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EP News: Allied Professionals
EP News: Allied Professionals Erica S. Zado, PA-C, FHRS From the Section of Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
Intermediate outcome of leadless pacemaker Knops et al (J Am Coll Cardiol 2015;65:1497, PMID 25881930) reported 1-year outcome after the implantation of a leadless pacemaker assessing both intermediate safety information and stability of pacing parameters. The study included 31 of the original 33 patients implanted with this completely new type of pacemaker followed for 1-year. The current device is single chamber only, and the most common indication was atrial fibrillation with atrioventricular block or slow ventricular response in 21 (68%). The authors found that no device-related complications occurred in months 3–12 and the lead parameters (pacing threshold, lead impedance, and R wave) remained stable over the course of the year. The authors conclude that this novel pacing system may be a viable alternative to traditional pacing systems, and continued assessment in larger randomized trials is reasonable.
Leadless pacemakers The leadless pacemaker has the leads and generator all contained as a single unit that is then implanted in the right ventricular (RV) apex. It was developed in part to mitigate the most common complications of pacemaker implantation: pocket hematoma and infection, lead dislodgment, and fracture. The initial implant and short-term outcome data were reported by Reddy et al (Circulation 2014;129:1466, PMID 24664277). The pacemaker has a steroid-eluting helix on one end to screw into the RV apex and a “docking mechanism” on the other end on which the delivery catheter or retrieval device can attach. The pacemaker is delivered to the heart via femoral vein access (18-F sheath). The pacemaker is 42 mm long and 5.99 mm in diameter. It can be repositioned if necessary to achieve adequate sensing and pacing parameters by reattaching to the docking mechanism and unscrewing the helix. The device is currently a single chamber only with a unique rate response mechanism that uses the temperature of the surrounding blood in the RV to determine whether someone is exercising.
In the initial study including 33 patients, 70% of devices were implanted with no repositioning required, with an average procedure time of 28 minutes. Despite the large sheath required for access, no vascular complications (hematoma, pseudoaneurysm, or atrioventricular fistula) were noted. R-wave amplitude and pacing threshold improved from implant to the next day and were stable over 3-month follow-up. There were 2 complications (6%) including 1 serious adverse event. One patient had cardiac perforation requiring surgical repair, who then had a stroke on postoperative day 5 and died 2 weeks later. Another patient inadvertently had the device placed in the left ventricle via a patent foramen ovale. Once discovered on fluoroscopy, it was retrieved and implanted in the RV apex without any consequence. A third patient had the device removed 5 days after implant because the patient had rapid ventricular tachycardia (VT) with syncope and needed an implantable cardioverter-defibrillator. VT was not thought to be caused by the pacemaker as the patient went on to have recurrent VT after the pacemaker was removed. There are several concerns that will need to be answered by studies including larger numbers of patients. Currently this is only a single-chamber system and only 10%–20% of patients undergo single-chamber implant. Newer devices can be implanted in multiple chambers with some sort of communication system for coordinated activity. Also, the rate response mechanism uses the temperature of the surrounding blood, and it is unclear whether this will be adequate for more sedentary patients. It is also unclear whether the device will be able to be retrieved in the case of infection or after battery depletion. Therefore, for device “replacement” a new device may need to be implanted next to the old device, which is left in place. Initially, there was anxiety about device embolization to the pulmonary artery, but this did not occur in this small study. As with any new device or procedure, there can be unexpected consequences that will become evident only with further evaluation in larger numbers of patients.
Address reprint requests and correspondence: Ms Erica S. Zado, Section of Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Founders 9, 3400 Spruce St, Philadelphia, PA 19104. E-mail address: [email protected].
1547-5271/$-see front matter
http://dx.doi.org/10.1016/j.hrthm.2015.05.009
Intermediate outcome of leadless pacemaker Knops et al (J Am Coll Cardiol 2015;65:1497, PMID 25881930) reported 1-year outcome after the implantation of a leadless pacemaker assessing both intermediate safety information and stability of pacing parameters. The study included 31 of the original 33 patients implanted with this completely new type of pacemaker followed for 1-year. The current device is single chamber only, and the most common indication was atrial fibrillation with atrioventricular block or slow ventricular response in 21 (68%). The authors found that no device-related complications occurred in months 3–12 and the lead parameters (pacing threshold, lead impedance, and R wave) remained stable over the course of the year. The authors conclude that this novel pacing system may be a viable alternative to traditional pacing systems, and continued assessment in larger randomized trials is reasonable.
Leadless pacemakers The leadless pacemaker has the leads and generator all contained as a single unit that is then implanted in the right ventricular (RV) apex. It was developed in part to mitigate the most common complications of pacemaker implantation: pocket hematoma and infection, lead dislodgment, and fracture. The initial implant and short-term outcome data were reported by Reddy et al (Circulation 2014;129:1466, PMID 24664277). The pacemaker has a steroid-eluting helix on one end to screw into the RV apex and a “docking mechanism” on the other end on which the delivery catheter or retrieval device can attach. The pacemaker is delivered to the heart via femoral vein access (18-F sheath). The pacemaker is 42 mm long and 5.99 mm in diameter. It can be repositioned if necessary to achieve adequate sensing and pacing parameters by reattaching to the docking mechanism and unscrewing the helix. The device is currently a single chamber only with a unique rate response mechanism that uses the temperature of the surrounding blood in the RV to determine whether someone is exercising.
In the initial study including 33 patients, 70% of devices were implanted with no repositioning required, with an average procedure time of 28 minutes. Despite the large sheath required for access, no vascular complications (hematoma, pseudoaneurysm, or atrioventricular fistula) were noted. R-wave amplitude and pacing threshold improved from implant to the next day and were stable over 3-month follow-up. There were 2 complications (6%) including 1 serious adverse event. One patient had cardiac perforation requiring surgical repair, who then had a stroke on postoperative day 5 and died 2 weeks later. Another patient inadvertently had the device placed in the left ventricle via a patent foramen ovale. Once discovered on fluoroscopy, it was retrieved and implanted in the RV apex without any consequence. A third patient had the device removed 5 days after implant because the patient had rapid ventricular tachycardia (VT) with syncope and needed an implantable cardioverter-defibrillator. VT was not thought to be caused by the pacemaker as the patient went on to have recurrent VT after the pacemaker was removed. There are several concerns that will need to be answered by studies including larger numbers of patients. Currently this is only a single-chamber system and only 10%–20% of patients undergo single-chamber implant. Newer devices can be implanted in multiple chambers with some sort of communication system for coordinated activity. Also, the rate response mechanism uses the temperature of the surrounding blood, and it is unclear whether this will be adequate for more sedentary patients. It is also unclear whether the device will be able to be retrieved in the case of infection or after battery depletion. Therefore, for device “replacement” a new device may need to be implanted next to the old device, which is left in place. Initially, there was anxiety about device embolization to the pulmonary artery, but this did not occur in this small study. As with any new device or procedure, there can be unexpected consequences that will become evident only with further evaluation in larger numbers of patients.
Address reprint requests and correspondence: Ms Erica S. Zado, Section of Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Founders 9, 3400 Spruce St, Philadelphia, PA 19104. E-mail address: [email protected].
1547-5271/$-see front matter
http://dx.doi.org/10.1016/j.hrthm.2015.05.009