PV ablation guided by AI resulted feasible, achieving a high rate of isolated PVs, with a low complication rate, and allowed a high single-procedure arrhythmia-free survival at 14 months.
In this multicenter registry, RF ablation using a new surround flow catheter, with CF sensor, resulted as feasible, achieving a high rate of isolated PVs. Procedural and fluoroscopy times and success rates were comparable with other techniques with a low complication rate.
Methods and results A 58 years-old man was admitted to our intensive care unit for syncope due to inconstant capture of epicardial ventricular lead. His cardiovascular history began 20 years before when he underwent single chamber pacemaker implantation with insertion of a passive fixation ventricular lead for symptomatic complete atrio ventricular block (AVB). Electrical parameters were good at implantation. However, during follow-up a gradual and progressive increase of pacing threshold occurred, with no changes in impedance values, finally leading to complete loss of ventricular capture. Hence, 2 years later, the lead was extracted and a new transvenous ventricular lead was placed in septal position. All electrical parameters were optimal at the end of the procedure. However, in the following months threshold values gradually increased as previously observed. The referring clinicians decided to surgically extract both the device and transvenous lead and to implant an epicardial ventricular lead connected to an abdominal generator. The pacemaker worked properly for about 17 years until he was transferred to our institution with evidence of inconstant lead capture at maximum pacing outputs. A temporary transvenous pacemaker was immediately inserted. Clinical examination, laboratory exams, and echocardiography were normal. Cardiac magnetic resonance (MRI) was not feasible due to the epicardial lead. Thus, in order to obtain cardiac substrate characterization, we decided to perform high density multielectrode voltage mapping of the right ventricular endocardium with HD Grid multielectrode mapping catheter (HD Grid mapping catheter sensor enabled, Abbott Technologies, Minneapolis, MN). Electroanatomic voltage map allows distinction of areas of healthy myocardium (>1.5 mV) from scar tissue (<0.5 mV). Unexpectedly, voltage mapping highlighted no scar zones, showing a globally normal endomyocardial surface. Therefore, a new endocavitary pacemaker was inserted in right prepectoral region and an active fixation right ventricular lead was placed on mid-ventricular septum. A backup pacing lead was placed in a more apical position in an area of endocardial healthy myocardium. Post-procedural sensing, impedance and capture threshold were optimal (0.3 V × 0.4 ms for mid-septal lead and 0.3 × 0.4 ms for the other one). At 1 month follow-up mid-septal lead’s threshold was slightly increased (1.0 V × 0.4 ms) and further increase was observed at 3-month outpatient visit (1.75 V × 0.4 ms). Capture threshold of the other lead and other parameters were stable. The patient received remote monitoring for home surveillance of the implanted system. Home monitoring shows a trend toward a progressive increase of pacing threshold of the mid-septal lead and stable value of the other electrode. Conclusions The present report suggests an innovative use of high-density mapping with HD Grid catheter to characterize endocardial right ventricular myocardium in a patient with contraindication to cardiac MRI and recurrent failure of previous implanted pacing systems for unknown reason and to guide effective lead placement in areas of normal endocardial voltage. Combined use of telemedicine and high-resolution mapping technique allowed us to avoid unnecessary high risk reintervention for novel epicardial lead placement.
Background Cardiac resynchronization therapy (CRT) is an established treatment in patients with heart failure and prolonged QRS duration. A biventricular device is implanted to achieve faster activation and more synchronous contraction of the ventricles. Despite the convincing effect of CRT, 30–40% of patients do not respond. We decided to investigate the role of multipoint pacing (MPP) in a selected group of patients with right ventricle (RV)-to-left ventricle (LV) intervals less than 80 ms that do not respond to traditional CRT. Methods We will enrol 248 patients in this patient-blinded, observational, clinical study aiming to investigate if MPP could decrease LV end-systolic volume (ESV) in patients with RV-to-LV interval less than 80 ms. MPP will be activated ON at implant in patients with RV-to-LV delay less than 80 ms and OFF in RV-to-LV at least 80 ms. At follow-up the activation of MPP will be related to CRT response. The primary study endpoint will be the responder rate at 6 months, defined as a decrease in LV ejection fraction, LV end-diastolic volume, LV end-systolic volume (LVESV) at least 15% from baseline. Secondary outcomes include 12 months relative percentage reduction in LVESV and a combined clinical outcome measure of response to CRT defined as the patient being alive, no hospitalization due to heart failure, and experiencing an improvement in New York Heart Association functional class (Composite-Score). Conclusion Reducing the nonresponder rate continues to be an important goal for CRT. If an increase in reverse remodelling can be achieved by MPP, this study supports the conduct of larger trials investigating the role of MPP on clinical outcomes in selected patients treated, right now, only with traditional CRT. Trial registration ClinicalTrials.gov, NCT02713308. Registered on 18 March 2016.
Quadripolar leads allow RV-to-LV interval maximization. An optimal RV-to-LV interval seems achievable in the majority of patients, especially if the leads present a long inter-electrode distance.
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