Effectiveness and Reliability of Selected Site Pacing for Avoidance of Phrenic Nerve Stimulation in CRT Patients with Quadripolar LV Leads: The EffaceQ Study.

BACKGROUND: Cardiac resynchronization therapy (CRT) relies on sufficient left ventricular (LV) pacing with safety margin to phrenic nerve stimulation (PNS). Previous studies introduced LV vector reprogramming in bipolar coronary sinus leads to optimize LV pacing and avoid PNS. We investigated the efficacy and reliability of quadripolar leads in CRT. METHODS: The EffaceQ study enrolled 344 patients with de novo CRT implantation with a quadripolar LV lead in an observational, prospective multicenter study. The study was powered to demonstrate that in at least 90% of patients with an implanted quadripolar LV lead, a viable LV pacing configuration (LVPC) is available (primary end point: LV pacing threshold ≤2.5 V/0.5 ms, sufficient PNS margin). RESULTS: Quadripolar leads were successfully implanted in 96% of patients. A total of 278 of 299 (93.0%) patients with complete data met the criteria for viable LVPC. With the use of traditional LVPCs, a viable LVPC would have been available (268 of 299 patients; P = 0.002) in significantly fewer patients (89.6%). In any LVPC, PNS was inducible in 65.0% of patients and 22.6% of patients reported PNS during ambulatory 3-month follow-up. LVPC reprogramming was performed in 49.8% of patients. PNS inducibility decreased from distal to proximal electrodes, whereas LV pacing thresholds increased from distal to proximal. At prehospital discharge, 5.9 ± 2.8 viable LVPCs were observed, stable during follow-up. The quadripolar electrode offered significantly more LVPC for LV optimization and PNS avoidance. CONCLUSION: Quadripolar LV leads yield high numbers of patients with viable LVPCs and alternatives for noninvasive repositioning of LV pacing.

Clinical efficacy of left ventricular pacing vector programmability in cardiac resynchronization therapy defibrillator patients for management of phrenic nerve stimulation and/or elevated left ventricular pacing thresholds: insights from the Efface Phrenic Stim study.

AIMS: Elevated left ventricular (LV) pacing thresholds or phrenic nerve stimulation (PNS) might be possible reasons for absence of continuous and effective biventricular stimulation. This study investigated the benefit and clinical efficacy of the ability to choose one out of three different LV pacing vectors for the management of suboptimal LV pacing thresholds and PNS. METHODS AND RESULTS: This prospective, observational multicentre study enrolled 132 patients (Pts) implanted with a cardiac resynchronization therapy defibrillator, that offers three LV pacing vectors: (i) Bipolar; (ii) LVtip ↔ RVcoil; (iii) LVring ↔ RVcoil (RV = right ventricular). Left ventricular pacing thresholds and PNS thresholds were obtained in sitting and left lateral body position for all programmable LV pacing vectors at hospital discharge and follow up (FU). In 97%, a bipolar transvenous LV lead was successfully implanted. In 87% of Pts at least one acceptable pacing vector could be identified that provides good pacing threshold (≤ 2.5 V at 5 ms) and acceptable margin to PNS (≥ 2:1). This is an increase of 18% compared with conventional bipolar systems (74%) with two LV vectors and of 25% compared with unipolar systems (70%). The LVtip ↔ RVcoil vector provided the best LV pacing thresholds, but the highest rate of PNS. CONCLUSIONS: The programmability of LV pacing vectors is a powerful feature to avoid PNS and obtain acceptable LV pacing thresholds. In order to retain reprogramming options for LV vectors during FU, LV pacing leads with at least two electrodes should be chosen whenever possible.

Closure of Left Atrial Appendage With Persistent Distal Thrombus Using an Amplatzer Amulet Occluder.

A 73-year-old patient with permanent atrial fibrillation presented for left atrial appendage (LAA) occlusion. Transesophageal echocardiography demonstrated a thrombus in the distal LAA. This image series illustrates a "no touch" technique that was used to ensure successful implantation of an Amplatzer Amulet LAA occlusion device without the use of an embolization protection system.