Cardiac Resynchronization Therapy With a Quadripolar Electrode Lead Decreases Complications at 6 Months: Results of the MORE-CRT Randomized Trial.

Objectives: The aim of this study was to test the hypothesis that a quadripolar left ventricular (LV) lead results in fewer LV lead-related events than a bipolar cardiac resynchronization therapy (CRT) system in a prospective randomized trial.

Background: Bipolar LV leads cannot be implanted at the optimal site in up to 10% of patients who need CRT, because of anatomic or technical challenges (pacing threshold, phrenic stimulation, or mechanical instability).

Methods: The MORE-CRT (More Options Available With a Quadripolar LV Lead Provide In-Clinic Solutions to CRT Challenges) trial enrolled 1,078 patients.

Pacemaker-induced transient asynchrony suppresses heart failure progression.

Uncoordinated contraction from electromechanical delay worsens heart failure pathophysiology and prognosis, but restoring coordination with biventricular pacing, known as cardiac resynchronization therapy (CRT), improves both. However, not every patient qualifies for CRT. We show that heart failure with synchronous contraction is improved by inducing dyssynchrony for 6 hours daily by right ventricular pacing using an intracardiac pacing device, in a process we call pacemaker-induced transient asynchrony (PITA).

Spinal cord stimulation is safe and feasible in patients with advanced heart failure: early clinical experience.

Aims: Pre-clinical work suggests that upper thoracic spinal cord stimulation (SCS) may have therapeutic effects in the treatment of heart failure (HF). We therefore aim to assess the safety and feasibility of SCS in HF patients.

Methods And Results: A prospective, randomized, double-blind, crossover pilot study was conducted in symptomatic HF patients receiving optimal medical therapy.

Improvement in acute contractility and hemodynamics with multipoint pacing via a left ventricular quadripolar pacing lead.

Introduction: A quadripolar left ventricular (LV) pacing can deliver multipoint pacing (MPP). It is unknown if this confers improved cardiac function compared to conventional cardiac resynchronization therapy (CRT).

Methods And Results: We aimed to characterize changes in acute cardiac contractility and hemodynamics with multisite left ventricular "multipoint" pacing (MPP) in a prospective multicenter study in patients implanted with a CRT-defibrillator incorporating a quadripolar LV lead.

Design of an acute dP/dt hemodynamic measurement protocol to isolate cardiac effect of pacing.

Background: Invasively measured maximum increase in left ventricular pressure (LV dP/dtmax) has been used to assess biventricular (BiV) pacing. We quantified extracardiac factors contributing to its variability, and developed a protocol to minimize these effects in an acute pacing experiment.

Methods And Results: Continuous pressure was recorded by a guidewire sensor placed in the LV.

Acute effects of multisite left ventricular pacing on mechanical dyssynchrony in patients receiving cardiac resynchronization therapy.

Background: A novel quadripolar left ventricular (LV) pacing lead has the ability to deliver multisite LV pacing (MSLV). We set out to characterize the safety and changes in acute mechanical dyssynchrony with MSLV in cardiac resynchronization therapy (CRT) patients.

Methods And Results: Prospective multicenter study in 52 patients receiving CRT.

Acute haemodynamic comparison of multisite and biventricular pacing with a quadripolar left ventricular lead.

Aims: Pacing from multiple sites in the left ventricle (LV) may bring about further resynchronization of the diseased heart compared with biventricular (BiV) pacing. We compared acute haemodynamic response (LV dP/dtmax) of multisite and BiV pacing using a quadripolar LV lead.

Methods And Results: In 21 patients receiving cardiac resynchronization therapy, a quadripolar LV lead and conventional right atrial and ventricular leads were connected to an external pacing system.

Feasibility of using multivector impedance to monitor pulmonary congestion in heart failure patients.

Purpose: Pulmonary edema (PE) is associated with fluid accumulation in the lungs. Device-based impedance measurements have been used to detect fluid overload prior to hospitalization. However, studies have reported a high false positive rate (FPR).

Spinal cord stimulation protects against atrial fibrillation induced by tachypacing.

Background: Spinal cord stimulation (SCS) has been shown to modulate atrial electrophysiology and confer protection against ischemia and ventricular arrhythmias in animal models.

Objective: To determine whether SCS reduces the susceptibility to atrial fibrillation (AF) induced by tachypacing (TP).

Methods: In 21 canines, upper thoracic SCS systems and custom cardiac pacing systems were implanted.

Pacing electrode selection in a quadripolar left heart lead determines presence or absence of phrenic nerve stimulation.

A 60-year-old ischaemic patient presented for routine cardiac resynchronization therapy (CRT)-D implantation. An investigational quadripolar left ventricular lead was placed in the posterolateral vein. Phrenic nerve stimulation (PNS) was observed, but it occurred during pacing from only one of the four electrodes.

Lead design and initial applications of a new lead for long-term endovascular vagal stimulation.

Background: Vagal nerve stimulation (VNS) has negative chronotropic and dromotropic effects. We developed and tested an endovascular spiral vagal stimulation lead (ESVL) designed to follow the projection of the cardiac branches of the vagus nerve around the superior vena cava (SVC) to optimize VNS.

Methods: ESVL contained six 5-mm coil electrodes, spaced 5-mm apart with a spiral guidewire to provide shape.