Peak frequency mapping of atypical atrial flutter.

INTRODUCTION: Peak frequency (PF) mapping is a novel method that may identify critical portions of myocardial substrate supporting reentry. The aim of this study was to describe and evaluate PF mapping combined with omnipolar voltage mapping in the identification of critical isthmuses of left atrial (LA) atypical flutters. METHODS AND RESULTS: LA omnipolar voltage and PF maps were generated in flutter using the Advisor HD-Grid catheter (Abbott) and EnSite Precision Mapping System (Abbott) in 12 patients. Normal voltage was defined as ≥0.5 mV, low-voltage as 0.1-0.5 mV, and scar as <0.1 mV. PF distributions were compared with ANOVA and post hoc Tukey analyses. The 1 cm radius from arrhythmia termination was compared to global myocardium with unpaired t-testing. The mean age was 65.8 ± 9.7 years and 50% of patients were female. Overall, 34 312 points were analyzed. Atypical flutters most frequently involved the mitral isthmus (58%) or anterior wall (25%). Mean PF varied significantly by myocardial voltage: normal (335.5 ± 115.0 Hz), low (274.6 ± 144.0 Hz), and scar (71.6 ± 140.5 Hz) (p < .0001 for all pairwise comparisons). All termination sites resided in low-voltage regions containing intermediate or high PF. Overall, mean voltage in the 1 cm radius from termination was significantly lower than the remaining myocardium (0.58 vs. 0.95 mV, p < .0001) and PF was significantly higher (326.4 vs. 245.1 Hz, p < .0001). CONCLUSION: Low-voltage, high-PF areas may be critical targets during catheter ablation of atypical atrial flutter.

Efficacy and Safety of Adjunctive and Primary Use of the TightRail Mechanical Cutting Sheath for Lead Extraction.

BACKGROUND: Rotational cutting tools are increasingly used in transvenous lead extraction. There are limited data on their safety and efficacy, particularly when used adjunctively for stalled progression. The aim of this study was to evaluate the utilization, safety, and effectiveness of mechanical rotational cutting tools for transvenous lead extraction. METHODS: Patients undergoing transvenous lead extraction at a single tertiary center (April 2015 to January 2021, n=586) were included in this retrospective analysis. The study characterized the 251 patients (42.8%) whose cases involved the TightRail mechanical cutting tool. RESULTS: Among 251 patients, 526 leads were extracted and TightRail was used for 70.5%. The TightRail was used adjunctively with the laser for 65.2% of leads, 97.8% of the time as the second tool after stalled progression. Using a multivariable logistic regression model, we found that active-fixation leads (odds ratio, 2.78 [95% CI, 1.62-4.78]; P=0.0002), dual-coil leads (odds ratio, 3.39 [95% CI, 1.87-6.16]; P<0.0001), and lead dwell time (odds ratio, 1.16 [95% CI for 1-year increase, 1.11-1.21]; P<0.0001) were factors independently associated with adjunctive TightRail use. Stalled progression requiring TightRail occurred most often in the innominate vein and superior vena cava (59.3%). The clinical success rate was 96.8%, and the rate of major adverse events was 2.8%. Only 1 major adverse event was observed during TightRail use. CONCLUSIONS: Rotational cutting with TightRail was used in 42.8% of transvenous lead extractions, predominantly in an adjunctive manner after stalled laser progression in the innominate vein and superior vena cava, and more frequently for dual-coil and leads with longer dwell times. Adjunctive TightRail use carries a low risk of major complications.

Neuromodulation therapy for atrial fibrillation.

Atrial fibrillation has a multifactorial pathophysiology influenced by cardiac autonomic innervation. Both sympathetic and parasympathetic influences are profibrillatory. Innovative therapies targeting the neurocardiac axis include catheter ablation or pharmacologic suppression of ganglionated plexi, renal sympathetic denervation, low-level vagal stimulation, and stellate ganglion blockade. To date, these therapies have variable efficacy. As our understanding of atrial fibrillation and the cardiac nervous system expands, our approach to therapeutic neuromodulation will continue evolving for the benefit of those with AF.

Vertebral artery transection with pseudoaneurysm and arteriovenous fistula requiring antegrade and retrograde embolization.

Traumatic vertebral artery injury is a rare, life-threatening injury that has been increasingly managed with endovascular intervention. However, an antegrade endovascular approach alone can fail to occlude traumatic pseudoaneurysms (PSAs) and arteriovenous fistulas (AVFs), requiring high-risk surgical reoperation. We have presented the case of a 27-year-old man with traumatic right vertebral artery PSA and AVF. Despite successful ipsilateral coil embolization, the PSA and AVF persisted via retrograde filling from the contralateral vertebral artery. Distal coil embolization was achieved through the contralateral vertebral artery in a novel "up and over" approach through the basilar artery. The findings from our case report have broadened the endovascular options for complicated traumatic injuries.

Omnipolar Versus Bipolar Electrode Mapping in Patients With Atrial Fibrillation Undergoing Catheter Ablation.

BACKGROUND: Peak-to-peak bipolar voltage varies with electrode orientation, fractionation, and collision events. Novel, omnipolar mapping is less dependent on electrode orientation but has limited data in humans. OBJECTIVES: This study sought to compare bipolar peak-to-peak voltage with omnipolar maximum voltage (Vmax) during sinus rhythm in the left atrium of patients with persistent (PerAF) or paroxysmal atrial fibrillation (PAF). METHODS: Baseline voltage maps were generated with bipolar and omnipolar mapping in 20 patients undergoing de novo catheter ablation for PerAF or PAF and 9 patients with known scar from prior cardiac surgery, to validate voltage-based scar approximations. Low voltage was defined as <0.5 mV and scar <0.1 mV. Mean voltage was compared with unpaired t testing. Percent low voltage and scar were compared with chi-square testing. A point-to-point comparison was performed with Bland-Altman analysis. RESULTS: The mean age was 62.2 ± 9.9 years, 34% were women, and 41% had heart failure. Omnipolar mapping identified significantly higher mean voltage than bipolar mapping and classified less points as low voltage (PerAF: 32.90% vs 43.40%; PAF: 19.20% vs 25.60%) and scar (PerAF: 7.72% vs 12.10%; PAF: 4.03% vs 6.07%) (all P < 0.0001). Omnipolar Vmax displayed significant disagreement with bipolar by Bland-Altman analysis. Scar and low-voltage approximations were validated in atria with known scar, in which bipolar mapping overestimated the extent of low voltage (P < 0.0001) and scar (P < 0.0001). CONCLUSIONS: Omnipolar mapping identifies higher voltage and has greater specificity for the detection of low voltage and scar than conventional bipolar mapping in patients with PerAF or PAF.

Statin Therapy in Ischemic Stroke Models: A Meta-Analysis.

Statins, drugs known for lipid lowering capabilities and reduction of cardiovascular disease, have demonstrated neuroprotective effects following ischemic stroke in retrospective clinical and animal studies. However, dosing (methods, time, type of statin, and quantity) varies across studies, limiting the clinical applicability of these findings. Furthermore, a comprehensive review of statins in edema and blood-brain barrier (BBB) breakdown is needed to provide insight on diverse, less explored neuroprotective effects. In the present study, we conduct a meta-analysis of publications evaluating statin administration in animal models of ischemic stroke. We review statins' most effective dosing regimen in four outcomes-infarct, edema, BBB breakdown, and functional outcome-to characterize several parameters of benefit associated with statin administration. A search term was constructed to identify experimental murine studies exploring statin use after transient middle cerebral artery occlusion (tMCAO) in PubMed, Web of Science, and Embase. Extracted data included statin type, dose, time and method of administration, and the four predetermined outcomes (functional outcome, edema, BBB breakdown, and infarction). A meta-analysis and stratified meta-regression were conducted using the standardized mean difference (SMD) method for continuous measurements. Included publications were assessed for bias using SYRCLE's RoB tool for animal studies. A total of 24 studies were included. Statin administration significantly reduced infarct volume (p < 0.0001), edema volume (p < 0.002), and neurological deficit (p < 0.0001). Simvastatin and pravastatin were most effective in reducing infarct volume when compared with atorvastatin (p = 0.0475, p = 0.0004) and rosuvastatin (p = 0.0036, p < 0.0001). Pravastatin outperformed all others in functional outcome. Subcutaneous (SC) injection was most effective in all outcomes. Statin therapy reduced BBB breakdown according to our systematic review. Mean study quality was 4.6/10. While statin therapy evidently improves neurological outcome following ischemic stroke, this analysis adds to our understanding of dosing and statins' effects on edema and BBB breakdown. These findings will aid the design of future studies investigating statin use and have larger implications for the clinical care of ischemic stroke patients.