Evaluation of an adaptive, rule-based dosing algorithm to maintain therapeutic anticoagulation during atrial fibrillation ablation.

Background: Cerebral thromboembolism during atrial fibrillation (AF) ablation is an infrequent (0.17%) complication in part owing to strict adherence to intraprocedural anticoagulation. Failure to maintain therapeutic anticoagulation can lead to an increase in events, including silent cerebral ischemia. Objective: To evaluate a computerized, clinical decision support system (CDSS) to dose intraprocedural anticoagulation and determine if it leads to improved intraprocedural anticoagulation outcomes during AF ablation. Methods: The Digital Intern dosing algorithm is an adaptive, rule-based CDSS for heparin dosing. The initial dose is calculated from the patient's weight, baseline activated clotting time (ACT), and outpatient anticoagulant. Subsequent recommendations adapt based on individual patient ACT changes. Outcomes from 50 cases prior to algorithm introduction were compared to 139 cases using the algorithm. Results: Procedures using the dosing algorithm reached goal ACT (over 300 seconds) faster (17.6 ± 11.1 minutes vs 33.3 ± 23.6 minutes pre-algorithm, P < .001). ACTs fell below goal while in the LA (odds ratio 0.20 [0.10-0.39], P < .001) and rose above 400 seconds less frequently (odds ratio 0.21 [0.07-0.59], P = .003). System Usability Scale scores were excellent (96 ± 5, n = 7, score >80.3 excellent). Preprocedure anticoagulant, weight, baseline ACT, age, sex, and renal function were potential predictors of heparin dose to achieve ACT >300 seconds and final infusion rate. Conclusion: A heparin dosing CDSS based on rules and adaptation to individual patient response improved maintenance of therapeutic ACT during AF ablation and was rated highly by nurses for usability.

Bipolar radiofrequency ablation creates different lesion characteristics compared to simultaneous unipolar ablation.

INTRODUCTION: Both bipolar and simultaneous radiofrequency ablation (bRFA, simRFA) have been used to treat thick midmyocardial substrate as well as during circular, multipolar ablation between shorter distances. OBJECTIVES: We sought to evaluate the biophysical parameters of simRFA, sequential unipolar RFA (seqRFA), and bRFA. METHODS: Bovine myocardium was placed in a circulating saline bath. To simulate thick substrate conditions, two open irrigated ablation catheters were oriented across from each other, with myocardium in between. Thermocouples were placed in the center, ±2 mm, of the myocardium. Unipolar ablations were performed sequentially or simultaneously at 50 W for 60 seconds and compared to bRFA using the same settings. In addition, to simulate multipolar ablation, two open irrigated ablation catheters were oriented on the same side and perpendicular to myocardium at 1, 2, and 4 mm spacing. SimRFA were performed at 15 and 25 W for 60 seconds and compared to bRFA. RESULTS: For thicker tissue, simRFA produced similar lesion volume and depth compared to bRFA but with a lesion geometry similar to seqRFA. Unlike seqRFA and simRFA, bRFA had a necrotic core spanning the myocardium. Core depths, volumes, and temperatures were significantly greater for bRFA lesions compared to simRFA or seqRFA (Figure, P < .001). Similar results were consistent for bRFA and simRFA at shorter spacings. CONCLUSIONS: BRFA has greater core lesion temperatures, corresponding to a denser and larger necrotic core, than either simRFA or seqRFA. This may have implications for considering the optimal strategy for deep midmyocardial substrates or during multipolar ablation.

Optimal Strategies to Reduce Inappropriate Implantable Cardioverter-defibrillator Shocks.

Since the widespread implementation of implantable cardioverter-defibrillators (ICDs), their effectiveness in various situations has become well-established. However, despite many advances in both the technology and its utilization, inappropriate therapy remains a risk. Here, we review ICD shocks, their effect on outcomes, and current methods to reduce inappropriate therapy, finding overall that inappropriate ICD shocks are common and associated with adverse outcomes. However, strategies do exist to minimize inappropriate shock rates including device selection and programming, medication, catheter ablation, and remote monitoring. Overall, ICDs are useful in reducing the risk of sudden cardiac death, but many patients with an ICD will receive an inappropriate shock. Understanding strategies to prevent inappropriate shocks is crucial to improving the care of patients with ICDs.

Impact of Alcohol Consumption on Atrial Fibrillation Outcomes Following Pulmonary Vein Isolation.

BACKGROUND: Moderate to heavy alcohol use has been shown to be associated with increased atrial fibrillation (AF) incidence. However, the relationship between alcohol use and AF recurrence after pulmonary vein isolation (PVI) is not well known. OBJECTIVE: We sought to study the impact of different alcohol consumption levels on outcomes after AF ablation. METHODS: A retrospective analysis was performed of 226 consecutive patients undergoing first time PVI for AF. Clinical data were collected including alcohol intake classified into 3 groups: none-rare (< 1 drink/ week), moderate (1-7 drinks/ week), and heavy (> 7 drinks/ week). Patients were followed for recurrences within the first 3 months (blanking period; early recurrence) and after 3 months up to 1 year (late recurrence) after the ablation. RESULTS: Paroxysmal and persistent AF had early recurrence rates of 29.1% and 32.2%, and late recurrence rates of 30.2% and 44.1%, respectively. The none-rare alcohol group had a higher frequency of diabetes mellitus (p=0.007). Neither moderate or heavy alcohol consumption, in reference to the none-rare group, was significantly predictive of early or late AF recurrence on adjusted multivariate logistic regression analysis (p>0.05). CONCLUSION: Despite known associations between alcohol and incidence of AF, alcohol consumption is not associated with early or late AF recurrence after PVI in this cohort.