Switching Competition between Electron and Energy Transfers in Porphyrin-Fullerene Dyads.

Porphyrin-fullerene dyads were intensively studied as molecular donor-acceptor systems providing efficient photoinduced charge separation (CS). A practical advantage of the dyads is the possibility to tune its CS process by the porphyrin periphery modification, which allows one to optimize the dyad for particular applications. However, this tuning process is typically composed of a series of trial stages involving the development of complex synthetic schemes. To address the issue, we synthesized a series of dyads with properties switching between electron and energy transfer in both polar (benzonitrile) and nonpolar (toluene) media and developed a computation procedure with sufficient reliability by which we can predict the CS properties of the dyad in different media and design new dyads. The dyads photochemistry was established by conducting ultrafast transient absorption studies in toluene, anisole, and benzonitrile. The most crucial step in computational modeling was to establish a procedure for correction of the electronic-state energies obtained by DFT so that the effects of the electron correlation and the long-range interactions are properly incorporated. We also carried out standard electrochemical measurements and show that our computation approach predicts better thermodynamics of the dyads in different solvents.

Botulinum Toxin-Chitosan Nanoparticles Prevent Arrhythmia in Experimental Rat Models.

Several experimental studies have recently demonstrated that temporary autonomic block using botulinum toxin (BoNT/A1) might be a novel option for the treatment of atrial fibrillation. However, the assessment of antiarrhythmic properties of BoNT has so far been limited, relying exclusively on vagal stimulation and rapid atrial pacing models. The present study examined the antiarrhythmic effect of specially formulated BoNT/A1-chitosan nanoparticles (BTN) in calcium chloride-, barium chloride- and electrically induced arrhythmia rat models. BTN enhanced the effect of BoNT/A1. Subepicardial injection of BTN resulted in a significant antiarrhythmic effect in investigated rat models. BTN formulation antagonizes arrhythmia induced by the activation of Ca, K and Na channels.

Long-term suppression of atrial fibrillation by botulinum toxin injection into epicardial fat pads in patients undergoing cardiac surgery: Three-year follow-up of a randomized study.

BACKGROUND: Botulinum toxin (BTX) injections into epicardial fat pads in patients undergoing coronary artery bypass grafting (CABG) has resulted in suppression of atrial fibrillation (AF) during the early postoperative period through 1-year of follow-up in a pilot program. OBJECTIVE: The purpose of this study was to report 3-year AF patterns by the use of implantable cardiac monitors (ICMs). METHODS: Sixty patients with a history of paroxysmal AF and indications for CABG were randomized 1:1 to either BTX or placebo injections into 4 posterior epicardial fat pads. All patients received an ICM with regular follow-up for 3 years after surgery. The primary end point of the extended follow-up period was incidence of any atrial tachyarrhythmia after 30 days of procedure until 36 months on no antiarrhythmic drugs. The secondary end points included clinical events and AF burden. RESULTS: At the end of 36 months, the incidence of any atrial tachyarrhythmia was 23.3% in the BTX group vs 50% in the placebo group (hazard ratio 0.36; 95% confidence interval 0.14-0.88; P = .02). AF burden at 12, 24, and 36 months was significantly lower in the BTX group than in the placebo group: 0.22% vs 1.88% (P = .003), 1.6% vs 9.5% (P < .001), and 1.3% vs 6.9% (P = .007), respectively. In the BTX group, 2 patients (7%) were hospitalized during follow-up compared with 10 (33%) in the placebo group (P = .02). CONCLUSION: Injection of BTX into epicardial fat pads in patients undergoing CABG resulted in a sustained and substantial reduction in atrial tachyarrhythmia incidence and burden during 3-year follow-up, accompanied by reduction in hospitalizations.

Globular chitosan prolongs the effective duration time and decreases the acute toxicity of botulinum neurotoxin after intramuscular injection in rats.

Botulinum neurotoxin (BoNT) is used for an increasing number of neurological and non-neurological indications and disorders. Since the duration of action of this neurotoxin is limited, the goal of the work was to improve the pharmacological time course of BoNT. We explored the effect of several polysaccharides on the duration of action of BoNT/A1 in rat electromyography. The formulation of BoNT/A1 containing globular chitosan increased the threshold stimulation intensity almost 2 times in 30 days after injection if compared with the baseline threshold. However, conventional linear chitosan, heparin and hyaluronic acid did not have such an effect. In addition, we compared the effectiveness of different doses of BoNT/A1 (25, 50, 75, and 100 U) with globular chitosan and compared the acute toxicity of this formulation with that of BoNT/A1 in physiological saline after intramuscular injection. The results demonstrated that the dose 25 U of BoNT/A1 with globular chitosan was both effective and safe for animals after intramuscular injection. The assessed median lethal dose (LD50) for intramuscular injection in rats was 1.4 times higher for a combination of BoNT/A1 with globular chitosan than that for a solution of BoNT/A1 in physiological saline. Thus, the results of our study have provided evidence that intramuscular injection of the formulation of BoNT/A1 (25 U) containing globular chitosan in rats is safe and significantly prolongs the effective duration time of BoNT/A1.

Incidence of atrial fibrillation detected by continuous rhythm monitoring after acute myocardial infarction in patients with preserved left ventricular ejection fraction: results of the ARREST study.

Aims: Cardiac arrhythmias following acute myocardial infarction (AMI) can be associated with major adverse cardiovascular events. Data on the "real incidence" of post-MI arrhythmias are limited. We aimed to determine the rate and burden of cardiac arrhythmias by the use of insertable cardiac monitors (ICM) in patients with preserved left ventricular ejection fraction (LVEF) after AMI. Methods and results: In this prospective observational study, patients with LVEF ≥40% who underwent PCI within 7 days following AMI were enrolled to receive an ICM. Primary outcome was the incidence of new-onset atrial fibrillation (AF) measured by the ICM during a follow-up of 2 years; results: Of 165 consecutive patients with AMI, 50 (30.3%) eligible patients were recruited (mean age 57.8 ± 8.3, 88% male). During follow-up, AF was the most frequently detected arrhythmia. Twenty-nine (58%, 95% CI: 42-70%) patients developed new-onset AF, with a cumulative rate of all detected arrhythmias of 65%. Median time to the first detected AF episode was 4.8 months and the peak cumulative AF burden was detected between 3 and 6 months. Twenty-seven (93%) out of 29 patients with AF were asymptomatic. Cox regression analysis found that baseline troponin level (hazard ratio [HR] for 1 ng/mL increment: 1.03, 95% CI: 1.01-1.06, P = 0.01) and CHA2DS2-VASc score of 4 (HR: 11.42, 95% CI: 1.01-129.06, P = 0.04) were independent risk factors of new-onset AF post-AMI. Conclusion: AF is a frequent but largely underestimated cardiac arrhythmia after AMI. More rigorous monitoring strategies resulting in crucial medical interventions (e.g. implementation of oral anti-coagulation) are needed. Clinical Trial Registration: http://www.clinicaltrials.gov. Unique identifier: NCT02492243.

Pulmonary vein isolation with concomitant renal artery denervation is associated with reduction in both arterial blood pressure and atrial fibrillation burden: Data from implantable cardiac monitor.

BACKGROUND: Renal artery denervation (RDN) has provided incremental atrial fibrillation (AF) suppression after pulmonary vein isolation (PVI) in patients with AF in the setting of drug-resistant hypertension. OBJECTIVE: To assess the relationship between changes of mean blood pressure (BP) and AF recurrences/AF burden after PVI combined with RDN. METHODS: All patients from two randomized studies with symptomatic paroxysmal AF and/or persistent AF and resistant hypertension who underwent PVI-only (n=37) or PVI with RDN (n=39), and implantable cardiac monitor (ICM) implantation were eligible for this study. Mixed-effects linear models were used to investigate the effect of RDN on mean BP and mean AF burden and associations between the two during the 12-month follow-up. RESULTS: Concomitant RDN was associated with a significant reduction in both mean AF burden (2.43 [95% CI: 1.76-3.09] % vs 6.95 [95% CI: 5.44-8.45] %) and mean BP (104 [95% CI: 103-106] mm Hg vs 112 [95% CI: 110-113] mm Hg). Decrease in mean BP was positively correlated with decline in mean AF burden: reduction of 5-10 mm Hg was accompanied by a 7.0% decreased mean AF burden, with greater reduction (up to 20 mm Hg) associated with on average 17.7% lower mean AF burden. CONCLUSIONS: Renal artery denervation when added to PVI decreases AF recurrences, AF burden, and mean BP. Reduction in mean BP is associated with both AF burden and recurrences. Further large-scale studies are needed to define the mechanistic pathway(s) of the antiarrhythmic effects of RDN.

Effect of left atrial appendage excision on procedure outcome in patients with persistent atrial fibrillation undergoing surgical ablation.

BACKGROUND: Catheter ablation is less successful for treatment of persistent atrial fibrillation (PersAF) than for paroxysmal atrial fibrillation. Some studies suggest that left atrial appendage (LAA) isolation in addition to pulmonary vein isolation (PVI) is required to maximize the benefits for PersAF after ablation. OBJECTIVE: The purpose of this study was to compare the efficacy and safety of 2 surgical ablation approaches for PersAF via video-assisted thoracoscopy: PVI + box lesion and PVI + box lesion + LAA excision. METHODS: We randomly assigned 176 patients with PersAF to video-assisted thoracoscopic surgical ablation with PVI + box lesion (88 patients) or PVI + box lesion + LAA excision (88 patients). The primary endpoint was freedom from any documented atrial arrhythmia lasting >30 seconds after a single ablation procedure without antiarrhythmic drug (AAD). RESULTS: After 18 months of follow-up, 61 of 86 patients (70.9%) assigned to PVI + box lesion were free from recurrent atrial fibrillation compared to 64 of 87 patients (73.6%) assigned to PVI + box lesion + LAA excision after a single ablation procedure without AAD (P = .73). Freedom from any atrial arrhythmia after a single procedure with or without AAD was also nonsignificant (70.9% vs 74.7%, respectively). There were no significant differences between groups with regard to adverse events, including death, transient ischemic attack, stroke, pneumothorax, and hydrothorax. CONCLUSION: Among patients with PersAF, no reduction in the rate of recurrent atrial fibrillation was found when LAA excision was performed in addition to PVI and box lesion during surgical ablation.

Long-Term Suppression of Atrial Fibrillation by Botulinum Toxin Injection Into Epicardial Fat Pads in Patients Undergoing Cardiac Surgery: One-Year Follow-Up of a Randomized Pilot Study.

BACKGROUND: Animal models suggest that the neurotransmitter inhibitor, botulinum toxin, when injected into the epicardial fat pads can suppress atrial fibrillation inducibility. The aim of this prospective randomized double-blind study was to compare the efficacy and safety of botulinum toxin injection into epicardial fat pads for preventing atrial tachyarrhythmias. METHODS AND RESULTS: Patients with history of paroxysmal atrial fibrillation and indication for coronary artery bypass graft surgery were randomized to botulinum toxin (Xeomin, Merz, Germany; 50 U/1 mL at each fat pad; n=30) or placebo (0.9% normal saline, 1 mL at each fat pad; n=30) injection into epicardial fat pads during surgery. Patients were followed for 1 year to assess maintenance of sinus rhythm using an implantable loop recorder. All patients in both groups had successful epicardial fat pad injections without complications. The incidence of early postoperative atrial fibrillation within 30 days after coronary artery bypass graft was 2 of 30 patients (7%) in the botulinum toxin group and 9 of 30 patients (30%) in the placebo group (P=0.024). Between 30 days and up to the 12-month follow-up examination, 7 of the 30 patients in the placebo group (27%) and none of the 30 patients in the botulinum toxin group (0%) had recurrent atrial fibrillation (P=0.002). There were no complications observed during the 1-year follow-up. CONCLUSIONS: Botulinum toxin injection into epicardial fat pads during coronary artery bypass graft provided substantial atrial tachyarrhythmia suppression both early as well as during 1-year follow-up, without any serious adverse events. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01842529.