An unusual cause of inappropriate shocks delivered by an implantable cardioverter defibrillator.

INTRODUCTION: Cardiac implantable electronic device (CIED) complications present significant challenges in clinical practice, especially in elderly patients with multiple comorbidities. Common adverse events include infection, lead malfunction, and device migration. Twiddler's Syndrome, a rare but serious CIED complication characterised by patient manipulation causing lead displacement and device malfunction, is often underreported. The literature consists mainly of case reports and small series, providing limited guidance on prevention and management. As CIEDs are critical for managing cardiac arrhythmias and heart failure, understanding and addressing Twiddler's Syndrome is essential. This case report aims to contribute to the literature by detailing a case of Twiddler's Syndrome, emphasising the importance of a multidisciplinary approach for optimal management. CASE PRESENTATION: A 59-year-old male presented with discomfort around his implantable cardioverter defibrillator (ICD) site and the sternal area over the past two days. He denied pain, dyspnoea, or dizziness. Clinical examination revealed a normal heart rhythm and no peripheral pulse deficit. Ultrasound revealed a reduced left ventricular ejection fraction. The atrial lead was not visible, and the shock coil was misplaced. ICD interrogation showed inappropriate shocks due to sensing artifacts and exit block in both leads, with no arrhythmias detected. An X-ray confirmed lead dislodgement and significant entanglement in the pocket. The patient was diagnosed with Twiddler's Syndrome and scheduled for surgical revision. DISCUSSION/CONCLUSIONS: Dilated cardiomyopathy (DCM), characterised by left ventricular dilatation and dysfunction, accounts for a significant proportion of systolic heart failure cases. Despite advancements in heart failure management, DCM patients remain at high risk for sudden cardiac death (SCD), making ICD implantation crucial. However, CIED placement carries risks of complications, including Twiddler's Syndrome. This condition can lead to lead dislodgement and device malfunction, resulting in inappropriate shocks and potential patient harm. In this case, a single-session extraction and re-implantation were successfully performed using a multidisciplinary approach, emphasising the importance of comprehensive management strategies to address such complications effectively. Regular follow-up showed no adverse events, highlighting the procedure's success and the potential benefits of using advanced antimicrobial adjuncts to prevent infections. This case underscores the need for awareness and standardised protocols for managing Twiddler's Syndrome to improve patient outcomes in the growing population of CIED recipients.

Use of a taurolidine containing antimicrobial wash to reduce cardiac implantable electronic device infection.

AIMS: TauroPace (Tauropharm, Bavaria Germany), a taurolidine solution for combating cardiac implantable electronic device (CIED) infection, was compared with a historical control of 3% hydrogen peroxide (H2O2) in a prospective observational study. METHODS AND RESULTS: The device pocket was irrigated, and all hardware accessible within (leads, suture sleeves, pulse generator) was wiped with H2O2, TauroPace, or taurolidine in a galenic formulation during any invasive CIED procedure at the study centre. Only CIED procedures covered by TauroPace or H2O2 from 1 January 2017 to 28 February 2022 were included for analysis. Patients who underwent >1 procedure were censored for the last treatment group and reassigned at the next procedure. The primary endpoint was major CIED infection within 3 months. The secondary endpoints were CIED infection beyond 3 months, adverse events potentially related to the antimicrobial solutions, CIED system, procedure, and death, till the end of follow-up. TauroPace covered 654 procedures on 631 patients, and H2O2 covered 551 procedures on 532 patients. The TauroPace group had more patient risk factors for infection than the H2O2 group (P = 0.0058) but similar device and procedure-specific risk factors (P = 0.17). Cardiac implantable electronic device infection occurred in 0/654 (0%) of the TauroPace group and 6/551 (1.1%) of the H2O2 group (P = 0.0075). Death occurred in 23/654 (3.5%) of the TauroPace group and 14/551 (2.5%) of the H2O2 group (P = 0.33). Non-infection related adverse events were rarer in the TauroPace (3.8%) than the H2O2 (6.0%) group (P = 0.0802). CONCLUSION: TauroPace is safe but more effective than H2O2 in reducing CIED infection. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05576194.

Longevity decoded: Insights from power consumption analyses into device construction and their clinical implications.

INTRODUCTION: The longevity of a cardiac implantable electronic device (CIED) depends on how quickly the powers consumed by the device's functions exhaust its usable battery energy. A mathematical model for CIED power consumptions was developed and validated against longevity data from manufacturers. METHODS: The programmable parameters for the Resonate X4 cardiac resynchronization therapy defibrillators (CRT-Ds) on the Boston Scientific (St. Paul, MN, USA) online longevity calculator were designated as independent terms in the sum for the total power consumption. The reciprocal of longevity was plotted against variations in these terms. Linear and nonlinear regression analyses were used to fit the plots. The power consumed by pacing was theoretically derived and used as the calibrating tool for estimating the powers consumed by other functions and the usable battery energy. The same methodology was applied to the longevity data of other manufacturers' CRT-Ds. RESULTS: Single chamber 100% pacing at 60 beats/min, 2.5 V, 0.4 ms, 500 Ω consumes ≈ 144 J/year. Shock therapy is 45-85% energy efficient. Multichamber pacing modes and maintaining readiness to pace a chamber consume power even if no pacing is delivered. Switching voltage regulation is theoretically more energy efficient than linear voltage regulation for powering pacing. CONCLUSIONS: The powers consumed by therapy functions are dictated by the patient's clinical needs, but healthcare professionals can extend device longevity by switching off dormant functions and simplifying the pacing mode. Choosing a device model with large usable battery energy, low background power, and energy efficient pacing and shock therapy for implantation will increase the probability of a long service lifespan.

Technologies for Prolonging Cardiac Implantable Electronic Device Longevity.

Prolonged longevity of cardiac implantable electronic devices (CIEDs) is needed not only as a passive response to match the prolonging life expectancy of patient recipients, but will also actively prolong their life expectancy by avoiding/deferring the risks (and costs) associated with device replacement. CIEDs are still exclusively powered by nonrechargeable primary batteries, and energy exhaustion is the dominant and an inevitable cause of device replacement. The longevity of a CIED is thus determined by the attrition rate of its finite energy reserve. The energy available from a battery depends on its capacity (total amount of electric charge), chemistry (anode, cathode, and electrolyte), and internal architecture (stacked plate, folded plate, and spiral wound). The energy uses of a CIED vary and include a background current for running electronic circuitry, periodic radiofrequency telemetry, high-voltage capacitor reformation, constant ventricular pacing, and sporadic shocks for the cardiac resynchronization therapy defibrillators. The energy use by a CIED is primarily determined by the patient recipient's clinical needs, but the energy stored in the device battery is entirely under the manufacturer's control. A larger battery capacity generally results in a longer-lasting device, but improved battery chemistry and architecture may allow more space-efficient designs. Armed with the necessary technical knowledge, healthcare professionals and purchasers will be empowered to make judicious selection on device models and maximize the utilization of all their energy-saving features, to prolong device longevity for the benefits of their patients and healthcare systems.

First rib and venous anomalies - Anatomical challenges for transvenous implantation of cardiac electronic devices.

Atypical anatomy may be encountered unexpectedly and undiagnosed in clinical practice, and this is especially important during the performance of interventional procedures such as transvenous implantation of cardiac electronic devices. The body of the first rib can be absent. If this not noticed, pneumo-/haemothroax may be induced during subclavian vein puncture as the needle may enter the first intercostal space rather than the costo-clavicular angle. The cephalic vein may pursue a supraclavicular course, the axillary vein may drain into an intercostal vein rather than the axillary vein, and the entire length of the axillary-subclavian-brachio-cephalic vein may be absent. Device implanters should be vigilant about the possibility of these anatomical variations, and be equipped with the knowledge and spectrum of alternative techniques needed to deal with them.

Multi-site multi-polar left ventricular pacing through persistent left superior vena cava in tricuspid valve disease.

Multi-site multi-polar left ventricular pacing through the coronary sinus (CS) may be preferred over endocardial right ventricular or surgical epicardial pacing in the presence of tricuspid valve disease. However, the required lead placement can be difficult through a persistent left superior vena cava (PLSVC), as the CS tends to be hugely dilated and side branches tend to have sharp angulations (>90°) when approached from the PLSVC. Pre-shaped angiography catheters and techniques used for finding venous grafts from the ascending aorta post coronary bypass surgery may help with lead placement in such a situation.

Differential lead component pulling as a possible mechanism of inside-out abrasion and conductor cable externalization.

BACKGROUND: Conductor cable externalization with protrusion (CCE*) is highly prevalent among the Riata 8F and ST 7F defibrillation (DF) leads and infrequently present in the QuickSite and the QuickFlex coronary sinus (CS) leads (St. Jude Medical, Sylmar, CA, USA). A model for CCE* based on differential lead component pulling and conjugate extension with reciprocal compression-bending was developed. Extension of a proximal lead body segment by pectoral or cardiac movements causes reciprocal compression-bending of a distal lead body segment mediated by inextensible conductor cables running down a lead body fixed at various points by fibrous adhesions. The "sawing" action of these cables under tension causes inside-out abrasion of insulation leading to CCE*. METHODS: DF leads from different manufacturers and the QuickFlex and QuickFlex µ CS leads were subjected to simulated differential pulling. RESULTS: Restitution from differential pulling followed three patterns: complete, partial without escalation, and incomplete with escalation. Only the last pattern (only shown by the Riata 8F and ST 7F leads) was associated with an increased risk to CCE*. For CS leads, deformation concentrated on the more flexible segment when the lead body did not have a uniform construction. CONCLUSIONS: The Durata, Riata ST Optim, QuickFlex µ, and Quartet leads should be relatively immune to CCE*. The Durata leads are extremely resistant to longitudinal deformation and probably cause mediastinal displacement rather than differential pulling in response to pectoral movements in vivo. Implantation techniques and lead designs can be used to minimize the risk of CCE*. A bench test for CCE* can be constructed.

The European TauroPace™ Registry.

BACKGROUND: Cardiac implantable electronic device (CIED) placement comes with certain complications. CIED infection is a severe adverse event related to CIED placement. In randomised controlled trials, the preoperative intravenous administration of antibiotics and the adjunctive use of an antibiotic mesh envelope resulted in significant reduction in infections related to cardiac implantable electronic devices. The adjunctive use of taurolidine for this purpose is relatively novel and not considered in the guidelines. The required evidence may consist of a set of clinical studies. METHODS: The European TauroPaceTM registry (ETPR) prospectively evaluates every consecutive invasive procedure involving any CIED with adjunct TauroPace™ use in the contributing centres. As the estimation of the infection rate needs to be defensible, only interventions registered prior to the procedure will be followed-up. The endpoint is a major cardiac implantable electronic device infection according to the novel CIED infection criteria (1). Secondary endpoints comprise all-cause mortality, complications, adverse events of all grades, and major CIED infections during all follow-up examinations. The follow-up times are three months, twelve months, and eventually 36 months, as acute, subacute, and long-term CIED infections are of interest. RESULTS: As the rate of CIED infections is expected to be very low, this registry is a multicentre, international project that will run for several years. Several reports are planned. The analyses will be included in the case number calculations for future randomised controlled trials. CONCLUSIONS: The ETPR will accumulate large case numbers to estimate small event rates more precisely; we intend to follow up on participants for years to reveal possible late effects.

Use of Taurolidine in a Patient With a Cardiac Implantable Electronic Device Protrusion.

We report the successful salvage of cardiac implantable electronic device pulse generator protrusion sealed by the surrounding skin in a frail patient presenting 5 months after the last surgical revision. (Level of Difficulty: Advanced.).

Salvage of Cardiac Implantable Electronic Device Pocket Infection with Skin Erosion in Frail 92-Year-Old.

We reported the novel use of a taurolidine-containing antimicrobial solution in the successful salvage of a partially exposed and polymicrobially infected cardiac implantable electronic device pulse generator in a frail patient unfit for lead extraction. The old, salvaged device was entirely internalized, and there were no signs of recurrent infection at 9 months follow-up.

Eradication of Ventricular Assist Device Driveline Infection in Paediatric Patients with Taurolidine.

Ventricular assist devices (VADs) are used to provide mechanical circulatory support to patients with end-stage heart failure. The driveline connecting the external power source to the pump(s) of the intra-corporal VAD breaches the protective skin barrier and provides a track for microbes to invade the interior of the patient's body. Driveline infection constitutes a major and potentially fatal vulnerability of VAD therapy. Driveline infection cannot traditionally be salvaged and requires the extraction of the entire VAD system. We report here the successful eradication of a VAD driveline infection with a taurolidine-containing antimicrobial solution used for preventing the infection of cardiac implantable electronic devices. If replicated in more cases, the novel treatment concept described here may provide a valuable alternative management strategy of salvage rather than explantation for VAD driveline infection.

Yoked catheter positioning in transseptal endocardial left ventricular lead placement.

BACKGROUND: Transseptal (TS) endocardial left ventricular (LV) lead placement may be needed for cardiac resynchronization therapy, and often requires crossing a preformed puncture in the interatrial septum (IAS) with a lead delivery catheter inserted from an upper body vein (UBV), which can be difficult or impossible to achieve by manipulation from its hub. Consequently, yoked superior approach TS catheterization was developed. METHODS: A loop snare housed in a deflectable delivery catheter inserted from an UBV captured the guide wire extending out of a TS sheath inserted from the right femoral vein into the inferior vena cava (IVC). After the IAS had been punctured, the guide wire was left in the left atrium (LA) and the TS sheath withdrawn into the IVC. The delivery catheter was advanced over the snare onto the guide wire, and then pushed by the TS sheath across the IAS puncture into the LA. The snare released the guide wire and was withdrawn. The delivery catheter was manipulated to point toward the LV for lead deployment. If that was not possible, the IAS puncture was dilated with an electrophysiology (EP) catheter housed in a second TS sheath alongside the first one. The EP catheter was captured by the snare and manipulated across the IAS puncture into the LV. The delivery catheter was advanced over the EP catheter directly into the LV. RESULTS: The technique was tried in four patients with challenging anatomy and allowed successful endocardial LV lead placement in all. CONCLUSIONS: Yoked catheter positioning facilitates TS endocardial LV lead placement.

Achieving permanent left ventricular pacing-options and choice.

Cardiac resynchronization therapy (CRT) requires permanent left ventricular (LV) pacing. Coronary sinus (CS) lead placement is the first line clinical approach but can be difficult or impossible; may suffer from a high LV pacing threshold, phrenic nerve stimulation, and dislodgement; and produces epicardial LV pacing, which is less physiological and hemodynamically effective and potentially more proarrhythmic than endocardial LV pacing. CS leads can usually be extracted with direct traction but may require use of extraction sheaths. Half of CS side branches previously used for lead placement may be unusable for the same purpose after successful lead extraction, and 30% of CS lead reimplantation attempts may fail due to exhaustion of side branches. Surgical epicardial LV lead placement is the more invasive second line approach, produces epicardial LV pacing, and has a lead failure rate of approximately 15% in 5 years. Transseptal endocardial LV lead placement is the third line approach, can be difficult to achieve, but produces endocardial LV pacing. The major concern with transseptal endocardial LV leads is systemic thromboembolism, but the risk is unknown and oral anticoagulation is advised. Among the new CRT recipients in the United States and Western Europe between 2003 and 2007, 22,798 patients may require CS lead revisions, 9,119 patients may have no usable side branches for CS lead replacement, and 1,800 patients may require surgical epicardial LV lead revision in the next 5 years. The CRT community should actively explore and develop alternative approaches to LV pacing to meet this anticipated clinical demand.

Infraatrial supraventricular tachycardias: mechanisms, diagnosis, and management.

Tachycardias are traditionally classified as either ventricular tachycardia (VT) or supraventricular tachycardia (SVT). VT can be defined as a tachycardia which requires only ventricular structures for perpetuation. SVT is defined in terms of exclusion of VT and hence is any tachycardia which requires participation of at least one supraventricular structure for perpetuation. Certain SVTs require only participation of the atrioventricular node (AVN) and the His bundle (HB) but not the atrial myocardium or any of the great thoracic veins for perpetuation and hence can be described as "infraatrial." The three main mechanisms of infraatrial SVTs are: (1) intranodal atrioventricular reentrant tachycardia; (2) junctional ectopic tachycardia; and (3) nodoventricular reentrant tachycardia. The clinical significance of infraatrial SVTs is that they are compatible with any A:V ratio and even atrioventricular (AV) dissociation. Infraatrial SVTs are often suspected when a narrow complex tachycardia presents with apparent AV dissociation and a counterintuitive A:V ratio of < 1:1. However, if the same tachycardia is conducted with aberrant conduction or preexcitation, a broad complex tachycardia with an A:V ratio of < 1:1 will arise and that can be easily mistaken for VT. The possible patterns of electrical association and dissociation between different cardiac structures are examined, and how individual types of infraatrial SVT can be diagnosed and managed are reviewed.

Delayed cardiac perforation by defibrillator lead placed in the right ventricular outflow tract resulting in massive pericardial effusion.

A 76-year-old man received a dual-chamber implantable cardioverter defibrillator (ICD), with the defibrillator lead positioned within the right ventricular outflow tract. The lead parameters at the time of implantation were satisfactory and the post-procedure chest X-ray showed the leads were in place. The patient was cardioverted from atrial fibrillation during defibrillation threshold testing and commenced on anticoagulation immediately. One month post implantation, he experienced multiple ventricular tachycardia episodes all successfully treated with antitachycardia pacing and shocks by his ICD, but he fell and hit his chest against a hard surface during one of these attacks. He developed a massive pericardial effusion and computed tomography confirmed cardiac perforation by the defibrillator lead. Pericardiocentesis was performed and the defibrillator lead replaced with a different model positioned at the right ventricular apex. The patient made an uneventful recovery. The management and avoidance of delayed cardiac perforation by transvenous leads were discussed.

An ergonomic guide catheter slitting technique designed to avoid lead dislodgement.

BACKGROUND: Guide catheters help deliver endocardial leads to specific locations within the heart, but their disengagement afterwards can be challenging. Slitting the catheter open over the lead may require the creation of an artificial platform to provide support for the blade and cause lead dislodgement through a sideways drag on the catheter by the hand pulling it or a forward push by the hand holding the blade. An alternative ergonomic technique addressing these shortcomings was developed. METHODS: The ipsilateral elbow presses against the iliac fossa or anterior superior iliac spine to support the hand holding the blade. The other hand pulls the catheter in small steps with constant adjustments of the direction of pull and the angle of the blade to ensure alignment of the different parts. If necessary, the hand pulling the catheter will drop it to reduce any loop in the catheter segment between the blade and the exit site of the catheter from the patient's body. The technique was tried on all guide catheters which required slitting during cardiac rhythm device procedures by a single operator. RESULTS: Thirty-two guide catheters from different manufacturers were successfully slit without dislodging any leads. The leads might slide forward into the heart during catheter slitting but their positions could all be adjusted by pulling them back afterwards. DISCUSSIONS: The ergonomic slitting technique should facilitate the use of guide catheters for positioning endocardial leads by reducing the risk of lead dislodgement. It proved useful and successful when applied to guide catheters from different manufacturers. Its general utility needs to be assessed in a wider clinical setting.

An early phase of slow myocardial activation may be necessary in order to benefit from cardiac resynchronization therapy.

BACKGROUND: Not all patients with a QRS duration longer than 140 milliseconds respond to cardiac resynchronization therapy (CRT). The same QRS duration may correspond to different spatiotemporal patterns of myocardial activation that influence response to CRT. METHODS: Electrocardiographic imaging based on 80 chest wall electrodes was used to construct the spatiotemporal myocardial activation map in 46 consecutive patients before CRT. The cumulative percentage of myocardium activated was plotted against time expressed in terms of quintiles of the overall QRS duration. Changes in the left ventricular ejection fraction and end-diastolic diameter, maximum oxygen consumption per minute, brain natriuretic peptide level, and 6-minute walk distance after 6 months of CRT were compared across different patterns with 1-way analysis of variance. RESULTS: Data from 34 patients were available for analysis. Four spatiotemporal patterns of myocardial activation could be identified: triphasic (fast-slow-fast) (13), uniform (8), fast-slow (7), and slow-fast (6). The overall QRS duration was similar in the 4 groups (166 +/- 19 vs 138 +/- 21 vs 157 +/- 26 vs 152 +/- 37 milliseconds, P = not significant [NS]). The ejection fraction showed a trend of greater increases for the triphasic (6.5% +/- 7.0%) and slow-fast (15.5% +/- 6.4%) patterns than for the uniform (4.0% +/- 13.3%) and fast-slow (8.0% +/- 6.1%) patterns (P = NS). The end-diastolic diameter showed a trend of greater decreases for the triphasic (-3.7% +/- 5.3%) and slow-fast (-7.0% +/- 6.7%) patterns than for the uniform (0.8% +/- 6.7%) and fast-slow (0.0% +/- 4.6%) patterns (P = NS). The maximum oxygen consumption per minute showed a trend of greater increases for the triphasic (1.2 +/- 4.2 mL/kg/min) and slow-fast (4.1 +/- 2.7 mL/kg/min) patterns than for the uniform (0.1 +/- 4.1 mL/kg/min) and fast-slow (1.0 +/- 2.1 mL/kg/min) patterns (P = NS). The brain natriuretic peptide level decreased significantly more for the triphasic (-450 +/- 1269) and slow-fast (-3121 +/- 1512) patterns than for the uniform (762 +/- 1036) and fast-slow (718 +/- 2530) patterns (P = .0003). The 6-minute walk distance increased significantly more for the triphasic (29 +/- 89) and slow-fast (40 +/- 23) patterns than for the uniform (6 +/- 87) and fast-slow (37 +/- 45) patterns (P = .0003). CONCLUSIONS: Different spatiotemporal patterns of myocardial activation exist among patients with broad QRS complex and may affect response to CRT. An early phase of slow myocardial activation (the triphasic fast-slow-fast and the slow-fast patterns) may be necessary for a patient to benefit from CRT.

Activation patterns during selective pacing of the left ventricle can be characterized using noninvasive electrocardiographic imaging.

BACKGROUND: Noncontact endocardial mapping allows accurate beat-to-beat reconstruction of the reentrant pathway of ventricular tachycardia and improves outcomes after ablation. Several studies support electrocardiographic imaging (ECGI) as a means of noninvasively outlining epicardial activation despite constraints of internal geometry. However, few have explored its clinical application. This study aims to evaluate ECGI during selective left ventricular (LV) pacing, relative to an invasive approach. METHODS: Multisite pacing was performed within the left ventricles of 3 patients undergoing invasive procedures. Simultaneous recording of endocardial potentials using a noncontact multielectrode array and body surface potentials (BSP) using an 80-electrode torso vest was performed. A total of 16 recordings were made. The inverse solution was applied to BSP to reconstruct epicardial activation. Single-paced beats from real and virtual electrograms were used to construct 3-dimensional isochronal and isopotential maps. Endocardial and epicardial data were then superimposed onto a single geometry to allow quantitative comparison of activation foci. RESULTS: Good correlation was observed between endocardial activation patterns and those reconstructed from BSP using ECGI. This was repeatedly demonstrated in all LV regions except for the septum (3 recordings). Epicardial isochronal maps were able to locate early and late activation to mean distances of 13.8 +/- 4.7 and 12.5 +/- 3.7 mm from endocardial data. Isopotential maps localized pacing sites with comparable accuracy (14 +/- 5.3 mm). CONCLUSIONS: Body surface potentials and reconstructed epicardial activation patterns during LV pacing correlate well with endocardial data acquired invasively. The exception was during pacing of the septum. Although early results are encouraging, further quantitative data are required to fully validate and apply this noninvasive tool in the clinical arena.

Preexcitation masking underlying aberrant conduction: an atriofascicular accessory pathway functioning as an ectopic right bundle branch.

Preexcitation and aberrant conduction both cause a broad QRS complex. An unusual case of an atriofascicular accessory pathway effectively functioning as an ectopic right bundle branch and responsible for both physiologically normal ventricular activation and pathologic preexcited tachycardias as part of a split AV node-bundle branch system is presented.

Isorhythmic interaction between a dual-chamber pacemaker and an intrinsic rhythm: pacemaker malfunctioning or not?

A patient underwent cardiac surgery (including a biatrial maze procedure) for congenital heart disease and paroxysmal atrial tachycardia. Previously, a dual-chamber pacemaker was inserted for bradycardia. Postoperative ECG showed a narrow complex rhythm interspersed with pacing stimuli that appeared premature and unable to capture. The phenomenon was due to isorhythmic interaction between the pacemaker and the patient's own intrinsic rhythm, which is compatible with normal pacemaker functioning. The different patterns possible for the phenomenon and the necessary conditions for their occurrence are elucidated.