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Biomedical subjects

T A Preston

Publications and source records attributed to T A Preston.

At least 19 recordsLinked to original sources
PubMed1985

The patent system and cardiac pacing: is the system serving its users?

Patents have been utilized to protect technical innovations in pacemakers virtually since their inception and are becoming increasingly important to the industry. In the U.S. alone, about 100 patents are granted each year covering pacer-related technology and reflecting the main areas of technical development. The increase in the number of outstanding patents has been accompanied by a significant increase in patent litigation among pacer companies. The rate and cost of pacer-related patent litigation raises a question of whether the system is being used to its best advantage. A recommendation is made for an industry-sponsored board to aid in voluntary settlement of patent disputes.

Humans↗
PubMed1982

Termination of ventricular tachycardia by programmed extrastimuli from an externally-activated permanent pacemaker.

Two patients with hemodynamically well-tolerated recurrent ventricular tachycardia, drug resistant and previously requiring numerous external electrical cardioversions, had a permanent pacemaker implanted which could be programmed to deliver extrastimuli to convert the ventricular tachycardia to normal sinus rhythm. The patient- or physician-activated device can be programmed to induce or terminate ventricular tachycardia with extrastimuli delivered at the predetermined intervals which consistently induced or terminated the arrhythmia in the electrophysiology laboratory, allowing repeated evaluation of drug regimens. The pacemaker has reliably, painlessly, and consistently induced and terminated repeated episodes of ventricular tachycardia. This programmable pacemaker offers an alternative therapy for patients with hemodynamically well-tolerated refractory ventricular tachycardia.

Aged↗
PubMed1979

Surgical trials.

Explore the source record for details and available documents.

Clinical Trials as Topic↗
PubMed1979

Permanent rapid atrial pacing to control supraventricular tachycardia.

A case is reported of a patient who had continuous supraventricular tachycardia with a ventricular rate of about 170. The arrhythmia was refractory to drugs and DC countershock, and did not convert with atrial pacing. Rapid atrial stimulation controlled the ventricular rate by simulating atrial fibrillation (pacing at 300-400/min), or by simulating a faster atrial tachycardia with 2:1 conduction (pacing at 205-210/min). This form of therapy was used on a permanent basis for more than five months.

Adult↗
PubMed1978

The automatic rate adjustment pacemaker. The possibilities of rate hysteresis.

Since the first use of pacemakers there have been attempts to regulate the fixed, or basic rate of implanted pulse generators. Earlier models employed the use of magnets or percutaneous needles to change the pacemaker rate after implantation. A recent development is the programmable pacemaker, which utilizes external electromagnetic signals to alter the basic rate. A series of engineering advances have resulted in automatic pacemaker rate changes, as first embodied in the hysteresis pacemaker. Notable modifications of the basic hysteresis concept include gradual pacemaker rate changes, and variable hysteresis or rate changes dependent on electrophysiologic events. Many of these technical advances are unknown to physicians, but are disclosed in patents. In general, negative hysteresis favors emergence of underlying non-pacer rhythms, whereas positive hysteresis suppresses underlying rhythms of any type. The automatic rate adjustment pacemaker represents an attempt to derive the advantages of negative hysteresis while eliminating the disadvantages of abrupt rate changes. The unit automatically searches for a sinus rhythm slower than the basic pacing rate, by periodically gradually slowing its rate to a lower level.

Arrhythmias, Cardiac↗
PubMed1977

Drug management of stable angina pectoris.

Nitroglycerin and long-acting nitrates are the pharmacologic mainstays of antianginal therapy, both for acute attacks and for prophylaxis. Propranolol is often effective for prophylaxis in patients incompletely helped by nitrates. A holistic approach is stressed. Appropriate drug use will effect marked improvement in most pateints.

Angina Pectoris↗