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Biomedical subjects

P O Littleford

Publications and source records attributed to P O Littleford.

9 recordsLinked to original sources
PubMed1984

A temporary external DDD pacing unit.

A device for temporary external DDD pacing was developed using a modified permanent pulse generator, and temporary atrial and ventricular electrode catheters were inserted pervenously. The atrial lead was a J type and the ventricular lead had a remote anode in the superior vena cava. With a special clamp and appropriate connectors the permanent DDD pulse generator provided unipolar external DDD pacing. The device was evaluated in 13 patients to control bradyarrhythmias or for overdrive pacing in an attempt to control tachyarrhythmias. Nine patients were ambulatory; all had continuous electrocardiographic monitoring. The device was used for 1 to 12 days (mean 4.9). Eight patients benefited from temporary DDD pacing and 7 had permanent DDD pacemakers implanted. In 1 patient, atrial fibrillation developed, 2 patients had brief episodes of ventricular lead displacement and another required reprogramming because of loss of ventricular capture. Results suggest that the device is applicable for a clinical trial of DDD pacing before possible permanent implantation when attempting to improve cardiac output or control arrhythmias.

Aged↗
PubMed1984

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.

Atrial Function↗
PubMed1983

Pacemaker-mediated tachycardias: a rapid bedside technique for induction and observation.

The DDD pacemaker allows sensing and pacing in both chambers and can, therefore, maintain atrioventricular synchrony. However, this pacemaker creates an additional anterograde conduction system between the atrium and ventricle and, in the presence of ventriculoatrial (VA) conduction, the possibility of pacemaker-mediated tachycardia exists. A simple bedside technique that does not require catheterization or expensive equipment was used to detect VA conduction. Just after DDD pacer implantation, an attempt was made to detect VA conduction in 31 patients. Ambulatory monitoring (Holter) was done for 24 hours after implantation and at 2 to 4 and 6 to 8 weeks after implantation to detect pacemaker-mediated tachycardia. Attempts to induce pacemaker-mediated tachycardia were made using a special programmable external stimulator at follow-up after implantation. It was found that (1) all the 17 patients with detectable VA conduction had pacemaker-mediated tachycardia when the atrial refractory period was less than the VA conduction time, (2) pacemaker-mediated tachycardias were not inducible or detected spontaneously when atrial refractory period was equal to or greater than VA conduction time + 50 ms, (3) VA conduction was not detectable in 9 of the 17 patients at a later visit. Six of these 9 received antiarrhythmic therapy or had developed congestive heart failure. VA conduction has important implications in patients with DDD pacemakers and can be readily evaluated at the bedside.

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PubMed1981

A new temporary atrial pacing catheter inserted percutaneously into the subclavian vein without fluoroscopy: a preliminary report.

A permanently formed "J" shaped 6F bipolar electrode catheter specially designed to facilitate temporary atrial pacing was constructed and tested in 15 patients. A pair of rigid, "orienting wings" was fixed to the catheter 28 cm from a large spherical tip electrode to establish directional orientation of the "J" while in the right atrium. Rapid percutaneous introduction is possible with a peel-away sheath via the subclavian vein. Positioning in the right atrium can be accomplished without fluoroscopy. The catheter could be inserted and positioned against the right atrial wall generally in less than three minutes and required little or no additional manipulation for capture. No instance of loss of capture was documented during subsequent continuous monitoring as the catheter remained in place from one to thirteen days. Ease of insertion of this electrode catheter, as well as stability, provided an effective method for temporary atrial pacing without fluoroscopy. This novel catheter design warrants testing in a large patient population by others and could have a potential application to other types of catheter needs.

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PubMed1979

Method for the rapid and atraumatic insertion of permanent endocardial pacemaker electrodes through the subclavian vein.

One hundred sixty-four permanent pacemaker implantations through the subclavian vein were accomplished by 17 different physicians at four institutions utilizing a specially constructed peel-away introducer. Fourteen attempts (8.3 percent) to cannulate the subclavian vein were unsuccessful. There were four cases of pneumothorax (2.4 percent) and two cases of hematoma formation (1.2 percent). The procedure has the advantage of a rapid and atraumatic insertion of a variety of transvenous pacemaker electrodes, and the avoidance of surgical dissection for a venous entrance site.

Cardiac Catheterization↗