Autonomic Effects of Pulsed Field vs Thermal Ablation for Treating Atrial Fibrillation: Subanalysis of ADVENT.

BACKGROUND: Autonomic denervation is an ancillary phenomenon during thermal ablation of atrial fibrillation (AF), that may have synergistic effects on symptomatic improvement and long-term freedom from AF. Pulsed field ablation (PFA), a nonthermal ablation modality, was noninferior to thermal ablation in treating AF; however, PFA's relative myocardial selectivity may minimize autonomic effects. OBJECTIVES: This study sought to compare heart rate (HR) and heart rate variability (HRV) metrics as markers of autonomic function after ablation using PFA vs thermal ablation. METHODS: ADVENT (The FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation) was a randomized pivotal study comparing PFA (pentaspline catheter) with thermal ablation (radiofrequency [RF] or cryoballoon [CB]) for treating paroxysmal AF. Baseline HR was acquired from a pre-ablation 12-lead electrocardiogram, whereas follow-up HRs, as well as HRV (standard deviation of all normal to normal RR intervals, standard deviation of 5-minute average RR intervals) metrics, were derived from 72-hour Holter monitors at 6 and 12 months. RESULTS: This study included 379 paroxysmal AF patients undergoing PFA (n = 194) or thermal ablation (n = 185; n = 102 RF, n = 83 CB) completing 6- and 12-month Holter monitoring. Compared with PFA, thermal patients had significantly greater increases in HR from baseline to 6 months (ΔHR; 10.1 vs 5.9 beats/min; P = 0.02) and 12 months (ΔHR; 8.8 vs 5.2 beats/min; P = 0.03). This increase in HR at 6 and 12 months was similar between CB and RF (P = 0.94 and 0.83, respectively). HRV, both standard deviation of all normal to normal RR intervals and standard deviation of 5-minute average RR intervals, were significantly lower at both 6 and 12 months after thermal ablation compared with PFA (P < 0.01). CONCLUSIONS: PFA's effect on the autonomic nervous system was attenuated compared with thermal ablation. Whether this affects long-term freedom from AF or symptomatic bradycardia/pauses after AF ablation requires further study.

High-density mapping and ablation of concealed low-voltage activity within pulmonary vein antra results in improved freedom from atrial fibrillation compared to pulmonary vein isolation alone.

BACKGROUND: Despite advancements, the goal of durable pulmonary vein isolation (PVI) in all patients undergoing ablation for atrial fibrillation (AF) remains elusive. New high-density mapping (HDM) allows detection of concealed low-voltage signals (CLVSs) that persist after PVI and may represent vulnerabilities in the lesion set. OBJECTIVE: The purpose of this study was to determine the incidence of CLVSs after PVI and the effect of CLVS ablation on outcomes. METHODS: We conducted a case control study comparing 150 patients undergoing HDM-guided PVI and subsequent CLVS mapping and ablation (39 redo, 111 de novo) against 452 historical controls undergoing traditional PVI alone. PVI was similarly performed and confirmed in both groups. RESULTS: Baseline characteristics were similar, except left atrial size was larger in the HDM-guided group. Acute PVI was achieved in nearly all patients in both groups. In the HDM group, 31 of 150 patients exhibited CLVS after luminal PVI, and all were subsequently eliminated. During mean follow-up of 320 days, after controlling for baseline characteristics, the HDM-guided group exhibited a hazard ratio of 0.19 in freedom from AF (P <.001). De novo patients exhibited a hazard ratio of 0.44 relative to redo patients in the HDM-guided group. Both subgroups exhibited significantly lower event rates compared to controls in log-rank analysis (P <.001). CONCLUSION: CLVSs are commonly identified with HDM after PVI, likely representing vulnerabilities in antral lesion sets. Ablation of these targets seems to significantly improve freedom from AF compared to PVI alone.

Feasibility and safety of same-day discharge after implantable cardioverter defibrillator placement for primary prevention.

BACKGROUND: In the current age of ever-increasing healthcare costs, it is of utmost importance to adopt strategies that reduce hospital stay and cost, while still maintaining patient safety. In this study we review our approach of same-day discharge following implantable cardioverter defibrillator (ICD) placement for primary prevention of sudden cardiac death (SCD). METHODS: We conducted a retrospective chart review of 415 consecutive patients who underwent ICD implantation for prevention of SCD between 2007 and 2010. Patients were divided into an outpatient group (Group A) and an inpatient group (Group B). We evaluated the patients' demographics, comorbidities, and the rate of short-term surgical complications on or before the 2-week follow-up appointment. RESULTS: Of 252 patients included in Group A, 198 (78.6%) were successfully discharged on the same day (Group A1). At the 2-week wound check appointment, four patients (2%) had minor surgical site bleeding, one patient had a hematoma, and one patient developed fever and swelling around the implantation site. Of the Group A patients, 54 (21.4%) were not discharged on the same day (Group A2). A total of 53 patients were included in Group B, four (7.5%) developed a hematoma at the 2-week follow-up wound check visit. CONCLUSIONS: Procedure-related complications after ICD placement are rare. Same-day discharge is safe and feasible following ICD placement for primary prevention of SCD and hence a reduction in healthcare costs can be achieved by decreasing the length of hospital stay.

Echocardiographic parameters to predict inadequate defibrillation safety margin in patients receiving implantable cardioverter defibrillators for primary prevention.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) have become an important part of the management of patients with congestive heart failure. At the time of ICD implantation, ventricular fibrillation (VF) is induced to assess adequate energy required for defibrillation. There are multiple parameters which influence the defibrillation safety margin (DSM); however, these factors are not well-established when ICDs are implanted for the primary prevention of sudden cardiac death (SCD) in patients with severe systolic dysfunction. We evaluated multiple clinical and echocardiographic parameters as predictors of adequate DSM in patients referred for ICD implantation for the primary prevention of SCD. METHODS: We prospectively enrolled 41 patients for ICD implantation with clinical indications for the primary prevention of SCD. Two blinded independent readers evaluated the prespecified echocardiographic parameters. These included left ventricular (LV) mass, indices of right ventricular and LV systolic and diastolic functions, and LV geometric dimensions. Basic clinical demographics, including age, gender, comorbidities, and etiology of cardiomyopathy, were also evaluated. DSM was established using our standard protocol for defibrillation testing which includes VF with successful first shock terminating VF at a value at least 10 J below the maximum output of the implanted device. High defibrillation thresholds (DFT) were defined as >21 J. RESULTS: The mean age is 61.8 ± 14.7 years, with men comprising the majority of the patients (73 %). The only clinical variables which predicted the high DFT were age (in years) (54.5 ± 17.5 vs. 65.7 ± 11.3, p = 0.044), QRS duration (in milliseconds) (116.0 ± 29.5 vs. 110.5 ± 21.8, p = 0.03), LV mass (in grams) (241.0 ± 77.9 vs. 181.9 ± 52.3, p = 0.006), and LV mass index (in grams per square meter) (111.1 ± 38.2 vs. 86.4 ± 21.1, p = 0.02). On multivariate logistic regression analysis, LV mass was the only independent predictor of low DFT (≤22 J) in patients with ICD implanted for the primary prevention of SCD. CONCLUSION: LV mass may help predict an adequate DSM in patients who are referred for ICD implantation for the primary prevention of SCD. These results may help distinguish the patients who may require high-energy devices prior to the implantation procedure. These results may help distinguish patients requiring high-energy devices, coils, or advanced programming prior to implantation and appropriate referral to electrophysiologists.

Cryoballoon in AF ablation: impact of PV ovality on AF recurrence.

INTRODUCTION: Complete occlusion of the pulmonary veins (PV) is crucial for successful PV isolation. While two different sizes of cryoballoons (23 and 28 mm) are available, complete occlusion is not always achieved in any given PV. We investigated the role of PV ostial anatomy during cryoballoon PV occlusion grading and atrial fibrillation (AF) recurrence rate. METHODS: PV ostial diameter was analyzed in 168 consecutive patients (111 men, 61 ± 10 years, 124 paroxysmal (px) and 44 persistent AF) using cardiac computed tomography (CT) prior to procedure. The ovality index at the PV ostial level was calculated in any given PV. During follow-up, 7-day holter monitors were performed at 1, 3, 6, 9, 12, 18 and 24 months post-ablation. RESULTS: The success rate at 12 ± 6 months follow-up was 69% including a 3-month blanking period (px AF: 66%; persistent AF 77%). The ovality index of the left-sided PVs was significantly larger ("more oval") than that of the right-sided PVs (p<0.001). An optimized PV occlusion in all individual PVs (complete occlusion, grading 4/4) was achieved during ablation in 49% of patients with AF recurrence and in 73% of patients without AF recurrence (p=0.004). Patients with AF recurrence had "more oval" left-sided PVs compared to patients free from AF recurrence (LSPV 0.40 ± 0.2 vs. 0.33 ± 0.2; p=0.04 and LIPV 0.41 ± 0.3 vs. 0.32 ± 0.2; p=0.03), whereas no significant association was found for right sided PVs. CONCLUSION: The ostial PV anatomy seems to have an important impact on clinical outcome and should be considered when planning and performing cryoballoon AF ablation procedures.

Atrial fibrillation in cardiac resynchronization therapy patients: should we ablate the atrioventricular node?

Prevalence of persistent atrial fibrillation in patients undergoing cardiac resynchronization therapy remains high. Several factors, including suboptimal biventricular capture rates, compound the significant mortality and response rates in patients with atrial fibrillation and severe heart failure. Atrioventricular nodal ablation provides the best mean of rate control in this population. In this article, the authors evaluate a recently published trial addressing this issue in a prospective fashion and discuss the results and clinical applications.

Atrial fibrillation: an independent risk factor for nonaccidental falls in older patients.

BACKGROUND: Nonaccidental falls are often the result of a combination of factors including cardiovascular disorders such as orthostatic hypotension and unspecified cardiac arrhythmias. The objective of this study was to determine if there is an association between atrial fibrillation (AF) and nonaccidental falls. METHODS: We reviewed the records of 442 consecutive patients >65 years old who presented to the Emergency Department at the University of Utah Medical Center with a complaint of fall. RESULTS: Two-hundred eleven patients presented with nonaccidental fall, 231 patients with accidental fall. Patients with nonaccidental fall were more likely to be older, have a history of hypertension and neurological disorders, and taking five or more medications when compared to patients with accidental fall. Despite a similar prevalence of sinus rhythm at presentation, the prevalence of a history of AF was significantly higher in patients with nonaccidental fall compared to patients with accidental fall (26% vs 15%; P = 0.003). After adjusting for clinically and statistically significant predictors with a multivariate logistic regression analysis, AF, neurological disorders, and age ≤81 years were independent predictors of nonaccidental fall. In patients ≤81 years old (median age), the risk of nonaccidental falls was 2.5 times greater in patients with a history of AF when compared to those without a history of AF (odds ratio = 2.53 [confidence interval 95% 1.3-5], P = 0.007). CONCLUSION: AF is an independent risk factor for nonaccidental falls. Our results emphasize the need to screen for AF in patients presenting with nonaccidental fall.

A novel double cryoballoon strategy in persistent atrial fibrillation: a pilot study.

AIMS: Cryoballoon technology is a promising technique in paroxysmal atrial fibrillation (AF) ablation. However, success rates in patients with persistent AF have not been convincing. There is a trend toward performing more extensive procedures that are referred to as 'pulmonary vein isolation plus.' To combine pulmonary vein isolation (PVI) and antral substrate modification, we used both the 23-mm and 28-mm cryoballoon in a single approach in patients with persistent AF. METHODS AND RESULTS: 33 consecutive patients (26 men, age 60 ± 10 years, LA size 44 ± 5 mm) with persistent AF were prospectively included. All patients underwent the "double balloon strategy:" at least two applications at each pulmonary vein (PV) using the smaller 23-mm balloon to isolate the PV at the ostial level plus at least one additional freeze by the 28-mm balloon at the wide PV antral level. 7-day Holter monitors were performed during follow-up at 1, 3, 6, 9, 12, 18 and 24 months post-ablation. 131 of 133 PVs were targeted and isolated (98.4 %). A mean of 14 ± 2 cryoballoon applications per patient or 3.5 ± 1.5 applications per vein were performed. After a single procedure and mean follow-up of 15 ± 3 months, 69.7 % of patients remained in sinus rhythm (3-month blanking period). There were no major complications. CONCLUSIONS: In persistent AF, the "double balloon strategy;" combining the small and large cryoballoon allowed ostial PV isolation followed by antral cryoablation is feasible, safe and associated with a favorable outcome.

Trends in inflammatory biomarkers during atrial fibrillation ablation across different catheter ablation strategies.

INTRODUCTION: Chest pain after atrial fibrillation (AF) ablations is a common complaint with a wide differential diagnosis including coronary events. Elevation of troponins (Trop I) has been shown with radio-frequency (RF) ablation for atrial fibrillation. New devices including cryoballoon and multipolar ablation catheters have been introduced as alternative methods. We aim to compare cardiac injury following AF ablations according to different ablation technologies. METHODS: In consecutive patients undergoing AF ablations with RF ablation, cryoballoon or multipolar ablation catheter (PVAC), Trop I, creatine kinase (CK) and CRP were analyzed immediately prior to and 24h following completion of ablation. Coronary events and symptoms and serial ECGs post procedure were evaluated. RESULTS: A total of 243 patients were included, 18.5% of them females. The mean age was 63 ± 11 years old. Baseline Trop I, CK and CRP levels were within normal range in all patients. After RF ablation Trop I, CK and CRP levels were elevated in 100%, 20% and 91% of patients respectively (Trop I 3.55 pg/ml [range: 0.60-24.01 pg/ml], CK 147 U/l [range: 56-380 U/l] and CRP 2.15 mg/dl [range: 0.28-20.98 mg/dl]). All post-procedure Trop I levels were above the range of myocardial infarction (>0.15 ng/ml). After cryoballoon ablation, Trop I and CK levels were significantly higher than after RF or PVAC ablation (p<0.001). No ischemic ECG changes were documented. CONCLUSIONS: Trop I elevations are not specific for ischemia in the setting of chest pain after AF ablation. Cryoballoon ablation resulted in a higher amount of cardiac injury.

Dark regions of no-reflow on late gadolinium enhancement magnetic resonance imaging result in scar formation after atrial fibrillation ablation.

OBJECTIVES: The aim of this study was to assess acute ablation injuries seen on late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) immediately post-ablation (IPA) and the association with permanent scar 3 months post-ablation (3moPA). BACKGROUND: Success rates for atrial fibrillation catheter ablation vary significantly, in part because of limited information about the location, extent, and permanence of ablation injury at the time of procedure. Although the amount of scar on LGE MRI months after ablation correlates with procedure outcomes, early imaging predictors of scar remain elusive. METHODS: Thirty-seven patients presenting for atrial fibrillation ablation underwent high-resolution MRI with a 3-dimensional LGE sequence before ablation, IPA, and 3moPA using a 3-T scanner. The acute left atrial wall injuries on IPA scans were categorized as hyperenhancing (HE) or nonenhancing (NE) and compared with scar 3moPA. RESULTS: Heterogeneous injuries with HE and NE regions were identified in all patients. Dark NE regions in the left atrial wall on LGE MRI demonstrate findings similar to the "no-reflow" phenomenon. Although the left atrial wall showed similar amounts of HE, NE, and normal tissue IPA (37.7 ± 13%, 34.3 ± 14%, and 28.0 ± 11%, respectively; p = NS), registration of IPA injuries with 3moPA scarring demonstrated that 59.0 ± 19% of scar resulted from NE tissue, 30.6 ± 15% from HE tissue, and 10.4 ± 5% from tissue identified as normal. Paired t-test comparisons were all statistically significant among NE, HE, and normal tissue types (p < 0.001). Arrhythmia recurrence at 1-year follow-up correlated with the degree of wall enhancement 3moPA (p = 0.02). CONCLUSIONS: Radiofrequency ablation results in heterogeneous injury on LGE MRI with both HE and NE wall lesions. The NE lesions demonstrate no-reflow characteristics and reveal a better predictor of final scar at 3 months. Scar correlates with procedure outcomes, further highlighting the importance of early scar prediction.

Cross-sectional imaging obtained immediately following radiofrequency atrial fibrillation ablation does not predict endoscopic evidence of esophageal injury.

BACKGROUND: Radiofrequency atrial fibrillation ablation (AFA) is commonly performed in patients with atrial fibrillation. It is imperative to develop a strategy for the early detection of esophageal lesions secondary to AFA. The current protocol is to obtain cross-sectional imaging before and immediately after the procedure. If patients have evidence of esophageal inflammation, they undergo esophagogastroduodenoscopy (EGD). We hypothesized that esophageal abnormalities seen on imaging immediately post-ablation are a poor predictor of the damage seen during EGD. METHODS: Patients referred for EGD following AFA from 1/2009 to 11/2010 were included. Two endoscopists reviewed and scored the EGD images. Two radiologists reviewed the post-AFA imaging studies. For computed tomography (CT) scans, esophageal inflammation was scored from 0 to 2. For T2 and delayed magnetic resonance imaging (MRI) pictures, esophageal enhancement was scored from 0 to 2, with the circumference involved as 0, <50%, or >50%, and the length of esophageal enhancement in mm. RESULTS: In total, 76 patients were included; 22 patients had only endoscopic images and 54 had both endoscopic and radiologic images for review. Of the post-AFA imaging studies, 16 were CTs and 60 were MRIs. The kappa score for the inter-rater agreement of esophageal inflammation on EGD was 0.4584 (moderate). For MRIs, the kappa scores for T2 images were 0.1980 and 0.2857 for edema and circumference, respectively. For delayed images, the kappa scores were 0.2687 and 0.3101 for edema and circumference, respectively. The kappa scores were negative between EGD score by T2 edema (-0.2104) and circumference (-0.2212), and between EGD score and delayed edema (-0.0588) and circumference (-0.0446). When measures were treated as dichotomous, the overall agreement between CT measures and EGD scores was kappa = 0, for T2 measures and EGD kappa = -0.2963, 95% confidence interval (CI) (-0.5643, -0.0282), and between delayed measures kappa = -0.0244, 95% CI (-0.1420, -0.0932). CONCLUSIONS: There was no agreement between immediate imaging and the endoscopic findings of esophageal inflammation after AFA. A longer period of time between AFA and obtaining an imaging study may be useful in detecting patients with significant esophageal injury who should undergo EGD to assess for complications of AFA. Further studies are needed in order to determine the best modalities and optimal timing to detect post-AFA esophageal damage in an attempt to prevent the formation of atrial-esophageal fistulas.

Syncope in the emergency department: comparison of standardized admission criteria with clinical practice.

AIMS: Syncope is a major health care problem that accounts for many emergency department (ED) and hospital admissions. This study was conducted to investigate the short-term risk of serious events in patients presenting to the ED with syncope and to compare guideline-based admission criteria with those adopted in clinical practice. METHODS AND RESULTS: A single-centre retrospective analysis was performed on ED visits between January and June 2009. We used the ICD-9 code 780.2 for syncope as the primary diagnosis. The prevalence of serious events within 7 days of the index presentation was evaluated. In addition, admissions and discharges were classified as being appropriate or inappropriate based on standardized guideline-based criteria integrated in a new Faint-Algorithm developed at the University of Utah. Two hundred and fifty-four ED visits met the inclusion criteria. One hundred and thirty-six patients were discharged home and the remaining 118 were admitted. The prevalence of serious events in the discharged and admission groups were 5 and 10, respectively, (P= NS). According to the Faint-Algorithm, the number of inappropriate discharges and admissions were 8 out of 136 and 69 out of 118, respectively. Using the Faint-Algorithm, only 57 patients instead of 118 patients should have been admitted resulting in a 52% reduction in admission rate. Furthermore, in the remaining 197 patients who should have been discharged, the prevalence of serious events was not significantly different than that observed in the 136 patients who were actually discharged (3% vs. 4%). CONCLUSION: There are significant numbers of inappropriate discharges and admissions in patients presenting with syncope. The standardized guideline-based criteria integrated in the new Faint-Algorithm provide promise but require further prospective evaluation.

Implantation of cardiac rhythm devices during concomitant anticoagulation or antiplatelet therapy.

Cardiac rhythm devices are increasingly being utilized as the population ages and the incidence of chronic heart failure, bradyarrhythmias and the indications for pacing and prevention of sudden cardiac arrest expand. The number of patients receiving oral anticoagulants and dual antiplatelet therapy is similarly increasing. Implantation of cardiac rhythm devices during concomitant use of oral anticoagulants or antiplatelet regimens poses an increased risk of perioperative bleeding complications. Traditionally, heparin-based bridging protocols have been recommended for such patients to mitigate the bleeding risk while reducing the risk of thrombotic complications. Although the literature is limited, an appraisal of the literature reveals that bridging may not be the best strategy. We review the literature and propose strategies to promote successful perioperative outcomes, while reducing the risk of bleeding or thrombosis during the time of implantation for patients on chronic anticoagulation and antiplatelet therapies.

Electromagnetic interference between external defibrillator and cardiac resynchronization therapy-pacemaker (CRT-P) devices.

BACKGROUND: Implantable heart rhythm devices are susceptible to interference in hospitals where electromagnetic interference (EMI) sources are ubiquitous. CASE DESCRIPTION: We report three cases in which EMI from the external defibrillator caused the inability to interrogate Boston Scientific cardiac resynchronization therapy-pacemaker (CRT-P) devices. We have documented interference with the Boston Scientific CRT-P Contact Renewal device model numbers H120/H125 (Natick, MA, USA) and two brands of external defibrillators: the Philips Heartstart XL model number M4735A (Andover, MA, USA) and the Hewlett-Packard Codemaster model number M1722B (Palo Alto, CA, USA). For device implants, we routinely place external pacing pads with the external defibrillator in the "standby" mode for transcutaneous pacing so that only the pacer "start/stop" button needs to be pressed when necessary. We have not been able to interrogate three consecutive Boston Scientific CRT-P devices prior to closure while the external defibrillator had the back-up pacing mode on "standby." In our initial case, a second device was opened because this interaction was not recognized. We documented EMI with the standby pacing mode ON and discovered that by disabling only the "standby" pacing mode on the external defibrillator, the device could be interrogated without difficulty. CONCLUSIONS: This is a case series reporting EMI with a Boston Scientific CRT-P Contact Renewal device H120/H125 telemetry from an external defibrillator with pacing mode on "standby." Failure to recognize this important interaction may lead to inappropriate device and resource utilization.

Renal dysfunction and atrial fibrillation recurrence following cardioversion.

BACKGROUND: No previous study has assessed the role of renal impairment in predicting the long-term risk of atrial fibrillation recurrence after cardioversion. METHODS: One hundred and fifty-nine consecutive patients with persistent atrial fibrillation undergoing successful cardioversion were enrolled. Renal function was assessed based on the estimated glomerular filtration rate (eGFR) at baseline and during follow-up. Patients were prospectively followed up for eGFR and recurrence of atrial fibrillation up to 1 year. RESULTS: Patients were divided into 4 groups based upon their eGFR (group 1 >90 mL/min: 33 patients, group 2: 60-90 mL/min: 55 patients, group 3: 30-59 mL/min: 53 patients, group 4: <30 mL/min: 18 patients). Overall, 101 out of 159 (64%) patients experienced atrial fibrillation recurrence within 1 year follow-up. Atrial fibrillation recurrence was independently associated with the level of reduction of eGFR at baseline (eGFR < 30 mL/min: hazard ratio [HR] 6.82, P < 0.001; eGFR 30-59 mL/min: HR 3.31, P = 0.01; eGFR 60-90 mL/min: HR 2.10, P = 0.13; eGFR > 90 mL/min reference group). In patients with maintained sinus rhythm after 12-month follow-up eGFR was increased (8.46 ± 9.49 mL/min [range -7 to 43]), whereas patients with atrial fibrillation recurrence showed a decrease in eGFR over time (-5.75 ± 9.4 [range -32 to 25], P < 0.001). CONCLUSION: Among a group of patients with persistent atrial fibrillation undergoing successful cardioversion, impaired renal function (based on estimated GFR) was associated with an increased risk of atrial fibrillation recurrence. Maintenance of sinus rhythm was associated with improvement in eGFR in patients with mild or moderate renal insufficiency.

Association of left atrial fibrosis detected by delayed-enhancement magnetic resonance imaging and the risk of stroke in patients with atrial fibrillation.

OBJECTIVES: This study tried to determine the association between left atrial (LA) fibrosis, detected using delayed-enhanced magnetic resonance imaging (DE-MRI), and the CHADS(2) score (point system based on individual clinical risk factors including congestive heart failure, hypertension, age, diabetes, and prior stroke) variables, specifically stroke. BACKGROUND: In patients with atrial fibrillation (AF), conventional markers for the risk of stroke base their higher predictive effect on clinical features, particularly previous stroke history, and not individual LA pathophysiological properties. We aimed to determine the association between LA fibrosis, detected using DE-MRI, and the CHADS(2) score variables, specifically stroke. METHODS: Patients with AF who presented to the AF clinic and received a DE-MRI of the LA were evaluated. Their risk factor profiles, including a CHADS(2) score, were catalogued. The degree of LA fibrosis was determined as a percentage of the LA area. Any history of previous strokes, warfarin use, or cerebrovascular disease was recorded. RESULTS: A total of 387 patients, having a mean age of 65 ± 12 years, 36.8% female, were included in this study. A history of previous stroke was present in 36 (9.3%) patients. Those patients with previous strokes had a significantly higher percentage of LA fibrosis (24.4 ± 12.4% vs. 16.2 ± 9.9%, p < 0.01). A larger amount of LA fibrosis was also seen in those patients with a higher CHADS(2) score (≥ 2: 18.7 ± 11.4 vs. <2: 14.7 ± 9.2, p < 0.01). A logistic regression analysis of all variables except strokes (CHAD score) demonstrated that LA fibrosis independently predicted cerebrovascular events (p = 0.002) and significantly increased the predictive performance of the score (area under the curve = 0.77). CONCLUSIONS: Our preliminary, multicenter results suggest DE-MRI-based detection of LA fibrosis is independently associated with prior history of strokes. We propose that the amount of DE-MRI-determined LA fibrosis could represent a marker for stroke and a possible therapeutic target with potential applicability for clinical treatment for patients with AF.

High prevalence of right ventricular dysfunction in ICD patients with shocks: a potential new predictor in risk stratification.

BACKGROUND: Despite identifying several risk factors for sudden cardiac death, our ability to predict arrhythmic events in patients with an implantable cardioverter defibrillator (ICD) remains poor. The purpose of this study was to determine if patients who received appropriate ICD shocks had a higher degree of right ventricular (RV) dysfunction at baseline when compared to patients who did not receive ICD shocks. METHODS: We conducted a 1:2 case-control, retrospective study comparing RV end-diastolic and end-systolic areas (RV ED and RV ES areas, respectively), fractional RV area change, and RV wall thickness in 19 consecutive patients who received appropriate ICD shocks (shock group) with another group of 38 patients who did not receive ICD shocks (no-shock group). RESULTS: There was no significant difference in the RV end-diastolic areas between the groups. However, patients who experienced ICD shocks had a higher RV end-systolic area and a lower RV fractional area change when compared to patients without ICD shocks, 16.3 ± 4.9 cm(2) and 27.7 ± 9.0% in the shock group versus 14.2 ± 4.4 cm(2) and 35.8 ± 10.3% in the no-shock group; (p = 0.08 and 0.004, respectively). Furthermore, the RV wall thickness was greater in patients with ICD shocks when compared to patients without ICD shocks, 0.49 ± 0.05 cm and 0.44 ± 0.04 cm, respectively (p = 0.001). Utilizing a logistic regression analysis and after controlling for variables with univariate significance (p < 0.1), RV wall thickness independently predicted ICD shocks (OR 13.9 mm(-1) change of RV thickness, p = 0.004). CONCLUSION: Our findings suggest that some measurements of RV function might prove to be useful in predicting future arrhythmic events. Additional prospective studies are needed to test this hypothesis.

Atrial fibrosis helps select the appropriate patient and strategy in catheter ablation of atrial fibrillation: a DE-MRI guided approach.

UNLABELLED: MRI for AF Patient Selection and Ablation Approach. INTRODUCTION: Left atrial (LA) fibrosis and ablation related scarring are major predictors of success in rhythm control of atrial fibrillation (AF). We used delayed enhancement MRI (DE-MRI) to stratify AF patients based on pre-ablation fibrosis and also to evaluate ablation-induced scarring in order to identify predictors of a successful ablation. METHODS AND RESULTS: One hundred and forty-four patients were staged by percent of fibrosis quantified with DE-MRI, relative to the LA wall volume: minimal or Utah stage 1; <5%, mild or Utah stage 2; 5-20%, moderate or Utah stage 3; 20-35%, and extensive or Utah stage 4; >35%. All patients underwent pulmonary vein (PV) isolation and posterior wall and septal debulking. Overall, LA scarring was quantified and PV antra were evaluated for circumferential scarring 3 months post ablation. LA scarring post ablation was comparable across the 4 stages. Most patients had either no (36.8%) or 1 PV (32.6%) antrum circumferentially scarred. Forty-two patients (29%) had recurrent AF over 283 ± 167 days. No recurrences were noted in Utah stage 1. Recurrence was 28% in Utah stage 2, 35% in Utah stage 3, and 56% in Utah stage 4. Recurrence was predicted by circumferential PV scarring in Utah stage 2 and by overall LA wall scarring in Utah stage 3. No recurrence predictors were identified in Utah stage 4. CONCLUSIONS: Circumferential PV antral scarring predicts ablation success in mild LA fibrosis, while posterior wall and septal scarring is needed for moderate fibrosis. This may help select the proper candidate and strategy in catheter ablation of AF.

The prevalence and cost of the faint and fall problem in the state of Utah.

BACKGROUND: Understanding the frequency and economic impact of faint and fall is a prerequisite for the creation of cost-effective diagnostic approaches. METHODS: We evaluated the total number of patients presenting with faint or fall to the University of Utah Health Care System between November 1, 2008, and October 31, 2009. Using these data, we estimated the prevalence and total cost of the faint and fall problem in the state of Utah. RESULTS: A total of 1,936 and 6,043 patients presented with faint and fall resulting in a total number of visits equal to 2,701 and 8,163, respectively. The yearly prevalence of faints was 9.5 patients (13.2 visits) per 1,000 inhabitants and the yearly prevalence of falls was 29.8 patients (40.2 visits) per 1,000 inhabitants. The prevalence of faints and falls progressively increased with age, reaching the values of 40 and 115 per 1,000 inhabitants in subjects aged >80 years. In both patient populations, two-thirds of visits were outpatient evaluations. While the cardiovascular service was involved in the outpatient evaluation of faint visits in 24% of the cases, <1% of outpatient fall visits resulted in a cardiovascular consultation. The average payments received per faint and fall patient evaluations were $2,517 and $3,200, respectively, resulting in an estimated yearly cost equal to $90,901,958 and $351,959,040, respectively. CONCLUSION: This study highlights the magnitude of the faint and fall problem in the state of Utah. Our results provide all stakeholders with a frame of reference for the creation of cost-effective diagnostic approaches.