Implementation of a Low-Dose, High-Frequency Cardiac Resuscitation Quality Improvement Program in a Community Hospital.

Background: In 2015 the American Heart Association launched the Resuscitation Quality Improvement (RQI) Program to address the urgent need to improve in-hospital cardiac arrest survival through a novel competency-based model for health care provider (HCP) cardiopulmonary resuscitation (CPR) training. This innovation differs from the traditional Basic Life Support (BLS) training model by providing self-directed, low-dose, high-frequency CPR skill activities with the objectives of skills mastery and retention. A program implementation study was conducted at the first hospital in the state of Illinois to adopt RQI in 2016.

Non-clinical and Pre-clinical Testing to Demonstrate Safety of the Barostim Neo Electrode for Activation of Carotid Baroreceptors in Chronic Human Implants.

The Barostim neo™ electrode was developed by CVRx, Inc.to deliver baroreflex activation therapy (BAT)™ to treat hypertension and heart failure. The neo electrode concept was designed to deliver electrical stimulation to the baroreceptors within the carotid sinus bulb, while minimizing invasiveness of the implant procedure.

Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension.

Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity.

Global- and renal-specific sympathoinhibition in aldosterone hypertension.

Recent technology for chronic electric activation of the carotid baroreflex and renal nerve ablation provide global and renal-specific suppression of sympathetic activity, respectively, but the conditions for favorable antihypertensive responses in resistant hypertension are unclear. Because inappropriately high plasma levels of aldosterone are prevalent in these patients, we investigated the effects of baroreflex activation and surgical renal denervation in dogs with hypertension induced by chronic infusion of aldosterone (12 μg/kg per day). Under control conditions, basal values for mean arterial pressure and plasma norepinephrine concentration were 100±3 mm Hg and 134±26 pg/mL, respectively.

Regulation of renin secretion and arterial pressure during prolonged baroreflex activation: influence of salt intake.

Chronic electric activation of the carotid baroreflex produces sustained reductions in sympathetic activity and arterial pressure and is currently being evaluated as antihypertensive therapy for patients with resistant hypertension. However, the influence of variations in salt intake on blood pressure lowering during baroreflex activation (BA) has not yet been determined. As the sensitivity of arterial pressure to salt intake is linked to the responsiveness of renin secretion, we determined steady-state levels of arterial pressure and neurohormonal responses in 6 dogs on low, normal, and high salt intakes (5, 40, 450 mmol/d, respectively) under control conditions and during a 7-day constant level of BA.

Minimally invasive system for baroreflex activation therapy chronically lowers blood pressure with pacemaker-like safety profile: results from the Barostim neo trial.

Background: Previous trials have demonstrated clinically significant and durable reductions in arterial pressure from baroreflex activation therapy (BAT), resulting from electrical stimulation of the carotid sinus using a novel implantable device. A second-generation system for delivering BAT, the Barostim neo™ system, has been designed to deliver BAT with a simpler device and implant procedure.

Methods: BAT, delivered with the advanced system, was evaluated in a single-arm, open-label study of patients with resistant hypertension, defined as resting systolic blood pressure (SBP) ≥140 mm Hg despite treatment with ≥3 medications, including ≥1 diuretic.

Sustained suppression of sympathetic activity and arterial pressure during chronic activation of the carotid baroreflex.

Following sinoaortic denervation, which eliminates arterial baroreceptor input into the brain, there are slowly developing adaptations that abolish initial sympathetic activation and hypertension. In comparison, electrical stimulation of the carotid sinus for 1 wk produces sustained reductions in sympathetic activity and arterial pressure. However, whether compensations occur subsequently to diminish these responses is unclear.

Effects of electrical stimulation of the carotid sinus baroreflex using the Rheos device on ventricular-vascular coupling and myocardial efficiency assessed by pressure-volume relations in non-vagotomized anesthetized dogs.

We investigated the effects of the carotid sinus baroreflex on coupling of the left ventricle (LV) and the arterial system in twelve anesthetized dogs, with all nerves and carotid sinus circulation intact and instrumented to measure LV pressure and volume. The Rheos(R) device was used to directly electrically stimulate the carotid sinus baroreceptors. Stimulation resulted in a significant reduction in systolic blood pressure (SBP), 95.

Prolonged activation of the baroreflex decreases arterial pressure even during chronic adrenergic blockade.

Previous studies suggest that prolonged electric activation of the baroreflex may reduce arterial pressure more than chronic blockade of alpha(1)- and beta(1,2)-adrenergic receptors. To determine whether central inhibition of sympathetic outflow has appreciable effects to chronically reduce arterial pressure by actions distinct from well-established mechanisms, we hypothesized that chronic baroreflex activation would lower arterial pressure substantially even during complete alpha(1)- and beta(1,2)-adrenergic receptor blockade. This hypothesis was tested in 6 dogs during adrenergic blockade (AB; 18 days) with and without electric activation of the carotid baroreflex (7 days).

Defibrillation energy requirements using a left anterior chest cutaneous to subcutaneous shocking vector: implications for a total subcutaneous implantable defibrillator.

Background: Subcutaneous implantable defibrillators (ICDs) are being developed to facilitate ICD implantation.

Objective: The purpose of this study was to estimate the human defibrillation energy requirement (DER) using a left chest cutaneous (Q) to subcutaneous (SQ) shocking vector.

Methods: Twenty patients undergoing implantation of an indicated ICD were enrolled (15 males, age = 63 +/- 12 years; ejection fraction = 0.

Long-term subthreshold electrical stimulation of the left stellate ganglion and a canine model of sudden cardiac death.

Objectives: We sought to develop a high-yield canine model of sudden cardiac death (SCD).

Background: Because electrical stimulation is a powerful means to elicit nerve sprouting, we hypothesize that subthreshold electrical stimulation is more effective than nerve growth factor (NGF) infusion in inducing nerve sprouting and SCD in dogs with myocardial infarction (MI) and complete atrioventricular block (CAVB).

Methods: We gave subthreshold electrical stimulation to the left stellate ganglion (LSG) in six normal dogs for 41 +/- 9 days (protocol 1) and to six dogs with MI and CAVB for 41 +/- 29 days, while continuously monitoring their cardiac rhythm (protocol 2).

T wave alternans as a predictor of spontaneous ventricular tachycardia in a canine model of sudden cardiac death.

Introduction: We recently developed an ambulatory canine model of spontaneous ventricular tachycardia (VT) and sudden cardiac death by creating myocardial infarction, complete AV block, and infusion of nerve growth factor to the left stellate ganglion. Whether or not T wave alternans is associated with the spontaneously occurring episodes of VT in our model was unclear.

Methods And Results: Through intracardiac electrograms obtained from an implantable cardioverter defibrillator, we manually measured T wave amplitudes prior to VT and while the dogs were at rest (baseline, no VT).