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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↗
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↗
PubMed1976

Personality patterns in insomnia. Theoretical implications.

Subjects with a primary complaint of insomnia (N = 124) were evaluated with Minnesota Multiphasic Personality Inventories (MMPIs). A high percentage of subjects (85%) had one or more MMPI scales elevated to a pathological degree. The scales most elevated were, in order. 2 (depression), 7 (psychasthenia), and 3 (conversion hysteria). A striking finding was the preponderance of depression. This was indicated by the frequency in which scale 2 was elevated above 70, the frequency in which this this scale had the highest elevation, and the frequency of MMPI code types that included scale 2. Four common MMPI code types representing various types of depression were noted, indicating considerable homogeneity for code types in this sample. The predominant personality styles in this sample were characterized by the internalization of psychological distrubances rather than by acting out or aggression. We propose that this internalization produces a state of constant emotional arousal and resultant physiological activation and that this process is a psychophysiological mechansim underlyling insomnia.

Adolescent↗