Epicardial Pacemaker Research Articles

Integrated home monitoring predicts lead failure in a pacemaker dependent 4-year-old girl

A 4-year-old girl with post-surgical complete atrioventricular block received an epicardial dual chamber pacemaker system. During further growth intermittent exit block occurred, first misinterpreted as neurological seizures. The epicardial lead was replaced using a transvenous approach, and a pacemaker with an integrated home monitoring facility was implanted. After her discharge, a rise in the pacing threshold automatically initiated an event message. On the basis of this information, the patient was called in and imminent dislodgement of the ventricular lead was diagnosed by x-ray. The lead was repositioned and was found stable over 1-year follow-up.

Complete Atrioventricular Block due to a Hydatid Cyst Located in the Interventricular Septum: A Case Report

We report a case of complete atrioventricular block and tricuspid valve insufficiency due to a cardiac hydatid cyst located in the interventricular septum that occurred in a 19-year-old male patient. Surgery was carried out with the help of cardiopulmonary bypass. The cyst was excised, and the interventricular septum was closed with an autologous pericardial patch treated with glutaraldehyde. The tricuspid valve insufficiency was repaired with annuloplasty. A dual-chamber epicardial pacemaker was implanted. The postoperative course was uneventful, and the patient was doing well 6 months after discharge. This is the first report of a cardiac hydatidosis case for which the repair of the interventicular septum, tricuspid annulopasty, and permanent pacemaker implantation were performed during the same operation.

Medium-term follow-up and modes of failure following epicardial pacemaker implantation in young children†

Young children suffering from congenital or post-operative AV-block require life-long pacemaker stimulation. Due to the anatomical prerequisites initially epicardial electrodes are implanted and the generator is placed in the upper abdominal wall. The following study investigated modes of failure leading to reoperation in this group of technically challenging patients. Between October 2000 and May 2005, a total of 21 infants (age 3 days to 5 years) underwent pacemaker implantation using a subxyphoidal incision for newborns (and a partial lower or complete median sternotomy for older children). Nine patients had previous cardiac surgery for complex congenital defects. The remaining 12 young children suffered from congenital AV-Block (CAVB). Twenty-one bipolar epicardial electrodes (Medtronic Capsure epi) were fixed to the right ventricle, 15 had additional implantation of a bipolar atrial lead. The pacemaker generator (Medtronic Kappa 701) was implanted into the right upper abdominal wall. Indications for revision were recorded. No mortality was observed; pacing and sensing parameters remained stable up to a 5-year follow-up. A total of four reoperations occurred. Three of the four revisions were caused by ventricular electrode fracture. At revision, two electrodes were broken at the crossing between the pericardial cavity and the abdominal wall, one bipolar lead at the Y-division into the two tip electrodes. One reoperation was due to a pacemaker recall. All revisions were performed without complications. In our institute epicardial pacing in young children was associated with a satisfactory clinical outcome, but also a significant number of failures leading to reoperation, mainly due to electrode fracture caused by the muscular activity of this patient group. Reoperations were performed at a low risk.

Cardiovascular Involvement in 8 Dogs with Blastomyces dermatitidis Infection

Background:Blastomycosis is a common systemic fungal infection in dogs.Hypothesis:Dogs with cardiovascular involvement may have abnormalities in electrical conduction and valvular function, and may have a worse prognosis.Animals:Eight client‐owned animals.Methods:Dogs with cardiovascular lesions caused by blastomycosis were identified from retrospective evaluation of medical records.Results:Five dogs had de novo infections and 3 had recurrences of previously treated infections. Harsh labored breathing, lethargy, and anorexia were the most common historic complaints. Three dogs had syncope. Physical examination and clinicopathologic data were typical of blastomycosis and included dyspnea, increased lung sounds, and lethargy. In addition, 3 dogs had heart murmurs and 1 had a third‐degree atrioventricular block. Four dogs had myocarditis and 2 had pericarditis or epicarditis. Two dogs had cardiac signs attributed to extracardiac compression by fungal granulomas and clinical signs were relieved by treatment. Half of the remaining 6 dogs were euthanized; 2 of these were not treated. Of the remaining 3 dogs, 1 dog died acutely while sleeping; the second died intraoperatively during an attempt to place an epicardial pacemaker; and the third had Blastomyces‐induced endocarditis and died of heart failure.Conclusions and Clinical Importance: Blastomycosis should be considered in the differential diagnosis of dogs from endemic areas with inflammatory myocarditis, heart block, heart base or intracardiac mass lesions, syncope, or endocarditis.

An alternate technique to pacing in complex congenital heart disease: Assessment of the left thoracotomy approach

Pacing in children with congenital heart disease often requires alternate approaches to standard transvenous pacing. The surgical approach used to implant the pacemaker leads has been shown to impact lead survival. There is a paucity of pediatric literature describing the experience using a left thoracotomy approach. To report on short- and mid-term experiences with pacemaker implant via the left thoracotomy approach in children with complex congenital heart disease. Data were abstracted retrospectively from patients' hospital charts. To date, the left thoracotomy technique has been used in 11 patients with complex heart disease, with a median of three prior cardiac operations. The median patient age was five years (range of two months to 23 years of age). The pacing indications were acquired postoperative atrioventricular block (n=5), sinus node dysfunction (n=5) and long QT syndrome (n=1). There were no intraoperative complications or long-term complications from this approach. The pacing thresholds at implant and follow-up were acceptable in all patients. One patient died in follow-up for reasons unrelated to the pacemaker or arrhythmia. The placement of epicardial pacemaker leads via the left thoracotomy approach is a safe and effective alternative to transvenous pacing in pediatric patients with complex congenital heart disease.

Clinical Outcome of 193 Extracardiac Fontan Patients: The First 15 Years

We sought to evaluate the mid-term outcome of hospital survivors with extracardiac Fontan circulation. Few data exist about the mid-term and long-term results of the extracardiac Fontan operation. From November 1988 to November 2003, 221 patients underwent an extracardiac Fontan procedure as primary (9 patients) or secondary (212 patients) palliation, at a mean age of 72.2 months (range 13.1 to 131.3 months). A total of 165 of 193 early survivors underwent programmed noninvasive follow-up evaluations and at least one cardiac catheterization. The overall survival, including operative deaths, was 85% at 15 years. Freedom from late failure among hospital survivors is 92% at 15 years. A total of 127 of 165 survivors (77%) were in New York Heart Association functional class I. The incidence of late major problems was 24% (42 major problems in 36 of 165 patients): 19 patients had arrhythmias (11%), 5 patients had obstruction of the extracardiac conduit (3%) and 6 of the left pulmonary artery (3.5%), and 5 patients experienced ventricular failure (3%), leading to heart transplantation in 3 patients. Protein-losing enteropathy was found in two patients (1%). The incidence of late re-interventions was 12.7% (21 of 165 patients, including 15 epicardial pacemaker implantations). Four patients died (2.3%), two after heart transplantation. After 15 years of follow-up, the overall survival, the functional status, and the cardiopulmonary performance of survivors of the extracardiac Fontan procedure compare favorably with other series of patients who underwent the lateral tunnel approach. The incidence of late deaths, obstructions of the cavopulmonary pathway, re-interventions, and arrhythmias is lower than that reported late after other Fontan-type operations.

Unipolar ventricular pacing reduces inappropriate shocks from a separate cardioverter defibrillator in a post-Fontan patient

This report describes a 20-year-old man with complex congenital heart disease and inappropriate epicardial implantable cardioverter defibrillator (ICD) shocks secondary to double counting of ventricular-paced spikes and QRS complexes from a separate bipolar epicardial dual-chamber pacemaker. Adjusting to a unipolar paced-ventricular mode resolved any double counting via pacemaker-ICD interaction.

An unexpected finding during gastroscopy

At the age of 3 years, the patient had undergone surgery for repair of an atrial septal defect and had an epicardial pacing system placed for congenital atrioventricular block. This was replaced with an endocardial dual chamber pacemaker at the age of 15 years. The epicardial pulse generator and leads were left in situ. Now aged 23 years old, the patient presented with a 48-hour history of right shoulder tip pain, palpitations, rigors and subsequent melaena. On examination she was pyrexic (40°C) with vague upper abdominal tenderness. She had no overt features of bacterial endocarditis. Her chest X-ray shows both the endocardial and epicardial pacing system in situ (Figure 1). Preliminary haematological investigations revealed a microcytic hypochromic anaemia (7.4 g/dl), neutrophilia (25x109/ml), an erythrocyte sedimentation rate of 121 mm/hr and a C-reactive protein of 272 mg/litre. Repeated blood cultures were negative. Transoesophageal echocardiography showed no evidence of valvular or pacemaker lead vegetations. Gastroscopy revealed the redundant epicardial pacemaker generator inside the stomach with evidence of gastric ulceration (Figure 2). After initial resuscitation with blood products and parenteral antibiotics she underwent surgery where through a gastrostomy the pulse generator was retrieved. At laparotomy the left lobe of the liver appeared unhealthy and subsequent computed tomography scan of the abdomen confirmed the presence of multiple intrahepatic abscesses (Figure 3). It was decided that the hepatic abscess were not suitable for percutaneous drainage as they were multiple and predominantly in the left lobe of the liver. She continued on a protracted course of intravenous antibiotics and made a full recovery thereafter.

Cardiovascular Involvement in 8 Dogs with Blastomyces Dermatitidis Infection

Blastomycosis is a common systemic fungal infection in dogs. Dogs with cardiovascular involvement may have abnormalities in electrical conduction and valvular function, and may have a worse prognosis. Eight client-owned animals. Dogs with cardiovascular lesions caused by blastomycosis were identified from retrospective evaluation of medical records. Five dogs had de novo infections and 3 had recurrences of previously treated infections. Harsh labored breathing, lethargy, and anorexia were the most common historic complaints. Three dogs had syncope. Physical examination and clinicopathologic data were typical of blastomycosis and included dyspnea, increased lung sounds, and lethargy. In addition, 3 dogs had heart murmurs and 1 had a third-degree atrioventricular block. Four dogs had myocarditis and 2 had pericarditis or epicarditis. Two dogs had cardiac signs attributed to extracardiac compression by fungal granulomas and clinical signs were relieved by treatment. Half of the remaining 6 dogs were euthanized; 2 of these were not treated. Of the remaining 3 dogs, 1 dog died acutely while sleeping; the second died intraoperatively during an attempt to place an epicardial pacemaker; and the third had Blastomyces-induced endocarditis and died of heart failure. Blastomycosis should be considered in the differential diagnosis of dogs from endemic areas with inflammatory myocarditis, heart block, heart base or intracardiac mass lesions, syncope, or endocarditis.

Comparison of Modern Steroid-Eluting Epicardial and Thin Transvenous Pacemaker Leads in Pediatric and Congenital Heart Disease Patients

Optimal pacemaker lead choice in pediatric patients eligible for either epicardial or transvenous leads remains unclear. We compared performances of modern thin transvenous (TTV) and steroid-eluting epicardial (SEE) leads in patients followed at one pediatric center. Retrospective review of patients with qualifying leads implanted from August 1997 to March 2004. Threshold energy (TE) at implant and follow-up, sensing thresholds, lead complications, and repeat pacing-related procedures were analyzed. Lead performances were compared using t-tests, Wilcoxon rank-sum tests and Cox regression. Survival curves were plotted using Kaplan-Meier analysis. A total of 370 implant procedures, 521 leads, and 1549 visits were evaluated. In all, 256 leads were SEE (49%, 184 implants) and 265 were TTV (51%, 186 implants). Median follow-up was 29 months (range 1-80 months). Patients with SEE systems were younger at implant (6 vs. 17 yrs, p < 0.001), and more had congenital heart defects (82% vs. 57%, p < 0.001). At follow-up, ventricular TEs were higher for SEE leads at implant (p < 0.001), 1 month (p < 0.001), and up to 4 years (p = 0.019). When compared across all follow-up durations combined, TTV TEs were significantly lower than SEE TEs for both atrial and ventricular leads (p < 0.001). A total of 70 repeat procedures were performed in 60 patients during the study period, which comprised 18% of SEE and 14% of TTV system patients (p = NS). In all, 18 TTV and 19 SEE leads failed (p = NS). Estimated freedom from lead failure at 1, 3, and 5 years was 97%, 88%, 85% for TTV leads and 96%, 92%, and 58% for SEE leads (log rank P = NS). Both SEE and TTV leads showed good mid-term performance and survival in our cohort. Higher TEs seen for SEE leads, especially ventricular and unipolar leads, may result in higher current drain and thus more generator replacements than TTV systems. Lead failure rates were comparable across lead types. TTV leads offer a promising alternative to SEE systems in terms of performance for young patients without intracardiac shunting who do not require open-chest surgery for another indication.

Modes of Failure Following Epicardial Pacemaker Implantation in Young Infants

Young infants suffering from congenital or postoperative AV-block require life-long pacemaker stimulation. Due to the anatomical prerequisites initially epicardial electrodes are implanted and the generator is placed in the upper abdominal wall. The following study investigated modes of failure leading to reoperation in this group of technically challenging patients. Between 10/2000 and 05/2005 a total of 21 infants (age 3 days to 5 years) underwent pacemaker implantation using a partial lower or complete median sternotomy. Nine had previous cardiac surgery for complex congenital defects. Different uni- and bipolar epicardial electrodes (Medtronic Capsure® epi) were fixed to the right ventricle, 15 had additional implantation of a bipolar atrial lead. The pacemaker generator (Medtronic Kappa® 701) was implanted into the right upper abdominal wall. A total of four reoperations occurred during the follow up period (19%), indications for revision were recorded. Three of the four revisions were caused by ventricular electrode fracture. At revision two electrodes were broken at the crossing between thorax and the abdominal wall, one bipolar lead at the division into the two tip electrodes. One reoperation was due to a pacemaker recall. All revisions could be performed by electrode or pacemaker change without complications. Pacing and sensing parameters remained stable during midterm follow-up. Epicardial pacing in young infants is associated with a significant number of failures leading to reoperation, mainly due to electrode fracture caused by the muscular activity of this patient group. Reoperations can be performed at a low risk.

Dual Chamber Epicardial Pacing for the Failing Atriopulmonary Fontan Patient

The atriopulmonary Fontan circulation leads to arrhythmias, heart failure, or protein-losing enteropathy, eventually requiring conversion. In hesitant patients, we evaluated the effect of dual chamber pacing as a time-buying measure. Between 1997 and 2004, 9 patients (aged, 6 to 18 years) with an atriopulmonary Fontan connection and sinus node dysfunction received dual chamber epicardial pacemaker systems. Indications included refractory arrhythmias (n = 5), protein-losing enteropathy (n = 2), heart failure with effusions (n = 1), and exercise intolerance (n = 2). Data were compared between hospital discharge after pacemaker implantation and last follow-up. There was no mortality or morbidity. At a follow-up of 3.3 +/- 1.0 years, lead survival was 100%. Both atrial (impedance = 683 +/- 40 Ohm; threshold = 0.8 +/- 0.1 V at 0.5 ms; sensing P waves = 3.3 +/- 0.8 mV) and ventricular (impedance = 630 +/- 68 Ohm; threshold = 1.3 +/- 0.3 V at 0.5 ms; sensing R waves = 8.7 +/- 2.5 mV) leads retained satisfactory pacing characteristics at last control, better than those at discharge. Arrhythmias subsided in all instances and no longer required medication in 3 patients. Protein-losing enteropathy improved temporarily in 1 patient and disappeared in another. Exercise intolerance diminished, and heart failure was controlled. Although most atriopulmonary Fontan circulations will need conversion with arrhythmia surgery, patients may delay out of fear. Dual chamber pacing improves single ventricle hemodynamics and can help decompensated Fontan patients. In a multiple-redo setting, a left lateral thoracotomy provides safe access and allows for quantitatively reliable and durable epicardial pacing.

Anesthetic management of the neonate with congenital complete heart block: a 16‐year review

Anesthesia for patients with complete heart block can be associated with significant hemodynamic instability. The aim of this study is to review our anesthetic experience of neonates with congenital complete heart block (CCHB) who underwent placement of either a temporary epicardial pacing system or a permanent epicardial pacemaker. The anesthetic management of neonates with CCHB who underwent pacemaker placement at a single institution over a 16-year period was reviewed. Twenty-four neonates were identified, 17 with a structurally normal heart (NL) and seven with associated congenital heart defects (CHD). Median (range) gestational age was 36.9 (26-41) weeks, birth weight 2.9 (1.0-4.1) kg, and baseline heart rate 47 (38-80) b.min(-1). A temporary epicardial pacing system was placed in six patients (four CHD, two NL; P = 0.003) following institution of mechanical ventilation and inotropic support for a low cardiac output state, and a permanent epicardial pacemaker was placed in 18 patients. Atropine 0.02 mg.kg(-1) IV prior to induction (n = 5) increased heart rate less than 20%. Intraoperative hypotension was documented in nine neonates, five of seven with CHD and four of 17 with NL (P = 0.02). In four patients (44%) hypotension occurred despite concurrent inotropic support. Intraoperative cardiac arrest occurred in one neonate, necessitating institution of extracorporeal membrane oxygenation. Two patients (8.3%) died in hospital from complex CHD and complications of prematurity. Early institution of mechanical ventilation, inotropic support and pacing are necessary in the neonate with CCHB and poor hemodynamic function, particularly with coexisting CHD or prematurity.

Failure of Automatic Capture Verification in an Epicardial Pacemaker System

Epicardial pacing is frequently used in pediatric patients with congenital heart disease. Automatic threshold determination has been reported to be safe in epicardial lead systems. We report a case of falsely low ventricular thresholds determined by automatic capture verification in a patient with complete loss of capture due to a lead fracture.

Beneficial hemodynamic response of transthoracic cardiac pacing in a 2 kg preterm neonate

To describe the beneficial hemodynamic effect of transthoracic external pacing compared with epicardial pacing in a 2 kg premature neonate with congenital complete heart block, hydrops and complex congenital heart disease. Transthoracic epicardial pacing was instituted at a rate of 120 beats/min to treat life-threatening bradycardia (HR 50-60 beats/min), hypotension (BP 45/20 mmHg) and severe lactic acidosis (pH 7.18, lactate 7.5 mmol/l) despite significant catecholamine support. Due to the size of the patient, the external pacing electrodes were placed on the back and front of the patient's chest. To achieve ventricular capture, the electric output had to be increased to 140 mA, resulting in symmetric chest movements. Transthoracic pacing resulted in an immediate improvement of the cardiovascular status, with an adequate blood pressure (BP 60/25 mmHg) and normalization of acid-base-balance. After the insertion of an epicardial pacemaker (paced rate at 140 beats/min), a significantly lower blood pressure was achieved (BP 50/25 mmHg), indicating an additive effect of the rhythmic chest movements to the blood pressure. Unfortunately, third-degree burns were detected on the patients back 1 day after pacemaker insertion. Transthoracic pacing is a life-saving option in an emergency situation, when maximal pharmacological support fails to maintain adequate cardiac output. It may have some additional beneficial effect on blood pressure generation in these patients. To prevent skin injury, the output used needs to be as low as feasible, and the period of pacing as brief as practicable.

Usefulness of Unipolar Epicardial Ventricular Electrogram for Triggering of Intraaortic Balloon Counterpulsation During Off-Pump Coronary Artery Bypass Surgery in Patients with Hemodynamic Instability Complicating Acute Coronary Syndromes

During off-pump coronary artery bypass graft (CABG) surgery for patients requiring preoperative intraaortic balloon counterpulsation (IABP) support, errors in timing of IABP during mobilization of the heart can induce unstable hemodynamic conditions. We applied a simple technique for triggering IABP accurately during off-pump CABG: one end of an epicardial pacemaker wire is placed on the surface of the left ventricle, and the other end is linked to one of the precordial V leads. This technique provided an exact detection of R-wave potentials in any position of the heart during the off-pump CABG procedure. Ten patients with hemodynamic instability complicating acute coronary syndromes underwent off-pump CABG with this technique, including grafting to the circumflex system, safely and successfully.

A Simple Method of Triggering Balloon Counterpulsation Accurately During Off-Pump Coronary Artery Bypass Surgery

With increasing experience, off-pump coronary artery bypass grafting for high-risk patients can be performed safely. However, in patients who need intraaortic balloon counterpulsation support, mistriggering of intraaortic balloon counterpulsation during mobilization of the heart can induce unstable hemodynamic conditions. My colleagues and I have developed a simple method of detecting the trigger signal accurately: an epicardial pacemaker wire is placed close to the apex of the left ventricle, and 1 precordial V lead is disconnected and then linked to the epicardial pacemaker wire. This method provides an excellent detection of R-wave potentials in any position of the heart throughout an entire off-pump coronary artery bypass grafting procedure.

第3度房室ブロックを呈した犬にVVI型ペースメーカー植え込み術を行った1例

Electrocardiograms of a 6-year-old male Chesapeake Bay Retriever with a history of depression and anorexia revealed critical bradycardia, and disassociation of P waves (166 beats/min) and QRS complexes (20beats/min). Antiarrythmic medical therapy had no effect, and echocardiograms revealed normal myocardial contractility. From these findings, we diagnosed the dog as having a third-degree atrioventricular block. The animal was anesthetized, and a permanent artificial epicardial WI pacemaker was implanted under temporary transvenous endocardial pacing. Anesthetic and postoperative recovery was uneventful, and clinical signs improved immediately. Twelve months after the implantation, the patient was doing well with no clinical signs and no medication. This case suggests that the risk involved in general anesthesia for implantation due to bradycardia can be avoided by means of temporary transvenous endocardial pacing.

Robotic Cardiac Surgery at Epworth Hospital

Epworth Hospital is the first in the southern hemisphere to acquire the da Vinci Robot to facilitate minimally invasive cardiac surgery. Applications for this new technology include mitral valve repair, atrial septal defect closure, single coronary artery bypass graft to coronary arteries on the front of the heart, ablative surgery for atrial fibrillation and insertion of epicardial pacemaker electrodes. A team of surgeons from the Epworth Hospital have trained at East Carolina University (ECU) Greenville, North Carolina, USA; including surgeons, anesthetists, perfusionist and nurses. Following this, during a week in March, a proctoring surgeon from the USA, Dr. Wiley Nifong, assisted the Epworth team with their initial seven operations, which all proceeded without incident. The initial operative times were longer than the standard surgery, although with additional experience, now totalling 24 patients in all, these times have shortened considerably. The experience to date is summarized as an Addendum to this manuscript.

Subtotal Innominate Vein Occlusion After Unsuccessful Pacemaker Implantation for Resynchronization Therapy

Cardiac resynchronization therapy is increasingly used to treat patients with poor left ventricular function and asynchronous left ventricular contraction. Generally, a transvenous approach is used for implantation of pacing leads. However, coronary sinus lead implantation may be associated with various problems that may result in abandoning of the procedure. In this report a patient is described with subtotal innominate vein occlusion after such a procedure who underwent video-assisted thoracoscopic surgery (VATS) for implantation of epicardial left ventricular pacemaker leads for resynchronization therapy.