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.

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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.

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Background: Societal guidelines have set prerequisites regarding procedures conducted in the EP lab. Despite metrics for management of EP cases, no clear guidelines exist for use of hemodynamic drugs to support complex ablations, particularly in setting of structural heart disease. Objectives: We sought to understand the variety and range of vasoactive medication use in patients undergoing PVC/VT ablation. Methods: Patients undergoing PVC or VT ablation, from January 2015 to December 2016, at our institution were analyzed. Demographics, echocardiography, and procedural details, including vasoactive medication use, were analyzed. Results: Sequential patients undergoing PVC or VT ablation (70 in each arm) were studied. Those undergoing PVC ablation (56 +/- 14 years, 30% female) had an average EF of 58% in comparison to 44% (p<0.01 for EF difference) in VT ablation patients (60 +/- 13 years, 20% female); more VT patients (62%) were under general anesthesia. Pressors were administered in 86% of cases with the significant majority (63%) consisting of alpha-agonists (phenylephrine, ephedrine, epinephrine). Importantly, 48% of cases required continuous drip initiation (Figure). Regardless of case type or abnormal EF, drip initiation with or administration of multiple bolus doses of alpha-agonists was much more frequent compared to inotropes (Figure). In a subset of patients with EF ≤ 35%, 96% received vasoactive medications with 73% receiving a continuous drip or multiple bolus doses of phenylephrine. Conclusions: Vasoactive medication use during ventricular EP cases is common. Regardless of baseline EF, a propensity for use of alpha-agonists exists that may affect the treatment of patients with abnormal LV function. More studies are needed to assess the impact of pressor use on patient safety and procedural endpoints in the EP lab. Figure: