Mapping and Ablation of Frequent Post-Infarction Premature Ventricular Complexes

Mapping of Post-Infarction PVCs .  Introduction: Premature ventricular complexes (PVCs) occur frequently in patients with heart disease. The sites of origin of PVCs in patients with prior myocardial infarction and the response to catheter ablation have not been systematically assessed. Methods and Results: In 28 consecutive patients (24 men, age 60 ± 10, ejection fraction [EF] 0.37 ± 0.14) with remote myocardial infarction referred for catheter ablation of symptomatic refractory PVCs, the PVCs were mapped by activation mapping or pace mapping using an irrigated-tip catheter in conjunction with an electroanatomic mapping system. The site of origin (SOO) was classified as being within low-voltage (scar) tissue (amplitude ≤1.5 mV) or tissue with preserved voltage (>1.5 mV). The SOO was confined to endocardial scar tissue in 24/28 patients (86%). The SOO was outside of scar in 3 patients and could not be identified in 1 patient. At the SOO, local endocardial activation preceded the PVC by 46 ± 19 ms, and the electrogram amplitude during sinus rhythm was 0.48 ± 0.34 mV. The PVCs were effectively ablated in 25/28 patients (89%), resulting in a decrease in PVC burden on a 24-hour Holter monitor from 15.6 ± 12.3% to 2.4 ± 4.2% (P < 0.001). The SOO most often was confined to scar tissue located in the left ventricular septum and the papillary muscles. Conclusion: Similar to post-infarction ventricular tachycardia, PVCs after remote myocardial infarction most often originate within scar tissue. Catheter ablation of these PVCs has a high-success rate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1002-1008, September 2010)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79266/1/j.1540-8167.2010.01771.x.pd

Complex Electrograms Within the Coronary Sinus: Time- and Frequency-Domain Characteristics, Effects of Antral Pulmonary Vein Isolation, and Relationship to Clinical Outcome in Patients with Paroxysmal and Persistent Atrial Fibrillation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73243/1/j.1540-8167.2008.01175.x.pd

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements