P wave synchronous pacing using anchored atrial electrode implanted without thoracotomy

Delay of onset of second degree pacemaker block by beta-blockade in patients with P-synchronous pacemakers

Second degree pacemaker block is a safety mechanism of the synchronous pacer at atrial rates above 120-130. The aim of the present study was to determine the work level at which pacemaker block occurred before and after beta-blockade. Seven patients (mean age 53 y.) were submitted to graded, submaximal exercise on a bicycle ergometer without drug and after 0.8 mg pindolol i.v. (6 pats.) or alprenolol orally (1 pat.). Pacemaker block developed at much higher total work after beta-blockade in 3 patients (5800 vs. 1900 kpm. p less than 0.0005), while 4 patients had to stop work due to exhaustion before pacemaker block occurred. Total work increased significantly after beta-blockade (p less than 0.005). Lack of a stable i.v. atrial electrode has delayed the extensive use of the synchronous pacemaker. The design of the generator, however, is not optimal block occurs is too low for a number of patients. beta-Blockade effectively delays the occurrence of pacemaker block and can be of therapeutic value. It is suggested that the P-synchronous pacer should be redesigned with a programmable basic rate (50-70 beats/min) and a programmable upper rate (130-180 beats/min) to ensure that the obvious physiologic advantages of the atrial triggered pacemaker can be maintained both at rest and during physical exercise.

Usefulness of a new active-fixation lead in transvenous temporary pacing from the femoral approach

Temporary transvenous pacing is associated with a high incidence of complications with a substantial dislocation rate reported to occur in more than one-third of patients. This article describes a novel 3.5 Fr temporary pacing lead using active fixation in a consecutive series of 42 patients with prolonged (> or = 48 hours) temporary pacing. The dislocation rate was 4.8%, while in 7.1% of patients inappropriate pacing (more than a twofold increase of initial pacing threshold) was observed. The total procedural related complication rate (dislocation, inappropriate pacing, local infection, and/or thrombosis) was 31% during a mean duration of pacing of 5.96 +/- 2.6 days. Ambulatory pacing was performed in the vast majority (74%) of patients. Temporary transvenous pacing using an active-fixation lead is safe and permits long-term ambulatory pacing with a low dislocation rate.

Amplitude and direction of atrial depolarization using a multipolar floating catheter: principles for a single lead VDD pacing

VDD stimulation using a single catheter for atrial sensing and ventricular sensing and pacing has become a reality. In order to compare the quality of the cavitary atrial electrogram (AEG) and to determine the intraatrial P wave direction and conduction time (CT), we compared, in an acute study, three different types of atrial electrode systems using four different leads, in 53 patients in sinus rhythm. The three electrode systems were: (1) one experimental system with quadripolar orthogonal electrodes using the Goldreyer concept; (2) one experimental system with quadripolar whole ring electrodes; (3) two systems with diagonally oriented half-ring electrodes, one experimental quadripolar and one bipolar CCS commercial (Polysafe A-Track lead). For the experimental systems, the four electrodes forming two independent bipolar pairs were situated on the intraatrial floating portion of a single lead and one supplemental electrode was distally positioned in the right ventricular apex. Bipolar AEGs were recorded at the high and at the low levels of the right atrium. For the CCS lead, the single bipolar AEG was recorded at the high level of the right atrium only. The highest AEG amplitude and the highest values for ventricular far-field rejection were provided by both diagonally oriented half-ring electrodes at the high atrial level and by the whole ring electrodes at the low atrial level. For both atrial levels, the orthogonal electrode system provided the smallest AEG amplitudes, the highest ventricular electrogram amplitudes, and therefore, the smallest values for ventricular far-field rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical evaluation of a new temporary atrial pacing catheter: results in 100 patients

Absence of a temporary atrial electrode that is stable and easily positioned has limited the use of atrial pacing in the hospital setting. A novel electrode involving a performed, 6F "J"-shaped catheter with a 10F anodal sphere and proximal fixed orienting wings 28 cm from the anodal tip was constructed. This design facilitated percutaneous insertion into the subclavian vein and positioning without fluoroscopy. Over a 15-month period, five physicians used the device in 100 patients for control of bradycardia in 56, overdrive suppression of atrial or ventricular tachyarrhythmias in 29, conversion and control of paroxysmal atrial tachycardia in seven, and temporary atrial-ventricular sequential pacing in eight patients with complete heart block. In 75 patients the electrode was inserted at the bedside without the benefit of fluoroscopy. Average insertion time was 2.5 minutes, initial thresholds were good, and lead stability evaluated by x-ray films and ECG recordings was excellent. The duration of pacing with the lead was 4.3 days (mean) and ranged from 1 to 23 days, with episodes of capture failure in only seven cases. Two of these cases were readily corrected by repositioning. This new electrode system could be rapidly inserted with excellent stability and reliability for days. Its ease of use could expand the role of temporary atrial pacing.

Dual chamber sequential pacing management of sinus node dysfunction: advantages over single-chamber pacing

Sixty-nine patients receiving atrioventricular sequential (DVI) pacemakers are compared to 67 patients receiving ventricular demand (VVI) pacemakers for control of the symptoms of sinus node dysfunction. The populations were similar with comparable preparing incidences of each assayed symptom and number of symptoms per patient (symptom density). Syncope was well controlled by both DVI and VVI pacing. DVI pacing was better than VVI pacing for control of all other symptoms. Symptom density response: DVI pre, 3.3 +/- 0.95; post, 0.43 +/- 0.63; VVI pre, 3.2 +/- 0.97; post 1.75 +/- 1.44 (p less than 0.000). Atrial electrode problems were encountered in five (7.3%) of the DVI patients and one (0.74%) ventricular electrode required repositioning.

Atrial pacing from the coronary vein. Ten-year experience in 50 patients with implanted pervenous pacemakers

During the past ten years, pervenous atrial pacemakers have been implanted in 50 patients (mean age 68 years, 60% males) using an electrode positioned in the coronary vein. The indications for atrial pacing were symptomatic sinus bradycardia (72%), atrial brady-tachy syndrome (20%), and recurrent tachyarrhythmias (8%). Atrial pacemakers have been implanted for a total of 1531 pacing months, average 31 months per patient, median 26 months and range 3-97 months. Effective atrial pacing has been achieved with Medtronic model 5818 and 6904 electrodes. Unipolar or bipolar atrial pacing has been equally effective, and commercially available Medtronic 5950, Cordis 162 and CPI 602 pulse generators have been utilized without difficulty. A total of 11 electrode related malpacing events occurred in the ten-year period with a malpacing event rate of 10% in the first pacing month, 1.1% per paced month during the next six months, and 0.25% per paced month thereafter. Life table analysis reveals that effective atrial pacing was achieved in 76% of the patients during a follow-up of more than five years. This experience substantiates the long-term safety and effectiveness of atrial pacing from the coronary vein using standard pacemaker electrodes and generators.

Detector electrode introduced by mediastinoscopy for atrial triggered cardiac pacing. A follow-up of electrode function in 82 patients

An atrial detector electrode was introduced by mediastinoscopy in 82 patients requiring permanent cardiac pacing. There were no complications. An adequate P wave was recorded in 80 patients. During the following week, the P wave became ineffective in 5 patients; angina occurred in 2 and atrial arrhythmias in 2. Atrially triggered ventricular pacing established in 73 patients and was followed in 71 patients for a period of 1 to 113 months. In 17 cases, it had to be terminated because of an ineffective or unstable P wave,in 6 cases because of atrial arrhythmias, and in 4 cases because of advanced age and recurrent infections. The method is technically simple and place little stress on the patient.

Therapeutic uses of permanent pervenous atrial pacemakers: A review

The available techniques for permanent pervenous atrial pacing have been reviewed with particular emphasis on the coronary vein approach. The major therapeutic uses for permanent atrial pacing include sinus node dysfunction, recurrent ventricular tachyarrhythmias, and intractable supraventricular tachycardias. Special types of atrial pacing involve the use of bifocal atrioventricular sequential pacing, paired atrial pacing, and rapid atrial pacing generators. The potential problems associated with the coronary vein atrial pacing method are discussed.

Permanent pervenous atrial pacing from the coronary vein. Long-term follow-up

This report details our clinical experience during a 12 to 63 month follow-up period in 30 patients with permanent pervenous atrial pacemakers implanted in the coronary vein prior to May 1972. Indications for permanent atrial pacing included 20 patients with symptomatic sinus bradycardia, seven with atrial brady-tachy syndrome refractory to pharmacologic therapy, and three patients with atrial overdrive suppression for intractible ventricular arrhythmias. The average duration of atrial pacing was 29.2 ± 2.4 ( sem ) months, median 24 months. A bipolar electrode was used in 28 patients and a unipolar system in two. The atrial signal was of sufficient amplitude (>1.5 mV) to permit atrial demand pacing when required. The atrial pacing threshold averaged 2.0 ± 0.2 ma initially and increased by less than 1.0 ma at the time of battery replacement 20 months later. Only four of 30 patients (13%) developed pacemaker related problems during the 879 pacing months of this follow-up period. Coronary vein perforation or thrombosis was not observed, and there were no pacemaker related deaths. The coronary vein provides a safe and effective electrode location for long-term permanent pervenous atrial pacing.