Background. Cardiac hypertrophy results in an increased deposition of the extracellular matrix (ECM) proteins fibronectin and collagen. Recent evidence indicates that angiotensin II (Ang II) might have an important role in the development of myocardial fibrosis accompanying cardiac hypertrophy. We sought to determine whether fibroblasts of cardiac origin (isolated from neonatal and adult animals) express

The electrophysiologic profile of KCB-328 in this canine model of AFL, particularly its lack of reverse use-dependent effect on atrial refractoriness, suggests that it may have significant antiarrhythmic potential in treatment of atrial arrhythmias.

BACKGROUND: The electrophysiologic mechanisms of the persistence of atrial fibrillation (AF) after its initiation are not well understood. Therefore, the electrophysiologic characteristics of the right atrium were evaluated in an acute, pacing-induced model of AF in the pig in order to identify parameters associated with persistence of AF. METHODS AND RESULTS: AF was induced by rapid atrial pacing in 30 anesthetized, open-chest, juvenile pigs. Sustained (S) AF was defined as that lasting >10 minutes, nonsustained (NS) AF <10 minutes but >30 seconds, and no (N) AF <30 seconds. Activation mapping and programmed stimulation (S1S1 = 200 ms) was performed at 56 electrodes on the right atrial free wall, to determine ERP (mean and minimum), dispersion of refractoriness (ERPdisp, ELEdisp), conduction velocity (CV), wavelength, AF cycle length (mean of 10 beats), and AF cycle length/time (electrical remodeling). SAF was induced in 10 pigs, NSAF in 9, and NAF in 11. AF cycle length was shorter in SAF and/vs NS vs NAF (P <.001). Mean ERP (107 +/- 9 and/vs 122 +/- 5 vs 142 +/- 9, p <.001) and wavelength (7 +/- 1 and/vs 9 +/- 1 vs 11 +/- 1, P <.001) were shorter in SAF and/vs NSAF vs NAF. Minimum ERP was shorter in SAF and NSAF vs NAF (P <.001). CV at cycle lengths of 200 and 150 msec was not different between groups. Dispersion of ERP was greater in SAF and/vs NSAF vs NAF (8 +/- 1 and/vs 11 +/- 1 vs 19 +/- 4, P <.001). CONCLUSIONS: Persistence of AF correlated with shorter ERP and wavelength, and greater dispersion of ERP and electrical remodeling. There was no correlation with CV.

Objective Advanced machine learning technology provides an opportunity to improve clinical electrocardiogram (ECG) interpretation, allowing non‐cardiology clinicians to initiate care for atrial fibrillation (AF). The Lucia Atrial Fibrillation Application (Lucia App) photographs the ECG to determine rhythm detection, calculates CHA2DS2‐VASc and HAS‐BLED scores, and then provides guideline‐recommended anticoagulation. Our purpose was to determine the rate of accurate AF identification and appropriate anticoagulation recommendations in emergency department (ED) patients ultimately diagnosed with AF. Methods We performed a single‐center, observational retrospective chart review in an urban California ED, with an annual census of 70,000 patients. A convenience sample of hospitalized patients with AF as a primary or secondary discharge diagnosis were evaluated for accurate ED AF diagnosis and ED anticoagulation rates. This was done by comparing the Lucia App against a gold standard board‐certified cardiologist diagnosis and using the American College of Emergency Physicians AF anticoagulation guidelines. Results Two hundred and ninety seven patients were enrolled from January 2016 until December 2019. The median age was 79 years and 44.1% were female. Compared to the gold standard diagnosis, the Lucia App detected AF in 98.3% of the cases. Physicians recommended guideline‐consistent anticoagulation therapy in 78.5% versus 98.3% for the Lucia App. Of the patients with indications for anticoagulation and discharged from the ED, only 25.0% were started at discharge. Conclusion Use of a cloud‐based ECG identification tool can allow non‐cardiologists to achieve similar rates of AF identification as board‐certified cardiologists and achieve higher rates of guideline‐recommended anticoagulation therapy in the ED.

Successful ICD implantation can be safely performed with no or fewer episodes of VF induction using a modified ULV testing method.