur in about 5% of patients undergoing ICD implantation and may be predicted by LV dilation and amiodarone use. SQ array insertion reliably corrects this problem over other interventions with a low rate of procedural complication.

Predictors of appropriate implantable cardioverter defibrillator (ICD) therapy in primary prevention patients with ischemic and nonischemic cardiomyopathy.

BACKGROUND: We sought to assess predictors of appropriate implantable cardioverter defibrillator (ICD) therapy in patients receiving primary prevention ICDs. METHODS: Four hundred twenty-one consecutive patients (ischemic and nonischemic) undergoing primary prevention ICD implantation were studied. Patients were grouped based on the presence/absence of appropriate ICD therapy. Summary data and stored electrograms from ICDs were reviewed to determine appropriateness of therapy. Predictors of therapy were assessed by both univariate and multivariate Cox regression analysis. RESULTS: Of 421 primary prevention patients undergoing ICD implantation, 79 (19%) had received appropriate ICD therapies. By univariate comparison, nonsustained ventricular tachycardia (NSVT), male sex, left ventricle diastolic diameter (LVDD), and hypertension were all significant predictors for ICD therapy over a mean follow-up time of 751 +/- 493 days (P

Incidence of left ventricular function improvement after primary prevention ICD implantation for non-ischaemic dilated cardiomyopathy: a multicentre experience.

BACKGROUND: The SCD-HeFT study demonstrated a benefit of primary prevention implantable cardioverter-defibrillator (ICD) implantation in patients with non-ischaemic dilated cardiomyopathy (NIDCM). However, NIDCM may improve spontaneously, even after waiting 6-9 months on optimal medical treatment. OBJECTIVE: To assess the incidence of left ventricular (LV) function improvement in patients receiving primary prevention ICDs for NIDCM. METHODS: All patients with NIDCM receiving primary prevention ICDs (non-cardiac resynchronisation therapy) from 2005 to the present at our institutions were retrospectively studied. All patients had NIDCM confirmed by a lack of significant stenoses on coronary angiography, a lack of significant valvular abnormalities on echo, and LV dysfunction with ejection fraction (EF) <35%. All patients had to have had a diagnosis of NIDCM for at least 9 months and be receiving optimal medical treatment for at least 3 months before implant according to the guidelines. All patients had at least New York Heart Association (NYHA) II symptoms. Baseline and follow-up EF was documented by quantitative echo and/or multi-gated acquisition scan. RESULTS: 332 patients were identified by a database search. Patients were aged 67+/-11 years, 75% of them were male, NYHA 2.3+/-0.7, with EF 25+/-13%, and LV diastolic diameter 61+/-10 mm. Time from initial NIDCM diagnosis to implant was 11+/-6 months and duration of medical treatment before implant was 8+/-5 months. Treatment at the time of implant included ACE inhibitors or ARBs (85%), beta blockers (77%), spironolactone (53%), loop diuretic (63%) and digoxin (50%). Repeat EF assessment was available in 309/332 (93%) 8+/-6 months after implant. EF improved to >35% in 37/309 (12%) patients. Patients who improved had a shorter time from diagnosis to implant (9+/-3 vs 13+/-5 months respectively, p=0.03). No other significant predictors were identified for patients with improved EF. CONCLUSIONS: In spite of following guidelines for implantation of primary prevention ICDs in patients with NIDCM, a substantial number of patients (12%) experience improvement in LV function to levels above those recommended for ICD implant. A shorter time from diagnosis to implant may predict post-implant improvement.

Dofetilide is safe and effective in preventing atrial fibrillation recurrences in patients accepted for catheter ablation.

AIMS: The aim of this study was to assess the safety and efficacy of dofetilide among patients refractory to other anti-arrhythmic drugs (AADs) and accepted for atrial fibrillation (AF) ablation. METHODS AND RESULTS: One hundred and twenty-seven of 454 patients (69% male, 58% paroxysmal, age 60 +/- 10 years, AF duration 8 +/- 7 years) scheduled for AF ablation between February 2004 and May 2008 were treated with dofetilide. Patients had failed 1.9 +/- 1.1 AADs. Anti-arrhythmic drugs were stopped five half-lives before ablation and 3 months for amiodarone. Patients were followed for 15 +/- 7 months with routine and symptom-driven monitoring. Success was defined as no further AF and partial success as a 50% reduction in frequency/duration of AF episodes. Thirty-six patients started dofetilide 158 +/- 167 days before ablation: 9 had no improvement, 16 experienced partial success, 8 had no further AF, and 2 improved enough to forgo ablation. Seventy-one patients started dofetilide immediately following ablation, of which 14 had no improvement, 22 experienced partial success, and 32 had no further AF. Twenty patients started dofetilide 119 +/- 153 days post-ablation, of which four had no improvement, seven experienced partial success, and nine had no further AF. Six patients discontinued dofetilide during initiation for QT prolongation. CONCLUSION: Dofetilide appears safe and effective in preventing AF in patients refractory to other AADs undergoing catheter ablation.