Epicardial Pacemaker Research Articles

Using Software-Based Simulation for Resident Physician Training in the Management of Temporary Pacemakers

An understanding of epicardial pacing is essential for the postoperative management of patients having cardiac surgery. By developing a software-based epicardial pacing program to be used with the existing patient simulator, resident physicians may be exposed to various clinical scenarios that might be encountered while caring for a postoperative heart patient. This experience will assist junior residents with no prior experience to become familiar and competent in the management of epicardial pacemakers. The simulation session used the human patient simulator in combination with an internally developed computer program using Flash animation to present arrhythmias and various epicardial pacing interventions commonly used in the postoperative period. By modeling the Flash animation software after a pulse generator, the user is able to make adjustments (type of pacing, rate of pacing, and chamber output) as if using an actual pulse generator. A group of 15 anesthesiology residents who had minimal or no epicardial pacing experience underwent the simulation training. Feedback was obtained by an anonymous postscenario questionnaire. A detailed description of the scenario and computer program is provided. All participants provided positive feedback and have strongly agreed that the simulation session improved their understanding and management of epicardial pacemakers. Our experience with epicardial pacing simulation was demonstrated to be effective in increasing the confidence of junior anesthesiology residents with little or no prior experience with regard to the management of temporary pacemakers.

Usefulness of Transtelephonic Monitoring in Epicardial Pacemaker Systems

Transtelephonic monitoring (TTM) of pediatric patients with cardiac pacemakers (PMs) has been shown to have high sensitivity and specificity in identifying PM malfunction. The objective of this study is to determine if there is a difference in the rate of abnormal TTM findings in transvenous versus epicardial PM systems. Our TTM database was reviewed. Patients younger than 21 years of age enrolled for TTM between 1990 and 2010 were included. The abnormal TTM recordings (not including elective replacement indicator) were identified. Logistic regression was used for statistical analysis. Note that P < 0.05 was considered significant. We identified 186 patients. There were 75 (40%) epicardial systems. The mean age at TTM enrollment was 6.8 ± 5.9 years (2 months-20.2 years). There were 41 (22%) patients with abnormal TTM findings. The abnormalities were found in 23/75 (31%) epicardial and 18/111 (16%) transvenous systems (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.13-4.62, P = 0.02). When controlling for age and presence of heart disease the OR for abnormal transmission in epicardial systems compared with transvenous was 2.1 (95% CI: 1.03-4.43, P = 0.04). Patients with epicardial systems were more likely to have capture abnormalities on TTM than transvenous systems (OR: 6.1, 95% CI: 1.9-19.5, P = 0.002). Pediatric patients with epicardial PM systems are more likely to have abnormal TTM test (particularly capture problems) than patients with transvenous systems regardless of age or presence of heart disease. Consequently, patients with epicardial PM systems should be followed closely with TTM.

A Rare Case of Left Anterior Chest Bleeding in a Female With Takayasu Disease

A 70-year-old female was referred to our hospital for pyrexia and repeated pulsatile left anterior chest bleeding. She had invasive left breast cancer and Takayasu arteritis and had undergone ascending aortobifemoral bypass, epicardial pacemaker implantation, and coronary artery bypass grafting 20 years ago. The bleeding was occurring near the site of cutaneous metastasis of the carcinoma and the pacemaker generator. The cause was suspected to be pacemaker infection, and the generator was removed. Nevertheless, intermittent bleeding continued; therefore, we performed angiography. This showed leakage of the contrast medium from near the ascending aorta-synthetic

Pacemaker malfunction due to mechanical failure of the lead–header interface

An 8 year old female spayed Boxer dog, diagnosed with concurrent vasovagal syncope and arrhythmogenic right ventricular cardiomyopathy, presented for routine evaluation approximately three months following epicardial pacemaker implantation. Routine device interrogation revealed intermittent loss of ventricular capture and intermittent failure to appropriately sense. Following evaluation of chronic impedance data, failure of the pacemaker lead–header interface or lead conductor fracture was suspected. Radiographic and pacemaker interrogator findings suggested incomplete lead insertion into the device header with intermittent loss of ventricular capture and variable pacemaker sensing. We hypothesize that either the presence of a loose or cross-threaded set screw or operator error at the time of device implantation may have caused this complication. This report details the diagnosis of mechanical failure of the lead–header interface, a complication not previously reported in a veterinary patient.

The effectiveness of rigid pericardial endoscopy for minimally invasive minor surgeries: cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation

BackgroundThe efficacy and safety of rigid pericardial endoscopy as the promising minimally invasive approach to the pericardial space was evaluated. Techniques for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were developed.MethodsTwo swine and 5 canines were studied to evaluate the safety and efficacy of rigid pericardial endoscopy. After a double pericardiocentesis, a transurethral rigid endoscope was inserted into the pericardial space. The technique to obtain a clear visual field was examined, and acute complications such as hemodynamic changes and the effects on intra-pericardial pressure were evaluated. Using custom-made needles, pacemaker leads, and forceps, the applications for cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation were also evaluated.ResultsThe use of air, the detention of a stiff guide wire in the pericardial space, and the stretching of the pericardium with the rigid endoscope were all useful to obtain a clear visual field. A side-lying position also aided observation of the posterior side of the heart. As a cell transplantation methodology, we developed an ultrasonography-guided needle, which allows for the safe visualization of transplantation without major complications. Pacemaker leads were safely and properly implanted, which provides a better outcome for cardiac resynchronizing therapy. Furthermore, the success of clear visualization of the pulmonary veins enabled us to perform epicardial ablation.ConclusionsRigid pericardial endoscopy holds promise as a safe method for minimally invasive cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation by allowing clear visualization of the pericardial space.

Minimally Invasive Transxiphoid Approach to the Cardiac Apex and Caudoventral Intrathoracic Space

To describe a minimally invasive surgical technique for procedures involving the caudoventral compartment of the thoracic cavity. Case series. Dogs (n = 13). Thirteen dogs; undergoing epicardial pacemaker implantation (9), palliative pericardial window (2), perforated right ventricle repair with epicardial pacemaker implantation (1), and peritoneopericardial diaphragmatic hernia (1) were operated by a transxiphoid approach. Dogs were positioned in dorsal recumbency and the bony xiphoid process was dissected free of adjoining tissue and transected proximally and distally. The distal transection was proximal to the cartilaginous junction of the process and the diaphragm. Entry to the thoracic cavity without penetration of the abdomen provided access for surgical treatment. All dogs recovered without complication. No dogs required thoracostomy tube placement. Transxiphoid approach is minimally invasive and provides adequate exposure for disorders of the caudoventral thoracic cavity.

Temporary Epicardial Pacemaker Wires: Significance of Position and Electrode Type

To determine the pacing and sensing properties of different temporary epicardial pacemaker electrodes after cardiac surgery depending on position at the heart and time after surgery. From September 2009 to October 2010, 60 patients undergoing cardiac surgery were prospectively randomized into two groups: group O: Osypka-electrodes (n = 30), group M: Medtronic-electrodes (n = 30). In position 1, the bipolar electrodes were inserted onto the anterior wall of the right ventricle and at the right atrial auricle, in position 2, onto the diaphragmal wall of the right ventricle and at the aortic aspect of the superior vena cava medial close to the atrium. Sensing values and pacing thresholds were measured for all electrodes during surgery, on day 1 and every second day up to day 10 after surgery. In both groups, pacing thresholds (both positions) were higher during surgery (ventricle 3.1 ± 0.6 V, atrium 3.1 ± 0.3 V) than at day 1 (ventricle 2.4 ± 0.7 V, atrium 2.4 ± 0.3 V) and increased during the perioperative course until day 10 (ventricle 4.7 ± 1.0 V, atrium 4.9 ± 1.1 V, p = 0.04, p = 0.02). P and R wave amplitudes did not change over time (atrium 5.1 ± 0.1 mV initially, 4.2 ± 0.1 mV at removal (p = ns); ventricle 10.4 ± 0.2 mV vs. 10.1 ± 0.25 mV). Group M had better median pacing thresholds compared with group O (atrium: 2.9 ± 0.6 V vs. 3.9 ± 0.7 V, p = 0.04 and ventricle: 2.6 ± 0.6 V vs. 3.9 ± 0.6 V, p = 0.045). Atrial position 1 was superior to position 2 concerning pacing thresholds of Medtronic electrodes (2.1 ± 0.3 mV vs. 3.4 ± 0.4 mV, p = 0.02). Osypka-electrodes were easier to handle due to their more pliable texture. 1. Up to postoperative day 10, adequate pacing and sensing performance was achieved by both electrode types in each position. 2. Medtronic electrodes had better pacing thresholds in atrium and ventricle after day 5. 3. Positioning of pacemaker electrodes does not alter functionality. 4. Handling of Osypka electrodes was easier than that of Medtronic electrodes.

Surgical Placement of Permanent Epicardial Pacing Systems in Very Low-Birth Weight Premature Neonates

Few studies have characterized the surgical outcomes following epicardial pacemaker placement in very low-birth weight infants with congenital complete heart block. This study was undertaken to review the surgical experience with this patient population based on data from a large multi-institutional registry. The Pediatric Cardiac Care Consortium (PCCC) multi-institutional database was retrospectively reviewed to identify premature, low-birth weight neonates that underwent surgical placement of an epicardial pacing system for heart block. We reviewed 179 patients with birth weights less than 1.5 kg that underwent a major operative procedure. Of these, 10 patients underwent surgical placement of an epicardial pacing system for heart block. Patients had heart block in otherwise structurally normal hearts (n = 6) or heart block associated with complex structural congenital cardiac anomalies (n = 4). There were no deaths directly related to the surgical placement of the epicardial pacing system. There were no immediate complications with either lead or generator placement. One generator pocket was revised three months following placement. Survival to discharge was 60%. The four deaths occurred at a mean of 11 days (range 1-45 days) following the procedure. Neonates born with prematurity and congenital heart block represent a challenging subset of patients with significant mortality. Generator pocket breakdown and infection have been considered barriers to optimal short- and long-term outcomes. Among cases in the PCCC, there were no deaths or major complications that could be attributed to permanent epicardial pacemaker placement. These data suggest that an aggressive surgical strategy may be justified.

LEFT HEART ATRIAL AND VENTRICULAR EPICARDIAL PACING THROUGH A LEFT LATERAL THORACOTOMY TO TREAT PAEDIATRIC COMPLETE ATRIOVENTRICULAR BLOCK

ObjectivesTo investigate the feasibility, advantages and results of using Left heart atrial and ventricular epicardial pacing to treat paediatric complete atrioventricular block.MethodsEight children diagnosed as complete atrioventrcular block (CAVB) ineffectively...

Single surgical procedure combining epicardial pacemaker implantation and subsequent extraction of the infected pacing system for pacemaker-dependent patients

Management of pacemaker infection in pacing-dependent patients is often challenging. Typically, temporary pacing is used while antibiotic therapy is given for a number of days before reimplantation of a new endocardial system. This results in a prolonged hospital stay and complications associated with temporary pacing. In this study, we examine the feasibility of performing a single combined procedure of epicardial pacemaker implantation followed by system extraction. One hundred consecutive infected pacemaker-dependent patients underwent implantation of 2 epicardial ventricular leads and were converted to a ventricular demand pacing system. The infected pacing system was then extracted during the same procedure. Patients were followed up for 12 months. Significant pericardial bleeding developed during the procedure in 3 patients. The presence of the pericardial drain positioned during the implantation of the epicardial pacing system meant that cardiac tamponade did not occur, allowing surgical repair with sternotomy to be carried out under stable hemodynamic conditions. Two of these 100 patients died in the 30-day postoperative period; 1 death was due to septic shock and 1 to pulmonary distress. Median 1-year epicardial pacing thresholds were stable and excellent (1.4 ± 0.9 volts). However, 1 of the 2 leads developed increased thresholds in 6 patients, which led to the exclusive use of other ventricular lead. A single combined procedure of surgical epicardial pacemaker implantation and pacemaker system extraction appears to be a safe and effective method for managing pacemaker-dependent patients with infected pacemakers.

Epicardial pacemaker implantation in an elderly patient with pre-existing bilateral subclavicular deep brain stimulators

A 78-year-old woman presented with complete atrioventricular block, with a slow ventricular escape rhythm of 38 bpm. The patient received bilateral subthalamic nucleus deep brain stimulation (DBS) in 1998, because of uncontrolled fluctuations and dyskinesia due to advanced Parkinson’s disease. As both neurostimulators (Soletra neurostimulators, Medtronic Inc.) were implanted in the subclavicular region bilaterally, an epicardial pacemaker (PM) (Evia SR-T, Biotronik Inc.) was implanted (Fig. 1A). DBSs were turned off during pacemaker implantation. As recommended by the manufacturer, the generator was implanted more than 15 cm away from DBSs. It was implanted by minimally invasive subxiphoid approach and placed in an abdominal pocket, below the fascia of the right rectus abdominis muscle. The ventricular electrogram amplitude was 10.4 mV, the pacing threshold was 0.9 V/0.4 ms pulse width, and the lead impedance was 468 Ohms. A second ventricular lead was implanted and left capped, for later use, in case the first lead fails. The output setting of the right DBS was 3.0 V with a pulse width of 90 ms, at a stimulation frequency of 160 Hz. The output

Editorial Comment: The axillary incision to repair congenital heart defects

The axillary area presents interesting characteristics. The skin is extremely mobile and stretchable, the thoracic wall is practically muscle free, it is away from the breast gland and an adducted arm hides it. These factors, because of their cosmetic potential, undoubtedly make this area attractive for a surgical access to the heart. Yan [1] has used this route not only to close the classical secundum type of atrial septal defects, but also, like us [2], to repair more complex defects such as partial atrioventricular canals, perimembranous ventricular septal defects (VSDs) and partial abnormal pulmonary venous returns. We also use a mirror incision on the left side to implant epicardial pacemaker electrodes on the left atrial appendage and on the left ventricle [3]. Even if the results, as reported in the present study, are similar to those obtained by a conventional sternotomy, one has to concede that the exposure makes the repair more difficult and the manipulation of the surgical instruments more demanding. We commonly stratify the difficulty of a cardiac operation within a scale of five or six classes [4]. This approach sets any operation in a higher level of difficulty, usually by an increment of one class—if not two classes. Not surprisingly, in Yan’s paper, the procedure was performed exclusively by experienced surgeons and not by trainees. Obviously, our primary concern is aimed at the benefit of our patients. To provide a cosmetically superior incision with the same quality of cardiac repair is indisputably a step forward [5]. This enthusiastic view must, however, be tempered. First, the deliberate increase of the difficulty of any operation, even if this degree remains low in good hands, will fatally result in an excess—probably considered as anecdotal, but still an excess—of residual defects or complications. This part of the problem will never be fully appreciated by our scientific analysis, even with the use of large meta-analyses of literature reports, because a negative outcome in what is considered a trivial operation is unlikely to ever be reported. Secondly, what can be good for our patients can be bad for our residents and our education programmes. The training of a cardiac surgeon requires the performance of operations with progressive degrees of difficulties. The amputation from their curriculum of the easiest operations (either graded in a higher category or performed by senior members) will confront junior surgeons directly with technically challenging operations, and will possibly result in an increased morbidity—but in another group of patients. This seems similar to sending an apprentice diver for an acrobatic dive directly up the 5- or 10-m platform when he has hardly had a chance to try it out on the 1- or 3-m springboard. The intensity of the splash created by the entry to the water (for us, the surgical stress and morbidity inflicted on the patient) is prone to be markedly high for many dives until the technique is eventually mastered. Thirdly, the temptation to accept compromises in order to force the approach is difficult to resist. The two challenges of our surgery have always been the permanent control of the circulation and the repair of the heart. Controlling both of them through a 5-cm incision is an acrobatic undertaking. Every cannula, tourniquet or clamp participates in the cluttering of the operative field and the temptation becomes great to use smaller ones or to get rid of one of them simply to disengorge the place. Likewise, the temptation to provide only a partial repair of the defect is rampant, and the fact that a concomitant leaking aortic valve in subaortic VSDs was never directly tackled in Yan’s series bothers us. We are proponents of a minimally invasive approach to repair simple cardiac defects and we are even proponents of the axillary incision [6], but with two conditions: the security of the circulation should never be compromised and the cosmetics of the repair should primarily be visible on the heart.

The “rope and stick” and the “safety snare”: Two new techniques for tricky lead extractions

A 77-year-old pacemaker-dependent male was referred to our institution for extraction of a single-chamber pacing system for device infection. He received in 1998 a dual-chamber pacemaker with two passive leads (Pacesetter membrane-E 1450 T/1420 T) for complete atrio-ventricular block. After device-replacement he developed a pocket infection managed with antibiotic, removal of the device and excision of almost all the extravascular portion of the two leads and re-implant of a single-chamber device (year 2009) on the opposite site (the patient was in permanent atrial fibrillation). After many local revisions of the residual left pocket the patient was referred to our hospital. We decided to perform full extraction of all the leads and the device (increased C-reactive protein and blood samples positive for S. epidermidis). The procedure was carried out under conscious sedation in a hybrid-room with an active surgical back-up. After heavy debriding we obtained only few centimeters of the abandoned right-ventricular (RV) lead. However, it was enough to advance a locking stylet (LLD, Spectranetics Corporation, Colorado Springs, USA) to the lead tip. Manual traction was ineffective and a 14F laser-sheath (Spectranetics Corporation, Colorado Springs, USA) was advanced until the space between the clavicle and the first rib. Thereafter it was not possible to further advance the sheath, but a new attempt of manual traction was effective in freeing the right ventricular lead (Fig. 1-A). However, the left superior route proved to be ineffective for reaching the intravascular atrial lead. Considering the closeness of the proximal-edge of the atrial lead to the area which prevented laser sheath advancement, we feared that the same heavy adhesions could prevent percutaneous lead extraction by any approach. We advanced a medium curl 7F ablation catheter into the right atrium through an 18F femoral introducer and after many attempts, we were able to border the atrial lead (Fig. 1-B). In the meantime a 20-snare (Andrasnare: Andramed GmbH, Reutlingen, Germany) was advanced through a second femoral introducer to reach the tip of the ablation catheter and stabilize it (Fig. 1-C,D). A combined traction of both the ablation catheter and the snare (i.e. respectively the “stick” and “rope” of the title) was able to free both the proximal portion of the atrial lead and the distal end of the more recently implanted RV lead (Fig. 2-E). The RV lead was then effortlessly extracted from the subclavian access. Instead, the atrial lead appeared heavily trapped inside the atrial appendage. In order to avoid an atrial tear by insisting with simple traction we stabilized the lead with the first 20-snare while the 14F laser sheath was advanced into the inferior vena cava through a femoral introducer with a second 20-snare inside, which was used to secure the terminal part of the broken lead (Fig. 2-F). The laser sheath was then advanced over the secured lead up to the right atrial appendage while the first snare was maintained loosely around the system as a safety measure (“safety snare”). After few further laser bursts the outer insulation of the lead suddenly broke and came out of the sheath leaving the inner conductor, connected to the tip of the lead, exposed inside the laser sheath (Fig. 2-G). The presence of the “safety snare” allowed to stabilize once more the remaining part of the lead which was again reached by the second snare inside the 14F laser sheath permitting to free it in few further laser burst (Fig. 2-H). In view of the pacemaker-dependency and the double sub-clavicle access we implanted an epicardial pacemaker via sub-xyphoid route. Fig. 2After stabilizing the ablation catheter (arrow 5) with the snare (arrow 6), a combined traction was effective in freeing both the proximal portion of the atrial lead (arrow 3) and the terminal portion of the last RV lead (arrow 4, the screw mechanism was jammed). In the meantime a bipolar catheter (arrow 7) was advanced into the RV in view of pacemaker dependency of the patient (Panel E). After ineffective traction of the atrial lead by the snare, the laser sheath was advanced over a second snare (arrow 8) through the 18F femoral introducer (arrow 9) (Panel F). After reaching the tip of the atrial lead we delivered laser bursts with caution, the first snare was advanced outside the laser sheath as a safety measure (the “safety snare”, arrow 6). However, the outer insulation suddenly broke after few laser bursts leaving the inner conductor alone (panel G) inside the laser sheath (3a tip of atrial lead, 3b exposed inner conductor, 3c outer insulation). The “safety snare” was used to stabilize the inner conductor that was then reached with the second snare after completely removing the insulation. Few laser bursts were effective in freeing the tip of the atrial lead (3a, panel H). View Large Image Figure Viewer Download Hi-res image

Intracardiac Migration of Operatively Placed Epicardial Pacing Leads

This study describes intracardiac migration of epicardial pacemaker leads after open heart surgery in 2 patients. Discovery of these pacemaker leads or remnants led to diagnostic confusion until an appropriate diagnosis was established by both invasive and noninvasive means. Intracardiac migration of epicardial pacemaker leads has only rarely been reported. Migration to other noncardiac organs has also been reported infrequently. Awareness of this unusual occurrence should avoid postoperative confusion in recognizing origin of said artifacts.

Long-term outcomes following infection of cardiac implantable electronic devices: a prospective matched cohort study

ObjectiveTo assess long-term outcomes and predictors of mortality in patients treated according to current recommendations for cardiac implantable electronic device (CIED) infection.DesignTwo-group matched cohort study.SettingTertiary-care institution.PatientsConsecutive patients admitted for CIED...

Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium

Congenital long QT syndrome (LQTS) is an inherited disorder characterized by QT prolongation and polymorphic ventricular tachycardia known as torsade de pointes. The underlying cellular mechanism is prolonged ventricular repolarization caused by mutations in genes encoding cardiac ion channels or membrane adaptors. The disease can be diagnosed at any age and, very rarely, it can be diagnosed prenatally or in the neonatal period. Isolated noncompaction of the ventricular myocardium (INCVM) is defined as the presence of prominent ventricular trabeculations and deep intertrabecular recesses within the endomyocardium. This report describes a newborn baby presenting with polymorphic ventricular tachycardia whose diagnosis was LQTS and INCVM. Ventricular tachycardia did not respond to medical treatment, and a transient epicardial pacemaker was inserted surgically on his 30th day of life for atrioventricular block and bradycardia. The transient epicardial pacemaker was upgraded to an epicardial intracardiac defibrillator on his 40th day. The concomitant occurrence of INCVM, LQTS, and atrioventricular block needs to be evaluated further.

Canine Model of Cardiorenal Failure

The heart and the kidneys act in tandem to regulate blood pressure, vascular tone, diueresis and to maintain intravascular volume homeostasis. Besides, the kidneys have a neuroendocrine function with interdependent physiological actions regulated by the renin-angiotensin-aldosterone system, sympathetic nervous system, and vasopressin and aterial natriuretic peptide. To investigate these complex pathophysiological mechanisms, a canine model for Congestive Heart Failure (CHF) compromised with Renal Dysfunction (RF) was used, to characterize the hemodynamic and neurohumoral aspects of renal function in 21 dogs. Five dogs were used as controls. Bipolar epicardial pacemaker leads were implanted at the apex of the right ventricle in 8 dogs and the dogs were subjected to ventricular pacing at 250-270 beats/min with an external pacemaker (Nihon Kohden) for a period of 11-21 days. This rapid pacing produced CHF. RF was induced by removal of the right kidney with ligation of the small branches of the left kidney in 8 dogs. Three dogs of each of the CHF and RF groups were used to produce CHF and RF in combination; one dog died due to infection. The glomerular filtration rates of the dogs with RF, CHF and CHF+RF were significantly lower than those of the controls, although among the dogs with RF, CHF and CHF+RF, there were no significant differences. In spite of no differences in blood pressure and renal hemodynamics, the levels of plasma renin activity, norepinephrine and vasopressin of CHF+RF group were significantly higher than those of RF and CHF groups. Taken together, these data suggest that in patients with CHF compromised by RF neurohumoral factors are maximally activated.

Permanent Epicardial Pacing in Pediatric Patients: 12-Year Experience at a Single Center

Permanent cardiac pacing is not often done in children, and when done is usually accomplished through epicardial pacing. We reviewed a 12-year experience with the implantation of epicardial pacemakers by our clinical group. Fifty-three patients who underwent their first implantation of an epicardial pacemaker before the age of 18 years and between 1997 and 2009 were included in our study. The mean age of the patients at the time of first pacemaker implantation was 5.7±4.8 years. Indications for pacemaker implantation included postoperative or congenital atrioventricular block and sinus node dysfunction. The patients underwent 105 operations for the replacement of pacemaker pulse generators and 75 operations for the replacement of pacemaker leads. The most commonly used generator mode was the rate-responsive accelerometer-based (DDDR) mode, which was used in 40.9% of the patients. We used more non-steroid-eluting leads (70.1%) than steroid-eluting leads (29.1%). The overall duration of follow-up in the study was 8.0±4.5 years (range, 2.1 months to approximately 17.0 years). Freedom from the need for generator replacement was 98.0%, 60.7%, and 11.1% at 1, 5, and 8 years, respectively. A tendency toward early generator exhaustion was observed among younger patients (p=0.058). The generator mode used for pacing did not significantly affect generator longevity. Freedom from the need for lead replacement was 98.3%, 83.8%, and 63.6% at 1, 5, and 10 years, respectively. The mean longevity of the leads used in the study was 10.8±0.8 years. Neither patient age at the time of lead implantation nor type of lead significantly affected lead longevity. Lead longevity was sufficiently long and did not vary significantly according to type of lead. Generator longevity was not affected by lead type, generator mode, or patient age at the time of pacemaker implantation.

Permanent cardiac pacing in a 2.5 month-old infant with severe cyanotic breath-holding spells and prolonged asystole

We report the case of a 2.5 month-old infant with cyanotic breath-holding spells, loss of consciousness and seizures. Prolonged asystole up to 70 s despite cardiopulmonary resuscitation was documented by 24 hour Holter monitoring. An epicardial pacemaker was implanted followed by no further loss of consciousness and seizures during spells in a six month follow-up period.

Capability of a new paediatric oesophageal Doppler monitor to detect changes in cardiac output during testing of external pacemakers after cardiac surgery

The Cardio QP™ oesophageal Doppler monitor measures the velocity time integral of the blood flow in the descending aorta. Based on system integrated normograms of the aortic cross-sectional area of a paediatric population, the cardiac output is calculated and displayed. Evaluation of the capability of the Cardio QP™ to detect changes in cardiac output during desynchronizing ventricular pacing (VVI) in children after cardiac surgery. Eleven children (6 female, 5 male) with epicardial pacemaker electrodes admitted to the paediatric intensive care unit (PICU) after corrective surgery for congenital heart defects. Mean age: 6.3 (2.1-15.0) months, mean body weight: 5.3 (3.5-7.8) kg. After baseline measurements of cardiac output (base I), we performed 3 steps, each lasting 5 min: (1) ventricular pacing (VVI), (2) baseline (base II) recording, (3) atrial pacing (AOO). We measured the effects on haemodynamic parameters and blood gases as well as on the measured cardiac output. Ventricular pacing, with atrio-ventricular dyssynchrony, led to a significant drop in blood pressure and central venous saturation. Cardiac output parameters showed a decrease in stroke volume (SV) from 4.9±2.2 to 4.2±2.1 ml (P = 0.005) and cardiac index (CI) (2.6±1.1-2.1±0.8 ml/min/m(2)) (P = 0.009) during ventricular pacing. Cardiac index and haemodynamic parameters during atrial stimulation did not show significant changes from baseline. The Cardio QP™ seems to be capable of detecting slight changes in cardiac output.