Cardiac Contractility Modulation: A Technical Review.

Therapeutic options for the management of systolic congestive heart failure involving newer implantable device technologies that were not previously available now exist. Cardiac contractility modulation (CCM) has been shown to benefit patients with class III systolic heart failure with an ejection fraction of 25%-45% not indicated for biventricular pacing. Despite the increased use of CCM, there is a significant knowledge deficit in the general electrophysiology community regarding its clinical management. This significantly relates to the different functional characteristics of CCM compared to those encountered in traditional cardiac rhythm management devices. Improved evaluation and troubleshooting of CCM for therapeutic effect will benefit from advanced education. The goal of this review is to present pertinent technical aspects relating to CCM therapy management in a simplified fashion, all the while providing a clinical context to facilitate greater expertise.

Atrial fibrillation associated with heart failure treated by a 2-lead CRT-DX system (BIO-AffectDX): Study design and clinical protocol.

BACKGROUND: Evidence to support use of cardiac resynchronization therapy (CRT) among patients with both heart failure (HF) and atrial fibrillation (AF) is largely limited to retrospective or post hoc subanalyses. Data from a prospectively enrolled and contemporary cohort are needed. OBJECTIVE: We aim to better characterize the changes from baseline in HF patients with concomitant AF subsequently implanted with a 2-lead CRT-DX system capable of sensing in the atrium, aggregating diagnostics, and delivering CRT therapy. The primary objective of this study is to evaluate the percentage of all HF subjects with an improvement in a clinical composite score from pre-CRT implant to 12 months. METHODS: The study is a US-based, prospective, observational multicenter clinical trial conducted at up to 50 sites and enrolling approximately 400 subjects with a follow-up period of 1 year. Multiple subject assessments, atrial rhythm status, and device interrogation will be collected at follow-up visits occurring at 3, 6, and 12 months postimplant. RESULTS: A Clinical Events Committee will adjudicate subject HF events, arrhythmia events, death events, and all device-classified ventricular tachycardia and ventricular fibrillation episodes with treatment that are collected throughout the follow-up period. Their decisions are based on independent physician review of the data from sites and device interrogation. CONCLUSION: The BIO-AffectDX study aims to provide further insight into the expected outcomes from CRT treatment in patients with HF and AF.

Catheter Ablation in the Treatment of Atrial Fibrillation.

Catheter ablation (CA) of the pulmonary veins for atrial fibrillation (AF) is growing exponentially and is the most commonly performed electrophysiologic procedure. Initial descriptions focused on CA for paroxysmal AF, and now more recently expanded in application to persistent AF and those with comorbid heart failure. Efforts to improve success have and continue to address issues such as pulmonary vein "reconnection" following ablation through different ablative energy modalities, and the use of a "hybrid" surgical/endocardial combined approach in persistent forms of AF. Technologic advances as well are concurrently seeking to improve safety, particularly regarding the incidence of atrio-esophageal fistula in this seemingly ever-growing ablation population.

A simple technique for relocating chronic CIED leads to a subpectoral position for relief of erosion and pain.

BACKGROUND: Methodology specific for moving superficial chronically implanted transvenous pacing leads to a subpectoral pocket is not described in the literature. Relocation of prepectoral leads and generator to a submuscular pocket for relief of erosion and pain with minimal pectoral trauma is possible by applying a variant of a previously described submammary tunneling technique. METHODS: All patients presenting for device follow-up, elective battery replacement, or system upgrade over an 8-month period were considered for relocation if experiencing significant thinning or pain over their prepectoral implant. Those selected for relocation then had their system moved subpectorally via the tunneling technique. Patients were followed for 6 months postoperatively for procedurally related complications and resolution of preprocedure symptoms. RESULTS: Thirty-two leads in 14 patients were all successfully relocated. Of the relocated leads, five (16%) were a three-pin connector implantable cardioverter defibrillator lead. Three patients (21%) in the group required short-term prescription analgesia in the immediate postdischarge period. Pain and erosion concerns abated in the study group by the 3-month follow-up. CONCLUSIONS: Relocation of superficial pacing leads with CIED generator to a subpectoral pocket facilitated by this tunneling method is successful, safe, and can accommodate single and multipin leads with minimal pectoral trauma and no nerve damage.

Coronary venous angioplasty to facilitate transvenous left ventricular lead placement: A single-center 13-year experience.

BACKGROUND: Barriers to successful left ventricular lead placement within the coronary venous anatomy may include focal stenoses, thromboses, phrenic nerve stimulation, vessel tortuosity, small vessel caliber, nonexcitable tissue, and valve presence. A large series describing the utilization of coronary venous angioplasty (CVAP) for relief of these issues is absent in the literature. OBJECTIVE: We report our experience on all patients treated with CVAP in a single-center 13-year experience. METHODS: Forty-seven patients with CVAP (64% male, mean age 67 ± 12 years) were treated by five different implanting physicians for approved cardiac resynchronization therapy indications. The reason for CVAP was categorized by obstacle (focal occlusion, valve presence, small caliber vessel) and location. The number, type, and size of balloon used, inflation characteristics, complications, and success of lead deployment crossing the point of intervention were all tabulated. RESULTS: Seventy-seven percent of patients (36/47) had successful CVAP. The most common reason for intervention was a focal occlusion (24/47; 51%), followed by valve presence (13/47; 28%), and small vessel caliber (10/47; 21%). Focal occlusions were most successfully managed with CVAP (23/24; 96%), followed by small vessel caliber (7/10; 70%) and valve presence (6/13; 46%). The reason for failure was most commonly due to failure to relieve the obstruction (5/11; 45%), thrombosis (3/11; 27.3%), dissection (2/11; 18.2%), and inability to pass the balloon through the occlusion (1/11; 9.0%). There were no significant complications developed from CVAP utilization. CONCLUSION: In a large analysis, CVAP can be safely and successfully performed in the majority of instances required.

Positioning of left ventricular pacing lead guided by intracardiac echocardiography with vector velocity imaging during cardiac resynchronization therapy procedure.

INTRODUCTION: Intraoperative modality for "real-time" left ventricular (LV) dyssynchrony quantification and optimal resynchronization is not established. This study determined the feasibility, safety, and efficacy of intracardiac echocardiography (ICE), coupled with vector velocity imaging (VVI), to evaluate LV dyssynchrony and to guide LV lead placement at the time of cardiac resynchronization therapy (CRT) implant. METHODS: One hundred and four consecutive heart failure patients undergoing ICE-guided (Group 1, N = 50) or conventional (Group 2, N = 54) CRT implant were included in the study. For Group 1 patients, LV dyssynchrony and resynchronization were evaluated by VVI including visual algorithms and the maximum differences in time-to-peak (MD-TTP) radial strain. Based on the findings, the final LV lead site was determined and optimal resynchronization was achieved. CRT responders were defined using standard criteria 6 months after implantation. RESULTS: Both groups underwent CRT implant with no complications. In Group 1, intraprocedural optimal resynchronization by VVI including visual algorithms and MD-TTP was a predictor discriminating CRT response with a sensitivity of 95% and specificity of 89%. Use of ICE/VVI increased number of and predicted CRT responders (82% in Group 1 vs 63% in Group 2; OR = 2.68, 95% CI 1.08-6.65, P = 0.03). CONCLUSION: ICE can be safely performed during CRT implantation. "Real-time" VVI appears to be helpful in determining the final LV lead position and pacing mode that allow better intraprocedural resynchronization. VVI-optimized acute resynchronization predicts CRT response and this approach is associated with higher number of CRT responders.