Mulpuru, Siva K.

Femoral ExtractionLaser and radiofrequency energy–assisted lead extraction has greatly facilitated this complex procedure. Although success rates are high, in some instances alternate methods of extraction are required. In this review, we discuss techniques for femoral extraction of implanted leads and retained fragments. The major tools available, including commonly used snares and delivery tools, are discussed. We briefly describe combined internal jugular and femoral venous extraction approaches, as well as complimentary utilization of more than one technique via the femoral vein. Animated and procedural sequences are included to help the reader visualize the key components of these techniques.

RVOT Atypical VariantsBackgroundRight ventricular outflow tract (RVOT) arrhythmias are a common form of ventricular tachycardia (VT) in patients with structurally normal heart. The underlying mechanism is due to triggered activity. Mapping and ablation is relatively straightforward targeting the earliest point of activation. Previously reported causes of difficult ablation in the RVOT region include under recognized right ventricular cardiomyopathy/sarcoidosis, presence of endocavitary structures, close proximity to the coronary vasculature, and origin from non‐RVOT structures.Methods and ResultsWe identified all patients undergoing PVCs/sustained RVOT VT ablation from January 2013 to December 2013. This included 33 patients. Of these, we identified procedures that were considered difficult despite a single morphology arrhythmia being targeted and no underlying cardiomyopathy present. Difficulty was specifically considered when ablation at the earliest site of activation was not successful and eventual successful ablation was at a distance of greater than 15 mm from the early activation site. We identified 3 patients (n = 3, 100% male) with evidence of reentrant arrhythmia based on slow conduction zones necessary for the tachycardia/arrhythmia, mid diastolic signals during VT or preceding bigeminal PVCs, pace mapping from the site abnormal signals reproducing the arrhythmia morphology but with prominent conduction delay, the entire cycle length of the tachycardia or coupling interval for the PVCs being mapping, or based on reset characteristics.ConclusionIn patients with atypical forms of RVOT VT, careful mapping and ablation of the myocardial sleeves near the pulmonic valve can eliminate the arrhythmia.

Epicardial Access and ObesityIntroductionPercutaneous epicardial access for ablative therapies is an increasingly common technique utilized for refractory ventricular arrhythmias. There are, however few known data on obesity and complication rates associated with this procedure.Methods and ResultsWe retrospectively reviewed the charts of subjects undergoing epicardial access at Mayo Clinic between January 2004 and June 2013. Baseline clinical and echocardiographic data were collected for each subject, who was then classified into body mass index (BMI) categories as underweight, normal weight, overweight, and obese based on a BMI of <18.5, 18.5–24.99, 25–29.99, and ≥30, respectively. Events and complications were recorded, and procedural and clinical success rates were determined.There was no statistically significant difference in access approach, procedural or clinical outcomes, or complications among the BMI categories. Note that 95.1%, 91.7%, and 93.1% derived procedural success among the normal weight, overweight, and obese categories, respectively (P value = 0.81). Similarly, there was no difference in clinical outcomes with success rates of 68.3%, 66.7%, and 75.9% between the respective groups (P value = 0.54). At 5 years, there was a trend toward increased mortality among obese individuals (28.8%) compared to normal weight (8.8%) and overweight (9.8%) patients (P value = 0.139).ConclusionPercutaneous epicardial access, mapping, and ablation can be performed in obese individuals with similar outcomes to those of lower weight category. Obesity should not preclude the use of percutaneous epicardial access when clinically indicated.

BackgroundWe aimed to determine the long‐term outcomes of percutaneous lead extraction and stent placement in patients with pacemaker‐induced superior vena cava (SVC) syndrome.MethodsThe study retrospectively screened patients who underwent lead extraction followed by central vein stent implantation at Mayo Clinic (Rochester, MN, USA), from January 2005 to December 2012, to identify the patients with pacemaker‐induced SVC syndrome. Demographic, clinical, and follow‐up characteristics of those patients were collected from electronic medical records.ResultsSix cases were identified. The mean (standard deviation) age was 56 (15) years (male, 67%). All patients had permanent dual‐chamber pacemakers, with a mean 11‐year history of pacemaker placement. The entire device system was explanted in five patients; one patient had a 21‐year‐old pacemaker lead that could not be removed. Eight stents were implanted in six patients: five patients had one stent, one patient had three. A new pacemaker system was reimplanted through the stented vein in five patients. Technical success was achieved in all patients, without any complication. Symptoms rapidly resolved in all patients after stent deployment. The mean follow‐up duration was 48 months (range, 10–100 months). Three patients remained symptom free. Reintervention with percutaneous balloon venoplasty was successful in three patients with symptom recurrence.ConclusionPercutaneous stent implantation after lead removal followed by reimplantation of leads is a feasible alternative therapy for pacemaker‐induced SVC syndrome, although some cases may require repeat intervention.

Renal Vein Stimulation Increases Blood PressureBackgroundNeurocardiogenic syncope (NCS) is a common and sometimes debilitating disorder, with no consistently effective treatment. NCS is due to a combination of bradycardia and vasodilation leading to syncope. Although pacemaker devices have been tried in treating the bradycardic aspect of NCS, no device‐based therapy exists to treat the coexistent vasodilation that occurs. The renal sympathetic innervation has been the target of denervation to treat hypertension. We hypothesized that stimulation of the renal sympathetic nerves can increase blood pressure and counteract vasodilation in NCS.Methods and ResultsHigh‐frequency stimulation (800–900 pps, 10 V, 30–200 seconds) was performed using a quadripolar catheter in the renal vein of 7 dogs and 1 baboon. A significant increase in blood pressure (BP; mean [SD] systolic BP 117 [±28] vs. 128 [±33], diastolic BP 75 [±19] vs. 87 [±29] mmHg) was noted during the stimulation, which returned to baseline after cessation of stimulation. The mean increase in systolic and diastolic BP was 13.0 (±3.3) (P = 0.006) and 10.2 (±4.6) (P = 0.08), respectively.ConclusionWe report the first ever study of feasibility and safety of high‐frequency electrical stimulation of the renal sympathetic innervation to increase BP in animal models. This has potential applications in the treatment of hypotensive states such as NCS.