Permanent pervenous transseptal atrial pacing. Canine experiments and a clinical case

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)

Cardiogenic hypertension in maturing dogs

The purpose of this study was to evaluate whether the heart can induce high blood pressure by maintaining an inappropriately elevated cardiac output/body weight ratio during growth. Direct (femoral artery) mean arterial pressure (MAP), heart rate, cardiac output/body weight ratio (as defined by M-mode echocardiography), and total peripheral vascular resistance were measured and calculated every 2 months in nine conscious dogs during development from 2 to 10 months of age. In four dogs a J-shaped catheter for atrial pacing was chronically implanted at the age of 3 months, and their hearts were permanently paced at 130 beats/min until maturity. The aim of atrial pacing was to prevent the natural slowing of the heart rate and, consequently, to maintain a cardiac output/body weight ratio that was inappropriately high in relation to age during growth. Five dogs were studied as controls. No hemodynamic differences were observed until the age of 4 months. From the age of 5 to 10 months heart rate was kept at 130 beats/min by atrial pacing in the atrially paced group, and the mean cardiac output/body weight ratio did not decrease (196 +/- 24 vs 191 +/- 34 [SE] ml/min/kg). MAP rose from 62 +/- 4 to 116 +/- 8 mm Hg, and total peripheral resistance increased from 0.34 +/- 0.07 to to 0.61 +/- 0.09 mm Hg/ml/min/kg.(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.

A new atrial transseptal pacing electrode

The atrial septum provides a convenient structure to which a transvenous electrode can be attached securely. The Brokenbrough cardiac catheterization technique has been used to gain access to the left atrium. A new electrode has been fabricated which can be inserted into the left atrium through the lumen of a Brockenbrough catheter. The electrode is composed of a stainless steel coil attached inside the proximal end of a platinum cylinder at the cardiac terminal. Three Elgiloy wires, having a wing configuration, are attached inside the distal end of the platinum cylinder. The coil and cylinder are insulated by silicone rubber and the metallic surface area of the distal electrode tip equals 5 mm2. This electrode has been implanted without difficulty or complications in five patients with tachycardia-bradycardia syndrome.

Clinical experience with transvenous atrial pacing

Twelve patients were paced with a transvenous J-shaped bipolar electrode positioned in the right atrial appendage. All had chronic sinoatrial dysfunction and 5 had paroxysmal atrial arrhythmia: 2 had recent myocardial infarction, 1 angina decubitus, and 1 ventricular pre-excitation. Atrioventricular sequential pacing was employed in this last patient and this mode of pacing was substituted for atrial pacing in one other. The remaining 10 patients were paced from the atrium only. Electrode displacement occurred in 2 patients and 2 others had a rise in pacing threshold. After repositioning the electrode or substituting a more powerful pacemaker, sustained atrial capture was achieved in 3 of these 4. Sensing of spontaneous P waves was present constantly in 4 and variably in 3 of 9 patients. Symptomatic improvement was obtained in 10 patients. A bipolar pacemaker with a variable output voltage and a relatively high demand sensitivity is optimal for atrial pacing. Measurements of intra-atrial voltage with various electrode configurations in 7 patients suggest that atrial sensing may more often be achieved when the reference electrode is situated in the upper part of the right atrium than when it is close to the electrode tip in the atrial appendage.