A Prospective Randomized Trial of Apixaban Dosing During Atrial Fibrillation Ablation: The AEIOU Trial.

OBJECTIVES: This study sought to determine whether uninterrupted apixaban would have similar rates of bleeding and thromboembolic events as does minimally interrupted apixaban at the time of atrial fibrillation (AF) ablation and to compare those results with rates in historical patients treated with uninterrupted warfarin. BACKGROUND: The safety, efficacy, and optimal dosing regimen for apixaban at the time of AF ablation are uncertain. METHODS: This prospective, multicenter clinical trial enrolled 306 patients undergoing catheter ablation for nonvalvular AF and randomized 300 to uninterrupted versus minimally interrupted (holding 1 dose) periprocedural apixaban. A retrospective cohort of patients treated with uninterrupted warfarin at the same centers was matched to the apixaban-treated subjects for comparison. Endpoints included clinically significant bleeding, major bleeding, and nonhemorrhagic stroke or systemic embolism (SE) from the time of ablation through 30 days. RESULTS: There were no stroke or SE events. Clinically significant bleeding occurred in 11.3% of 150 evaluable patients on uninterrupted apixaban and 9.7% of 145 evaluable patients on interrupted apixaban (risk difference: 1.7% [95% confidence interval: -5.5% to 8.8%]; p = NS). Rates of major bleeding were 1.3% with uninterrupted apixaban, and 2.1% with interrupted (risk difference: -0.7%; p = NS). The rates of clinically significant and major bleeding were similar for all apixaban patients combined (10.5% and 1.7%), compared with the matched warfarin group (9.8% and 1.4%). CONCLUSIONS: Both uninterrupted and minimally interrupted apixaban at the time of AF ablation were associated with a very low rate of thromboembolic events, and rates of both major (<2%) and clinically significant bleeding were similar to uninterrupted warfarin. (Apixaban Evaluation of Interrupted Or Uninterrupted Anticoagulation for Ablation of Atrial Fibrillation [AEIOU]; NCT02608099).

Ranolazine safely decreases ventricular and atrial fibrillation in Timothy syndrome (LQT8).

Long QT eight (LQT8), otherwise known as Timothy syndrome (TS), is a genetic disorder causing hyper-activation of the L-type calcium channel Cav 1.2. This calcium load and the resultant increase in the QT interval provide the substrate for ventricular arrhythmias. We previously presented a case in a patient with TS who had a profound decrease in his burden of ventricular arrhythmias after institution of an L-type calcium channel blocker. Although this patient's arrhythmia burden had decreased, he displayed an increasing burden of atrial fibrillation and still had bouts of ventricular fibrillation requiring defibrillator therapy. Basic research has recently shown that ranolazine, a multipotent ion-channel blocker, may be of benefit in patients with LQT8 syndrome. This case report details the decrease of atrial fibrillation and ventricular fibrillation events in our LQT8 patient with the addition of ranolazine.

Medtronic Sprint Fidelis lead recall: determining the initial 5-year management cost to Medicare.

BACKGROUND: The Medtronic Sprint Fidelis defibrillator lead has a high failure rate and was recalled in October 2007. OBJECTIVE: The purpose of this study was to determine the incremental cost of the management of this lead to Medicare. METHODS: Real hospital cost data in U.S. dollars were collected on 32 patients with a Medtronic Sprint Fidelis lead who underwent lead revision. Of these patients, 15 were excluded because they had insurance coverage other than that provided by the Centers for Medicare & Medicaid Services. Seventeen patients with Medicare or Medicaid coverage underwent lead revision either electively (n = 6) or after being hospitalized for multiple shocks caused by a lead fracture (n = 11). Eighty-eight percent of the patients underwent extraction of the Fidelis lead at the time of lead revision. A decision model was made that outlines the potential management of the lead recall over time. The existing literature and Medtronic data were reviewed for parameters included in the decision model. The model assumed that 175,000 patients were alive with an implanted Fidelis lead at the time of the recall and that the annual failure rate will be 1.8% over the first 5 years. It was also assumed that 1% of patients without a lead fracture would also undergo elective lead revision each year and that the proportion of patients who would have the Fidelis lead extracted rather than abandoned would be 20:80. Estimates with ranges were used for parameters for which no data are available. The industry standard rate of lead failure was estimated based on the Sprint Quattro model 6947 lead, and this was subtracted from the estimated rates for the Sprint Fidelis lead such that the incremental cost of the lead failure could be estimated. RESULTS: The cost of lead revision trended higher when the Fidelis lead was extracted rather than abandoned ($45,077 ± $11,693 vs $33,802 ± $33, P = .20). In 5 years, the estimated cost impact of the Medtronic Sprint Fidelis lead recall to Medicare will be $287,000,000 (range $176,000,000-$1,186,000,000, October 2007 USD). CONCLUSION: The cost impact of managing a defibrillator lead with a high failure rate to Medicare will be substantial.

Late potential at the high ventricular septal level in a patient with Brugada: possible mechanisms and clinical implications.

The Brugada syndrome (BS) accounts for approximately 20% of cases of sudden cardiac death in patients with structurally normal hearts. The electrophysiologic basis for ST-segment elevation in the precordial electrocardiogram (ECG) leads that characterize the Brugada phenotype and its strong linkage to ventricular tachycardia (VT)/ventricular fibrillation is still a subject of controversy. Electrocardiographic manifestations of the syndrome have been attributed to one of two basic mechanisms: (1) conduction delay in the right ventricular (RV) epicardial-free wall in the region of the outflow tract or (2) premature repolarization of the RV epicardial action potential secondary to loss of the action potential dome. Signal-averaged ECG recordings have demonstrated late potentials that extend beyond the QRS complex in patients with the BS, especially in the anterior wall of the RV outflow tract. The basis for these epicardial late potentials remains a subject of interest among basic and clinical electrophysiologists. Endocardial late potentials in BS are even less well understood. We present a case of a patient with Brugada syndrome with a distinct endocardial late potential in the high ventricular septum coinciding with the ST-segment elevation. We discuss the possible mechanisms for this intracardiac finding and its clinical significance. We also review the effect of isoproterenol infusion on both the late potential and the surface ECG.

Initial experience using a radiofrequency powered transseptal needle.

INTRODUCTION: The purpose of this study was to determine the safety and efficacy of using a novel radiofrequency (RF) powered transseptal needle to perform transseptal puncture (TSP). METHODS: TSP was performed in 35 consecutive patients undergoing left-sided catheter ablation (mean age = 51 years; male = 71%) using a RF powered transseptal needle (NRG, Adult Large and Standard Curve C1, 71 cm, Baylis Medical Company, Inc.). Prior TSP had been performed in 34% of patients. The transseptal apparatus was positioned with the tip of the dilator engaged in the fossa ovalis. RF energy was delivered to the tip of the transseptal needle using a proprietary RF generator at 10 W for 2 seconds as gentle pressure was applied to the needle. RESULTS: In 5 of the 41 TSPs, the needle crossed into the left atrium before RF energy was delivered. In 35 of the remaining 36 punctures, the needle was successfully advanced into the left atrium after application of RF current. In 1 patient, the TSP with the powered needle was unsuccessful but was accomplished using a standard needle. The only complication was a transient right atrial thrombus, which occurred in 2 patients. CONCLUSION: A radiofrequency powered transseptal needle can be used to perform TSP safely and successfully without the need for significant mechanical force, even in patients who have undergone TSP previously. Additional studies are needed to determine whether a powered transseptal needle should be used routinely.

Functional impact of high clopidogrel maintenance dosing in patients undergoing elective percutaneous coronary interventions. Results of a randomized study.

The currently recommended maintenance dose of clopidogrel is often associated with inadequate platelet inhibition, suggesting the need for a higher dose. The aim of this pilot study was to assess the functional impact of a high (150 mg/day) maintenance dose of clopidogrel in patients undergoing elective percutaneous coronary intervention (PCI). This is a prospective, randomized, platelet function study which was performed in elective PCI patients assigned to treatment with either a 75 mg (n = 20) or 150 mg (n = 20) daily maintenance dose of clopidogrel for 30 days; afterwards, all patients resumed standard dosing. Platelet aggregation was performed using light transmittance aggregometry following 20 microM and 5 microM adenosine diphosphate (ADP) stimuli 30 days after randomization and 30 days after resuming standard dosing. Patients treated with 150 mg/day clopidogrel had lower 20 microM ADP-induced platelet aggregation compared to patients on 75 mg/day (52.1 +/- 9% vs. 64.0 +/- 8%; p < 0.001; primary endpoint). The dose-dependent effect was confirmed by the absolute and relative increase in platelet aggregation after resuming standard dosing (p < 0.001). No changes were observed in patients randomized to standard dosing. Parallel findings were observed following 5 microM ADP stimuli for all assessments. A broad variability in clopidogrel-induced antiplatelet effects was observed irrespective of dosing. In conclusion, a 150 mg/day maintenance dose regimen of clopidogrel is associated with reduced platelet reactivity and enhanced platelet inhibition compared to that achieved with the currently recommended 75 mg/day in patients undergoing elective PCI.