Endocardial Lead Research Articles

Tricuspid valve stenosis caused by fibrous adhesions to an endocardial pacemaker lead in a dog

Acquired tricuspid valve stenosis (TVS) is a rare complication of endocardial lead placement in humans that has not been described in the veterinary literature. We describe a 6.5-year-old Border terrier that was presented with right-sided congestive heart failure 5.5 years after placement of a transvenous pacemaker. Severe TVS was confirmed by cardiac ultrasonography and appeared to be secondary to excessive endocardial pacemaker lead within the right atrium. Repositioning of the lead proved impossible and subsequent postmortem examination demonstrated fusion of the tricuspid valve (TV) leaflets around the endocardial lead with associated narrowing of the tricuspid valve orifice. In addition, the loop of the endocardial lead was anchored by thick fibrous tissue to the right atrial wall. This case report suggests that if sufficient endocardial lead is left inside the heart, in dogs undergoing transvenous pacemaker therapy, the redundant lead can become adherent to the tricuspid valve apparatus and cause valvular stenosis.

Left Phrenic Nerve Stimulation Due to Breakage of the Endocardial Right Ventricular Lead at the Costoclavicular Ligament

A 78‐year‐old man with a permanent pacemaker (PM) implanted in his left prepectoral area reported twitches in his left lateral abdominal region. Chest X‐rays revealed a broken right atrial (RA) lead and a fracture of the right ventricular (RV) lead at the left costoclavicular ligament. The electrocardiogram (ECG) and the Holler ECG revealed atrial fibrillation (AF) and an improperly functioning PM. We observed that the twitching seemed to correspond with each pacing beat and that it did not appear with his own beat. We suspected that the twitching was due to electric current leakage from the broken RV lead. We performed a PM re‐implantation with a screw‐in RV lead using the extrathoracic approach. After re‐implantation the twitching disappeared. Costoclavicular ligament related electrode lead fractures are not uncommon and electric current leaks can be a source of problems in cardiac pacing. In this case, the electric current leak from the broken RV lead at the costoclavicular ligament stimulated the left phrenic nerve.

Outcome of single-chamber, ventricular pacemakers with transvenous leads implanted in children

In children with bradyarrhythmias, ventricular demand, rate-responsive pacemakers (VVI/R PM) are often indicated, but no study is entirely dedicated to their outcome. We evaluated the outcomes of children with VVI/R PM implanted at our centre, with a retrospective analysis. Between 1990 and 2005, 117 children (63 with congenital heart defects), received VVI/R PM with endocardial lead at 5.3 +/- 3.9 years of age for atrioventricular block (n = 105) and sinus node dysfunction. The majority of the leads were unipolar (n = 78), tined (n = 110), and steroid eluting (n = 89). The leads were fixed to subcutaneous tissues by absorbable suture in all patients; in 17 patients, also an atrial loop was created. Follow-up (FU) was 7.8 +/- 4.1 years. There were 22 system failures (19%), due to lead malfunction (n = 20) and system erosion/infection. The log-rank test for equality of survivor functions showed no significant risk factor. However, lead malfunction occurred only in the group without loop, but FU duration was longer in these patients. Complications at implantation were haemothorax (2.5%) and lead dislodgement (5%). Clinically silent occlusion of the subclavian vein was documented at FU by Echo-Doppler in 5%. In this particular group of patients, VVI/R pacing has good results, but after long-term FU shows 19% of failures, mainly lead-related.

Ventricular Pacing Threshold Variations in the Young

Ventricular Capture Management (VCM) is a Medtronic Kappa pacemakers (PM) feature that automatically measures pacing threshold through detection of the evoked response after a pacing stimulus. The aim of this study was to evaluate the range of variation of ventricular pacing threshold in pediatric patients with endocardial and epicardial pacing leads. Thirty-one patients (median age 6.5 years) were implanted with a Kappa 901 PM for atrioventricular block or sinus node dysfunction. Congenital heart defects (CHD) were present in 58% of patients. Ventricular leads were epicardial in 52% of patients. VCM was programmed to automatically measure threshold every 2 hours. In a median follow-up of 12 months, 27,110 threshold measurements, 72% of which were successful, have been taken in 94% of patients. Measurement success was 99% in the endocardial leads group (age at implantation 12 +/- 6 years) and 31% in epicardial leads (age 4 +/- 5 years) (P < 0.05). Main reasons for unsuccessful measurements were high heart rate and, in a patient with an endocardial lead, competition with intrinsic rhythm. Undersensing or oversensing of the evoked responses was not detected. In all successful VCM measurements, epicardial pacing and CHD contributed to stability of thresholds (multivariate analysis). Pacing threshold showed specific circadian patterns: higher thresholds were found between 00.00 and 06.00 a.m., but the variation was low, 0.03 +/- 0.01 V. In conclusion, children and young patients show stable ventricular thresholds, especially in presence of CHD, and epicardial leads are at least as stable as endocardial leads. Ventricular pacing threshold showed a circadian variability similar to that described in adults, that does not seem to influence VCM functioning and PM programming.

A novel technique for right ventricular lead placement in a patient with a persistent left superior vena cava

Persistent left superior vena cava is the most common venous anomaly of the thorax. If unrecognized, it could lead to catheter malplacement and even vascular injuries. We describe a novel use of a Worley sheath for the delivery of a right ventricular (RV) endocardial pacing lead in a 65-year-old male with a persistent left superior vena cava. After failed attempts with the standard stylets, use of the Worley sheath aided successful lead deployment. We conclude that when used appropriately, the Worley sheath is a tool that could be helpful in pacing lead placement in patients with persistent left superior vena cava.

Increased incidence of subacute lead perforation noted with one implantable cardioverter-defibrillator

The rapid evolution of implantable cardioverter-defibrillator (ICD) leads has resulted in thinner active fixation leads. While these advances have made the leads more versatile, new configurations may be associated with unforeseen complications. The purpose of this study was to determine the incidence of perforation and dislodgement of defibrillator leads in a single center in the year 2005. All patients who underwent percutaneous ICD implantation at the Massachusetts General Hospital using an endocardial right ventricular lead were included in this study. The specific leads analyzed were the Riata (1580/1581 and 1590/1591, St. Jude Medical, St Paul, Minnesota, USA;) and Sprint Fidelis (6949-65, Medtronic, Minneapolis, Minnesota, USA.). Information was collected retrospectively. A total of 130 Riata leads and 111 Sprint Fidelis leads were implanted at the Massachusetts General Hospital during this time period. A total of five lead perforations occurred in patients implanted with the Riata lead as compared with none with the Sprint Fidelis lead (3.8% vs. 0%, respectively; P <.05). Two of the five patients with perforation required pericardiocentesis for tamponade. Clinical symptoms of perforation developed 1-10 days after implant. Moreover, there were five additional lead revisions in the Riata group, which were likely due to dislodgement and/or microperforation, as compared with none in the Sprint Fidelis group (7.7% vs. 0%, respectively; P <.005). In 2005, at one institution, there were significantly more cardiac perforations and lead revisions with the Riata lead as compared with the Sprint Fidelis right ventricular defibrillator lead. Further data are required to determine whether certain lead characteristics are responsible for this observation.

Left Phrenic Nerve Stimulation Due to Breakage of the Endocardial Right Ventricular Lead at the Costoclavicular Ligament

Left Phrenic Nerve Stimulation Due to Breakage of the Endocardial Right Ventricular Lead at the Costoclavicular Ligament

Fatal Inappropriate ICD Shock

Inappropriate implantable cardioverter defibrillator (ICD) therapy carries a low but relevant risk of ventricular proarrhythmia. In the present case, the extremely rare event of a fatal arrhythmia caused by inappropriate therapy is reported. Dislodgement of the ventricular lead to the level of the tricuspid annulus led to additional sensing of the atrial signal during sinus tachycardia. Spuriously, ventricular fibrillation was sensed and induced inappropriate ICD shocks. The fourth inappropriate shock caused ventricular fibrillation, which was subsequently undersensed by the dislodged lead due to low ventricular amplitudes. The ICD started antibradycardic pacing during ventricular fibrillation. After initial successful resuscitation, the patient died 1 week later due to severe hypoxic brain damage. Although not preventable in the present case, it underlines the necessity of immediate interrogation of the ICD after ICD therapy and deactivation of the ICD in the setting of a dislodged endocardial lead and intensive care monitoring of the patient until revision.

Transseptal endocardial left ventricular pacing: An alternative technique for coronary sinus lead placement in cardiac resynchronization therapy

Coronary sinus (CS) lead placement for transvenous left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) has a failure rate at implant and short-term follow-up between 10% and 15%. The purpose of this study was to assess the feasibility of transseptal endocardial LV pacing in patients in whom transvenous CS lead placement had failed. An atrial transseptal LV lead placement was attempted in 10 patients (six females, age 69.4 +/- 9.6 years), in whom CS lead placement for CRT had failed. After transseptal puncture and septal dilatation from the femoral route, the left atrium was cannulated with a combination of catheters and guide wires from the left or right subclavian vein. After advancement of this guide catheter into the LV, a standard bipolar screw-in lead could be implanted in the posterolateral wall. All patients were maintained on anticoagulant therapy with warfarin after implant. An LV lead could be successfully implanted in nine of the 10 patients. The stimulation threshold was 0.78 +/- 0.24 V, and the R-wave amplitude was 14.2 +/- 9.7 mV. At 2 months' follow-up, the stimulation threshold was 1.48 +/- 0.35 V with a 0.064 +/- 0.027 ms pulse width. There was no phrenic nerve stimulation observed in any of the patients. There were no thromboembolic complications at follow-up. LV transseptal endocardial lead implantation from the pectoral area is a feasible approach in patients with a failed CS approach and in whom epicardial surgical lead placement is not an option. Longer follow-up is warranted to determine the risk of thromboembolic complications.

Erosion of an Extrapericardial Implantable Cardioverter Defibrillator Patch Through the Gastric Fundus With Fistulous Tract Formation

Until as recently as the mid-1990s, implantable cardioverter defibrillator (ICD) leads were placed through thoracotomy as anterior and/or posterolateral patches. The defibrillator patches have reportedly been associated with a number of relatively common mechanical complications as well as less common complications, including patch migration or erosion into contiguous structures. We report a previously unreported late complication of epicardial defibrillator patch placement in which patch migration and erosion through the gastric fundus resulted in fistulous tract formation from the mediastinum to the lumen of the stomach. Although surgically implanted epicardial patch defibrillator systems are relatively uncommon in current U.S. practice, these devices are still used when specific anatomic or electrophysiological considerations preclude the use of more common endocardial lead systems. Several thousand patients with epicardial patch leads in place are still believed to be alive in the United States. In these patients, continued vigilance for lead-related complications is appropriate. Prompt surgical intervention is usually warranted when patch migration or complications such as the one described occur.

Lead Interaction: Rare Cause of Oversensing During Implantation Procedure of Implantable Cardioverter‐Defibrillator System

A variety of etiologies can cause erroneous detection in patients with implantable cardioverter defibrillator (ICDs). Interaction between two endocardial leads is rare and uncommon in causing electrical noise. During a reimplantation procedure of an ICD system in a 68-year-old man, additional electrical signals could be detected. The interaction between two endocardial defibrillation leads was identified as the cause of sensing problems. When it is not possible to extract the nonfunctional endocardial lead during implantation of the new electrode, it should be implanted away and not in parallel from the old one to avoid interaction between them. A variety of etiologies can cause erroneous detection in patiens with ICD. Interaction between two endocardial leads is rare and uncommon to cause electrical noise.

Pacing in adults with congenital heart disease

Adults with congenital heart disease constitute one of the fastest growing populations in cardiology. Pacing is an integral part of their therapy and may reduce their morbidity and mortality significantly. The current generation of pacemakers is more sophisticated and complex, and they are being utilized for indications other than conduction abnormalities, such as termination of tachycardia and improvement of heart failure. The complex anatomy and history of multiple previous surgeries in adults with congenital heart disease, however, pose many limitations and technical challenges related to the placement of a pacemaker. Unique and innovative approaches to endocardial lead placement and improved epicardial leads is making pacemaker implantation more feasible in these patients.

Upgrading of VVIR Pacemakers with Nonfunctional Endocardial Ventricular Leads to VDD Pacemakers in Adolescents

In some children with ventricular rate responsive demand (VVIR) pacemakers (PM), transvenous leads fail for technical reasons or patient's growth. The aim of this study is to describe our experience in adolescents with a nonfunctional ventricular lead in whom the lead was abandoned and an additional VDD lead was implanted. Of the 136 children who received a VVIR PM with an endocardial lead in our center, seven patients aged 7 (0.3-12) years [median (range)] at initial implantation, after 10 (5-15) years showed lead malfunction and underwent atrial synchronous ventricular inhibited pacing (VDD) PM upgrading at 16 (10-20) years. The VDD lead was inserted through the ipsilateral subclavian vein in five patients, the contralateral in two (venous occlusion in one and for operator choice in the first patient). The tip was positioned into the right ventricular apex, the atrial dipole along the lateral atrial wall. Fluoroscopy times were not significantly different from those measured in SSI PM implantation and in VVIR dual-chamber demand pacing (VVIR-DDD) upgrading. There were no intraprocedural complications. Follow-up duration is 12 (6-62) months. The VDD PM showed good function, no undersensing or oversensing. Tricuspid damage, new venous occlusion, and "twisting" of the two leads at x-ray were not documented. The first patient showed an infection of the old PM pocket after 1 year, local pain after 3 years, and endocarditis of the leads after 5 years. The upgrading of VVIR PM to VDD PM with the abandonment of the nonfunctional lead is feasible, with no intraprocedural complications and good PM function. Lead endocarditis occurred in one patient.

Ultrasonographic Predictors of Unsuccessful Cephalic Vein Approach During Pacemaker or Defibrillator Lead Implantation

The cephalic vein approach is a preferred route for endocardial lead implantation; however, it is associated with a significant failure rate. Anatomic abnormalities likely play an important role, but specific features have not been well characterized. Color Doppler ultrasonography was performed in 82 consecutive patients prior to endocardial lead implantation. Venous diameter, depth, flow velocity, and morphology were evaluated and comparisons made between the successful and failed implantations at various stages of the procedure. Endocardial lead implantation was unsuccessful in 14 patients (17%), with eight patients of venous isolation failure, 4 patients of cannulation failure, and 2 patients of guidewire crossing failure. Venous diameter was found to be the only independent predictor for isolation and implantation failure. The best cutoff value of cephalic venous diameter to predict unsuccessful cephalic venous approach was < or = 2.2 mm. In total, there were 10 patients with extensive cephalic vein tortuosity. In seven of these 10 patients, the incidence of standard guidewire crossing failure was significantly higher than that without a tortuous cephalic vein (7/10 vs 6/60, P < 0.001). After switching to a hydrophilic guidewire, crossing and navigation were successful in five of the seven patients. Color Doppler imaging is useful to identify cephalic vein characteristics. A small venous diameter is the ultrasonographic predictor for failure of cephalic vein approach. A tortuous venous morphology is associated with a high incidence of guidewire crossing failure, which can be mostly overcome by using a hydrophilic guidewire.

Large septic pulmonary embolism complicating extraction of an infected transvenous defibrillator lead

1 A-53-year-old man with known coronary artery disease and a istory of sustained monomorphic ventricular tachycardia underent placement of a dual-chamber implantable cardioverter-defirillator (ICD) in 2003. He presented to an outside facility with ever. His blood cultures were positive for Staphylococcus epiermidis, and the patient subsequently was transferred to our acility for further treatment. On physical examination he apeared well. He was afebrile, and his left infraclavicular ICD ocket was benign. A transthoracic echocardiogram (Figure 1A) evealed a large mobile vegetation (1.5 cm 1.5 cm) localized to he ICD lead within the right ventricle as it coursed through the ricuspid valve. Mild tricuspid regurgitation was present. A transenous endocardial lead extraction was performed using a comination of locking stylet and electrocautery dissection. All imlanted hardware was extracted without evidence of retained lead ragments. Immediately after the procedure, a transthoracic echoardiogram showed no evidence of vegetation within the heart and o change in valvular regurgitation. After the procedure, the paient developed left-sided pleuritic chest pain associated with feer. Computed tomographic scan of the chest confirmed a large ulmonary embolus (Figure 1B, filling defect) confined to the eft lower lobe pulmonary artery with evidence of pulmonary nfarction and consolidation (arrowhead). Intraoperative cultures f the pocket and lead tips were negative for bacterial growth; the atient had been receiving intravenous (IV) antibiotics for a few ays prior to the procedure. The patient was treated with 6 weeks f IV antibiotics and recovered without sequelae. He subsequently nderwent repeat ICD placement. With the ever-increasing number of cardiac pacemaker and CD placement procedures, physicians are likely to encounter ore patients with infected intravascular device hardware. he risk of pulmonary embolism complicating extraction of acemaker and ICD leads associated with vegetations 1 cm n size has been highlighted in the literature. The original bservation regarding the risk of embolization and larger vegtations was reported by Mugge et al, who demonstrated that 2 (47%) of 47 patients with vegetations 1 cm had evidence

Minimally Invasive Surgical Techniques for Cardiac Resynchronization Therapy of Heart Failure

Background Biventricular (BiV) pacing is a proven advantageous adjuvant therapy for patients with ventricular dyssynchrony associated with congestive heart failure. Endocardial left ventricular lead placement does have several limitations: 1) anatomic variations of the coronary venous system, 2) late lead dislodgement, and 3) phrenic/diaphragmatic stimulation. Epicardial lead placement is often a ‘rescue’ procedure after failed coronary sinus implantation but offers some advantages related to safety and a shorter implant time. The aim the study is to describe two different minimally invasive surgical techniques for LV epicardial lead placement for resynchronization therapy of patients with chronic heart failure. Methods Between December 2002 and December 2004, 88 patients (pts) underwent minimally invasive left ventricular lead placement, Videoendoscopic assisted surgery was performed in patients 31, and Minithoracotomy in 57. Fifty pts. (56.8%) were males, mean age was 67 ±8.3 years (35-83), 44 (54.5%) had previous cardiac surgery, 58 (66%) had ischemic cardiomyopathy, 20 (22.7%) NYHA III-IV, 31 (35%) had more than 3+ mitral regurgitation and 46 (52.3%) had implantable cardioverter defibrillators. Results There were no deaths. The mean hospital length of stay was 4.5 ± 3.2 days. Postoperative complications included non-dialysis renal failure in 4 pts. (4.5%), atrial fibrillation in 10 (11.3%), non sustained ventricular tachycardia in 3 (3.4%) and decompensate heart failure in 2 (6.2%). Significant improvements were observed in postoperative parameters in comparison to the preoperative period (Table). Conclusions Minimally invasive LV epicardial lead placement are effective and safety techniques, with minimal morbidity, and can be helpful in the treatment of this complex disease. Prospective randomized studies between epicardial and endocardial lead placements should further define the role of these different techniques in the resynchronization therapy for heart failure. ![Graphic][1] [1]: /embed/graphic-1.gif

Unique Bi-V Lead Setups for Closed-Loop Stimulation Rate Adaptation

The physiologic Closed Loop Stimulation (CLS) sensor translates localized myocardial impedance via an RV endocardial lead into pacing rates. CLS rate adaptation using non-traditional Bi-V lead configurations is unknown and was investigated. We examined acute (hall walk) and long-term rate adaptations over 7-14 months post implant in 5 CLS pacemaker patients with various non-traditional Bi-V configurations, positioning leads at RV apex and/or outflow tract, LV epicardium, or coronary sinus, with/without Y adaptors. Hall walks after CLS activation showed acute rate support in 4 of 4 patients tested. Patients were then CLS Bi-V paced for 6 to 8 months. Total atrial pacing varied 57-99% among 5 patients. CLS sensor-driven pacing occurred 22-95% of the time and spanned the full range between lower and maximum sensor rates for all patients. CLS provides rate-adaptive pacing in response to patients' metabolic needs during chronic and acute situations using non-traditional lead configurations. CLS rate adaptation may contribute physiologic benefits to CHF pts undergoing CRT and warrants further investigation.

High Pacing Impedances: Are You Overtorquing Your Leads?

Variations in measured pacing impedances that occur at the time of lead implantation remain largely unexplained and may be due to the morphology of the tissue-lead interface. An endocardial pacing lead was implanted under direct endoscopic visualization and parameters were measured for defined stages of implantation into multiple sites within the right atrium of in vitro swine hearts (n = 6, 38 implants), in vivo swine hearts (n = 2, 10 implants), and an in vitro human heart (n = 1, 15 implants). Steady increases in impedance values up to 2 turns fully fixed (2TF) were associated with minimal tissue distortion in all implants. Overtorquing of the in vitro swine implants resulted in severe distortion at the tissue-lead interface demonstrating either tissue wrapping (24 implants) or tissue coring (14 implants). Impedance and threshold values remained elevated (953 +/- 282 Omega, 7.86 +/- 3.0 V; both P < 0.05 vs 2TF) during tissue distortion/wrapping, while tissue-cored implants were associated with significant decreases (552 +/- 187 Omega, 6.2 +/- 2.2 V; both P < 0.05 vs 2TF). P-wave amplitudes demonstrated no significant changes or correlation to tissue distortion. Importantly, both swine in vivo and human in vitro data demonstrated similar trends compared with the swine in vitro data. In this study, one is able to directly observe and correlate the degree of distortion at the tissue-lead interface with measured electrical parameters. Instantaneous impedance values obtained during fixation serve as a superior indicator of an acceptable lead implantation, and should therefore be carefully monitored during implantation.

Minimally Invasive Surgical Alternatives for Left Ventricle Epicardial Lead Implantation in Heart Failure Patients

Biventricular pacing is a proven advantageous adjuvant therapy for patients with ventricular dyssynchrony associated with congestive heart failure. Endocardial left ventricular lead placement does have several limitations: anatomic variations of the coronary venous system and late lead dislodgement. Epicardial lead placement is often a rescue procedure but offers some advantages related to safety and a shorter implant time. Moreover, it allows visual selection of the best pacing site and multiplicity of pacing sites. Three minimally invasive surgical methods of left ventricular lead placement are outlined in this article, including specific indications and limitations. Biventricular pacing has been proposed as an adjuvant treatment for patients with heart failure and intraventricular conduction delay.

Cardiac resynchronisation therapy versus dual site right ventricular pacing in a patient with permanent pacemaker and congestive heart failure

A 46-year-old male patient who had long-term right ventricular (RV) pacing for symptomatic complete heart block, initially by an epicardial, later with an endocardial pacing lead at the RV apex, developed congestive heart failure (CHF) and chronic atrial fibrillation 7 years following the pacemaker implantation and was medically treated. During follow-up, his pacemaker was upgraded to a cardiac resynchronisation therapy (CRT) device, because of uncontrolled CHF symptoms, New York Heart Association (NYHA) functional class IV, while on drugs. The patient's symptomatic status improved to NYHA functional class II with CRT. After 17 months of CRT, the battery became depleted, because of the high capture threshold of the left ventricular lead. The patient was then given dual site RV pacing (RV outflow tract+RV apex) in place of CRT, which showed similar efficacy at 12 weeks follow-up.