Background: Patients receiving a left ventricular (LV), transvenous lead for Cardiac Resynchronization Therapy (CRT) are typically implanted with a bipolar lead. With two electrodes, these leads typically pace the heart via four unique vectors. In some cases, these choices do not provide flexibility to mitigate phrenic nerve stimulation, improve responder rate, or reduce high capture thresholds. Therefore, a research investigation of a multi-electrode lead was undertaken to determine if additional, useful pacing vectors could be ascertained. Methods: Acute lead performance data was collected from a total of eight canines. After the coronary sinus was accessed with a Daig Alliance™ catheter, the prototype, multi-electrode LV lead was placed in an anterior branch of the coronary venous anatomy through the use of a stylet and/or guidewire. A St. Jude Medical active fixation lead was subsequently placed in the right ventricle. All pacing threshold, R-wave, and impedance values were collected using a pacing system analyzer (PSA) Results: A comparison of the electrical performance of the multi-electrode lead is shown in the table below. Up to 24 pacing vectors were interrogated during each acute study. A sub-set of 10 vectors is shown here to demonstrate the performance range and to compare this lead with the standard vectors offered by bipolar LV leads. Conclusions: The novel, multi-electrode LV lead offers the potential for several additional beneficial pacing vectors beyond the currently available electrode configurations. In these canines, low acute pacing thresholds were measured for 9 of the 10 vectors and R-wave sensing values were acceptably high for all choices. These research results suggest that a multi-electrode lead could provide benefit through its expanded range of pacing vectors. Further testing is in progress to determine the long-term performance of this type of multi-electrode lead.

The efficacy of the new St Jude Medical (SJM) Far-Field Signal Reduction (FSR) lead, based upon optimization of the tip-to-ring electrode spacing (1.1 mm) and surface areas, has been demonstrated by chronic animal studies and acute human testing. This study, for the first time, was designed to evaluate the chronic sensing and pacing performance of the new FSR leads in pacemaker patients.

of possible explanation is role of stress before the procedure.

Introduction: The purpose of this study was to examine a bipolar screw‐in lead (NL), specially designed to reduce unwanted far‐field R‐wave (FFRW) signal detection in an acute human setting. The results were compared with animal experiments. Methods: The newly designed lead with a center‐to‐center distance between the anode and cathode electrodes of 3.23 mm, corresponding to an inter‐electrode spacing of 1.1 mm was implanted in nine canines with a follow‐up of 6 months. Sensing of P waves, FFRW signals, pacing threshold, and impedance was measured at regular intervals. As a result of the positive outcome with the animal study, an acute human experiment was performed. In patients scheduled for conventional dual chamber pacemaker implantation, the NL was compared to a Tendril ® Model 1388T bipolar screw‐in lead (St. Jude Medical, CRMD, Sylmar, CA). Results: Utilizing a tip‐to‐ring distance of 1.1 mm, the optimum P wave to FFRW ratio was found in animal experiments. In the acute human tests in 15 patients, the mean P‐wave voltage of the 1388T lead of 3.30 ± 1.54 mV was slightly larger than that of the NL, at 2.55 ± 1.11 mV, but did not differ significantly (P = 0.13). The FFRW voltage of the 1388T lead was 0.62 ± 0.37 mV and was significantly greater from that of the NL, at 0.10 ± 0.08 mV (P < 0.0001). Pacing thresholds and pacing impedances were comparable. Conclusion: Animal testing results were reproducible in the acute human test setting. The lead reduced the paced FFRW signal amplitudes significantly, allowing for high atrial sensitivity settings but without sensing the FFRW. A robust P‐wave signal could be retained.

Background: A new insulation material for cardiac leads has been developed and evaluated. The new hybrid material, a chemical co-polymer of high performance silicone rubber and polyurethane known as SPC™, has shown significant performance and reliability improvements beyond that of currently used insulations. The new SPC provides robust physical attributes similar to polyurethane 55D, yet is soft and flexible like silicone rubber, but has a lower surface friction, allowing easier venous passage. Moreover, SPC is virtually immune to abrasion wear and cyclic crushing, thus having potential for reduced insulation failures in the rib-clavicle crush region and in lead-to-can interaction. Lastly, based upon 2-year animal studies, SPC is very biostable, showing virtually no degradation.

of possible explanation is role of stress before the procedure.

Background: Oversensing of Far Field R-Waves (FFRW) continues to pose problems in modern pacemakers. FFRW oversensing may lead to inappropriate mode switching to non-atrial tracking modes. This may lead to misdiagnosis of atrial fibrillation thereby complicating therapeutic decision making. A new research concept lead was developed which attenuates FFRW signals while maintaining robust near-field (P-Wave) signals acutely and chronically, and also maintains low stable, pacing thresholds and typical pacing impedances.

During the past 35 years, many technological advantages have been made in cardiac pacemaker leads and in the pulse generator-to-lead connector. Advances have included development of: various coiled wire conductors [1]; new fixation means such as tines, fins, and helix mechanisms [1,2]; advances in electrodes such as microporous surfaced electrodes, small surface area electrodes, electrodes with special shapes which enhance electrical fields and tissue ingrowth and steroid eluting electrodes [3, 4]; improved insultion such as “high-performance” or “extra tear-resistant” silicone rubbers, and various polyurethanes [5]; and improved, standardized connectors such as the recent “VS-1” and proposed “IS-1” standard connector designs [6]. These advances have improved the performance, reliability, and the ease of implantation of pacemaker leads and pulse generators dramatically. Perhaps however, historically, one of the most significant advances in pacemaking was the development of the transvenous pacemaker lead which made the therapy of cardiac pacing a relatively safe and easy procedure for virtually all patients [7].

The purpose of this study was to evaluate various new lead anchoring sleeve designs. These designs were intended to allow coaxial bipolar leads to be tied down and remain securely in position with minimal damage to the lead body, whether tied down with moderate or high tie forces. Axial grooves were made on the outer and/or inner walls of various anchoring sleeve designs. Anchoring sleeves made of extra tear resistant (ETR) platinum catalyzed and peroxide catalyzed (MDX) silicone rubber of various shore, hardness were tested on various Siemens Pacesetter (S-P) and other manufacturers' lead bodies. Tests to slide the sleeves were conducted with the leads in dry and wet conditions, and with and without the Fast-Pass (Siemens Pacesetter, Inc.) coating for lubriciousness. Tie-down deformation of coils was measured from x-ray photos. Mechanical tests and stress calculations were also done to evaluate the mechanical properties of the different lead bodies being tested. The test results showed that compared with existing sleeves, the new design MDX sleeves with axial grooves on the outer wall of the anchoring sleeves provided much lower resultant deformation (62%-84%) on leads when tied down tightly, and exhibited similar sliding forces. Also, it was determined that the MDX anchoring sleeves provided much improved slip forces of two to three times higher than the ETR sleeves. Tie-down damage can also be significantly reduced by strengthening lead bodies. With the protection of the new sleeves, the tie-down damage of S-P leads was the lowest among all the manufacturers' polyurethane or silicone leads tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Cardiovascular ElectrophysiologyVolume 1, Issue 4 p. 313-334 The Evolution of Low Threshold Leads GERALD C. TIMMIS M.D., Corresponding Author GERALD C. TIMMIS M.D. From the Division of Cardiovascular Diseases, Royal Oak, MichiganAddress for reprints: Gerald C. Timmis, M.D., Division of Cardiovascular Diseases, William Beaumont Hospital, 3601 West Thirteen Mile Road, Royal Oak, Michigan 48072Search for more papers by this authorJOHN HELLAND B.M.E., JOHN HELLAND B.M.E. Medtronic, Inc., Minneapolis, MinnesotaSearch for more papers by this authorDOUGLAS C. WESTVEER M.D., DOUGLAS C. WESTVEER M.D. Electrophysiology Laboratory, William Beaumont Hospital, Royal Oak, MichiganSearch for more papers by this authorJAMES STEWART M.D., JAMES STEWART M.D. Electrophysiology Laboratory, William Beaumont Hospital, Royal Oak, MichiganSearch for more papers by this authorSEYMOUR GORDON M.D., SEYMOUR GORDON M.D. From the Division of Cardiovascular Diseases, Royal Oak, MichiganSearch for more papers by this author GERALD C. TIMMIS M.D., Corresponding Author GERALD C. TIMMIS M.D. From the Division of Cardiovascular Diseases, Royal Oak, MichiganAddress for reprints: Gerald C. Timmis, M.D., Division of Cardiovascular Diseases, William Beaumont Hospital, 3601 West Thirteen Mile Road, Royal Oak, Michigan 48072Search for more papers by this authorJOHN HELLAND B.M.E., JOHN HELLAND B.M.E. Medtronic, Inc., Minneapolis, MinnesotaSearch for more papers by this authorDOUGLAS C. WESTVEER M.D., DOUGLAS C. WESTVEER M.D. Electrophysiology Laboratory, William Beaumont Hospital, Royal Oak, MichiganSearch for more papers by this authorJAMES STEWART M.D., JAMES STEWART M.D. Electrophysiology Laboratory, William Beaumont Hospital, Royal Oak, MichiganSearch for more papers by this authorSEYMOUR GORDON M.D., SEYMOUR GORDON M.D. From the Division of Cardiovascular Diseases, Royal Oak, MichiganSearch for more papers by this author First published: August 1990 https://doi.org/10.1111/j.1540-8167.1983.tb01632.xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume1, Issue4August 1990Pages 313-334 RelatedInformation

A transvenous pacing lead with a porous electrode which slowly elutes the steroid, dexamethasone sodium phosphate, has been developed. Previous investigations show low and constant stimulation thresholds persisting over at least the first two years post‐implantation. As it is not known whether this low threshold results from the steroid or electrode configuration, a double blind study was designed to compare the same electrode configuration with and without steroid over a 2‐year follow‐up period. There were ten patients in each group with similar age, sex, indications for pacing and implantation data. Regular measurements of postoperative pulse duration thresholds were performed using a customized VVIM pulse generator programmed to 1.5 V output. For the first two days post‐implantation, there were no statistical differences in the pulse duration thresholds between the two pacing leads. From 2 weeks to 2 years the pulse duration thresholds for the steroid leads remained almost constant, whereas the leads without steroid showed a typical rise. The difference in pulse duration thresholds between the two groups of leads from two weeks onwards confirmed that it was the steroid rather than the electrode configuration which prevented the rise in chronic stimulation threshold.