Choice of Steerable Sheath Impacts Contact Force Stability During Pulmonary Vein Isolation.

A stable contact force (CF) is correlated with more effective radiofrequency (RF) ablation (RFA) lesions and long-term procedural outcomes. Efforts to improve catheter stability include jet ventilation, pacing, steerable sheaths, and CF-sensing ablation catheters. This study compares CF stability and effective RF lesions between two commercially available steerable sheaths. Thirty patients underwent first-time RFA at a single center using the Agilis™ NxT (Abbott, Chicago, IL, USA) or SureFlex™ (Baylis Medical, Montreal, Canada) steerable sheath. High-power short-duration RFA was utilized, targeting a 10-Ω drop. Sheath performance was assessed for the entire procedure and around each pulmonary vein (PV) in terms of mean CF, CF variability, RF time per lesion, and inefficient contact lesions (defined as lesions with a CF of less than 5 g for at least 10% of the RF delivery time). The operator-targeted mean CF was achieved using both sheaths; however, the overall CF variability was 12.8% lower when using the SureFlex™ sheath (p = 0.08). The CF variability was generally 16% greater in the right PVs than the left PVs (p = 0.001) but trended lower with the SureFlex™ sheath. There were 8% more inefficient contact lesions created when using the Agilis™ sheath as compared to the SureFlex™ sheath (p = 0.035), especially in the right inferior PV (p = 0.009). The RF time per lesion was, on average, 12% (1.4 seconds) shorter when using the SureFlex™ sheath than the Agilis™ sheath (p < 0.05). The choice of steerable sheath may affect both catheter stability and lesion quality, especially in the right PVs.

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.

Transseptal catheterization using a powered radiofrequency transseptal needle.

Mechanical pressure applied to a Brockenbrough needle at the fossa ovalis is the standard transseptal puncture technique. Circumstances where the fossa ovalis is thick or aneurysmal can make this method challenging. In this case, we illustrate the use of a radiofrequency powered transseptal needle to cross the fossa ovalis.

Comparison of hand-carried ultrasound assessment of the inferior vena cava and N-terminal pro-brain natriuretic peptide for predicting readmission after hospitalization for acute decompensated heart failure.

OBJECTIVES: We sought to compare the value of serial assessment with hand-carried ultrasound (HCU) of the inferior vena cava (IVC) with brain natriuretic peptide (BNP) to identify patients with acute decompensated heart failure (ADHF) who will be readmitted or seek emergency department treatment after hospital discharge. BACKGROUND: Congestive heart failure (CHF) is a leading cause for hospitalization and, once hospitalized, patients with CHF frequently are readmitted. To date, no reliable index exists that can be used to predict whether patients with ADHF can be discharged with low readmission likelihood. METHODS: A total of 75 patients who were admitted with a primary diagnosis of ADHF were followed. All patients were assessed at admission and discharge with the use of routine clinical evaluation, BNP measurement, and HCU evaluation of the IVC by physicians with limited training in ultrasound. RESULTS: During the 30-day follow-up, 31 patients were rehospitalized or presented to the emergency department. Patients who were subsequently readmitted could not be differentiated from those who were not readmitted by their demographics, comorbidities, vital signs, presence of symptoms/signs suggestive of persistent congestion, hospital length of stay, or net volume removal. Routine laboratory tests, including assessment of renal function, also failed to predict readmission with the exception of serum sodium. Although admission BNP was similar in patients readmitted and not readmitted, pre-discharge log-transformed BNP was greater in patients who subsequently were readmitted. Patients who required repeat hospitalization had a larger IVC size on admission as well as at discharge. In addition, patients who were readmitted had persistently plethoric IVCs with lower IVC collapsibility indexes. At discharge, only serum sodium, log-transformed BNP, IVC size, and collapsibility were statistically significant predictors of readmission. CONCLUSIONS: This study confirms that, once hospitalized, patients with CHF frequently are readmitted. Bedside evaluation of the IVC with a HCU device at the time of admission and discharge, as well as pre-discharge BNP, identified patients admitted with ADHF who were more likely to be readmitted to the hospital.