Transcatheter Non-Acute Retrieval of the Tines-Based Leadless Ventricular Pacemaker.

OBJECTIVES: We report our single-center experience of mid-term to long-term retrieval and reimplantation of a tines-based leadless pacemaker (Micra transcatheter pacing system; TPS). BACKGROUNDS: The TPS is a clinically effective alternative to transvenous single-chamber ventricular pacemakers. Whereas it is currently recommended to abandon the TPS at the end of device life, catheter-based retrieval may be favorable in specific scenarios. METHODS: We report on nine consecutive patients with the implanted TPS who subsequently underwent transcatheter retrieval attempts. The retrieval system consists of the original TPS delivery catheter and an off-the-shelf single-loop 7 mm snare. The procedure was guided by fluoroscopy and intracardiac echocardiography. RESULTS: After an implantation duration of 3.1 ± 2.8 years (range 0.4-9.0), the overall retrieval success rate was 88.9% (8 of 9 patients). The mean procedure time was 89 ± 16 minutes, and fluoroscopy time was 18.0 ± 6.6 min. No procedure-related adverse device events occurred. In the one unsuccessful retrieval, intracardiac echocardiography revealed that the TPS was partially embedded in the ventricular tissue surrounding the leadless pacemaker body in the right ventricle. After retrieval, three patients were reimplanted with a new TPS device. All implantations were successful without complications. CONCLUSIONS: A series of transvenous late retrievals of implanted TPS devices demonstrated safety and feasibility, followed by elective replacement with a new leadless pacing device or conventional transvenous pacing system. This provides a viable end-of-life management alternative to simple abandonment of this leadless pacemaker.

Quantification of artifacts during cardiac magnetic resonance in patients with leadless Micra pacemakers.

INTRODUCTION: When cardiac magnetic resonance (MR) is performed after previous leadless transcatheter pacemaker implantation, an image distortion has to be expected in the heart region and evaluation of myocardial tissue can be affected. In this clinical prospective study, we aim to assess the extent and impact of this artifact on individual ventricular segments and compare it to conventional pacing devices. METHODS: Total of 20 patients with leadless pacemaker placed in the right ventricle underwent cardiac MR imaging in a 1.5 Tesla scanner. A multiplanar segmentation was used to demarcate the left and right ventricular myocardium as well as the pacemaker-caused image artifact in systolic and diastolic time frames. Artifact size and its relative influence on myocardial segments were quantitatively assessed and expressed in AHA-17 model. RESULTS: Implanted leadless pacemaker caused an image artifact with a volume of 48 ± 5 ml. Most distorted were the apical septal (53 ± 23%), apical inferior (30 ± 18%), and midventricular inferoseptal (30 ± 20%) segments. The artifact intersection with basal and lateral segments was none or negligible (up to 2%). The portion of left ventricular (LV) myocardium affected by the artifact was significantly higher in systole (8 ± 4%) compared to diastole (10 ± 3%; p < .001). CONCLUSION: Implantation of leadless pacemaker represents no obstacle for cardiac MR imaging but causes an image artifact located mostly in septal, inferoseptal, and anteroseptal segments of apical and midventricular LV myocardium. With the exception of the apex, diastolic timing reduces the image distortion of all segments and improves global ventricular assessment.

Long-term follow-up of a patient undergoing interatrial shunt device implantation for treatment of heart failure with a preserved ejection fraction.

We herein present a case study of a patient with heart failure with a preserved ejection fraction and severe symptoms who underwent interatrial shunt device implantation and follow-up at a tertiary care heart failure clinic. The interatrial shunt device implantation was successful. No adverse events occurred, and the device prevented hospitalization for heart failure during long-term follow-up.

Efficacy and safety of novel temperature-controlled radiofrequency ablation system during pulmonary vein isolation in patients with paroxysmal atrial fibrillation: TRAC-AF study.

BACKGROUND AND PURPOSE: Saline-irrigated radiofrequency ablation (RFA) for atrial fibrillation (AF) is limited by the absence of reliable thermal feedback limiting the utility of temperature monitoring for power titration. The DiamondTemp (DT) ablation catheter was designed to allow efficient temperature-controlled irrigated ablation. We sought to assess the 1-year clinical safety and efficacy of the DT catheter in treating drug-refractory paroxysmal AF. METHODS: The TRAC-AF trial (NCT02821351) is a prospective, multi-center (n = 4), single-arm study which enrolled patients with symptomatic, drug-refractory, paroxysmal AF. Using the DT catheter, point-by-point ablation was performed around all pulmonary veins (PVs) to achieve PV isolation (PVI). Ablation was performed in a temperature-controlled mode (60 °C, max 50 W). Acute and chronic efficacy and safety was evaluated. RESULTS: Seventy-one patients (age 69.9 ± 11.0 years; 60.6% male) were ablated using the DT catheter. The mean fluoroscopy and RF ablation times were 9.3 ± 6.1 min and 20.6 ± 8.9 min, respectively. Acute isolation of all PVs was achieved in 100% of patients, and freedom from AF after 1 year was 70.6%. There were no steam pops, char, or coagulum on the catheter tip after ablation. There were few serious procedure/device-related adverse events including a single case of cardiac tamponade (1.4%) and transient ischemic attack (1.4). CONCLUSION: This first in man series demonstrates that temperature-controlled irrigated RFA with the DT catheter is efficient, safe, and effective in the treatment of paroxysmal AF. Randomized controlled trials are ongoing and will evaluate better the role of this catheter in relation to standard RFA. TRIAL REGISTRATION: Registered on the site ClinicalTrials.gov January 2016 with identifier: NCT02821351.

His bundle pacing after failure of cardiac resynchronization therapy: a case study.

His bundle pacing is a relatively new method of cardiac pacing. This method is used in patients with atrioventricular block to prevent heart failure associated with right ventricular pacing, and in patients with bundle branch block and cardiomyopathy. We report a patient with cardiomyopathy and left bundle branch block with failure of cardiac resynchronization therapy. Permanent His bundle pacing was associated with clinical improvement and improvement of parameters of cardiac function.

Permanent Percutaneous Carotid Artery Filter to Prevent Stroke in Atrial Fibrillation Patients: The CAPTURE Trial.

BACKGROUND: Patients with high stroke risk and atrial fibrillation who are unsuitable to oral anticoagulants (OACs) require other stroke prevention strategies. A novel permanent coil filter directly placed into both common carotid arteries (CCAs) was designed to capture emboli >1.4 mm in diameter. OBJECTIVES: The multicenter, nonrandomized, first-in-human clinical CAPTURE (Carotid Artery Implant for Trapping Upstream Emboli for Preventing Stroke in Atrial Fibrillation Patients) trial sought to determine the feasibility and safety of bilateral CCA filter placement. METHODS: Eligible patients had atrial fibrillation, CHA2DS2-VASc (Congestive heart failure, Hypertension, Age 75 years, Diabetes, Stroke/transient ischemic attack, Vascular disease, Age 65 to 74 years, Sex category) ≥2, OAC unsuitability, CCA size 4.8 to 9.8 mm, and no carotid stenosis >30%. Under ultrasound guidance, after direct transcutaneous carotid puncture with a 24-gauge needle, a motorized unit expels the filter to unfurl in the artery. Patients received aspirin/clopidogrel for 3 months, and aspirin thereafter. Primary endpoints were: 1) procedural success-bilateral, properly positioned CCA filters; and 2) 30-day incidence of major adverse events-death, stroke, major bleeding, filter migration, CCA thrombus, or stenosis. Carotid ultrasounds were conducted post-procedure, pre-discharge, at 1 week, and at 1, 3, 6, and 12 months. RESULTS: At 3 centers, 25 patients were enrolled: age 71 ± 9 years, CHA2DS2-VASc = 4.4 ± 1.0, prior embolism in 48%. Procedure success was 92% (23 of 25 patients); 1 patient had unilateral deployment. There were no device/procedure-related major adverse events; minor puncture site hematomas/edema occurred in 5 of 25 (20%). After 6-month mean follow-up, asymptomatic thrombi were detected in 4 patients (1 bilateral, 4 unilateral), adjudicated as captured (n = 3), unclassified (n = 2), or in situ (n = 0). In all patients, the thrombi dissolved with subcutaneous heparin. In 1 patient, 2 device/procedure-unrelated minor strokes occurred. CONCLUSIONS: Permanent carotid filter placement for stroke prophylaxis is technically feasible and safe. (Carotid Artery Implant for Trapping Upstream Emboli for Preventing Stroke in Atrial Fibrillation Patients [CAPTURE]; NCT03571789).

Heart rate reduction after ivabradine might be associated with reverse electrical remodeling in patients with cardiomyopathy and left bundle branch block.

Left bundle branch block increases the risk of death in patients with chronic heart failure. We herein report four clinical cases of patients with chronic heart failure caused by nonischemic cardiomyopathy with left bundle branch block that occurred when adding ivabradine to optimal medical therapy, resulting in reverse electrical and mechanical remodeling. This phenomenon might be explained by the effect of ivabradine on reverse remodeling of the left ventricle with improvement of intraventricular conduction.

Temperature-Controlled Radiofrequency Ablation for Pulmonary Vein Isolation in Patients With Atrial Fibrillation.

BACKGROUND: Saline irrigation improved the safety of radiofrequency (RF) ablation, but the thermal feedback for energy titration is absent. OBJECTIVES: To allow temperature-controlled irrigated ablation, a novel irrigated RF catheter was designed with a diamond-embedded tip (for rapid cooling) and 6 surface thermocouples to reflect tissue temperature. High-resolution electrograms (EGMs) from the split-tip electrode allowed rapid lesion assessment. The authors evaluated the preclinical and clinical performance of this catheter for pulmonary vein (PV) isolation. METHODS: Using the DiamondTemp (DT) catheter, pigs (n = 6) underwent discrete atrial ablation in a temperature control mode (60°C/50 W) until there was ∼80% EGM amplitude reduction. In a single-center clinical feasibility study, 35 patients underwent PV isolation with the DT catheter (study group); patients were planned for PV remapping after 3 months, regardless of symptomatology. A control group included 35 patients who underwent PV isolation with a standard force-sensing catheter. RESULTS: Porcine lesion histology revealed transmurality in 51 of 55 lesions (92.7%). In patients, all PVs were successfully isolated; no char or thrombus formation was observed. Compared with the control group, the study cohort had shorter mean RF application duration (26.3 ± 5.2 min vs. 89.2 ± 27.2 min; p < 0.001), shorter mean fluoroscopic time (11.2 ± 8.5 min vs. 19.5 ± 6.8 min; p < 0.001), and lower acute dormant PV reconduction (0 of 35 vs. 5 of 35; p = 0.024). At 3 months, 23 patients underwent remapping: 39 of 46 PV pairs (84.8%) remained durably isolated in 17 of these patients (73.9%). CONCLUSIONS: This first-in-human series demonstrated that temperature-controlled irrigated ablation produced rapid, efficient, and durable PV isolation. (ACT DiamondTemp Temperature-Controlled and Contact Sensing RF Ablation Clinical Trial for Atrial Fibrillation [TRAC-AF]; NCT02821351).