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Europace 11/2012; · 1.98 Impact Factor
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Europace 03/2012; 14(8):1220-1. · 1.98 Impact Factor
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ABSTRACT: Although Dr Albert Hyman in New York is believed to have built the first cardiac pacemaker in 1932, he acknowledges Dr Mark Lidwell in Sydney, Australia as having not only built a pacemaker, but also successfully used it to resuscitate a newborn infant in or before 1929. Fully implantable pacemakers, however, were not possible until 1958, following the development of the silicon transistor. Within three years of that first implant, a pulse generator attached to epicardial leads was implanted at the Royal Melbourne Hospital. About the same time, an engineer in Sydney with intermittent complete heart block who had received epicardial leads and an external pulse generator proposed a simple sensing circuit, leading to the design of the first demand pacing system. By the mid 1960s, physicians were inserting transvenous leads in the right ventricle attached to pulse generators implanted in the anterior abdominal wall. In 1963, an Australian pacemaker company, Telectronics, was founded in Sydney. This innovative company-designed many of the features of transvenous leads and pulse generators we take for granted today. Australia also played a leading role in the design or early evaluation of the lithium power source, lead fixation, steroid elution, automatic anti-tachycardia pacing algorithms and the minute ventilation rate adaptive sensor. This manuscript describes the challenges and frustrations of those pioneers: physicians, surgeons and biomedical engineers.
Heart Lung & Circulation 10/2011; 21(6-7):311-9. · 1.20 Impact Factor
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ABSTRACT: Transvenous pacing has revolutionized the management of patients with potentially life-threatening bradycardias and at its most basic level ensures rate support to maintain cardiac output. However, we have known for at least a decade that pacing from the right ventricle (RV) apex can induce left ventricle (LV) dysfunction, atrial fibrillation, heart failure, and maybe an increased mortality. Although pacemaker manufacturers have developed successful pacing algorithms designed to minimize unnecessary ventricular pacing, it cannot be avoided in a substantial proportion of pacemaker-dependent patients. Just as there is undoubted evidence that RV apical pacing is injurious, there is emerging evidence that pacing from the RV septum is associated with a shorter duration of activation, improved haemodynamics, and less LV remodelling. The move from traditional RV apical pacing to RV septal pacing requires a change in mindset for many practitioners. The anatomical landmarks and electrocardiograph features of RV septal pacing are well described and easily recognized. While active fixation is required to place the lead on the septum, shaped stylets are now available to assist the implanter. In addition, concerns about the stability and longevity of steroid-eluting active fixation leads have proven to be unfounded. We therefore encourage all implanters to adopt RV septal pacing to minimize the potential of harm to their patients.
Europace 08/2011; 14(1):28-35. · 1.98 Impact Factor
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ABSTRACT: A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2009 and compared to a similar survey conducted in 2005. There were contributions from 61 countries: 25 from Europe, 20 from the Asia Pacific region, seven from the Middle East and Africa, and nine from the Americas. The 2009 survey involved 1,002,664 pacemakers, with 737,840 new implants and 264,824 replacements. The United States of America (USA) had the largest number of cardiac pacemaker implants (225,567) and Germany the highest new implants per million population (927). Virtually all countries showed increases in implant numbers over the 4 years between surveys. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2005 survey, virtually all countries had increased the percentage of DDDR implants. Pacing leads were predominantly transvenous, bipolar, and active fixation. The survey also involved 328,027 ICDs, with 222,407 new implants and 105,620 replacements. Virtually all countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the USA (133,262) with 434 new implants per million population. This was the largest pacing and ICD survey ever performed, because of mainly a group of loyal enthusiastic survey coordinators. It encompasses more than 80% of all the pacemakers and ICDs implanted worldwide during 2009.
Pacing and Clinical Electrophysiology 06/2011; 34(8):1013-27. · 1.35 Impact Factor
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ABSTRACT: Prolonged right ventricular (RV) apical pacing produces dysynchronous ventricular contraction, which may result in left ventricular (LV) dysfunction, whereas septal pacing sites might reflect a more synchronous LV activation. This study examined a method of evaluating alternate RV pacing sites using a template scoring system based on measuring the angle of lead attachment in the 40° left anterior oblique (LAO) fluoroscopic view and its effect on altering the loop of lead in the RV.
Twenty-three consecutive patients for RV pacing were enrolled. Conventional active fixation leads were positioned in either the RV outflow tract (RVOT) or mid RV using a stylet designed for septal placement (Model 4140, St. Jude Medical, St. Paul, MN, USA). Using LAO cine fluoroscopy, a generous loop of lead was inserted into the RV chamber and the change in angle of attachment determined.
Successful positioning of pacing leads at the RVOT septum (18 patients) and mid-RV septum (five patients) was achieved. With introduction of more lead into the RV chamber, the angle of attachment in the LAO projection altered over a range of 6°-32° for all patients with a mean of 14.6 ± 6.6°. In 87% of patients, the range was predominantly within the same template score with only minor overlap into another zone.
This study shows that the angle of lead attachment in the RV is altered by introducing more lead, but in most cases, the template score remains the same. Further studies are required to determine the accuracy and efficacy of the templates.
Pacing and Clinical Electrophysiology 05/2011; 34(9):1080-6. · 1.35 Impact Factor
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Pacing and Clinical Electrophysiology 11/2010; 33(11):1293-7. · 1.35 Impact Factor
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ABSTRACT: Background: A pacemaker (PM) and Implantable Cardioverter-Defibrillator (ICD) Survey was undertaken in Australia and New Zealand for the calendar year 2009. Results and conclusions: For 2009, the number of new implants for Australia was 12,523 (11,850 in 2005) and 1277 for New Zealand (1134 in 2005). The number of new PM implants per million population was 565 for Australia (590 in 2005) and 299 for New Zealand (275 in 2005). Both countries had substantial increases in PM replacements. There were 446 biventricular PMs implanted in Australia (461 in 2005) and 45 in New Zealand (16 in 2005). Pulse generator types were predominantly dual chamber with 71% for Australia (72% in 2005) and 54% for New Zealand (51% in 2005). Transvenous pacing leads were overwhelmingly bipolar with marked increases in the use of active fixation leads; Australia 80% atrium, 75% ventricle and New Zealand 65% atrium, 62% ventricle. There was also a marked increase in the number of new ICDs implanted; Australia 3555 (2864 in 2005) and New Zealand 329 (134 in 2005). The new ICD implants per million population were 160 for Australia (142 in 2005) and 77 for New Zealand (33 in 2005). The usage of biventricular ICDs was 33% for Australia and 13% for New Zealand.
Heart Lung & Circulation 11/2010; 20(2):99-104. · 1.20 Impact Factor
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ABSTRACT: Prolonged right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction due to dysynchronous ventricular activation and contraction. Alternative RV pacing sites with a narrower QRS compared to RV pacing might reflect a more physiological and synchronous LV activation. The purpose of this study was to compare the QRS morphology, duration, and suitability of RV outflow tract (RVOT) septal and mid-RV septal pacing.
Seventeen consecutive patients with indication for dual-chamber pacing were enrolled in the study. Two standard 58-cm active fixation leads were passed to the RV and positioned in the RVOT septum and mid-RV septum using a commercially available septal stylet (model 4140, St. Jude Medical, St. Paul, MN, USA). QRS duration, morphology, and pacing parameters were compared at the two sites. The RV lead with less-satisfactory electrical parameters was withdrawn and deployed in the right atrium.
Successful positioning of the pacing leads at the RVOT septum and mid-RV septum was achieved in 15 patients (88.2%). There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites. The QRS duration in the RVOT septum was 151 ± 14 ms and in the mid-RV septum 145 ± 13 ms (P = 0.150).
This prospective observational study shows that septal pacing can be reliably achieved both in the RVOT and mid-RV with active fixation leads using a specifically shaped stylet. There are no preferences in regard to acute lead performance or paced QRS duration with either position.
Pacing and Clinical Electrophysiology 07/2010; 33(10):1169-73. · 1.35 Impact Factor
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Harry G Mond
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ABSTRACT: Prolonged right ventricular (RV) apical pacing is associated with progressive left ventricular dysfunction due to dysynchronous ventricular activation and contraction. RV septal pacing allows a narrower QRS compared to RV apical pacing, which might reflect a more physiological and synchronous ventricular activation. Previous clinical studies, which did not consistently achieve RV septal pacing, were not confirmatory and need to be repeated. This review summarizes the anatomy of the RV septum, the radiographic appearances of pacing leads in the RV, the electrocardiograph correlates of RV septal lead positioning, and the techniques and tools required for implantation of an active-fixation lead onto the RV septum. Using the described techniques and tools, conventional active-fixation leads can now be reliably secured to either the RV outflow tract septum or mid-RV septum with very low complication rates and good long-term performance. Even though physiologic and hemodynamic studies on true RV septal pacing have not been completed, the detrimental effects of long-term RV apical pacing are significant enough to suggest that it is now time to leave the RV apex and secure all RV leads onto the septum.
Pacing and Clinical Electrophysiology 04/2010; 33(7):888-98. · 1.35 Impact Factor
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ABSTRACT: The prognostic benefit of the implantable cardioverter-defibrillator (ICD) has been well established in multiple settings and its use is consequently widespread. Modern-day ICD systems use transvenous high-voltage leads to act as the interface between the heart and the generator, allowing for the sensing of a cardiac activity and the delivery of both bradycardia and tachycardia therapy, including high-voltage, high-current shocks. The ICD lead is in many ways the most fragile and critical component of the ICD system, and is subjected to more stress than any other implanted medical device. It has similar components to a pacing lead including tip and ring electrodes, fixation mechanism, conductors, insulators, and connector pins. In addition, it also contains the high-voltage shock coils that allow the delivery of defibrillation therapy to the cardiac tissue. The materials used to manufacture each of these components have undergone little evolution from their initial pacing lead-derived origin, but promising progress in this area is now occurring and better conductors and insulators have been developed. Lead body design continues to be multiluminal rather than coaxial, but various iterations of this basic paradigm continue to be investigated. In addition to miniaturization of the entire ICD lead, new industry standard lead connectors will also be introduced to reduce complexity and pocket bulk. However, long-term failure rates have been considerable, with lead failure related to both conductor and insulator malfunction. It is hoped that recent improvements in an ICD lead design and manufacture will result in a good functionality with a reliable long-term performance.
Pacing and Clinical Electrophysiology 10/2009; 32(10):1336-53. · 1.35 Impact Factor
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ABSTRACT: The detrimental effects of right ventricular (RV) apical pacing on left ventricular function has driven interest in alternative pacing sites and in particular the mid RV septum and RV outflow tract (RVOT). RV septal lead positioning can be successfully achieved with a specifically shaped stylet and confirmed by the left anterior oblique (LAO) fluoroscopic projection. Such a projection is neither always used nor available during pacemaker implantation. The aim of this study was to evaluate how effective is the stylet-driven technique in septal lead placement guided only by posterior-anterior (PA) fluoroscopic view.
One hundred consecutive patients with an indication for single- or dual-chamber pacing were enrolled. RV septal lead positioning was attempted in the PA projection only and confirmed by the LAO projection at the end of the procedure.
The RV lead position was septal in 90% of the patients. This included mid RV in 56 and RVOT in 34 patients. There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites.In the RVOT, 97% (34/35) of leads were placed on the septum, whereas in the mid RV the value was 89% (56/63).
The study confirms that conventional active-fixation pacing leads can be successfully and safely deployed onto the RV septum using a purposely-shaped stylet guided only by the PA fluoroscopic projection.
Pacing and Clinical Electrophysiology 10/2009; 33(1):49-53. · 1.35 Impact Factor
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ABSTRACT: Pacing from right ventricular (RV) septal sites has been suggested as an alternative to RV apical pacing in an attempt to avoid long-term adverse consequences on left ventricular function. Concern has been raised as to the relationship of the left anterior descending coronary artery (LAD) to pacing leads in these positions.
We retrospectively analyzed three cases in which patients with RV active-fixation leads in situ also had coronary angiography. Multiple fluoroscopic views were used to determine the relationship of the lead tip at various pacing sites to the coronary arteries. A lead placed on the anterior wall was in close proximity to the LAD, whereas septal and free wall positioning was not.
Placement of RV active-fixation leads on the septum avoids potential coronary artery compromise.
Pacing and Clinical Electrophysiology 08/2009; 32(7):894-7. · 1.35 Impact Factor
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ABSTRACT: The detrimental effects of right ventricular apical pacing on left ventricular function has driven interest in selective site pacing, predominantly on the right ventricular outflow tract (RVOT) septum. There is currently no information on long-term ventricular lead electrical performance from this site.
A total of 100 patients with ventricular lead placement on the RVOT septum undergoing pacemaker implantation for bradycardia indications were analyzed retrospectively. Lead positioning was confirmed with the use of fluoroscopy. Long-term (1 year) follow-up was obtained in 92 patients. Information on stimulation threshold, R-wave sensing, lead impedance, and lead complications were collected.
Lead performance at the RVOT septal position was stable in the long term. Ventricular electrical parameters were acceptable with stable long-term stimulation thresholds, sensing, and impedance for all lead types. One-year results demonstrated mean stimulation threshold of 0.71 +/- 0.25 V, mean R wave of 12.4 +/- 6.05 mV, and mean impedance values of 520 +/- 127 Omega. There were no cases of high pacing thresholds or inadequate sensing. Conclusions: This study confirms satisfactory long-term performance with leads placed on the RVOT septum, comparable to traditional pacing sites. It is now time to undertake studies to examine the long-term hemodynamic effects of RVOT septal pacing.
Pacing and Clinical Electrophysiology 03/2009; 32(2):172-6. · 1.35 Impact Factor
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ABSTRACT: The first cardiac pacemaker implants occurred in the late 1950s and involved insertion of epicardial or epimyocardial leads and abdominal pulse generators. By the mid 1960s, cardiologists were making attempts to insert transvenous leads into the right ventricle. These early unipolar leads had large, polished, high polarization electrodes, no fixation device, and no lumen in which to place a stylet for lead positioning. The lead implantation procedures were usually long and the irradiation to both patient and operator excessive. Pulse generators were powered by zinc-mercury cells, which were large, unreliable, and prone to sudden output failure. Postoperative complications such as lead dislodgement, exit block, and premature power source failure were very common with most patients requiring further surgery within a year. Little has been written of this period and in particular the experiences of the operators, such that today's pacemaker implanters have virtually no knowledge of this bygone era. This historical report by four Australian cardiologists details the operative procedures and follow-up management of those original pacemaker recipients.
Pacing and Clinical Electrophysiology 10/2008; 31(9):1192-201. · 1.35 Impact Factor
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ABSTRACT: A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2005 and compared to a similar survey conducted in 2001.
There were contributions from 43 countries: 16 from Europe, 13 from the Asia Pacific region, four from the Middle East and Africa, and 10 from the Americas. The United States had the largest number of cardiac pacemaker implants (223,425). Virtually all countries showed increases in implant numbers over the 4 years. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker, although indications data were not available for large implanting regions such as Europe, Australia, and the United States. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2001 survey, virtually all countries had increased the percentage of DDDR implants, together with a fall in single-lead VDD implants. Pacing leads were predominantly transvenous, bipolar, and passive fixation. There was, however, an increased use of active fixation leads in both the atrium and ventricle. All countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the United States (119,121) with 401 new implants per million population.
Although the numbers of participating countries have fallen, there still remains a group of loyal enthusiastic survey coordinators. Recruitment of new coordinators will hopefully continue in order to obtain a fully global experience of cardiac pacing and ICD usage.
Pacing and Clinical Electrophysiology 10/2008; 31(9):1202-12. · 1.35 Impact Factor
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ABSTRACT: Background:A worldwide cardiac pacing and implantable cardioverter-defibrillator (ICD) survey was undertaken for calendar year 2005 and compared to a similar survey conducted in 2001.Results:There were contributions from 43 countries: 16 from Europe, 13 from the Asia Pacific region, four from the Middle East and Africa, and 10 from the Americas. The United States had the largest number of cardiac pacemaker implants (223,425). Virtually all countries showed increases in implant numbers over the 4 years. High-degree atrioventricular block and sick sinus syndrome remain the major indications for implantation of a cardiac pacemaker, although indications data were not available for large implanting regions such as Europe, Australia, and the United States. There remains a high percentage of VVI(R) pacing in the developing countries, although compared to the 2001 survey, virtually all countries had increased the percentage of DDDR implants, together with a fall in single-lead VDD implants.Pacing leads were predominantly transvenous, bipolar, and passive fixation. There was, however, an increased use of active fixation leads in both the atrium and ventricle. All countries surveyed showed a significant rise in the use of ICDs with the largest implanter being the United States (119,121) with 401 new implants per million population.Conclusions:Although the numbers of participating countries have fallen, there still remains a group of loyal enthusiastic survey coordinators. Recruitment of new coordinators will hopefully continue in order to obtain a fully global experience of cardiac pacing and ICD usage.
Pacing and Clinical Electrophysiology 08/2008; 31(9):1202 - 1212. · 1.35 Impact Factor
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ABSTRACT: BACKGROUND: A pacemaker (PM) and implantable cardioverter-defibrillator (ICD) survey was undertaken in Australia (Au) and New Zealand (NZ) for 2005. RESULTS AND CONCLUSIONS: Compared to the 2001 survey, significant increases in implantation numbers were recorded. For 2005, the total new PMs implanted was 11,850 in Au (9498 in 2001) and 1134 in NZ (914 in 2001). The number of new PM implants per million population was 590 in Au (486 in 2001) and 275 in NZ (245 in 2001). Biventricular PMs were documented for the first time with 461 implants in Au and 16 in NZ. Pulse generator types were predominantly dual chamber with 73% in Au (70% in 2001) and 51% in NZ (54% in 2001). Pacing leads were overwhelmingly transvenous and bipolar with an increase in the use of active fixation leads in preference to tined leads. There was a marked increase in the use of ICDs with 2864 new implants in Au (956 in 2001) and 134 in NZ (86 in 2001). The new ICD implants per million population were 142 in Au (49 in 2001) and 33 in NZ (23 in 2001). ICDs were 35% biventricular in Au and 10% in NZ. The Au Northern Territory is included for the first time.
Heart Lung & Circulation 05/2008; 17(2):85-9. · 1.20 Impact Factor
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ABSTRACT: There is marked heterogeneity in right ventricular outflow tract (RVOT) pacemaker lead placement using conventional leads. As a result, we have sought to identify a reproducible way of placing a ventricular lead onto the RVOT septum.
A major determinant is the shape of the stylet used to deliver the active-fixation lead. We compared stylet shapes and configurations in patients who initially had a ventricular lead placed onto the anterior or free wall of the RVOT and then had the lead repositioned onto the septum. All leads were loaded with a stylet fashioned with a distal primary curve to facilitate delivery of the lead to the pulmonary artery, then using a pullback technique the lead was retracted to the RVOT. All lead placements were confirmed by fluoroscopy and electrocardiography. Anterior or free wall placement was achieved by the stylet having either the standard curve or an added distal anterior angulation. In contrast, septal lead positioning was uniformly achieved by a distal posterior angulation of the curved stylet. This difference in tip shape was highly predictive for septal placement (P < 0.001). With septal pacing, a narrower QRS duration was noted, compared to anterior or free wall pacing (136 vs 155 ms, P < 0.001). All pacing parameters were within acceptable limits.
Using appropriately shaped stylets, pacing leads can now be placed into specific positions within the RVOT and in particular septal pacing can be reliably and reproducibly achieved. This is an important step in the standardization of lead placement in the RVOT.
Pacing and Clinical Electrophysiology 08/2007; 30(8):942-7. · 1.35 Impact Factor
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ABSTRACT: BACKGROUND: Pacing from the right ventricular apex is associated with long-term adverse effects on left ventricular function. This has fuelled interest in alternative pacing sites, especially the septal aspect of the right ventricular outflow tract (RVOT). However, it is a common perception that septal RVOT pacing is difficult to achieve. METHODS AND RESULTS: In this article, we will review the anatomy of the RVOT and discuss the importance of standard radiographic views and the 12-lead electrocardiogram in aiding lead placement. We will also describe a method utilizing a novel stylet shape, whereby a conventional active-fixation, stylet-driven lead can be easily and reliably deployed onto the RVOT septum.
Pacing and Clinical Electrophysiology 05/2007; 30(4):482-91. · 1.35 Impact Factor
