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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. [ABSTRACT FROM AUTHOR]

With the dawn of a new millennium, physicians' demands for very thin transvenous leads able to be positioned in nontraditional sites like the Bachmann's bundle, the high and mid-right ventricular septum, and the His bundle have created new and exciting challenges for lead engineers. Bipolar leads can now be as thin and reliable as unipolar leads. Cathode electrodes are very small, porous, and demonstrate high impedance. To optimize stimulation thresholds, steroid-eluting passive- and active-fixation electrodes have become popular for use in the atrium and ventricle. To create thin lead body diameters, new insulation and conductor materials and lead body designs are necessary. Hybrid medical materials having the best features of silicone rubber and polyurethane will allow for reliable insulation. Conductor cables instead of helical coils permit strong thin diameter leads to be designed. Transvenous lead implantation using the traditional stylet may not be possible with thin diameter leads, necessitating the use of sophisticated workstations using steerable catheters to guide these new active-fixation leads to selective sites in the right heart. The pacing lead of the future may be very different from the one used today. Ironically, it will have features and implantation techniques similar to the transvenous leads designed prior to the use of the stylet. We are now approaching full circle in lead development, retracing the footprints of the early implanters of three and a half decades ago. [ABSTRACT FROM AUTHOR]

Selective site right ventricular pacing has been suggested as an approach to reduce the incidence of ventricular dysfunction and hopefully influence the morbidity resulting from traditional right ventricular apical pacing. Pacing from the right ventricular apex allows a stable ventricular rate, and together with atrial pacing and sensing, helps maintain atrioventricular synchrony but does not allow physiological activation of the left ventricle. Traditional atrial pacing sites like the right atrial appendage may encourage atrial tachyarrhythmias, whereas lead placement in right atrial septal sites may reduce the frequency of symptomatic atrial tachyarrhythmia episodes, especially when combined with prevention algorithms. Researchers attempting to pace the heart from these selective sites have been hindered by the lack of uniform definitions of where these sites actually lie and the inadequacy of tools to consistently reach these locations and verify correct placement. This lack of definition consensus may have contributed to the apparent conflict of data, particularly in the right ventricle. There is an urgent need for a standardization of terms and identifying measures for selective pacing sites. [ABSTRACT FROM AUTHOR]

Although the original atrial pacing leads were passive fixation and J shaped for right atrial appendage placement, the subsequent development of the active fixation screw-in lead found favor because of a perceived low incidence of lead dislodgment and a wider selection of atrial pacing sites. A bipolar atrial lead study was undertaken to compare the long-term atrial implant data in 215 patients. Study leads comprised one passive fixation, steroid-eluting lead (Medtronic CapSure SP, 119 patients) and three nonsteroid-eluting leads; two active fixation (Medtronic BISPING model 4058, 30 patients; and Telectronics ACCUFIX model 330-801, 44 patients) and one passive fixation (Telectronics ENCOR model 330-854, 22 patients). Bipolar atrial voltage stimulation thresholds and electrograms were measured using the Telectronics META DDDR immediately postimplantation, and at 1-, 3-, 6-, 12-, and 18-month follow-up. There were 135 males and the mean age 68 years. The incidence of lead dislodgment was 4% for active fixation and 2% for passive fixation. All nonsteroid leads showed a typical rise in stimulation threshold with the highest being the ACCUFIX followed by the BISPING and ENCOR. The steroid-eluting CapSure SP, however, demonstrated a flat response with 98% of leads at 18 months having a value < or = 1.3 volts allowing voltage programming to 2.5 volts (2:1 safety ratio). Telemeted electrograms showed no differences for all leads at all visits. For low voltage atrial pacing with a low incidence of dislodgment and satisfactory atrial sensing, the steroid-eluting passive fixation lead is superior to all nonsteroid-eluting leads. [ABSTRACT FROM AUTHOR]

Background: Heartbeat International is a little-known 501(c)(3) charitable organization, which for the past 25 years has been responsible for the implantation and follow-up of cardiac implantable electronic devices in over 9000 indigent recipients in predominantly developing countries. Although the concept was founded in Guatemala over 30 years ago, it took the vision and drive of Dr. Henry D. McIntosh, M.D., M.A.C.C, to create Heartbeat International in 1984.Discussion: The organization works through Pacemaker Banks established by local Rotary International chapters and other civic organizations in 24 countries over four continents and is dependent on the generosity of the implantable device manufacturers and teams of dedicated physicians and hospital personnel in the countries of operation. Since the vast majority of personnel are voluntary, 90 cents of every donated dollar directly supports the provision, implantation of devices, and follow-up care. Each US$500 provides a pacemaker to one needy patient. The organization's co-mission is also to educate and train implanting physicians in pacing and implantable cardioverter-defibrillator technology. The program remains dependent on the pacemaker manufacturers, who work in an environment of regulatory constraint and economic imperatives. With an ever growing demand for these devices, Heartbeat International will in the future need to increase its operating budget to purchase implantable inventory. [ABSTRACT FROM AUTHOR]

This report describes two electrocardiograms (ECGs) showing unusual manifestations of left anterior hemiblock (LAH). One revealed different degrees of incomplete LAH and the other documented the occurrence of 2:1 LAH. Understanding different degrees of LAH helps to interpret the ECG with regard to intraventricular conduction disorders and other ECG abnormalities., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The fusion of narrow-QRS sinus-generated beats with end-diastolic ventricular extrasystoles occurring in bigeminy can produce an electrocardiographic pattern difficult to differentiate from parasystole. Such an ECG should not be interpreted as 2:1 RBBB because of the variability of the PR intervals., Competing Interests: Authors declare no conflict of interests for this article., (© 2023 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Heart Rhythm Society.)

The well-defined concept of aberrant ventricular conduction was introduced over 100 years ago and, despite advances in cardiac physiology and electrophysiologic testing, it is still widely misunderstood. Aberrant ventricular conduction is due to physiologic refractoriness of the His-Purkinje system and in most cases does not reflect underlying conduction system disease. Electrophysiologically, aberrant ventricular conduction can manifest with premature atrial ectopics, the Ashman phenomenon with atrial tachyarrhythmias, concealed conduction, echo beats and with the sinus mechanism including rate dependent bundle branch block, bradycardia dependent bundle branch block and early sinus beats. It is important to recognise aberrant ventricular conduction in the context of a broad complex tachycardia, as the differentiation between supraventricular tachyarrhythmias with aberrant ventricular conduction and ventricular tachyarrhythmias carry different therapeutic and prognostic implications. This review will define the ECG footprints of aberrant ventricular conduction to allow accurate ECG interpretation., Competing Interests: Conflicts of Interest None., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

Background: A cardiac implantable electronic device (CIED) survey was undertaken in Australia and New Zealand for calendar year 2021. The survey involved pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). The survey was conducted on the 50 th anniversary of the first survey for both Australia and New Zealand in 1972; that initial survey being conducted by two of the current authors., Results and Conclusions: For 2021, there were 19,410 PMs (17,971 in 2017) sold in Australia for new implants and 2,282 (1,811 in 2017) sold in New Zealand. The number of new PM implants per million population was 755 for Australia (745 in 2017) and 446 for New Zealand (384 in 2017). Unlike previous recent surveys, the percentage of PM replacements compared to total sales in both Australia and New Zealand rose. Pulse generator types implanted were predominantly dual chamber; Australia 77% (73% in 2017) and New Zealand 70% (68% in 2017). There were 1,509 biventricular PMs implanted in Australia (1,247 in 2017) and 172 in New Zealand (118 in 2017). Transvenous pacing leads were >90% active fixation in the atrium and ventricle. There was an increase in ICD usage with Australia 4,519 new implants (4,212 in 2017) and New Zealand 449 (396 in 2017). New ICD implants per million population were 187 for Australia (175 in 2017) and 88 for New Zealand (90 in 2017). For the first time the survey included implantable event monitors with 6,933 being implanted in Australia. However, for proprietary reasons, survey figures for subcutaneous implantable defibrillators, leadless pacemakers and conduction system pacing have not been included. Both Australia and New Zealand have high PM and ICD implant numbers compared to the rest of the Asia Pacific region., (Crown Copyright © 2022. Published by Elsevier B.V. All rights reserved.)

The 12-lead resting electrocardiograph (ECG) of a patient with an implanted cardiac pacemaker is a snapshot of cardiac electrical activity at the time of recording and may provide valuable information on both pacemaker function and malfunction, as well as identifying the position of pacing leads in the heart. The traditional site for atrial pacing is within or adjacent to the right atrial appendage and paced P waves on the ECG have a normal frontal plane axis, whereas the traditional site for ventricular pacing is at the right ventricular apex with the ECG demonstrating a left bundle branch block configuration and a left axis. More recently, ventricular leads and to a lesser extent, atrial leads have been positioned in alternate non-traditional sites resulting in 12-lead ECG appearances which have characteristic features, that are generally poorly recognised. Left ventricular pacing results in a right bundle branch block configuration and an axis dependent on the position of the lead in the ventricle. This review will describe the ECG patterns of pacing lead positions in the right atrium and ventricle as well as positions in the left ventricle, whether intentional or unintentional., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

With the recognised physiologic value of dual chamber pacing, there was, at the commencement of the 1980s, an intense search for sensors to enable ventricular pacemakers to alter the pulse repetition rate in response to physiologic demand. Manufacturers fell into two main groups; those who chose highly physiologic sensors often requiring special pacing leads and those whose sensors allowed a standard pacing lead. Thirteen (13) sensors for rate adaptive pacing progressed at least to human investigational studies. Eventually the activity sensor, which responded quickly to exercise, but not to emotional stimuli or pyrexia and used a standard lead would predominate, with all manufacturers eventually accepting what was the least physiologic sensor investigated. The activity-based rate response was not dependent on cardiac or pulmonary disease, which could nullify the response with many of the other sensors. Three (3) other sensors survived that period and are still available today; minute ventilation, closed loop stimulation and central venous temperature, with the first two incorporated with activity as dual sensor systems. This review will outline the development of all the sensors used for rate adaptive pacing., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

In 1963, soon after the first ventricular pacemakers were implanted at the Royal Melbourne Hospital, attempts were made to identify impending pacing failure, thus preventing sudden death in these very vulnerable patients. By 1970, patient numbers had increased, a formal regular pacemaker clinic was established, and guidelines and protocols developed. The clinic was staffed by a physician, a biomedical engineer and cardiac technicians. The unipolar, asynchronous, non-programmable pulse generators were powered by mercuric oxide/zinc batteries and implanted in the abdomen, using either transvenous or epimyocardial leads. Although, pulse generators were electively replaced at 3 years, most had already been replaced because of power source depletion, electronic failure or lead issues. Testing in all patients involved an electrocardiographic rhythm strip and electronic analysis of the stimulus artefact using a calibrated high-speed storage oscilloscope. Results were compared to previous studies and significant changes were interpreted as impending power source depletion. As a result of this testing, 97% of cases of impending power source depletion were detected prior to failure. These findings allowed testing each 4 months and for pulse generator life to be extended beyond three years. With ventricular triggered pulse generators, new testing procedures were designed. With time, visiting regional centres and clinical evaluation of new products became important functions of the clinic., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

Programmability is a stable, reversible change in the operating parameters of a cardiac implantable electronic device. The era of non-invasive programming began in 1972, with the development of a dedicated hand-held battery-operated device. Prior to this, there had been crude attempts, involving invasive procedures or a magnet, to change the pacemaker operating parameters. A non-invasive programming system requires an implanted pulse generator and an external programmer, communicating via an energy link. This was initially a pulsed magnetic field allowing opening and closing of a reed switch in the pulse generator in synchrony with the pulses. Soon after, radiofrequency communication was introduced and involved transmission of pulsing on-off radiofrequency bursts, which allowed complex encoding, that recognised the implanted hardware, prevented mis-programming, had security features and confirmed successful programming. As programming became more complex and sophisticated, programmers evolved into desktop models with programming wands and printers. By 1978, multiprogrammable programmers with bidirectional telemetry were introduced and became a driving force in the development of new cardiac implantable technologies and devices., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

Cardiac pacing from the apex of the right ventricle has been shown to result in left ventricular dysfunction, atrial fibrillation, and increased mortality. To counter these effects, one of the strategies developed is avoidance of ventricular pacing when not necessary, using programmable algorithms to minimize ventricular pacing. Seven algorithms are available from 5 manufacturers. Four of the manufacturers have mode conversion algorithms that pace AAI(R) but, in the presence of failed atrioventricular (AV) conduction, demonstrate algorithm-offset and convert to DDD(R) with ventricular pacing. Three manufacturers do not have mode conversion but rather AV extension to encourage AV conduction. Each of these algorithms has a unique design and, when ventricular pacing is present, will regularly schedule conduction testing to encourage AV conduction and hence algorithm-onset. All of these algorithms seem to violate the rule of AV conduction by allowing the AV delay for sensed ventricular events to be longer than for ventricular paced events. The result is frequently bizarre electrocardiographic (ECG) appearances that often are unique to the company's algorithm but also suggest pacemaker malfunction. This review highlights and illustrates the features of these algorithms as they appear on ECG, and discusses other situations that result in unintended ventricular pacing., (Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.)

Ventricular ectopics, also known as ventricular extrasystoles, premature ventricular contractions or complexes (PVC) and ventricular premature depolarisations (VPD) are beats arising from within the ventricles. When they occur in groupings such as bigeminy, trigeminy, couplets and triplets they are referred to as ventricular ectopy. The electrocardiographic (ECG) footprints of a ventricular ectopic include a broad (>110 ms), premature, ventricular complex (QRS deflection); no evidence of pure atrioventricular (AV) conduction; a full, more than, or less than compensatory pause; and discordant QRS and T wave axis. Ventricular ectopy is a very common finding on Holter monitoring at all ages, but particularly in the elderly. In the otherwise normal heart, ventricular ectopy is generally infrequent and a benign finding, but in patients with heart disease, they may be a harbinger to more serious ventricular tachyarrhythmias. In this review, the range and manifestations of ventricular ectopy will be explored in detail with ECG examples., (Copyright © 2020 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Atrial ectopics, also known as a premature atrial complexes (PAC) or atrial premature depolarisations (APD), are supraventricular beats arising from a focus other than the sinus node. Because the various foci provide an array of electrocardiographic (ECG) appearances, an extensive, but confusing nomenclature has developed. Atrial ectopics are a very common finding on Holter ECG monitoring at all ages, the incidence increasing in frequency with age. In the otherwise normal heart, they are generally infrequent and an innocent finding, but in patients with heart disease, they may be a harbinger to more serious atrial tachyarrhythmias. In this review, the ECG footprints of atrial ectopy will be defined. These footprints include prematurity and P wave morphology. The associated features of variable atrioventricular (AV) conduction, variable post-ectopic pauses and variable QRS morphology due to aberrancy will also be discussed. Each of these features will be explained in detail with ECG examples., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

Corporeal and particularly extra-corporeal interference is a very common problem encountered with both resting electrocardiograph (ECG) tracings and ambulatory recordings. The interference may be either electrical or mechanical and if severe, may affect the interpretation of the tracings. The interference, seen as artefact, can be divided into obvious, subtle or complicated. Obvious artefact may result from poor electrode attachment or body motion, whereas electrical interference is predominantly 50 or 60 Hz alternating current or radiofrequency waves from power lines, electrical equipment, mobile phones, fluorescent lights and electrical diathermy. Careful attention to the application of electrodes and finding the best environment for performing a 12-lead ECG will eradicate most interference. When subtle, the artefact can mimic cardiac arrhythmias, leading to incorrect interpretation of the tracings. There is also a complicated interference group, usually due to implanted cardiac electronic pacing devices and neurostimulators. These create persistent artefact, which may result in repeated unsuccessful attempts at procuring an artefact free tracing. This manuscript will describe the genesis of interference, how an ECG machine or monitor deals with interference and will discuss the common causes of interference. The characteristic patterns will be described and clues provided on how to differentiate subtle artefact from cardiac arrhythmias., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

Background: A cardiac implantable electronic device (CIED) survey was undertaken in Australia and New Zealand for calendar year 2017 and involved pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs)., Results and Conclusions: For 2017, there were 17,971 (15,203 in 2013) new PMs sold in Australia and 1,811 (1,641 in 2013) implanted in New Zealand. The number of new PM implants per million population was 745 for Australia (652 in 2013) and 384 for New Zealand (367 in 2013). In both Australia and New Zealand, the number of PM replacements fell as a result of improved power source service life. Pulse generator types implanted were predominantly dual chamber; Australia 73% (74% in 2013) and New Zealand 68% (59% in 2013). There were 1,247 biventricular PMs implanted in Australia (661 in 2013) and 118 in New Zealand (83 in 2013). Transvenous pacing leads were overwhelmingly active fixation in both the atrium and ventricle. In Australia there was an increase in ICD usage with 4,212 new implants (3,904 in 2013), but a small fall in New Zealand to 396 (423 in 2013). The new ICD implants per million population were 175 for Australia (167 in 2013) and 90 for New Zealand (95 in 2013). There was a small reduction in biventricular ICDs in both Australia (2,195) and New Zealand (111)., (Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.)

Modern cardiac pacing systems have sophisticated software to document, evaluate and record intrinsic and paced rhythms as well as correct pacing abnormalities and rhythm disturbances by applying algorithms, which are generally company specific. To the cardiologist and technologist, these algorithms may be difficult to interpret on both the 12-lead electrocardiograph (ECG) and Holter ambulatory monitoring recordings, which are usually performed because of patient symptoms or physician concern. The tracings may appear bewildering and mimic pacemaker malfunction, thus leading to unnecessary tests or even surgery. This review will define the common programmed pacemaker modes and describe a range of ECG appearances of normal pacemaker function during the application of testing, correcting or therapy algorithms., (Copyright © 2018. Published by Elsevier B.V.)

In 1899, Karel Frederik Wenckebach described a cardiac arrhythmia with periodic dropped beats now referred to as a Wenckebach sequence. This was later shown to be due to a block in the atrioventricular node, but today, we identify Wenckebach sequences throughout the heart with most being recognised on the surface electrocardiograph as characteristic footprints. This manuscript will revisit Wenckebach atrioventricular block, the typical features of which only occur in about 15% of cases, with the remainder atypical. Earlier reports regarded Wenckebach atrioventricular sequences as rare as they are only occasionally seen on the surface 12-lead electrocardiograph. Today, however, with the increased use of ambulatory Holter monitoring, Wenckebach atrioventricular sequences occur in 4-6% of all traces and are particularly common at night in the young. Most, but not all cases are benign and the clinical spectrum will be reviewed. Atypical Wenckebach atrioventricular sequences are a complex group which will be analysed in detail with a broad range of illustrations. Outside the atrioventricular conducting system, such as in the sinus node, Wenckebach sequences may not be obvious as they are partially hidden from the electrocardiographic tracing. However, by understanding the sequence footprints, clues are available in interpreting tracing with periodic pauses. Dual chamber paced rhythms may show Wenckebach sequences due to electronic control of the atrioventricular delay. Rarely exit blocks at the cellular level in the atrium, ventricle or at the pacing electrode-tissue interface can demonstrate Wenckebach sequences recognised on the surface electrocardiograph., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Since its introduction as a clinical investigative tool, the 12-lead electrocardiograph (ECG) has been the gold standard for recognition of cardiac arrhythmias. The resting 12-lead ECG, however, gives only a rhythm snapshot in time, whereas arrhythmias maybe short-lived, paroxysmal and even asymptomatic making documentation in many patients very difficult. To overcome this, ambulatory ECG monitoring has been developed as a means of recording the ECG in patients over a set period of time, whether it be short-, medium- or long-term. With the miniaturisation of recording devices and advances in solid state technology, there has been a recent revolution in hardware design, so that the boundaries between these time-dependent devices have become blurred. Not surprisingly, the indications for monitoring have broadened as the quality and range of monitoring devices have become available. In this review, the indications for ambulatory ECG monitoring with emphasis on non-arrhythmic indications such as ST segment analysis, heart rate variability, signal averaged ECGs, diurnal QT and QTc analysis, obstructive sleep apnoea and vectorcardiography will be discussed. Also, the types of electrode systems used, lead placement, monitoring hardware, data collection, analysis and presentation as well as cost effectiveness of the investigation will be covered., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

The transvenous implantation of cardiac devices may sometimes cause serious complications involving the coronary arteries. The left anterior descending artery may be injured during nonapical right ventricular implantation while a right atrial lead may injure the right or circumflex coronary artery. Injury of a left internal mammary graft to a coronary artery may cause myocardial infarction.

Background: Malposition of electrocardiograph (ECG) leads is poorly recognised even by cardiologists who report tracings. When ECG tracings are regularly performed by doctors, nurses or technicians, lead malposition is very uncommon particularly if the operator can also interpret the findings. However, a significant proportion of 12-lead ECG tracings are today performed in a doctor's surgery or by private pathology services, often in haste without sufficient attention to correct lead positioning. As a result, a variety of malposition combinations occur, which in turn may confuse the interpreter of the ECG tracing, leading to incorrect diagnoses., Objectives: To investigate various combinations of ECG lead malposition and determine if characteristic findings can be summarised into identifiable footprints., Methods: In 10 normal subjects, 12-lead ECGs were performed with normal lead positioning as well as six limb lead malpositions and reversal of chest leads., Results: In all subjects, there was consistency in the ECGs performed allowing the creation of five characteristic and easily identifiable footprints., Conclusions: A summary of the footprints of ECG lead malposition should be readily available for those who perform ECGs, those who interpret the tracings and those responsible for clinical care., (Copyright © 2015 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Damage to the coronary arteries and related structures from pacemaker and implantable cardioverter-defibrillator lead implantation is a rarely reported complication that can lead to myocardial infarction and pericardial tamponade that may occur acutely or even years later. We summarize the reported cases of injury to coronary arteries and related structures and review the causes of troponin elevation in the setting of cardiac implantable electronic device implantation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: A pacemaker (PM) and implantable cardioverter-defibrillator (ICD) survey was undertaken in Australia and New Zealand for calendar year 2013., Results and Conclusions: For 2013, PMs sold as new implants in Australia was 15,203 (12,523 in 2009) and implanted in New Zealand were 1,641 (1,277 in 2009). The number of new PM implants per million population 652 for Australia (565 were in 2009) and 367 for New Zealand (299 in 2009). Although PM replacements rose in New Zealand, there was a fall in Australia as a result of improved power source service life. Pulse generator types sold in Australia were predominantly dual chamber 74% (71% in 2009) and implanted in New Zealand 59% (54% in 2009). There were 661 biventricular PMs implanted in Australia (446 in 2009) and 83 in New Zealand (45 in 2009). Transvenous pacing leads were overwhelmingly bipolar with preferences for active fixation leads, although, since 2009, there has been a minor resurgence in Australia of passive fixation lead usage in the atrium from 20 to ∼24%. There was also a marked increase in the ICD implants with 3904 new implants in Australia (3555 in 2009) and 423 in New Zealand (329 in 2009). The new ICD implants per million population were 167 for Australia (160 in 2009) and 95 for New Zealand (77 in 2009). Biventricular ICD implants increased significantly in both Australia (2211) and New Zealand (118)., (Published by Elsevier B.V.)

Although the first power source for an implantable pacemaker was a rechargeable nickel-cadmium battery, it was rapidly replaced by an unreliable short-life zinc-mercury cell. This sustained the small pacemaker industry until the early 1970s, when the lithium-iodine cell became the dominant power source for low voltage, microampere current, single- and dual-chamber pacemakers. By the early 2000s, a number of significant advances were occurring with pacemaker technology which necessitated that the power source should now provide milliampere current for data logging, telemetric communication, and programming, as well as powering more complicated pacing devices such as biventricular pacemakers, treatment or prevention of atrial tachyarrhythmias, and the integration of innovative physiologic sensors. Because the current delivery of the lithium-iodine battery was inadequate for these functions, other lithium anode chemistries that can provide medium power were introduced. These include lithium-carbon monofluoride, lithium-manganese dioxide, and lithium-silver vanadium oxide/carbon mono-fluoride hybrids. In the early 1980s, the first implantable defibrillators for high voltage therapy used a lithium-vanadium pentoxide battery. With the introduction of the implantable cardioverter defibrillator, the reliable lithium-silver vanadium oxide became the power source. More recently, because of the demands of biventricular pacing, data logging, and telemetry, lithium-manganese dioxide and the hybrid lithium-silver vanadium oxide/carbon mono-fluoride laminate have also been used. Today all cardiac implantable electronic devices are powered by lithium anode batteries., (©2014 Wiley Periodicals, Inc.)

The electrode-tissue interface is that area lying between the cathode of a low-voltage implantable pacemaker or cardioverter-defibrillator (ICD) lead and the endocardium or epi-myocardium of the cardiac chamber being paced. The electrical stimulus that is delivered to this interface is responsible for myocyte depolarization with consequent cardiac contraction. The process by which this occurs is reasonably well understood and any explanation requires a basic understanding of the physics and cellular electrophysiology of pacing. The effective and efficient delivery of electrical energy to the myocardium via the lead is dependent on many factors to be discussed in this review. However, despite numerous evolutionary changes occurring in the cathode's material, design, and surface configuration, it was not until the incorporation of steroid-elution to the electrode-tissue interface that reliable and significantly low stimulation threshold cardiac pacing became possible., (©2014 Wiley Periodicals, Inc.)

Introduction: Direct His bundle capture may negate ventricular electrical dyssynchrony induced by right ventricular (RV) apical pacing. We sought to evaluate if direct His bundle pacing is possible with conventional pacemaker lead implantation at various sites in the RV., Methods: Consecutive patients underwent RV pacing using standard implantable active fixation pacing leads in a random order in the RV outflow tract, middle RV, and RV apex at stimulation threshold and at increasing voltages of 2.5, 5, 7.5, and 10 volts (V). At each location, QRS width and morphology on 12-lead electrocardiograph (ECG) were compared in sinus and paced rhythm at the different voltages., Results: Twelve patients underwent a total of 2,160 paced QRS measurements. Progressive increases in stimulation voltage did not change QRS morphology or duration regardless of site of pacing (RV outflow tract, middle RV, and RV apex) in any of the 12 ECG leads. In addition, apart from the stimulation threshold between the RV outflow tract and RV apex, there was no statistically significant difference in QRS duration between the three pacing sites., Conclusion: In patients with a baseline normal QRS duration, none of the three conventional RV pacing sites were able to produce QRS narrowing and capture the His-Purkinje system. Furthermore, based on paced QRS duration as an indirect surrogate of electrical LV dyssynchrony, there was no clear advantage of one pacing site over another., (©2014 Wiley Periodicals, Inc.)

Introduction: There have been rare case reports of damage to adjacent coronary arteries by screw-in pacemaker and implantable cardioverter-defibrillator (ICD) leads. Our aim was to assess the proximity of pacemaker and ICD leads to the major coronary anatomy using cardiac computed tomography (CT)., Methods: Cardiac CT images were retrospectively analyzed to assess the spatial relationship of device lead tips to the major coronary anatomy., Results: Fifty-two right ventricular (RV) leads (17 apical, 35 nonapical) and 35 right atrial (RA) leads were assessed. Leads on the RV antero-septal junction (20 of 52) were close (median 4.7 mm) to, and orientated toward, the left anterior descending (LAD) coronary artery. RA leads in the anterior (26 of 35) and lateral (seven of 35) walls of the RA appendage were not close to (16.9 ± 7.7 mm and 18.9 ± 12.4 mm, respectively) and directed away from the right coronary artery. However, an RA lead adjacent to the superior border of the tricuspid valve was 4.3 mm from the right coronary artery and an RA lead on the medial wall of the RA appendage was 1.6 mm away from the aorta. An RV pacemaker lead in the lateral wall of the RV inlet was 3.4 mm from the right coronary artery., Conclusions: In our cohort, a majority of RV leads were on the antero-septal junction and close to the overlying LAD coronary artery. RA leads adjacent to the tricuspid valve or on the medial RA appendage were in close proximity to the right coronary artery and aorta, respectively., (©2013 Wiley Periodicals, Inc.)

Introduction: We aimed to assess the utility of cardiac computed tomography (CT) in the evaluation of right atrial (RA) and right ventricular (RV) pacemaker and implantable cardiac defibrillator lead perforation., Methods: Images from a 320-slice electrocardiogram-gated cardiac CT scanner were retrospectively independently analyzed by two reviewers for lead position, pericardial effusion, and perforation.Perforation results were correlated with pacing sensing, impedance, and threshold measurements., Results: A total of 52 patients had RV leads and 35 had RA leads. Five of 17 RV apical, one of 35 RV nonapical, and none of the 35 RA leads perforated through the myocardium on CT imaging criteria. Two "clinically" perforated leads (that had protruded 5 mm and 15 mm from the outer edge of the myocardium)had pericardial effusions and changes in pacing parameters, and required RV lead repositioning. In contrast,there were four apparent "radiologic" perforations (that had protruded only an average 1.5±0.5 mm from the outer edge of the myocardium) that did not require repositioning. These had the radiologic appearance of perforation on cardiac CT; however, they were not associated with pericardial effusions or significant changes in RV pacing lead sensing, impedance, and threshold measurements., Conclusions: Cardiac CT scanning with multiplanar reformatting is useful for documenting lead position and assessing for possible cardiac perforation. The clinical significance and natural history of leads with only the appearance of perforation on cardiac CT is uncertain.

Introduction: It is hypothesized that pacing the right ventricular (RV) septum is associated with less deleterious outcomes than RV apical pacing. Our aim was to validate fluoroscopic and electrocardiography (ECG) criteria for describing pacemaker and implantable cardioverter defibrillator RV "septal" lead position against the proposed gold standard: cardiac computed tomography (CT)., Methods: Using the conventional fluoroscopic criteria, we intended to place RV nonapical leads on the interventricular septum. Lead positions were later retrospectively analyzed with CT and correlated with ECGs and fluoroscopic projections: posterior-anterior, 40° left anterior oblique (LAO), 40° right anterior oblique (RAO), and left lateral., Results: Only 21% (nine of 35) of presumed "septal" RV nonapical leads using the conventional fluoroscopic criteria were on the true septum. A schema developed to define septal position in the RAO fluoroscopic view had high agreement with CT images. ECG criteria had only fair to moderate agreement with CT. The paced QRS duration was significantly longer (P < 0.001) with RV apical pacing (176 ± 10.7 ms), compared to RV nonapical pacing (144.5 ± 14.3 ms)., Conclusion: Using the conventional fluoroscopic criteria, only a minority of RV leads were implanted on the true RV septum. Instead, aiming for the middle of the cardiac silhouette in the RAO fluoroscopic view, confirming rightward orientation in the LAO view, and having a paced QRS duration <140 ms may allow the implanting cardiologist a simple, more accurate method to achieve true RV septal lead positioning., (©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.)

Cardiac implantable electronic devices (CIEDs) play a vital role in the management of cardiac rhythm disturbances. The devices are comprised of two primary components: a generator and lead joined by a connector. Original pacemaker lead connectors were created de novo at the time of implantation or replacement and were very unreliable. With the development of new lead designs, creation of a standard connector configuration, the IS-1 connector became mandatory. Similar connector development also occurred with the advent of the implantable cardioverter defibrillator (ICD), resulting in creation of the high voltage standard: the DF-1 connector. Differing from a pacemaker lead, the ICD lead connector requires one IS-1 connector and one or two DF-1 connectors, resulting in a large cumbersome lead connector and generator header block. Recently, a revolutionary quad pole single plug connector standard has been approved for market release. These are the single-pin DF4 and IS4 lead connectors that carry low- and high-voltage poles or all low-voltage poles, respectively. These connectors, together with new labeling guidelines, have simplified operative procedures and reduced errors, when mating lead connectors into the generator's connector block., (©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.)

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., (Copyright © 2011 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

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.

Background:  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., Methods:  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., Results:  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., Conclusions:  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., (©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.)

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., (©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.)

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., (2010. Published by Elsevier Inc.on behalf of Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. All rights reserved.)

Background: 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., Methods: 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., Results: 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)., Conclusions: 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., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

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.