Early clinical experience with the rechargeable cardiac pacemaker

After five years of laboratory development and experimental testing in animals, a rechargeable cardiac pacemaker powered by a specially designed nickel cadmium power cell was ready for human use. The bipolar coaxial pacing catheter connects to the pulse generator with a twist-lock mechanism, obviating the need for tools or ties. The small size of the pulse generator makes it easier to implant than conventional units. Recharging is performed by the patient at home for 90 minutes a week. This report details the early clinical experience with 26 patients who received this unit. All units are functioning and recharging according to specifications, and further clinical evaluation is now under way.     

Pacemaker dependent patients with device infection—a modified approach

A modified surgical concept for temporary cardiac pacing in pacemaker dependent patients requiring total removal of infected devices is presented. Proximal to the infected pocket a permanent bipolar pacing lead is placed transcutaneously into the ipsilateral subclavian or jugular vein. The lead is placed in the right ventricle and fixed into the skin using the suture sleeve. Pacing is established by connecting an external pacing generator. Subsequently the infected device can be removed completely. After wound dressing the externalized lead is connected to a permanent VVI-pacemaker allowing for prolonged temporary pacing.     

Breast cancer at the site of an implanted pacemaker]

We report here an 81-old-female patient who had a permanent pacemaker implanted in the right chest and who developed breast cancer near the site of the implanted generator. The cancer was diagnosed as stage I adenocarcinoma and radical mastectomy preserving pectoral muscles was indicated. During temporary pacing via the femoral approach, the pacemaker lead was transferred to the left subclavicular area crossing before the sternum and the generator was reimplanted in the left chest without use of lead extension kit. After reimplantation of the generator, radical mastectomy was performed. Clinical course was uneventful after the operation without infection or pacing failure. For the patient who needs surgical procedure in the site of implanted pacemaker generator, this technique of reimplantation is one of the useful choices.     

A Technique for Conducting Noninvasive Cardiac Electrophysiology Studies in Conscious Swine

A noninvasive method was developed in swine for conducting cardiac electrophysiology (EP) studies without the potential confounding effects of sedatives or anesthetics. Following a 1-week conditioning regimen in the EP laboratory, 3-month-old Hanford miniature swine underwent transvenous pacemaker (PM) implantation under isoflurane anesthesia. Two bipolar screw-in pacing leads were inserted into the left external jugular vein, with one positioned in the right atrial appendage and one in the myocardium at the right ventricular apex. The leads were attached to a multiprogrammable pulse generator, and the pacing system was placed in a subcutaneous pocket. At weekly intervals following implantation, conscious, unsedated swine were restrained in a sling for noninvasive programmed stimulation (NIPS) using a programmable telemetry system. A NIPS protocol to induce arrhythmias was performed separately for the atrium and ventricle. Data for this model are reported. Complications occurred in 6 of 26 animals studied and included one infection of the PM pocket, three cases of dislodgement of the atrial lead, and rotation of the generator within the pocket in two animals, preventing communication with the PM. This technique has been used to perform EP studies successfully in swine and has been utilized in a variety of studies of the cardiac conduction system.     

Simplified physiological pacing after cardiac surgery

Temporary pacing wires are routinely placed at the end of cardiac surgery. These pacing wires are helpful in maintaining patients with postoperative bradycardias, and physiological pacing is also more desirable in critically ill patients. We herein report our simplified procedure for atrial pacing. This technique uses commercially available intravenous pacing catheters. The catheter is passed through the skin, and its tip is placed at the pericardial oblique sinus just between the right and left pulmonary veins. Atrial pacing is then initiated with a temporary pulse generator. This procedure is simple and effective for patients undergoing cardiac surgery. We also report two clinical cases that satisfactorily underwent atrial pacing using this procedure.     

Extremely elderly patient in whom the pacing lead was implanted via the femoral vein

We report on an extremely elderly patient in whom we were unable to insert a pacing lead via the subclavian or internal jugular vein because of a superior vena cava obstruction; we instead inserted the pacing lead via the femoral vein. The patient was a 98-year-old male. Thirty-nine years previously, pacemaker implantation was performed for complete atrioventricular block. Afterwards, pacemaker replacement and reimplantation had been performed a total of 15 times. The patient was recently admitted because of pacing failure. Pacemaker replacement was performed, but pacing was not possible because of disconnection of the pacing lead. Insertion of a new pacing lead was attempted via both subclavian veins and the right jugular vein but failed; this approach was abandoned and temporary pacing was done. Superior vena cava obstruction was noted on chest computed tomography (CT), and pacing lead insertion through the superior vena cava was deemed unfeasible. Myocardial electrode implantation was also considered, but general anesthesia was deemed problematic because of the patient's extreme age. A pacing lead was inserted via the right femoral vein, and the generator was implanted in the right lower abdomen. Postoperative pacing was satisfactory.     

Electromagnetic interference of an external temporary pacemaker during maxillofacial and neck surgery.

Indirect inhibition of an external temporary pacemaker by electrocautery is reported. Before induction of general anesthesia for a hemimaxillectomy and radical neck dissection, a temporary transvenous demand pacemaker was inserted into a patient with a first-degree atrioventricular block and complete left bundle-branch block. Although we provided common precautions to prevent electromagnetic interference by electrocautery, pacing failure still occurred. It was thought to be caused by current dispersing from the active electrocautery electrode. This case suggests that occipital placement of the electrocautery ground plate should be considered during neck surgery in a patient requiring a temporary pacemaker.     

Temporary A-V sequential pacing using transluminal pacing electrodes

A case is presented which describes the initiation of atrialventricular (A-V) sequential pacing using atrial epicardial wires and an in situ transluminal ventricular pacing probe. A 68year-old female with a permanent A-V sequential pacemaker was scheduled for elective aortocoronary bypass. Following sternotomy, pacing function was converted to ventricular pacing (WI) with the use of electrocautery. A Chandler® V-pacing probe was introduced through a Paceport® (American Edwards) pulmonary artery catheter and with a paced increase in ventricular rate, the cardiac output increased from 2.8 to 3.2 L · min^-1. At the conclusion of cardiopulmonary bypass the patient was in sinus rhythm at a rate of 67 · min^-1 and was paced to a faster rate using bipolar atrial epicardial wires. The patient subsequently developed intermittent heart block so temporary A-V sequential pacing was established using atrial epicardial wires and the in situ ventricular pacing probe. Pacing was achieved at routine generator output settings of seven milliamps (mA) for both atrium and ventricle and at an A-V interval of 0.120 sec. This resulted in an immediate increase in cardiac output from 3.3 to 4.1L- min^-1. The compatability of these two pacing systems offers an increased margin of safety in cardiac surgery patients requiring atrial pacing, who are at risk for developing postoperative heart block.     

A case of complete atrioventricular block after induction of general anesthesia

A 75-year-old man with a past history of bilateral thalamic hemorrhage was scheduled for cholecystectomy and cholelithotomy under general anesthesia. Although the preoperative ECG showed a complete right bundle branch block, the echocardiogram revealed no abnormality. Anesthesia was induced with thiopental and vecuronium, and maintained with sevoflurane in oxygen. Soon after changing to the left decubitus position for the insertion of an epidural catheter, ECG showed complete atrioventricular block, which did not respond to atropine. Adrenalin was transiently effective, but arrhythmia continued. After administration of dopamine, norepinephrine and isoproterenol, we inserted a temporary transvenous pacemaker catheter, and the hemodynamics became stable by ventricular pacing. The operation was postponed. Subsequent cardiologic examination showed no ischemia. The atrioventricular block disappeared 7 hours after the induction of general anesthesia. We should be very careful with the anesthetic management of a patient with a complete right bundle branch block.     

Clinical Experience with Permanent Atrioventricular Sequential Pacing

In a 23-month period, we implanted 26 permanent atrioventricular (AV) sequential pacing units in 11 women and 15 men ranging from 37 to 85 years old (mean, 68 years). Indications for pacing were complete heart block in 12 patients and sick sinus syndrome in 14 patients.Cardiac index, using standard thermodilution techniques, was determined in 9 patients during ventricular pacing and AV sequential pacing at constant heart rate. Atrioventricular sequential pacing was superior in all patients, with a mean increase in cardiac index of 22% (p < 0.01). Complications of AV sequential pacing included the need to revise two pulse generator pockets due to the large size of the pulse generator. One transvenous atrial lead displacement occurred in a patient who had previously undergone right atrial appendage ligation at open-heart operation. No failures of pacing or sensing occurred during 279 patient-paced months.The theoretical hemodynamic advantage of AV sequential pacing has been confirmed in this clinical trial. Experience with electrode placement and improvements in pulse generator design should aid in eliminating complications with this pacing modality.     

Reprogramming of a pacemaker induced by electrocautery

A case is reported of reprogramming of a ventricular unipolar permanent pacemaker induced by electrocautery during biliary surgery. After skin incision and use of the unipolar electrosurgery unit, the CPI model 505 multiprogrammable pulse generator previously set at 70 b X min-1 abruptly fired at 120 b X min-1. Application of a magnet over the pacemaker reduced the heart rate to 100 b X min-1. After surgery, the pulse generator was successfully reprogrammed to a rate of 65 b X min-1. Based on the analysis of this case and of previous reports, it is suggested, so as to avoid such complications, that the unipolar electrocautery be avoided when the surgical field is near the pulse generator or lead: that the bipolar electrocautery be preferred; that a magnet and non-invasive programmer be available during and after surgery; and that a postoperative assessment of the pulse generator be carried out.     

Anesthetic management of an AAI pacemaker patient with paroxysmal atrial fibrillation during colorectal surgery

Perioperative management of patients with cardiac pacemakers may be challenging because of the increasing sophistication of these devices. We report a case of a patient with paroxysmal atrial fibrillation (PAF) and with a permanent AAIR (bipolar atrial-inhibited adaptive rate) pacemaker who suffered life-threatening episodes of arrhythmias during operation. The first episode was vagally induced PAF during bowel manipulation; the second, induced by the increased pacing threshold from the external electric cardioversion and hyperkalemia. Transcutaneous pacing provided cardiac pacing and stabilized the patient during the second episode. Thorough preoperative evaluation and prophylactic placement of temporary pacing or at least transcutaneous pacing are important for the avoidance and minimization of intraoperative complications in patients with sick sinus syndrome and with an AAI (atrial inhibited) pacemaker.     

Cardiac Pacemaker Infection: Surgical Management With and Without Extracorporeal Circulation

Background. Pacemaker infections are rare, but serious complications of pacemaker therapy. The generator pocket, the pacing leads, or both may be involved.

Methods. We report on 12 patients with infected pacemaker systems. Four patients suffered from localized generator pocket infections, 6 had infected leads, and 2 patients had both. Pacemaker systems were completely removed in all patients. When the infection was limited to the generator pocket, the pacemaker system was removed at the original implantation site. Extracorporeal circulation was employed for the explantation of infected pacing leads.

Results. No complications occurred in patients with localized generator pocket infections. One patient with infected leads who was preoperatively already in a serious clinical condition died of septic shock in the early postoperative period; another patient died of pulmonary complications after tricuspid valve replacement 14 months after pacemaker explantation. No recurrent infections were observed.

Conclusions. Explantation of the complete pacemaker system has proved a reliable method to eradicate infection. Complications have been rare, except in patients in a critically ill state who undergo cardiopulmonary bypass.     

Permanent cardiac pacing at a regional medical center.

In our experience with 98 patients, cardiac pacing has proved to be a low risk procedure with an acceptably low incidence of serious complications. Battery depletion requiring pulse generator replacement continues to be the major limitation of this technique. Placement of the pacing catheter within the coronary sinus has not been satisfactory, and measures are routinely taken to avoid this catheter position.     

Migration and colon perforation of intraperitoneal cardiac pacemaker systems

Epicardial pacemaker systems include pacing leads and a generator, which exceptionally may have to be implanted in the abdomen. We report three such pediatric cases where severe intraabdominal complications occurred owing to migration and erosion of the generators into visceral organs and urge extreme caution with this technique.     

Pacemaker implantation in a neonate with congenital complete heart block —A case report

Reported herein is our experience with pacemaker implantation in a neonate with complete AV block and without other concomitant cardiac anomalies. A male fetus exhibited an intrauterine heart rate of about 40 beats per minute on the electrocardiogram. An emergency pacemaker implantation was attempted at birth by means of intravenous temporary pacing to relieve signs of congestive heart failure. On the 28th day of life, a myocardial electrode was fixed on the right ventricular wall and the generator was positioned on the left side of the subcutaneous abdominal wall. A technical device was designed by means of packing pacemaker wire in a loop-forming fashion with a silastic sheet and was made in such a way as to adjust with growth of the patient. During the 2 year follow-up period, this technique proved to be effective. Our experience also supports the contention that pacemaker implantation in the newborn is feasible and beneficial in the treatment of congenital complete AV block.     

Temporary cardiac pacing for fatal arrhythmia in living-donor liver transplantation: three case reports

Cardiac pacing often turns out to be the only effective treatment of severe, life-threatening arrhythmias. We performed 77 living-donor liver transplantations (LDLT) from 1999 to 2007. In these cases, three recipients experienced fatal arrhythmia and required temporary cardiac pacing during the perioperative period. The first case was a 68-year-old woman diagnosed with liver cirrhosis and hepatocellular carcinoma (HCC). Her Model for End-Stage Liver Disease (MELD) score was 34. We performed LDLT using a right lobe graft. She showed complete atrioventricular block with cardiac arrest at postoperative day (POD) 42 after a bacterial infection. We performed a resuscitation and instituted temporary cardiac pacing. However, she was dead at POD 43. Pathologic findings at autopsy showed a diffuse myocardial abscess, which caused the fatal arrhythmia. The second case was a 58-year-old man diagnosed with HCC and liver cirrhosis; his MELD score was 9. We performed LDLT using a right lobe graft. He showed atrial fibrillation after septic shock. He also showed sinus bradycardia with a cardiac arrest at POD 10. We performed resuscitation and emergent temporary pacing. He recovered and was alive without recurrence of arrhythmia or infection. The third case was a 58-year-old woman diagnosed with multiple HCC. During preoperative regular check-up, she was diagnosed to have cardiac hypertrophy and was started on beta-blockers as treatment for cardiac hypertrophy. However, severe bradycardia necessitated temporary cardiac pacing. LDLT was performed safely after implantation of a pacemaker. Early use of temporary cardiac pacing for severe arrhythmias may be effective to maintain the hemodynamic state in LDLT.     

Temporary pacing through permanent myocardial electrodes.

A technique is presented for using a permanent myocardial electrode for temporary pacing with a lead extension. The permanent myocardial electrode may be attached to a permanent pulse generator after a few days if long-term pacing is required.     

The management of exposed cardiac pacemaker pulse generator and electrode using restricted local surgical interventions; subcapsular relocation and vertical-to-horizontal bow transposition techniques

This paper describes an approach to the treatment of exposed pacemaker generator and electrode. Local infection is controlled by the administration of systemic antibiotics and topical antibacterial solutions. Because the generator and lead are enveloped by an inert synthetic coating, it is possible to eradicate an infection without their removal if it is due to a weak opportunist pathogen fully sensitive to antibiotics. Thereafter, subcapsular relocation of the exposed generator or vertical-to-horizontal transposition of the exteriorised lead is carried out. These surgical interventions are designed to overcome the vertical force which tends to cause the extrusion of the pacing hardware.     

Clinical evaluation of a sutureless cardiac pacing lead: chronic threshold changes and lead durability

Chronic threshold changes and durability of the Medtronic 6917 sutureless cardiac pacing lead were evaluated in 100 consecutive patients. A bipolar pacing system was established in each patient. Lead failure occurred in 4 patients; all failures resulted from exit block or loss of adequate contact between electrode and myocardium. Electrode fracture or loss of lead insulation was not observed. Fifty patients had replacement of the pulse generator 27.4 +/- 1.8 months after implantation. Long-term stimulation threshold voltage was about 2.5 times greater and current was about 3.5 times greater than values obtained at initial implantation, yet they continued to permit safe and effective cardiac pacing.