Comparison of combined substrate-based mapping techniques to identify critical sites for ventricular tachycardia ablation.

BACKGROUND: Established electroanatomic mapping techniques for substrate mapping for ventricular tachycardia (VT) ablation includes voltage mapping, isochronal late activation mapping (ILAM), and fractionation mapping. Omnipolar mapping (Abbott Medical, Inc.) is a novel optimized bipolar electrogram creation technique with integrated local conduction velocity annotation. The relative utilities of these mapping techniques are unknown. OBJECTIVE: The purpose of this study was to evaluate the relative utility of various substrate mapping techniques for the identification of critical sites for VT ablation. METHODS: Electroanatomic substrate maps were created and retrospectively analyzed in 27 patients in whom 33 VT critical sites were identified. RESULTS: Both abnormal bipolar voltage and omnipolar voltage encompassed all critical sites and were observed over a median of 66 cm2 (interquartile range [IQR] 41.3-86 cm2) and 52 cm2 (IQR 37.7-65.5 cm2), respectively. ILAM deceleration zones were observed over a median of 9 cm2 (IQR 5.0-11.1 cm2) and encompassed 22 critical sites (67%), while abnormal omnipolar conduction velocity (CV <1 mm/ms) was observed over 10 cm2 (IQR 5.3-16.6 cm2) and identified 22 critical sites (67%), and fractionation mapping was observed over a median of 4 cm2 (IQR 1.5-7.6 cm2) and encompassed 20 critical sites (61%). The mapping yield was the highest for fractionation + CV (2.1 critical sites/cm2) and least for bipolar voltage mapping (0.5 critical sites/cm2). CV identified 100% of critical sites in areas with a local point density of >50 points/cm2. CONCLUSION: ILAM, fractionation, and CV mapping each identified distinct critical sites and provided a smaller area of interest than did voltage mapping alone. The sensitivity of novel mapping modalities improved with greater local point density.

Use of Direct Oral Anticoagulants in the Treatment of Left Ventricular Thrombus: Systematic Review of Current Literature.

BACKGROUND: Left ventricular thrombus (LVT) is an important complication in the setting of systolic dysfunction, particularly after acute myocardial infarction. Current guidelines recommend the vitamin-K antagonist, warfarin, for the treatment of LVT. AREA OF UNCERTAINTY AND STUDY QUESTION: The direct oral anticoagulants (DOACs) are being increasingly used for the management of this entity, despite lack of randomized trials in support of it or knowledge about their efficacy. We aimed to assess the frequency of use and the efficacy of DOACs in the treatment of LVT. DATA SOURCES: We searched published articles in Google Scholar, PubMed, MEDLINE, and Embase from the introduction of DOACs in any therapy until April 2018. Reports describing patients diagnosed with LVT and who were treated with a DOAC were examined. Patient characteristics, comorbidities, pharmacologic treatments, and outcomes were collected. The primary end points of this study were thrombus resolution and time to resolution. Other end points were bleeding and thromboembolic events. RESULTS: Thirty articles describing 41 patients were analyzed. The most common risk factors for LVT formation were male gender, ischemic heart disease, and low ejection fraction. Most patients were treated with rivaroxaban (51.2%), followed by apixaban (26.8%) and dabigatran (22%). Patients were treated with DOAC alone (46.3%), DOAC and aspirin (12.2%), DOAC and clopidogrel (2.4%), and triple therapy (39%). Thrombus resolution success rate was 81%, 100%, and 88.9% for rivaroxaban, apixaban, and dabigatran, respectively. The median time of thrombus resolution was 40 days, 36 days, and 24 days for rivaroxaban, apixaban, and dabigatran, respectively. One nonfatal bleeding event and one stroke event were reported while on a DOAC. CONCLUSIONS: The use of DOACs is a reasonable alternative to vitamin-K antagonists in the management of LVT.