Asymptomatic pulmonary embolism following pacemaker implantation

Acute transvenous pacemaker lead thrombosis early after implantation: A rare clinical scenario

Symptomatic thrombus formation due to a permanent pacemaker (PM) lead is a rare complication. It could be associated with serious outcome and should be suspected in patients who present with unexplained right heart failure, dyspnea, or syncope following dual-chamber PM implantation. A timely decision to perform an echocardiographic examination, followed by medical, thrombolytic, or surgical treatment can be necessary. We describe the case of an 84-year-old man who presented with syncope and hypotension a few days after PM implantation. A transesophageal echocardiography revealed a mobile mass in the right atrium attached to the pacemaker lead. Intravenous heparin allowed a complete resolution of the thrombus.

Lead-related infective endocarditis with vegetations: Prevalence and impact of pulmonary embolism in patients undergoing transvenous lead extraction

INTRODUCTION

The prevalence and impact of pulmonary embolism (PE) in patients with lead-related infective endocarditis undergoing transvenous lead extraction (TLE) are unknown.

METHODS

Twenty-five consecutive patients with vegetations ≥10 mm at transoesophageal echocardiography were prospectively studied. Contrast-enhanced chest computed tomography (CT) was performed before (pre-TLE) and after (post-TLE) the lead extraction procedure.

RESULTS

Pre-TLE CT identified 18 patients (72%) with subclinical PE. The size of vegetations in patients with PE did not differ significantly from those without (median 20.0 mm [interquartile range: 13.0-30.0] vs. 14.0 mm [6.0-18.0], p = 0.116). Complete TLE success was achieved in all patients with 3 (2-3) leads extracted per procedure. There were no postprocedure complications related to the presence of PE and no differences in terms of fluoroscopy time and need for advanced tools. In the group of positive pre-TLE CT, post-TLE scan confirmed the presence of silent PE in 14 patients (78%). There were no patients with new PE formation. Large vegetations (≥20 mm) tended to increase the risk of post-TLE subclinical PE (odds ratio 5.99 [95% confidence interval (CI): 0.93-38.6], p = 0.059). During a median 19.4 months follow-up, no re-infection of the implanted system was reported. Survival rates in patients with and without post-TLE PE were similar (hazard ratio: 1.11 [95% CI: 0.18-6.67], p = 0.909).

CONCLUSION

Subclinical PE detected by CT was common in patients undergoing TLE with lead-related infective endocarditis and vegetations but was not associated with the complexity of the procedure or adverse outcomes. TLE procedure seems safe and feasible even in patients with large vegetations.

Venous Obstruction in Cardiac Rhythm Device Therapy

PURPOSE OF REVIEW

A variety of complex vascular pathologies arise following the implantation of electronic cardiac devices. Pacemaker and defibrillator lead insertion may cause proximal venous obstruction, resulting in symptomatic venous congestion and the compromise of potential future access sites for cardiac rhythm lead management.

RECENT FINDINGS

Various innovative techniques to recanalize the vein and establish alternate venous access have been pioneered over the past few years. A collaborative team of electrophysiologists and vascular specialists strategically integrate the patient's vascular disease into the planning of electrophysiology procedures. When vascular complications occur after device implantation, the same team effectively manages both the resulting vascular sequelae and related cardiac rhythm device challenges. This review will outline the various vascular challenges related to device therapy and offer an effective strategy for their management.

Cardiac implantable electronic device lead-based masses and atrial fibrillation ablation: a case-based illustration of periprocedural anticoagulation management strategies

INTRODUCTION

Cardiac implantable electronic device (CIED) leads frequently develop echogenic masses. However, the nature of these masses is not well understood. In patients in whom atrial fibrillation (AF) catheter ablation is planned, there is concern that transseptal puncture may result in cerebrovascular embolism of these masses. The optimal therapeutic strategy in this setting remains undefined.

METHODS

We describe six patients identified over a 6-year period (2008-2014) with device lead-based masses prior to or at the time of AF ablation. We examined the anticoagulation strategy and periprocedural management based on mass identification.

RESULTS

In all six patients (age 39-73; four males), the device lead mass was found in the right atrium. The average mass size was 11 ± 1.3 mm. The majority of patients were already on anticoagulation (5/6; 83 %), and an intensified anticoagulation regimen was initiated (INR goal 3.0). In all six patients, the size of the device lead mass decreased on repeat imaging. In two sixths (33 %) patients, the lead-based mass completely resolved within 2 months. The remaining four patients had persistent lead-based masses (average follow-up of 10.9 ± 9.6 months).

DISCUSSION

We describe a series of patients with CIED lead-based masses found at the time of ablation. These cases illustrate that lead-based masses can disappear while patients are on high-intensity anticoagulation, most compatible with a thrombotic origin. These early data will need to be assessed in larger cohorts for further validation and evaluation of safety.

Acute stroke from paradoxical embolism of dense fibrous tissue following pacemaker lead extraction: salvation by mechanical thrombectomy

Systemic embolization is a dreaded complication of transvenous lead extraction (TLE), even without visible vegetations. Preoperative patent foramen ovale evaluation is important, justifying neurological surveillance or consideration of surgical extraction in selected cases. In case of stroke after TLE, mechanical thrombectomy is a successful therapy, and should be readily available.

Pulmonary embolism in patients with transvenous cardiac implantable electronic device leads

BACKGROUND

Cardiac implantable electronic devices (CIEDs) are commonly associated with transvenous lead-related thrombi that can cause pulmonary embolism (PE).

METHODS AND RESULTS

We retrospectively evaluated all patients with transvenous CIED leads implanted at Mayo Clinic Rochester between 1 January 2000, and 25 October 2010. Pulmonary embolism outcomes during follow-up were screened using diagnosis codes and confirmed with imaging study reports. Of 5646 CIED patients (age 67.3 ± 16.3 years, 64% men, mean follow-up 4.69 years) 88 developed PE (1.6%), incidence 3.32 [95% confidence interval (CI) 2.68-4.07] per 1000 person-years [men: 3.04 (95% CI 2.29-3.96) per 1000 person-years; women: 3.81 (95% CI 2.72-5.20) per 1000 person-years]. Other than transvenous CIED lead(s), 84% had another established risk factor for PE such as deep vein thrombosis (28%), recent surgery (27%), malignancy (25%), or prior history of venous thromboembolism (15%). At the time of PE, 22% had been hospitalized for ≥ 48 h, and 59% had been hospitalized in the preceding 30 days. Pulmonary embolism occurred in 22% despite being on systemic anticoagulation therapy. Out of 88 patients with PE, 45 subsequently died, mortality rate 93 (95% CI 67-123) per 1000 person-years (hazard ratio 2.0, 95% CI 1.5-2.7, P < 0.0001).

CONCLUSIONS

Though lead-related thrombus is commonly seen in patients with transvenous CIED leads, clinical PE occurs with a low incidence. It is possible that embolism of lead thrombus is uncommon or emboli are too small to cause consequential pulmonary infarction.

Right giant atrial thrombosis and pulmonary embolism complicating pacemaker leads

We describe a case of a patient with bilateral pulmonary embolism because of a giant intracardiac thrombus anchored on a right atrial pacemaker lead treated with unfractionated heparin and the consecutively complete thrombus resolution after 5-6 days.

Mobile Thrombus on Device Leads in Patients Undergoing Ablation

Background—

Mobile thrombi, not routinely recognized on transthoracic echocardiography, are frequently identified on cardiovascular implantable electronic device leads with intracardiac echocardiography (ICE) during ablation procedures. Their incidence, characteristics, and consequences have not yet been defined.

Methods and Results—

We used ICE to examine leads for thrombi and to measure the pulmonary artery systolic pressure in patients with a cardiovascular implantable electronic device presenting for ablation. Patient clinical characteristics, device type, and lead characteristics were correlated with presence of thrombi. Most patients had congestive heart failure (84%), with an average left ventricular ejection fraction of 40%. Thrombi were seen with ICE in 26 of 86 patients (30%) but were seen on transthoracic echocardiography in only 1 of the 26 patients. Thrombi on ICE were mobile, averaged 18±5.9 mm long by 4.4±2.3 mm wide, and were more commonly identified in the right atrium (n=25) than in the right ventricle (n=5). Thrombi were associated with higher pulmonary artery systolic pressure: 39±9 mm Hg with thrombi versus 33±7 mm Hg without thrombi (odds ratio, 1.11; 95% confidence interval, 1.03 to 1.20; P =0.01). No other characteristic assessed was associated with a significant difference in the presence of lead thrombi.

Conclusions—

Mobile thrombi on cardiovascular implantable electronic device leads are present in 30% of patients undergoing ablation and are readily identified with ICE despite being underrecognized with transthoracic echocardiography. Further study is warranted to determine whether lead thrombi are a clinically relevant source of pulmonary emboli in some patients with cardiovascular implantable electronic devices.

Ultrasound accelerated catheter directed thrombolysis for pulmonary embolus and right heart thrombus secondary to transvenous pacing wires

Acute pulmonary embolism is associated with a significant number of deaths each year, which are commonly attributed to deep venous thrombosis of the lower extremity. Pulmonary embolism due to right-sided cardiac thrombus associated with transvenous wires is a rare occurrence. Treatment considerations have been systemic anticoagulation with heparin or systemic thrombolytic therapy. A unique case of a patient with symptomatic PE and extensive atrial and ventricle thrombus formation associated with transvenous pacing wires treated with ultrasound accelerated catheter directed thrombolysis is presented.

Biventricular pacemaker lead thrombosis: a rare case treated with surgical thrombectomy

Right cardiac thrombosis is an infrequent complication after pacemaker implant. We report a patient who received a biventricular implantable cardioverter defibrillator, with a large mobile thrombus, adherent to the left ventricular lead. This catheter was partially dislocated, with a large, mobile loop through the right atrium and right ventricle; so the lead thrombus could alternately obstruct the pulmonary valve and the tricuspid valve. We believe that this is the first case of left ventricular lead thrombosis, in which the surgical treatment included thrombectomy with conservation of the catheter that was anchored to the internal right atrial wall in order to limit its great motility, maintaining the contribution to the cardiac resynchronization.

Predictors of venous obstruction following pacemaker or implantable cardioverter-defibrillator implantation: a contrast venographic study on 100 patients admitted for generator change, lead revision, or device upgrade

AIM

Venous obstruction following transvenous device implantation rarely cause immediate clinical problems. When lead revision or device upgrade is indicated, venous obstruction become a significant challenge. The aim of this study was to determine the predictors of venous obstruction after transvenous device implantation, and to asess likely effects of antiplatelet/anticoagulant drugs in preventing venous thrombosis.

METHODS AND RESULTS

Between March 2005 and July 2006, contrast venography was performed in 100 patients who were candidates for generator change, lead revision, or device upgrade. Vessel patency was graded as either completely obstructed, partially obstructed (>70%), or patent. The incidence of venous obstruction was 26%, with 9% of patients having total obstruction and 17% of patients exhibiting partial obstruction. No statistically significant differences between obstructed and non-obstructed patients were seen for age, sex, indication for device implantation, atrial fibrillation, cardiothoracic ratio, insulation material, operative technique, device type, and manufacturer (all Ps > 0.05). In a univariate analysis, multiple leads (P = 0.033), and presence of dilated cardiomyopathy (P = 0.036) were associated with higher risk of venous obstruction, whereas anticoagulant/antiplatelet therapy (P = 0.047) significantly reduced incidence of venous obstruction. Multivariate logistic regression analysis showed that only number of the leads (P = 0.039, OR: 2.22, and 95% CI: 1.03-4.76) and antiplatelet/anticoagulant therapy (P = 0.044, OR: 2.79, and 95% CI: 0.98-7.96) were predictors of venous obstruction.

CONCLUSION

Total or partial obstruction of the access veins occurs relatively frequently after pacemaker or ICD implantation. Multiple pacing or ICD leads are associated with an increased risk of venous obstruction, whereas antiplatelet/anticoagulant therapy appears to have a preventive effect on development of access vein thrombosis.

Acute Subclavian or Axillary Vein Occlusion During Biventricular Pacemaker Implantation

During biventricular pacemaker implantation, multiple punctures of the subclavian vein were performed and venous occlusion was apparent during the procedure, which in one case was stopped before lead insertion and in the other patient new access has to be forced through the occlusion by removing one of the already implanted leads. For implanting physicians, it is important to know that acute venous occlusion may occur during lead implantation.

Pacemaker lead thrombosis treated with atrial thrombectomy and biventricular pacemaker and defibrillator insertion

Right atrial thrombosis and pulmonary embolism are infrequent complications of pacemaker insertion. We report a patient with a large mobile thrombus on an endocardial DDD pacing lead and probable pulmonary embolism. We believe that this is the first case of pacemaker lead thrombosis in which treatment included insertion of an epicardial biventricular pacemaker and an implantable cardioverter-defibrillator.

Incidence and Risk Factors of Early Venous Thrombosis Associated with Permanent Pacemaker Leads

INTRODUCTION

Pacemaker lead implantation can cause thrombosis, which can be associated with serious local morbidity and complicated by pulmonary embolism. Few reliable estimates of the incidence of thrombosis have been reported. The contribution of established risk factors to venous thrombosis in patients with implanted pacemaker leads is unknown.

METHODS AND RESULTS

One hundred forty-five consecutive patients n = 145) underwent routine clinical and Doppler ultrasound evaluation for thrombosis before and 3, 6, and 12 months after lead implantation. Established risk factors for venous thrombosis were assessed in detail for all patients. Clinical outcome, including clinically manifest thrombosis, pulmonary embolism, associated pacemaker lead infection, complicated reinterventions, and death, was evaluated. Thrombosis was observed in 34 (23%) of 145 patients. Thrombosis did not cause any signs or symptoms in 31 patients but resulted in overt clinical symptoms in 3 patients. The absence of anticoagulant therapy, use of hormone therapy, and a personal history of venous thrombosis were associated with an increased risk of thrombosis. The risk of thrombosis increased in the presence of multiple pacemaker leads compared to a single lead.

CONCLUSION

Established risk factors for venous thrombosis and the presence of multiple pacemaker leads contribute substantially to the occurrence of thrombosis associated with permanent pacemaker leads. Risk factor assessment prior to implantation may be useful for identifying patients at risk for thrombotic complications. Preventive management in these patients is warranted.

Early Pacemaker Lead Thrombosis Leading to Massive Pulmonary Embolism

Clinically apparent pulmonary embolism is a rare complication of permanent transvenous pacing catheters. Here we report an unusual case of a 71-year-old man who developed massive pulmonary embolism 12 hours after a permanent transvenous pacemaker implantation in the absence of any patient-related predisposing factor. Transesophageal echocardiography showed a large thrombus within the right atrium closely attached to the pacemaker lead. Anticoagulation with heparin, followed by warfarin therapy, led to a complete resolution of the thrombus.

Long-term outcome of patients with multiple (> or = 3) noninfected transvenous leads: a clinical and echocardiographic study

To prospectively assess the incidence and clinical significance of thromboembolic complications in patients with multiple (> or = 3) noninfected transvenous leads; 48 consecutive patients were evaluated. Half of the patients had two ventricular leads and one atrial lead, 15 patients had two atrial leads and one ventricular lead, while 9 patients had two ventricular and two atrial leads. No additional care was provided except for aspirin (80 mg bid) and annually performed echo-Doppler studies. Clinical follow-up included signs and symptoms of subclavian and/or axillary vein thrombosis, the presence of right congestive heart failure, the number of hospital admissions, and death. Echo-Doppler studies assessed the presence of an enlarged right atrium or ventricle, right atrial or ventricular spontaneous contrast, and the presence of tricuspid regurgitation. During a total follow-up of 7.4 +/- 2.2 years there were no differences in the incidence of clinical variables as compared to age-matched controls with DDD pacemakers. The most common complication was transient venous thrombosis (mostly presenting as venous prominence 1-2 weeks after implantation), which was seen in 17% of the study group versus 15% in controls (NS). Cumulative mortality was not different in both groups (13% in the study group vs 15% in controls). No differences were present with respect to hospital admissions (1.1 +/- 0.27/year in the study group vs 1.2 +/- 0.30/year in the controls). In patients with multiple ventricular leads, tricuspid regurgitation on echo-Doppler studies was more frequent (24%) as compared to controls (4%); however, clinical signs of right heart failure were equally distributed. Thus, patients with multiple (> or = 3) noninfected leads have no clinical adverse outcome during long-term follow-up.

Long-term thrombosis after transvenous permanent pacemaker implantation

To assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis after long-term transvenous permanent pacemaker implantation, venograms were performed in 100 consecutive patients at the elective replacement of the pacemaker. Mean follow-up period after initial transvenous permanent pacemaker implantation was 6.0 years. The venograms demonstrated normal in 77 patients. The remaining 23 venograms showed venous stenosis in 11 patients and total obstruction in 12 patients. Twenty-one of these 23 patients had venous collateral circulation. No difference was found in the incidence of venous abnormalities according to the route of entry, the lead insulation, the total number of the implanted leads, and anticoagulant and antiaggregant drugs. All these patients have remained asymptomatic. In conclusion, the incidence of venous thrombosis after long-term transvenous pacing is 23% and the causes of venous thrombosis may be endothelial trauma and underlying venous stenosis. As this article describes a retrospective limited study, we cannot find the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis formation after transvenous permanent pacemaker implantation. Further prospective study will be needed to assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs.

Prethrombotic state due to hypercoagulability in patients with permanent transvenous pacemakers

Venous thrombosis is a relatively usual but serious complication of permanent transvenous pacing. However, the pathogenesis has not been defined. To clarify underlying abnormalities in the coagulation-fibrinolysis system in patients with permanent transvenous pacemakers, we measured serum levels of fibrinopeptide A (FPA), thrombin-antithrombin III complexes (TATs), plasmin-alpha 2 plasmin inhibitor complexes (PICs), D-dimer (D-D), beta-thromboglobulin (beta-TG), and platelet factor 4 (PF4) in 53 patients with permanent transvenous pacemakers and 10 control subjects. The patients were divided into two groups, as follows, according to the presence of mural thrombus documented along the pacing lead(s) by digital subtraction angiography and transesophageal echocardiography: Group Th (-), patients without venous route thrombus; and Group Th (+), patients with venous route thrombus. FPA and TAT levels increased significantly even in Group Th (-), and further increased in Group Th (+) compared with control subjects (FPA: 7.5 +/- 4.9, 15.3 +/- 8.8 vs 3.0 +/- 1.4 ng/mL, respectively, P < 0.05; TAT: 2.9 +/- 1.3, 4.8 +/- 2.3 vs 1.7 +/- 0.6 ng/mL, respectively, P < 0.05). There were no differences in levels of D-D, PIG, beta-TG, and PF4 among control subjects, Group Th (-), and Group Th (+). These findings suggest that the hypercoagulable state appears in patients with permanent transvenous pacemakers, even without apparent venous thrombosis. The patients with permanent transvenous pacemakers are thought to be in the prethrombotic state even if they have no venous route thrombosis.

Echographic detection of latent severe thrombotic stenosis of the superior vena cava and innominate vein in patients with a pacemaker: integrated diagnosis using sonography, pulse Doppler, and color flow

Thrombosis of the innominate vein and SVC is a serious complication in patients with pacemakers, inducing pulmonary embolism or SVC syndrome. Venography is the definitive method for its diagnosis; however, it is too invasive for related studies. The purpose of this study was to validate sonography, pulse Doppler, and color flow in detecting noninvasively innominate vein or SVC thrombosis in patients with pacemakers. In 53 patients with pacemakers, the 1 severe SVC stenosis and 18 severe innominate vein stenoses due to thrombosis were diagnosed by digital subtraction angiography. Sonography accurately showed the severe SVC stenosis due to thrombosis, but had limitations on the innominate vein thrombosis. Color flow demonstrated mosaic flow, indicating poststenotic turbulence due to stenosis of the innominate vein and SVC caused by thrombosis in 15 of 16 patients, and pulse Doppler disclosed absence of flow due to complete occlusion of the innominate vein in 2 of 2 patients. Sensitivity and specificity for detecting severe innominate vein stenosis due to thrombosis using combined color flow and pulse Doppler was 94% and 100%, respectively. In conclusion, sonography, pulse Doppler, and color flow allow accurate detection of severe innominate vein or SVC stenosis due to thrombosis, and are therefore useful for the follow-up of patients with a pacemaker.

Multiplane transesophageal echocardiographic evaluation of transvenous defibrillation leads

Permanent transvenous cardioverter-defibrillator leads were investigated by multiplane transesophageal echocardiography (TEE) (1) to determine whether intracardiac lead segments can be visualized, (2) to verify the position of the coils, and (3) to detect possible thrombus formation. The diagnostic information obtained in 62 patients by TEE was compared to that of transthoracic echocardiography (TTE). Abnormal findings were only visualized by multiplane TEE. However, further controlled studies are needed to determine the clinical relevance of displaced caval (one patient) and ventricular coils (15 patients), ventricular (1 patient) or atrial (6 patients) loops, and of clinically uneventful thrombi (13 patients).

Mildly symptomatic pulmonary emboli associated with electrophysiologic procedures. Indications for anticoagulant use

Symptomatic pulmonary emboli complicating electrophysiologic procedures are uncommon. Asymptomatic or mildly symptomatic embolic are likely much more common. This case report highlights the problem of extensive, but mildly symptomatic, pulmonary emboli occurring as a complication of electrophysiologic procedures, including catheter ablation. The role of anticoagulation during and following electrophysiologic procedures in preventing pulmonary emboli (which can have long-term sequelae) is unknown. Currently, there appears to be no consensus regarding the use of anticoagulants either during or following electrophysiologic procedures, including those involving catheter ablation. Based on the presumed frequency and potential long-term complications of pulmonary emboli, anticoagulation during electrophysiologic procedures should be recommended.

Comparative thrombogenicity of pacemaker leads

To evaluate the thrombogenicity of transvenous silicone and polyurethane pacemaker leads, 9 of 12 anesthetized Yorkshire pigs (27-32 kg) were implanted with silicone (n = 5) or polyurethane (n = 4) pacemaker leads via a femoral vein. The remaining three pigs served as controls. All 12 pigs were injected with autologous indium-111 labeled platelets (300-420 muCi) 24 hours before anesthesia induction. The pigs were monitored for 3 hours under a gamma camera. Radioactivity in blood and lead segments was measured with a gamma counter. Platelet deposits were denser on silicone leads (441.58 +/- 915.0 to 2.19 +/- 2.07) than on polyurethane leads (1.21 +/- 1.33 to 0.27 +/- 0.14) (P > 0.05). Denser platelet deposits were detected at the tip of all leads. Density of platelet deposits declined from tip to distal segments in silicone leads. The percentage of injected platelet radioactivity in the lungs of pigs with either silastic leads (12.9 +/- 2.3%) of polyurethane leads (10.1 +/- 2.2%) was higher than in the controls (4.6 +/- 0.5%) (P < 0.05). This difference indicates thrombus formation and embolization in the lungs early after lead implantation. Thrombogenicity of polyurethane leads may be lower than that of silicone leads.

The spectrum of thromboembolization in the central circulation

The right heart and great veins can be the harbinger of septic and aseptic thromboemboli, which can result in a spectrum of clinical syndromes. This report presents five distinct clinical scenarios of thromboembolization, the occurrence of which in the central circulation resulted in life-threatening sepsis and hemodynamic and pulmonary insufficiency. Recommendations for therapeutic intervention and a review of the literature also are presented.

Transesophageal echocardiography detects thrombus formation not identified by transthoracic echocardiography after the Fontan operation

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

DSA diagnosis of pulmonary embolization from intracardial thrombus in a patient with permanent pacing catheter

Pulmonary embolization in patients with implanted pacemakers is rare and an intracardiac thrombus attached to the distal end of a newly implanted ventricular endocardial electrode following removal of a previously implanted lead is a curiosity. We have documented such a case by digital subtraction angiography, a minimally invasive procedure that demonstrates both an intracardiac thrombus and secondary pulmonary embolization in a single procedure, which also allows simplified follow-up evaluation following therapy.

Pathologic findings related to the lead system and repeated defibrillations in patients with the automatic implantable cardioverter-defibrillator

The purpose of the present study was to examine at autopsy the effect of multiple defibrillations on the myocardium and the pathologic consequences of short- and long-term placement of the intravascular and interpericardial leads of the automatic implantable cardioverter-defibrillator. Twenty-five patients were examined at autopsy; 8 of them underwent lead implantation only and 17 received both leads and the automatic implantable cardioverter-defibrillator. Twelve patients (48%) died of ventricular tachycardia or ventricular fibrillation; seven (28%) died of other causes. Acute pericarditis occurred in all patients, resulting in a localized, progressive fibrosis around the apical patch lead without giving rise to pericardial restriction. Thrombus formation was associated with the superior vena cava spring electrode in four patients (17%) and the right ventricular rate-sensing electrode in one patient (4%). Asymptomatic pulmonary emboli occurred in two patients (8%). In one patient who underwent defibrillation 59 times, superior vena cava changes consisted of vein wall destruction, fibrosis and thrombus formation. Pathologic changes under the apical patch related to defibrillation were observed in seven patients; two of these had fewer than 5 defibrillations, one had 8 defibrillations and four had 21 to 74 defibrillations. These changes consisted of contraction band necrosis in four patients, vacuolar cytoplasmic clearing and loss of myocytes confined to the myocardium under the patch electrode in five patients who had multiple defibrillations. The observed pathologic changes were estimated to affect less than 2% of the total myocardial mass. Thus, the automatic implantable cardioverter-defibrillator lead system and multiple defibrillations result in localized myocardial injury confined to the tissue under the patch electrode.(ABSTRACT TRUNCATED AT 250 WORDS)

Right atrial thrombus and recurrent pulmonary emboli secondary to permanent cardiac pacing--a case report and short review of literature

A patient with a right atrial thrombus and recurrent pulmonary emboli secondary to permanent pacemaker insertion is described. Possible precipitating factors were damage to the subclavian vein, congestive heart failure, paroxysmal atrial fibrillation, and immobilization. Venography demonstrated a large atrial thrombus in the superior vena cava and right atrium. The patient was successfully treated with heparin and subsequently with warfarin and dipyridamole.