Utz Richter

Prevalence and predictors of low voltage zones in the left atrium in patients with atrial fibrillation

Aims To describe the extent and distribution of low voltage zones (LVZ) in a large cohort of patients undergoing ablation for paroxysmal and persistent atrial fibrillation (AF), and to explore baseline predictors of LVZ in these patients. Methods and results Consecutive patients who underwent a bipolar voltage map guided AF ablation, were enrolled. Voltage maps were conducted for each patient using 3-dimensional electroanatomical mapping system and LVZ were defined as areas of bipolar voltage < 0.5 mV. A total of 539 patients (309 male, age 65 ± 10 years) were included. Low voltage zones was present in 58 out of 292 patients with paroxysmal and 134 out of 247 persistent AF (P < 0.001). The area of LVZ was larger in patients with persistent as compare to paroxysmal AF, 5 cm2 (IQR 3-18.6) vs. 12.1 cm2 (IQR 3.6-28.5), P = 0.026, respectively. In the multivariate analysis age (OR 1.07, 95%CI 1.05-1.10, P < 0.001), female gender (OR 2.18, 95%CI 1.38-3.43, P = 0.001), sinoatrial node dysfunction (OR 3.90, 95%CI 1.24-12.21, P = 0.020), larger surface area of left atrium pr. cm2 (OR 1.01, 95%CI 1.00-1.02, P = 0.016), and persistent AF (OR 5.03, 95%CI 3.20-7.90, P<0.001) were associated with presence of LVZ. Conclusion In a large cohort of patients undergoing ablation for AF, the prevalence of LVZ was higher and LVZ areas larger in patients with persistent as compared with paroxysmal AF. The most frequent localization of LVZ was anterior wall, septum and posterior wall. Presence of LVZ was associated with higher age, female gender, larger LA surface area, and sinoatrial node dysfunction.

Heart-type fatty acid-binding protein and myocardial creatine kinase enable rapid risk stratification in normotensive patients with pulmonary embolism

BACKGROUND Risk assessments of hemodynamically stable patients with pulmonary embolisms (PE) remain challenging. In this context heart-type fatty acid-binding protein (H-FABP), creatine kinase isoenzyme MB (CK-MB), and troponin I (TnI) may hold prognostic utility for patients with pulmonary embolism. METHODS We included 161 consecutive normotensive (systolic blood pressure above 90 mm Hg) patients with confirmed PE to study the combined utility of echocardiographic signs of right ventricular dysfunction and several biomarkers (TnI, CK-MB, H-FABP). The primary endpoint was defined as death within 30 days after admission to the hospital. RESULTS Elevated biomarkers were measured in 26 patients (16.1%) for HFABP, in 66 (41%) for TnI and in 41 (25.5%) for CK-MB. Echocardiography revealed right ventricular dysfunction (RVD) in 99 (61.5%) patients. Overall, 16 patients (9.9%) died within the study period. In the H-FABP positive group 15 (57.7%) patients died compared to 13 (19.7%) patients in the TnI positive group and 15 (37.5%) patients in the CK-MB positive group (H-FABP positive vs TnI positive patients, P< .001; H-FABP positive vs CK-MB positive patients P= .13; CK-MB positive vs TnI positive patients P= .07). All elevated biomarkers correlated with the primary endpoint with H-FABP being strongly, CK-MB intermediately and TnI weakly associated with short term death (H-FABP r= 0.701, P< .001; CK-MB r= 0.486, P< .001; TnI r= 0.272, P= .001). In multivariate logistic regression analysis, a positive H-FABP test (OR 27.1, 95% CI 2.1-352.3, P= .001), elevated CK-MB levels (OR 5.3, 95% CI 1.3-23.3, P= .002) and a low systolic blood pressure on admission (OR 0.8, 95% CI 0.8-0.9, P< .001) emerged as independent predictors of 30-day mortality. CONCLUSIONS Both H-FABP and CK-MB are associated with short term mortality in normotensive PE patients and could be advantageous for risk stratification in this intermediate risk group.

Continuous monitoring after atrial fibrillation ablation: the LINQ AF study

Abstract Aims To study device performance, arrhythmia recurrence characteristics, and methods of outcome assessment using a novel implantable cardiac monitor (ICM) in patients undergoing ablation for atrial fibrillation (AF). Methods and results In 419 consecutive patients undergoing first-time catheter ablation for symptomatic paroxysmal (n = 224) or persistent (n = 195) AF an ICM was injected at the end of the procedure. Telemedicine staff ensured full episode transmission coverage and manually evaluated all automatic arrhythmia episodes. Device detection metrics were calculated for ≥2, ≥6, and ≥10 min AF detection durations. Four methods of outcome assessment were studied: continuous recurrence analysis, discontinuous recurrence analysis, AF-burden analysis, and analysis of individual rhythm profiles. A total of 43 673 automatic AF episodes were transmitted over a follow-up of 15 ± 6 months. Episode-based positive predictive values changed significantly with longer AF detection durations (70.5% for ≥2 min, 81.8% for ≥6 min, and 85.9% for ≥10 min). Patients with exclusive short episode recurrences (≥2 to <6 min) were rare and their arrhythmia detection was clinically irrelevant. Different methods of outcome assessment showed a large variation (46–79%) in ablation success. Individual rhythm characteristics and subclinical AF added to this inconsistency. Analysis of AF-burden and individual rhythm profiles were least influenced and showed successful treatment in 60–70% of the patients. Conclusion We suggest AF detection duration >6 min and AF burden >0.1% as a standardized outcome definition for AF studies to come in the future.

Endo-/Epicardial Catheter Ablation of Atrial Fibrillation: Feasibility, Outcome, and Insights Into Arrhythmia Mechanisms

Background: Until today, catheter interventional mapping and ablation of atrial fibrillation (AF) has been limited to the right and left atrial endocardium. We report feasibility, electrophysiological findings, and clinical outcome using a combined endo-/epicardial catheter approach for mapping and ablation of AF. Methods and Results: Fifty-nine patients with permanence of pulmonary vein isolation and further symptomatic recurrences of paroxysmal AF, persistent AF, or atrial tachycardia underwent reablation using biatrial endo-/epicardial mapping and ablation. Identification of arrhythmia substrates and selection of ablation strategy were based on sinus rhythm voltage mapping. Using continuous monitoring and a 3-month blanking period, freedom from AF/atrial tachycardia ≥2 minutes was defined as primary end point. In all patients, endo-/epicardial mapping and ablation was feasible using standard technologies of catheter access, 3-dimensional mapping, and radiofrequency ablation. Epicardial mapping and ablation did not add procedural risks. Exclusively epicardial low voltage substrates were found in 14% of the patients. For the first time, novel epicardial conduction abnormalities located in the epicardial fiber network were described in human AF patients (19% of the cohort). Epicardial ablation was needed in 80% of the patients. Over 23±10 months of follow-up freedom from arrhythmia recurrences measured 73%. Conclusions: Catheter-based endo-/epicardial mapping and ablation of AF was feasible and safe. Epicardial mapping provided new insights into AF mechanisms. Epicardial ablation increased transmurality of ablation lesions. Clinical outcome in this cohort of complex AF patients was favorable, indicating potential further development of current AF treatment.